annual and seasonal distribution of intertidal...

ANNUAL AND SEASONAL DISTRIBUTION OF INTERTIDAL FORAMINIFERA ANDSTABLE CARBON ISOTOPE GEOCHEMISTRY, BANDON MARSH, OREGON, USA

YVONNE MILKER1*, BENJAMIN P. HORTON

2,3,4, CHRISTOPHER H. VANE5, SIMON E. ENGELHART

6, ALAN R. NELSON7,

ROBERT C. WITTER8, NICOLE S. KHAN

2,3AND WILLIAM T. BRIDGELAND

9

ABSTRACT

We investigated the influence of inter-annual and seasonaldifferences on the distribution of live and dead foraminifera,and the inter-annual variability of stable carbon isotopes(d13C), total organic carbon (TOC) values and carbon tonitrogen (C/N) ratios in bulk sediments from intertidalenvironments of Bandon Marsh (Oregon, USA). Living anddead foraminiferal species from 10 stations were analyzedover two successive years in the summer (dry) and fall (wet)seasons. There were insignificant inter-annual and seasonalvariations in the distribution of live and dead species. Butthere was a noticeable decrease in calcareous assemblages(Haynesina sp.) between live populations and dead assem-blages, indicating that most of the calcareous tests weredissolved after burial; the agglutinated assemblages werecomparable between constituents. The live populations anddead assemblages were dominated by Miliammina fusca inthe tidal flat and low marsh, Jadammina macrescens,Trochammina inflata and M. fusca in the high marsh, andTrochamminita irregularis and Balticammina pseudomacres-cens in the highest marsh to upland. Geochemical analyses(d13C, TOC and C/N of bulk sedimentary organic matter)show no significant influence of inter-annual variations but asignificant correlation of d13C values (R = 20.820, p ,

0.001), TOC values (R = 0.849, p , 0.001) and C/N ratios (R= 0.885, p , 0.001) to elevation with respect to the tidalframe. Our results suggest that foraminiferal assemblagesand d13C and TOC values, as well as C/N ratios, in BandonMarsh are useful in reconstructing paleosea-levels on theNorth American Pacific coast.

INTRODUCTION

Fossil foraminifera are widespread indicators of pasttidal environments on low to high latitude coasts.Statistically significant populations in small sedimentsamples (e.g., from 1 cm thick samples of 1 to 5-cm-diameter cores; Birks, 1995) and high preservation potentialenable estuarine and marsh foraminifera to be used forenvironmental reconstructions that span thousands of years(e.g., Horton & Edwards, 2006). Estuarine and salt-marshforaminifera generally consist of agglutinated species thatare restricted to vegetated marshes and calcareous speciesof mudflats and sandflats (e.g., Phleger & Walton, 1950;Scott & Medioli, 1978; Horton & Edwards, 2006). Becausethe species composition of foraminiferal assemblages issensitive to the duration and frequency of tidal flooding(Scott & Medioli, 1978; Horton & Edwards, 2006),differences in modern intertidal assemblages can be usedto develop transfer functions to reconstruct former sealevels based on fossil assemblages (e.g., Guilbault et al.,1995; Horton et al., 1999; Gehrels, 2000; Horton &Edwards, 2006; Leorri et al., 2010; Kemp et al., 2013a).For example, along the Oregon coast of the Cascadiasubduction zone, former soils of high salt marshes andforests are abruptly overlain by the muddy sediment of tidalflats and low marshes (Nelson et al., 1996). Distinct changesin foraminiferal assemblages across such abrupt contactsrecord the subsidence of coastal wetlands (causing a suddenrelative sea-level rise) during great [moment magnitude(Mw) 8–9] earthquakes on the subduction-zone megathrustfault. Transfer function analysis of fossil faunas provides ameans of mapping the amount of subsidence during pastearthquakes and estimating earthquake magnitudes (e.g.,Guilbault et al., 1995; Nelson et al., 2008; Hawkes et al.,2010; 2011; Engelhart et al., 2013a; Wang et al., 2013).

Reconstruction of these relative sea-level changes is basedon the assumption that fossil (subsurface) and modern(surface) faunal assemblages have responded in the same wayto environmental (elevational) gradients across tidal wet-lands. That is, modern assemblages are accurate environ-mental analogs for fossil assemblages. However, a number ofstudies have shown that live populations in intertidal andsubtidal settings are temporally and spatially variable (e.g.,Buzas, 1968; Jones & Ross, 1979; Scott & Medioli, 1980;Horton, 1999; Murray & Alve, 2000; Swallow, 2000; Buzaset al., 2002; Cearreta et al., 2002; Debenay et al., 2006;Horton & Murray, 2006, 2007; Berkeley et al., 2008). Thisvariability suggests that foraminiferal populations areinfluenced by factors other than tidal inundation and, hence,these factors may influence the accuracy of sea-levelreconstructions. Scott & Medioli (1980) concluded that totalassemblages (live plus dead tests) are better modern analogsof fossil assemblages—and so are most suitable for

Journal of Foraminiferal Research fora-45-02-03.3d 4/3/15 14:39:27 146 Cust # 2310

1 Center for Earth System Research and Sustainability, Institute forGeology, University of Hamburg, Bundesstrasse 55, 20146 Hamburg,Germany; now at the Institute of Geophysics and Geology, LeipzigUniversity, Talstrasse 35, 04103 Leipzig, Germany

2 Sea Level Research, Department of Marine and Coastal Science,Rutgers University, 71 Dudley Road, New Brunswick, NJ, 08901, USA

3 Institute of Earth, Ocean and Atmospheric Sciences, RutgersUniversity, New Brunswick, NJ 08901, USA

* Correspondence author: E-mail: [email protected]

9 Oregon Coast National Wildlife Refuge Complex, P.O. Box 99,83673 North Bank Lane, Bandon, OR 97411, USA

8 U.S. Geological Survey, Alaska Science Center, 4210 UniversityDrive, Anchorage, AK 99508 – 4626, USA

7 U.S. Geological Survey, Geologic Hazards Science Center, 1711Illinois Street, Golden, CO 80401, USA

6 Department of Geosciences, University of Rhode Island, Wood-ward Hall, 9 East Alumni Ave, Kingston, RI, 02881, USA

5 British Geological Survey, Centre for Environmental Geochemis-try, Keyworth, Nottingham, NG12 5GG, UK

4 Earth Observatory of Singapore, Nanyang Technological Univer-sity, 50 Nanyang Avenue, Singapore 639798, Singapore

Journal of Foraminiferal Research, v. 45, no. 2, p. 146–166, April 2015

146

paleoenvironmental reconstructions—than live populationsalone, which reflect environmental conditions during a singlesampling period. In contrast, Murray (1982) and Horton(1999), observed that total foraminiferal assemblages areinfluenced by both production rate and taphonomicprocesses and concluded that dead assemblages are moresuitable for reconstructions. Taphonomic alteration offoraminiferal tests may also influence the accuracy of sea-level reconstructions. For instance, early diagenetic processesmay dissolve calcareous tests in acidic, organic-rich tidal orsubtidal environments (Schnitker et al., 1980; Goldstein &Watkins, 1999; Murray & Alve, 1999; Sanders, 2003;Berkeley et al., 2007).

Recently, the stable carbon isotopic composition (d13C%)and carbon to nitrogen (C/N) ratio of bulk sediment inintertidal environments have been tested to discern whetherthese geochemical indicators could be used in a similar wayas foraminiferal assemblages to reconstruct relative sea-levelchanges (Kemp et al., 2012; Engelhart et al., 2013b; Khan etal., 2015). These and other studies (e.g., Chmura & Aharon,1995; Lamb et al., 2007; Kemp et al., 2010) have shown thatthe d13C values from marsh sediment correspond well withmarsh elevation and hence the degree of tidal inundation(Wilson et al., 2005a, b), a variable that strongly influencesthe distribution of plants and the botanical composition ofintertidal sediment. In estuarine wetlands, a gradual changefrom a dominance of C3 to C4 plants has been observedalong salinity gradients (Chmura & Aharon, 1995). Howev-er, d13C values of sediment may also reflect allochthonousparticulate and/or dissolved carbon sources that may not berelated to salinity (e.g., Goni & Thomas, 2000; Lamb et al.,2006) and can be influenced by microbial processes thatresult in depleted d13C values of sediment relative to that ofplant tissues (e.g., Benner et al., 1987; Ember et al., 1987;Chmura et al., 1987; Malamud-Roam & Ingram, 2001;Lamb et al., 2006). A further limitation when using d13Cvalues for relative sea-level reconstruction is the limitedelevational range of C4 plants in certain regions (e.g., Kempet al., 2010, 2012). Before the routine use of stable carbonisotopic methods, C/N ratios were commonly used tocharacterize the source and degree of biological anddiagenetic alteration of organic matter (Tyson, 1995).Carbon/Nitrogen ratios distinguish between aquatic andterrestrial organic matter sources because aquatic organicmatter has a significantly higher bulk N content than that ofterrestrial organic matter (Tyson, 1995). However, recentstudies indicate that C/N ratios from intertidal environmentsare less suitable for relative sea-level reconstructions, becausesediment C/N values are significantly altered from sourceplant material during early diagenesis (e.g., Goni & Thomas,2000; Kemp et al., 2010). Further, it is unknown to whatdegree seasonal variations in the growth and decay ofdifferent plant species influence stable carbon isotopiccomposition and C/N ratios of bulk sediments in theseenvironments (Cloern et al., 2002).

We investigated the inter-annual and seasonal (dry to wetseason) variations in foraminiferal assemblages and inter-annual variations in stable carbon isotopic composition,total organic carbon (TOC) values and C/N ratios of bulksediment in an intertidal environment near Bandon, Oregon(Fig. 1) to answer the following questions: (1) Do forami-

nifera in the Bandon Marsh, which provides a potentialcoastal archive for relative sea-level reconstructions, show aninter-annual and/or seasonal variability, and do they clusterin vertical assemblage zones? (2) Do taphonomic processesinfluence the distribution of modern foraminiferal species inthe Bandon Marsh? (3) How do the stable carbon isotopiccomposition and C/N ratios of bulk sediment in the BandonMarsh vary with elevation and do these values show inter-annual variability? A better knowledge of the inter-annualand seasonal variations for both foraminiferal and geochem-ical data and their relation to elevation will help improve theaccuracy of reconstructions of relative sea-level changes usedto infer elevation changes during past great earthquakes atthe Cascadia subduction zone and along other tectonicallyactive coasts (e.g., Sawai et al., 2004; Cisternas et al., 2005;Dura et al., 2011).

STUDY AREA

The Bandon Marsh National Wildlife Refuge (NWR) issituated on the Pacific coast in southern Oregon (Fig. 1A)near the mouth of the Coquille River estuary (Fig. 1B). Thewildlife refuge encompasses 3.6 km2 and is composed of twounits: Bandon Marsh and Ni-les’tun Marsh. BandonMarsh, our study area, is a relatively undisturbed sandysalt marsh that has rapidly aggraded towards the riverduring the past century (Fig. 1C; Frenkel et al., 1981).

Tides in the lower Coquille River estuary are semidiurnaland mesotidal with a great diurnal range of 2.16 m (MeanHigh High Water, MHHW (2.132 m NAVD) to Mean LowLow Water, MLLW (0.030 m NAVD) (NOAA tide gaugestation Bandon, ID 9432373; http://tidesandcurrents.noaa.gov/datum-options.html). Mean sediment accumulationrate in Bandon Marsh, based on four surface elevationtable estimates (interval August 2009–December 2012), is8.7 mm/yr with a standard error of 62.5 mm.

The climate in the Bandon Marsh area is temperate withwarm and dry summers and wet and cool falls and winters(Peel et al., 2007). The mean daily air temperatures, measuredat the national weather station in Bandon (ID:GHCND:USC00350471) (http://www.ncdc.noaa.gov/cdo-web/datasets/GHCND/stations) for 2011 ranged between11.9 and 20.3uC in August 2011 (average 16.4uC) andbetween 4.2 and 16.4uC in October 2011 (average 12.0uC;Fig. 2). Mean daily air temperatures for 2012 ranged between12.8 and 16.9uC in July 2012 (average 14.5uC) and between5.8 and 15.6uC in October 2012 (average 10.9uC). Totalmonthly precipitation was low in 2011, with 1 mm in August2011 and 92 mm in October 2011, but higher in 2012 with20 mm in July 2012 and 199 mm in October 2012 (Fig. 2).

Bandon Marsh consists of a sparsely vegetated tidal flat(St., Station, 1 and 2) with around 15% Zostera nana and Z.marina vegetation (Nelson & Kashima, 1993; Brophy & vande Wetering, 2012). Tidal-flat sediment is sandy (67–90%),with low percentages of silt and clay (Fig. 3). The lowmarsh (St. 3 and 4) is characterized by the vascular plantsDistichlis spicata, Scirpus sp., Carex sp., and Juncusbalticus. Farther south in the Bandon Marsh, Nelson &Kashima (1993) found Scirpus americanus, Scirpus cernuus,and Carex lynbyei as the dominant low marsh plants in thesame area. Station 3 is similar to the tidal flat stations, with


FORAMINIFERA BANDON MARSH 147

a high sand content (67–90%), whereas St. 4 sedimentcontains more silt (40–70%) and clay (, 8%; Fig. 3).

The high marsh (St. 5–9) is dominated by Potentilla sp.,Carex sp., Lotus spp., and Juncus balticus, with Fescue sp.,Agrostis sp., Scirpus sp., and Distichlis spicata. Nelson &Kashima (1993) and Brophy & van der Wetering (2011)also noted Deschampsia caespitosa, Potentilla pacifica,Triglochin maritima, Agrostis alba, and A. stolonifera inthe high marsh south of our study area. Sediment in thehigh marsh is silty (54–81%) with lower percentages of clay(10–34%) and sand (0.5–34%; Fig. 3).

The transition zone between the highest marsh andupland in Bandon Marsh (St. 10) has high percentages ofPhalaris sp. and low percentages of Carex sp. andEquisetum sp. Sediment at St. 10 is similar in grain-sizedistribution to the high marsh stations (74% silt, 19% clay,and 7% sand; Fig. 3).

METHODS

SAMPLING STRATEGY

Ten sampling stations were installed on Bandon Marsh(Fig. 1C, Appendix 1) at NWR sampling stations. Surface

samples were taken in the dry summer season (16 August2011 and 24 July 2012) and in the wet fall season (14October 2011 and 12 October 2012) for foraminiferalanalyses. For geochemical analyses, we only analyzedsamples from three of the sampling periods (summer andfall 2011, and summer 2012) due to limitation on thenumber of samples that could be processed. Elevations weredetermined with a RTK-GPS and total station equipmentwith vertical precision of , 5 cm. Elevations are referencedto the North American Vertical Datum (NAVD88). Itshould be noted that there is an elevational hiatus betweenthe lower and higher elevation stations (St. 4 and 5) of60 cm, which is ,25% of the tidal range. Each stationconsists of a 1 m2 quadrat oriented N-S. Quadrats wereplaced at sites with uniform elevation and vegetation coverto avoid bias in samples taken from different corners of thequadrat. Two samples were collected at each station fromthe corners (A to D) of the quadrat in alternating sequentialorder: one sample of approximately 10 cm3 volume (10 cm2

surface sample by 1 cm thick) for foraminiferal analysis;and a second sample of approximately 20 cm3 volume(20 cm2 surface sample by 1 cm thick) for geochemical andgrain size analyses. The sample thickness and volume forforaminiferal analysis allows comparisons with similar


FIGURE 1. A) Map of the U.S. Pacific Northwest showing major features of the Cascadia subduction zone. B) Map of the Bandon Marsh NationalWildlife Refuge (NWR) showing the Bandon and Ni-les’tun marshes and installed tide gauges (a: Bandon tide gauge, NOAA Station ID 9432373; b:Coquille River (labelled ‘‘NL TG outside’’ in Brophy & van de Wetering, 2012). C) Sampling station locations in the Bandon Marsh (see Appendix 1).

148 MILKER AND OTHERS

studies (e.g., Scott & Medioli, 1978; Jennings & Nelson,1992; Horton et al., 1999; Horton & Edwards, 2006; Kempet al., 2009). The geochemical samples were immediatelyrefrigerated (,4uC) in darkness to limit microbial activityand prevent photo-oxidation of the organic components(Khan et al., 5). All inter-annual and seasonal foraminiferaland geochemical data, and grain-size data, can be found inthe supplementary material (Appendices 2 and 3).

FORAMINIFERAL ANALYSIS

The samples for foraminiferal analysis were stained withrose Bengal for identification of specimens living at timeof collection (Walton, 1952; Murray & Bowser, 2000),stored in a buffered ethanol solution to avoid dissolutionof calcareous tests, and refrigerated at 5uC. Wet samplevolumes were measured and samples were sieved through500 mm and 63 mm sieves and decanted. The greater than500 mm decanted fraction was examined for largerforaminifera before being discarded. A wet-splitter (Scott& Hermelin, 1993) was used to split the fraction between63 and 500 mm of each sample into eight equal aliquots asdescribed in Horton & Edwards (2006). Samples wereallowed to settle for 90 minutes. Foraminiferal tests werecounted wet to facilitate the detection of stainedforaminifera and to prevent drying of the organic residue,

which may result in consolidation or ‘‘pancaking’’ (deRijk, 1995). Only tests with the last few chambers stainedred were considered living at the time of collection.Foraminifera were counted under a binocular micro-scope. The foraminiferal species were identified followingthe taxonomic descriptions in Horton & Edwards (2006),Hawkes et al. (2010), and Wright et al. (2011). Juvenilespecimens of Trochammina inflata, Jadammina macres-cens and Balticammina pseudomacrescens that weredifficult to distinguish from each other were summarizedas juvenile trochamminids (Appendix 4). Specimens of thegenus Ammobaculites were combined into a single groupbecause these species were often broken, making itdifficult to identify them to the species level (Kempet al., 2009).

GEOCHEMICAL ANALYSIS

For analysis of stable carbon isotopes, TOC and C/Nratios of the surface sediments, approximately 1 cm3 of eachwet sediment sample was treated with 5% HCl for 18 hoursto remove inorganic carbon, rinsed with at least 1500 ml ofdeionized water and dried in an oven at 40uC overnight.Dried samples were ground to a fine powder and thenanalyzed in a Costech Elemental Analyzer coupled on-lineto an Optima dual-inlet mass spectrometer. The ratios were


FIGURE 2. Mean daily temperatures and daily precipitation measured at the national weather station in Bandon (ID: GHCND:USC00350471) forAugust 2011 (A), July 2012 (B), October 2011 (C) and October 2012 (D). Data were taken from the NOAA National Climatic Data Center (http://www.ncdc.noaa.gov/cdo-web/datasets/GHCND/stations).


calibrated through an acetanilide standard (formulaCH3CONHC6H5) because it contains both C and N atomsin proportions broadly similar to that found in vegetation,soils and sediments and is available at high purity at lowcost. All C/N and TOC values are expressed on a weightratio basis.

The subsamples for 13C/12C analyses were then combustedin the Costech Elemental Analyzer. The d13C values werecalculated relative to the Vienna Pee Dee Belemnite(VPDB) scale using a within-run laboratory standard(cellulose, Sigma Chemical prod. no. C-6413) calibratedagainst NBS 19 and NBS 22 standards (compare with Vaneet al., 2013). Replicate 13C/12C analysis of homogenizedsamples indicated a precision of ,0.1% (1 s).

GRAIN SIZE ANALYSIS

Grain size distributions of samples were determined withthe Beckman Laser Diffraction Particle Size AnalyzerLS320. Prior to analysis, samples were treated with 20%

hydrogen peroxide to oxidize the organic matter in thesediment and then rinsed twice with de-ionized water anddisaggregated with sodium hexametaphosphate for 24 hoursto disperse clay particles before being measured. Particlesize interpretations are based on the Wentworth Phi Scale(Wentworth, 1922) and reported as differential volume (thepercentage of total volume that each size class occupies).

STATISTICAL ANALYSIS

To determine the seasonal and inter-annual variations ofthe living foraminifera and the importance of life processesand post-depositional changes for dead foraminifera(Murray, 1991), we applied an ANOSIM (ANalysis OfSIMilarities) approach (Clarke, 1993). This non-parametrictest detects the difference between two or more groups ofsamples based on the distance measure between groups andthe conversion of these distances into ranks (Clarke, 1993).The Bray-Curtis similarity (Bray & Curtis, 1957) wasused as the distance metric. A two-way ANOSIM (5000permutations) was selected to determine the inter-annualand seasonal (dry vs. wet season) variations in the live anddead assemblages between the 2011 and 2012 samplingseasons. A one-way ANOSIM (5000 permutations) waschosen to determine the similarity between live and deadassemblages from both sampling seasons and years.

To classify the vertical distribution of live and deadforaminiferal assemblages, a prerequisite for reconstructingrelative sea-level change (e.g., Horton & Edwards, 2006), ahierarchical clustering method was applied. The unweightedpair group average (UPGMA) algorithm was used to definegroups on the basis of the mean distance between objects ineach group. The distance metric was selected according tothe cophenetic correlation, which is the linear Pearsoncorrelation between the original matrix and the dissimilaritymatrix (e.g., Legendre & Birks, 2012). We tested both theBray-Curtis similarity (Bray & Curtis, 1957) and Chorddissimilarity (Overpeck et al., 1985) distance measures,which are widely applied metrics for quantitative commu-nity data (Simpson, 2012). The cophenetic correlationsusing the Bray-Curtis and Chord dissimilarities arecomparable with R 5 0.917 and R 5 0.921 for livepopulations and R 5 0.943 and R 5 0.942 for the deadassemblages, respectively. The Bray-Curtis dissimilarity wasselected for further analysis because it has been shown to bethe more powerful distance metric for ecological datacompared to the Chord distance (Faith et al., 1987). AMonte Carlo test (1000 permutations) was performed tocalculate the percentages of exact replications of ourclusters.

For all analyses, we used the percentages of live and deadspecies of both seasons and years. For the two-wayANOSIM, samples were coded with integer numbersaccording to their season and year. The ANOSIM andUPGMA were made with the PaST software package,version 2.15 (Hammer et al., 2001).

To determine whether the d13C values and the C/N andTOC ratios show a relation to elevation, and to what extentthe d13C values, C/N and TOC ratios are influenced byinter-annual variability, we applied a Generalized LinearModel (GLM) to the geochemical data using the IBM SPSS


FIGURE 3. Grain-size distribution (percentages of clay, silt andsand) for Bandon Marsh stations in 2011 and 2012.


software package (version 20). The GLM is able to combinesystematic and random effects of a dependent variable tomore than one independent variables (Nelder & Wedder-burn, 1972). The gamma distribution (Fu & Moncher,2004) was assumed in the GLM (link function: identity).Year, numerically coded into two categories for 2011 and2012, and elevation, numerically coded into four categories(tidal flat, low marsh, high marsh and higher marsh-upland) were used as independent variables, and aninteraction was defined between year and elevation. Themaximum likelihood estimate, which is able to find thosemodel parameters that maximize the probability ofobserved data (Bolker et al., 2009), was used for the model.In addition, we calculated the Pearson correlation betweend13C, TOC and C/N values and elevation, and between d13Cvalues and C/N ratios.

RESULTS

DISTRIBUTION OF LIVE FORAMINIFERA

We found 277 to 777 live individuals [per 10 cm3 sedimentvolume, mean 5 491 6 (standard deviation of) 208] in thetidal flat, 213 to 532 individuals (mean 5 396 6 151) in thelow marsh, 178 to 544 individuals (mean 5 290 6 170) inthe high marsh, and 0 to 93 individuals (mean 5 30 6 43) inthe highest marsh to upland transition (Fig. 4). Higher totalnumbers (all stations) of live foraminifera (8442 individu-als) were observed in 2011 than were observed in 2012 (4805individuals).

Ten species were found in the live populations. Thepopulations are dominated by the agglutinated speciesMiliammina fusca, Balticammina pseudomacrescens, Tro-chamminita irregularis, Trochammina inflata and Jadam-


FIGURE 4. Relative abundance of the most abundant living foraminifera observed in August 2011 and July 2012 (left side) and in October 2011and 2012 (right side). Stations arranged according to their elevations along the sampling profile (Appendix 1). An elevation profile for the sampledstations with the tidal datums for MHHW (mean highest high water), MHW (mean high water) and MTL (mean tide level) adapted from the Bandontide gauge (NOAA Station ID 9432373) is shown at the bottom.


mina macrescens (Fig. 4), with minor amounts of Reophaxmoniliformis, Ammobaculites spp., Haplophragmoides wil-berti and juvenile trochamminids. We observed only onecalcareous species (Haynesina sp.).

The tidal flat (St. 1, 2) and low marsh (St. 3, 4) aredominated by M. fusca, with a relative abundance between46–100% among the 2011 and 2012 sampling intervals(Fig. 4). Haynesina sp. is also found within the low marshwith a maximum relative abundance of 48% in fall 2012. Inthe high marsh (St. 5–9), the abundance of M. fuscadecreases (maximum abundance of 50% at St. 9 in fall2011), to be replaced by J. macrescens, B. pseudomacrescensand T. inflata. Jadammina macrescens has higher relativeabundances at St. 8 (74% in summer 2011 and 48% in fall2011). Balticammina pseudomacrescens dominates at St. 9 inthe summer seasons with a relative abundance of 90% (2011)and 60% (2012). Trochammina inflata is more abundant atSt. 5–8 and has a maximum percentage of 57% at St. 8 insummer 2012. Trochamminita irregularis is generally thedominant species of the highest marsh to upland transition(St. 10), but its abundance varies between 84% in fall 2012 to0% in summer 2012. This variability is reflected in the

corresponding abundances of B. pseudomacrescens (e.g., 73%

in fall 2011 and 0% in summer 2012).

DISTRIBUTION OF DEAD FORAMINIFERA

We found 1041 to 1317 dead individuals (per 10 cm3

sediment volume; mean 5 1155 6 118) in the tidal flat, 707to 1191 individuals (mean 5 1054 6 234) in the low marsh,754 to 1923 individuals (mean 5 1282 6 582) in the highmarsh, and 2 to 402 individuals (mean 5 251 6 173) in thehighest marsh to upland transition (Fig. 5). High totalnumbers of dead individuals (27,535) were observed for2012 than were observed for 2011 (16,805).

The dead assemblages generally consist of the samespecies as the live populations, but with some notabledifferences (Fig. 5). The dominant species in the tidal flatand low marsh (St. 1–4) is M. fusca with a relativeabundance between 84–100%. Haynesina sp. has a signif-icantly lower relative abundance (maximum of 3%) thanfound in the live populations. The high marsh is charac-terized by more J. macrescens, B. pseudomacrescens and T.inflata and lower percentages of M. fusca. The greatest


FIGURE 5. Relative abundance of the most abundant dead foraminifera observed in August 2011 and July 2012 (left side) and in October 2011 and2012 (right side). Stations arranged according to their elevations along the sampling profile (Appendix 1). Elevation profile with the tidal datums forMHHW (mean highest high water), MHW (mean high water) and MTL (mean tide level) adapted from the Bandon tide gauge (NOAA Station ID9432373) is shown at the bottom.


abundance of J. macrescens in each sampling season occursat St. 8 (maximum of 69% in fall 2011). The maximumabundance of B. pseudomacrescens occurs at St. 9, but isvariable over time (29% fall 2012 to 74% summer 2011).The highest marsh to upland transition (St. 10) isdominated by T. irregularis with a relative abundancegreater than 45% in all sampling seasons and years.

ANNUAL AND SEASONAL PATTERNS IN SPECIES COMPOSITION

AND VERTICAL ZONATION

To test whether the live species distribution reflectssignificant inter-annual and/or seasonal patterns, weapplied a two-way ANOSIM analysis to the live popula-tions. Despite the variations in the relative abundance ofindividual species and the total numbers of living individ-uals for 2011 and 2012, the two-way ANOSIM shows nosignificant inter-annual variation (p 5 0.844, R 5 20.048).In addition, the two-way ANOSIM analysis shows nosignificant seasonal variation between the dry (summer)and wet (fall) seasons (p 5 1.000, R 5 20.087).

We applied the same analyses to the dead assemblages inorder to detect the importance of life processes and post-depositional changes. Similar to the live populations, wealso found no inter-annual variations (p 5 0.978, R 5

20.068) and no seasonal variation (p 5 0.998, R 5

20.078), although we observed variations in total numbersof dead individuals between 2011 and 2012. We also applieda one-way ANOSIM analysis to detect dissimilarities orsimilarities between the live and dead assemblages. Wefound a significant similarity between the live and deadassemblages (p 5 0.994, R 5 20.0412).

To classify the vertical distributions of the live popula-tions and dead assemblages, we combined foraminiferalrelative abundances from all seasons and years to perform acluster analysis on live populations and dead assemblages,separately.

The results of the applied Monte Carlo test on the livepopulations indicate that there are three main clusters(Fig. 6A) with a relative cluster replication of 40% forcluster I, 13% for cluster IIa, and 23% for cluster IIb.Cluster IIb consists of tidal flat and low marsh stations (St.1–4) with elevations between 1.34 and 1.48 m NAVD88.Miliammina fusca is the dominant species with a relativeabundance between 46–100%, with the presence of Hayne-sina sp. (maximum relative abundance of 48%; Fig. 6A).Cluster IIa includes all high marsh stations (St. 5–9) withelevations between 2.08 and 2.33 m NAVD88. This clusteris characterized by relatively high percentages of J.macrescens (up to 73%) and T. inflata (up to 56%). ClusterI contains stations from the high marsh (St. 7, 9) andhighest marsh to upland transition (St. 10) with elevationsbetween 2.29 and 2.42 m NAVD88. At these stations, B.pseudomacrescens and T. irregularis dominate with abun-dances between 11–73% and 7–84%, respectively.

The results of the applied Monte Carlo test on the deadforaminiferal assemblages show that there are also threemain clusters (Fig. 6B). The relative cluster replication is51% for cluster Ia, 50% for cluster Ib, and 66% for clusterII. The higher percentages of cluster replication suggest thatdead assemblage clusters are more stable and reproducible

than their living equivalents. Cluster II consists of tidal flatand low marsh samples (St. 1–4) with elevations between1.34 and 1.48 m NAVD88. In this cluster, M. fusca is thedominant species with a relative abundance between 84–100%. Cluster Ib contains all high marsh stations (BM St.5–9) with elevations between 2.08 and 2.33 m NAVD88,and is characterized by higher percentages of J. macrescens(14–69%) and T. inflata (0–37%). Cluster Ia includesstations from the elevated high marsh (St. 9) and highestmarsh to upland transition (St. 10) with elevations between2.33 and 2.42 m NAVD88. At these stations, T. irregularisand B. pseudomacrescens dominate with combined abun-dances of . 69% in each sample.

GEOCHEMICAL DISTRIBUTION OF BULK SEDIMENTS

The tidal flat and low marsh stations have heavier d13Cvalues, ranging between 220.7 and 222.0% in the tidal flat(St. 1, 2), and 221.3 and 224.3% in the low marsh (St. 3, 4)stations (Fig. 7). Lighter values were measured in the highmarsh and highest marsh to upland transition, with d13Cranging between 222.6% and 228.1% in the high marsh (St.5–9), and values between 229.1% and 227.8% in the highestmarsh to upland transition (St. 10; Fig. 7). The values showminimal inter-annual and seasonal variability in the tidalflat, low marsh and highest marsh/upland transition, butindicate a higher inter-annual and seasonal variability in thehigh marsh. For example at St. 5, d13C values ranged between222.9% in summer 2011 and 227.7% in summer 2012.

The C/N ratio of the bulk sediment generally increasesfrom the tidal flat to the upland stations regardless ofseason (Fig. 7). The tidal flat stations (St. 1, 2) arecharacterized by low C/N ratios between 8.0 and 8.6. Weobserved an increase in the C/N ratios from 8.3 to 12.6 inthe low marsh (St. 3–4). The high marsh (St. 5–9) ischaracterized by values ranging between 12.9 and 22.7 and,for the elevated highest marsh and upland (St. 10), weobserved values between 18.0 and 19.4. Again, the greatestinter-annual and seasonal variability was found in the highmarsh where the C/N ratios ranged between 15.2 in summer2011 and 21.1 in fall 2011, and between 22.7 in fall 2011 and16.5 in summer 2012 at St. 7 and 9, respectively.

The tidal flat and low marsh stations (St.1–4) have lowpercentages of TOC, ranging from 0.4–0.9% (St. 1–3) andfrom 3.6–5.0% (St. 4; Fig. 7). Higher and generallyincreasing TOC values were found for the high marshstations (St. 5–9), ranging from 6.6–38.9%. The highestTOC values were measured for highest marsh-upland St.10, ranging from 40.1–42.5%. The TOC values show aninter-annual variability between 2011 and 2012. Forexample TOC values range between 19.3% in fall 2011and 36.2% in summer 2012 at St. 5.

The d13C and C/N values (R 5 20.884; p , 0.001) andthe d13C and TOC (R 5 20.920; p , 0.001) both showsignificant negative correlations (Table 1). The tidal flatand low marsh stations (St. 1–4) have the heaviest d13Cvalues and low C/N and TOC values. The high marsh andhigher marsh to upland stations have lighter d13C andhigher C/N and TOC values (Fig. 8).

To determine inter-annual variability and correlationwith elevation, the median d13C, C/N and TOC values from



the 2011 and 2012 seasons were divided into four categoriesbased on vegetation (tidal flat, low marsh, high marsh andhigher marsh to upland) and compared. The medians of the2011 and 2012 d13C values are comparable in the low andhigh marsh, with 222.6% and 222.8% in the low marshand 224.7% and 226.0% in the high marsh, respectively(Fig. 9A). The medians of the d13C values in the tidal flatand higher marsh to upland show a higher variability, with220.7% and 222.0% in the tidal flat and 227.8% and229.5% in higher marsh to upland. The median C/N ratiosfor 2011 and 2012 are also similar within the defined

categories in both years, with 8.1 and 8.6 in the tidal flat,and 9.6 and 10.2 in the low marsh, and with slightly highervariability of 15.4 and 16.3 in the high marsh and 18.3 and19.4 in the highest marsh to upland transition (Fig. 9C).The medians of 2011 and 2012 TOC values are comparablefor the tidal flat and low marsh, with 0.5% and 0.6% in thetidal flat, and 2.9% and 2.0% in the low marsh. In the highmarsh and higher marsh to upland transition, the medianTOC values are again more variable, with 21.3% and 14.6%for the high marsh, and 40.4% and 42.5% in the highermarsh to upland transition (Fig. 9E).


FIGURE 6. Dendrograms from cluster analysis of live (A) and dead (B) foraminifera in Bandon Marsh with percentages of cluster replications(1000 permutations) for the clusters, and the percentages of the most common live and dead species. The stations (left side) are arranged according tothe cluster analysis results (Station labels: A, August 2011 samples; B, October 2011 samples; C, July 2012 samples; and D, October 2012 samples). Onthe right side, the elevational range for each cluster is shown (the boxes show the median and the 25th and 75th percentile and whiskers show theminimum and maximum elevations).


We applied a GLM to the d13C, C/N and TOC values todetermine the individual and combined effect of elevationand inter-annual variability on their distributions. Wefound a significant correlation with elevation (p , 0.001),but not with sampling year (p 5 0.953 for d13C, p 5 0.807for C/N and p 5 0.930 for TOC, respectively) or betweensampling year and elevation (p 5 0.689 for d13C, p 5 0.701for C/N and p 5 0.765 for TOC, respectively; Table 1;Figs. 9B, 9D and 9F). We further measured the Pearsoncorrelation between d13C, C/N and TOC values andelevation and found a significant positive correlation ofthe C/N and TOC values to elevation with p , 0.001 and R5 0.885 and R 5 0.849, respectively, and a significantnegative correlation of the d13C values to elevation with p ,

0.001 and R 5 20.820 (Table 1; Fig. 10).

DISCUSSION

INTER-ANNUAL AND SEASONAL FORAMINIFERAL DISTRIBUTION

AND THE INFLUENCE OF TAPHONOMIC PROCESSES

Time series analysis of live foraminiferal populations notonly detects inter-annual and/ or seasonal variations, butalso elucidates the underlying environmental conditions

influencing their distributions (e.g., Cearreta et al., 2002,2007). Our results demonstrate that inter-annual andseasonal variability have an insignificant influence on thedistribution of live species in the intertidal environments ofBandon Marsh, a conclusion that contrasts with those ofsome other studies (e.g., Buzas, 1965; Horton & Murray,2006, 2007). However, the lack of significant seasonalvariations in the live populations might be partly explainedby our sampling strategy, as we sampled Bandon Marsh insummer and fall in two successive years. A fullerunderstanding of the seasonal variations could be madethrough sampling in additional seasons and years. Howev-er, a great contrast in monthly precipitation occurs betweenthe two seasons that we sampled (Fig. 2). Based on a 30-yraverage (1981–2011), the monthly precipitation is low in thesummer months (July and August), with 11 and 14 mm permonth, respectively, but high in October with an average of103 mm per month (http://www.ncdc.noaa.gov/cdo-web/datasets/GHCND/stations). Precipitation influences theporewater salinity in salt marshes. For example, de Rijk(1995) has shown that foraminiferal distributions of theGreat Marshes, Massachusetts, reflect variations in salinity,the result not of tidal exposure but of changes in thebalance between seepage, precipitation and flooding. AtCowpen Marsh (UK), Horton & Edwards (2003, 2006) andHorton & Murray (2006, 2007) suggested that the greatestinter-annual variations in live and dead foraminiferalpopulations are found in summer and fall when bloomsof foraminifera occur. Buzas (1965) observed that the totalnumber of live individuals was greatest in the summer whenmaximum water temperature and highest abundance ofzooplankton and phytoplankton occurred in Long IslandSound, U.S. Atlantic coast. However, in the Humbleestuary (UK) and in the Bombay Hook National WildlifeRefuge (Delaware, USA), Alve & Murray (1994) andHippensteel et al. (2002), respectively, found high repro-duction rates of foraminifera in late spring. Debenay et al.(2006) found high reproduction rates of foraminifera in latespring and early fall in the Vie estuary (France).

The comparison of live populations and dead foraminif-eral assemblages reveals the influence of taphonomicalterations (e.g., destruction and transport of foraminiferaltests). For example, Haynesina sp. shows a higher relativeabundance in the live (St. 2, 48%) compared to dead


FIGURE 7. Bulk sediment TOC and d13C values and C/N ratiosfrom the Bandon Marsh stations measured in August 2011, October2011, and October 2012, and the elevation profile, with the tidaldatums for MHHW (mean highest high water), MHW (mean highwater) and MTL (mean tide level) adapted from the Bandon tide gauge.

TABLE 1. Correlations (R and p values) between d13C%, C/N andTOC values with elevation and the results of the Generalized LinearModel (GLM). For the GLM, the degree of freedom (df) and p valuesfor elevation (tidal flat, low marsh, high marsh and highest marsh toupland transition), year (2011, 2012), and interaction between elevationand year are shown. Significant correlations are given in bold.

p/R Elevation d13C C/N TOC

Elevation ,0.001 ,0.001 ,0.001d13C 20.820 ,0.001 ,0.001C/N 0.885 20.884 ,0.001TOC 0.849 20.920 0.927

GLM df p p p

Elevation 3 ,0.001 ,0.001 ,0.001Year 1 0.953 0.807 0.930Year*elevation 3 0.689 0.701 0.765


assemblages (St. 2, 3%; Figs. 4, 5). Our observationssuggest that the majority of calcareous tests of this specieswere dissolved after burial: we found a total of 719specimens (per 10 cm3) in the live populations, but only54 specimens (per 10 cm3) in the dead assemblages (n 5 5).Furthermore, the remaining dead specimens of Haynesinasp. often have signs of dissolution (e.g., fragile, incompleteand/or white tests). Taphonomic alterations of calcareousforaminifera have been observed elsewhere along theOregon coast (Jennings & Nelson, 1992; Hawkes et al.,2010; Engelhart et al., 2013b), as well as in other temperateintertidal environments (e.g., Murray & Alve, 1999;Edwards & Horton, 2000; Horton & Murray, 2006; Kempet al., 2013b). Reaves (1986), Green et al. (1993) andBerkeley et al. (2007) explained a higher rate of dissolutionof calcareous tests at the sediment-water interface withlowered porewater pH. Reaves (1986) suggested that ahigher amount of metabolizable organic matter causes ahigher rate of microbial decay, resulting in anoxic-sulfidicconditions and in the formation of ferro-sulfite minerals inmarsh soils. These minerals are oxidized during times ofreduced microbial activity, which lowers the pH, resultingin an undersaturation with respect to calcium carbonateand thus higher rates of dissolution. In Bandon Marsh, pHvalues between 5.2 and 5.6 were measured in 2011 (Brophy& van de Wetering, 2012). Alve & Nagy (1986) concludedthat pH values of # ,7 cause the dissolution of calcareoustests. From laboratory experiments on Ammonia beccariitests, Wang & Chappel (2001) and Le Cadre et al. (2003)observed dissolution when pH values were between or lowerthan 6 and 7.

Despite taphonomic loss of calcareous species, the livepopulations and dead assemblages have similar speciesdistributions because the assemblages are dominated byagglutinated foraminifera (.90% of the dead assemblages).The agglutinated specimens show little sign of taphonomicalterations, which has been shown elsewhere (e.g., Jonasson& Patterson, 1992; Goldstein & Watkins, 1999; Culver &Horton, 2005). Our results suggest that both live populationsand dead assemblages in Bandon Marsh are suitable for

paleoenvironmental reconstructions. However, in intertidalenvironments strongly influenced by early diagenetic disso-lution of calcium carbonate, dead foraminiferal assemblagesare the best modern analogues for fossil assemblages.

LIVE AND DEAD FORAMINIFERAL DISTRIBUTIONS IN

BANDON MARSH AND THEIR RELATION TO ELEVATION

In Bandon Marsh, we observed a strong vertical zonationof live populations and dead foraminifera. The tidal flatand low marsh (Zones IIb and II; Fig. 6) is dominated byM. fusca with contributions from Haynesina sp. in the livepopulations. Miliammina fusca has been reported as theindicator species of temperate tidal flat and low marshenvironments along the Oregon coast (Hunger, 1966;Jennings & Nelson, 1992; Hawkes et al., 2010; Engelhartet al., 2013b) and in other North American Pacific intertidalenvironments (Williams, 1989, 1999; Patterson et al., 1999;Kemp et al., 2013b). Jadammina macrescens and T. inflataare the most abundant species in the high marsh in both thelive and dead assemblages, with lesser contributions fromM. fusca and B. pseudomacrescens (Zone Ib and IIa, Fig. 6).Similar high marsh assemblages are also observed inOregon (Jennings & Nelson, 1992; Hawkes et al., 2010;Engelhart et al., 2013b), and in other temperate (Williams,1989; Patterson, 1990; Patterson et al., 1999) intertidalenvironments. The high marsh and highest marsh to uplandtransition zone (Zone Ia; Fig. 6) is dominated by T.irregularis and B. pseudomacrescens in both live populationsand dead assemblages. Trochamminita irregularis has beenrecognized as a highest high marsh and upland specieselsewhere along the Oregon coast (identified as Trocham-minita salsa in Nelson et al., 2008; Hawkes et al., 2010;Engelhart et al., 2013b), and (as T. salsa) from the saltmarshes of Chile (Jennings et al., 1995). But T. irregularis isalso notably absent from other Oregon intertidal environ-ments near our study site (Jennings & Nelson, 1992;Hawkes et al., 2010). Balticammina pseudomacrescens is aubiquitous species in Oregon intertidal environments,encountered from the middle marsh to the upland (Hawkeset al., 2010).


FIGURE 8. Scatter plot of stable carbon isotope (d13C) values versus C/N ratios and TOC values from the summer and fall 2011 and summer 2012seasons in Bandon Marsh.


GEOCHEMICAL DISTRIBUTION, INTER-ANNUAL

DISTRIBUTION AND RELATION TO ELEVATION

The d13C, C/N, and TOC values have significant linearcorrelations with elevation with respect to the tidal frame,and show no significant inter-annual variations (Table 1;Fig. 9A–F). Previous studies implied that sediment d13Creflects the C3/C4 botanical component preserved in thesediment, which is controlled by salinity and the degree oftidal inundation (e.g., Chmura & Aharon, 1995; Lambet al., 2006, 2007; Kemp et al., 2010). For example, inestuarine wetlands on the U.S. Atlantic coast, a gradualchange was observed from the dominance of C4 plants,producing carbon with heavier d13C values, relative to C3

plants with lighter d13C values, along a salinity gradient(e.g., Smith & Epstein, 1971; Chmura & Aharon, 1995;

Lamb et al., 2006). In Oregon coastal environments, marshvegetation predominantly consists of C3 plants, with C4

plants restricted mostly to the low marsh and tidal flat(Engelhart et al., 2013b). However, organic materialderived from freshwater or marine phytoplankton, andallochthonous particulate organic matter (POC) anddissolved organic matter (DOC), can have a stronginfluence on the d13C, C/N and TOC values of sedimentsin coastal environments that are frequently inundated bytides or rivers, or where autochthonous vegetation contrib-utes little to sediment organic matter (e.g., tidal flat or lowmarsh environments; Chmura & Aharon, 1995; Lamb et al.,2006). Vegetation cover is sparse in the tidal flat and lowmarsh of Bandon Marsh, and low TOC values (0.4 to 5.0%)suggest minimal input from in situ vegetation (Figs. 7, 11).The most abundant plants are Zostera nana and Z. marina


FIGURE 9. Box plots of median d13C, C/N and TOC values of the years 2011 and 2012, with 25th and 75th percentile (boxes) and 95% confidenceintervals (whiskers), for the tidal flat, low marsh, high marsh and highest marsh to upland stations (A, C, D). Results of the Generalized Linear Model(GLM) for the d13C, C/N and TOC values are also shown (B, D, F; Table 1).


(relative abundance of ,15% at St. 1, 2) and D. spicata (35–80% at St. 3, 4), with d13C values in the range of C4 plants(between , 210.0 to 213.5%; Smith & Epstein, 1970;Byrne et al., 2001). The C3 plants Scirpus spp. and Juncusbalticus (St. 3, 4), which have lighter d13C values between226.0 and 230% (Chmura & Aharon, 1995; Byrne et al.,2001), are much less abundant (20–40%) in these environ-ments. The d13C and C/N values that we observed in bulksediments for the tidal flat and low marsh range between220.7 and 224.3% and 7.7 and 12.6, respectively. Thesevalues reflect greater contributions from marine phyto-

plankton, which have d13C values between 216 and 227%(Goni and Thomas, 2000; Lamb et al., 2006; Park & Shin,2010;) and C/N ratios less than 10 (Meyers, 1994). The bulksediment d13C and C/N values also indicate the influence ofallochthonous marine POC (with d13C ratios between 218and 224% and TOC between 4 and 10%) and DOC (withd13C ratios between 222 and 225% and TOC between 7and 26%; Fig. 11).

The generally decreasing d13C values from the low marshto the upland (222.6 to 229.8%) indicate the increasingincorporation of terrestrial C3 plants, such as Scirpus spp.,


FIGURE 11. Ranges of d13C ratios and C/N values from different sources of organic material found in intertidal environments. This figure wasmodified from Lamb et al. (2006) and Khan et al. (2015).

FIGURE 10. Elevation versus d13C values (A) and C/N ratios (B) and TOC values (C) from summer 2011 and 2012, and fall 2011. Tidal datums,MHW (mean high water) and MHHW (mean highest high water) are adapted from the Bandon tide gauge.


(226.0 and 230%; Chmura & Aharon, 1995), Potentillaspp. (228.4%; Zheng & Shangguan, 2006) and Juncusbalticus (228.4%; Byrne et al., 2001), into sediments at theexpense of C4 plants. For example, the heavier mean d13Cvalues of St. 5, 6 and 8 (between 223.6 and 225.2%)compared to the lighter mean d13C values of high marsh St.7 and 9 (between 227.1 and 228.1%) can be explained bythe higher occurrence of D. spicata at St. 5, 6 and 8.However, the generally decreasing d13C values (from 223.6to 228.9%) and generally increasing C/N ratios (from 12.9to 22.7) from the high marsh to the upland could alsoindicate a dominance of C3 plants, as well as a decrease inthe influence of allochthonous particulate organic carbon(POC) and dissolved organic carbon (DOC) derived frommarine sources. These trends were evident at St. 5, 6 and 8compared to St. 7, 9 and 10, which are situated at higherelevations and a greater distance from open water (Fig. 11).Similar observations of increasing C/N ratios with increas-ing distance from the shore and elevation were found byWilson et al. (2005a, b) in the Mersey estuary (UK), byKemp et al. (2010, 2012) in an North Carolina (USA) saltmarsh, and by Engelhart et al. (2013b) in an Oregon (USA)salt marsh.

Despite significant correlations of d13C, C/N and TOCvalues with elevation in Bandon Marsh, the d13C, C/N andTOC ranges from the tidal flat and low marsh (St. 1–3)overlap (Fig. 10A–C). We further observed a correspond-ing overlap in d13C, C/N and TOC ranges for the low marsh(St. 4) with the high marsh (St. 5–7), and for values fromhigh marsh (St. 8, 9) and highest marsh to upland transition(St. 10) stations. Comparable observations of overlappingd13C values were made by Engelhart et al. (2013b), whofound similar d13C ratios between the tidal flat/low marshand the middle/high marsh zones at Siletz Bay, Oregon.Kemp et al. (2010, 2012) also observed a tendency for C/Nratios to converge to uniform values between 10 and 20 inmarsh and upland settings. The observed tendency foroverlap among d13C, C/N and TOC values indicates thatthese geochemical proxies provide less accurate indicatorsof former sea-level changes than do microfossils, but theseproxies have great potential to support sea-level recon-structions based on intertidal foraminifera.

Within our sampling design, the d13C, C/N and TOCvalues display no significant inter-annual variability.However, Hoffman & Bronk (2006) studied inter-annualand seasonal d13C variations of particulate organic matter(POM) in brackish to freshwater river stations in Virginiaand found higher inter-annual than seasonal variations ind13C of POM. The authors concluded that the spatial andtemporal variations in d13C of POM are caused by physicalmixing of estuarine and riverine POM and by variableamounts of POM in river discharge. Allen et al. (2007)studied the seasonal variation in d13C and C/N values intidal flat and low marsh sediments in southwest Englandand found changes in d13C of ,1%, and of C/N of .3between samples collected in January, May and August.Allen et al. (2007) explained these differences by a higheraccumulation of C3 plant detritus in winter and higheraccumulation of algal material in summer. Also Cloern etal. (2002) found a seasonal variability in d13C values ofselected plants from intertidal and subtidal freshwater

environments in the San Francisco Bay, i.e., a variabilityof ,1.5% for the C4 plant D. spicata and a highervariability, between 2.0 and 4.5%, for C3 plants such asJ. balticus, Salicornia virginica, Scirpus spp., and T.maritima. These authors also observed generally lower C/N ratios during the first emergence of shoots and roots inspring, then a gradual rise in C/N during spring andsummer, and a rapid increase in autumn and winter whenthe biomass was dying.

CONCLUSIONS

We investigated inter-annual and seasonal variations ofdistributions of live populations and dead foraminifera, andinter-annual variations in stable carbon isotopes (d13C),TOC values and C/N ratios in bulk sediments fromintertidal environments of Bandon Marsh (Oregon, USA)from summer (dry) and fall (wet) seasons for two successiveyears (2011, 2012). Results from ANOSIM (analysis ofsimilarity) of live and dead foraminiferal assemblagessuggest that both types of assemblages show no significantinter-annual or seasonal variations. The lack of significantseasonal variations in the live populations might be partlyexplained by our sampling strategy. Cluster analyses showthat live and dead assemblages show a distinct andcomparable vertical zonation: the tidal flat and low marshis dominated by Miliammina fusca; the high marsh ischaracterized by higher percentages of Jadammina macres-cens and Trochammina inflata; and the highest marsh toupland transition zone is dominated by Balticamminapseudomacrescens and Trochamminita irregularis. The onlycalcareous taxon encountered, Haynesina sp., is moreabundant in the living than in the dead assemblages ofthe tidal flat and low marsh, reflecting rapid post-depositional dissolution of calcareous tests. The d13C andTOC values and C/N ratios show a significant linearcorrelation to elevation across the intertidal zone with nosignificant inter-annual variations in these geochemicalproxies. The elevation-dependence of live populations anddead foraminiferal assemblages, as well as d13C and TOCvalues and C/N ratios, indicates that these variables can beused to reconstruct former relative sea levels, and hence, toinfer land-level changes during past great earthquakesalong the tectonically active Pacific coast of NorthAmerica.

ACKNOWLEDGMENTS

We thank William Kearney for analyzing the grain sizedata, Laura Brophy for providing the tide gauge data fromthe Coquille River, Manuel F.G. Weinkauf for guidanceand support regarding the ANOSIM and GLM analyses,the U.S. Fish and Wildlife Service for permission to workon Bandon Marsh National Wildlife Refuge, and the U.S.Geological Survey for providing the elevation data from theUSGS logger sets. We acknowledge Ian Wilkinson from theBritish Geological Survey (BGS) for his review and SteveCulver for providing the USGS review. We further thankthe two anonymous reviewers and the editor of JFR fortheir helpful comments. This project was supported byfunding from the German Science Foundation (DFG) to Y.



Milker (Award # MI 1508/2-1), and by funding from theNational Science Foundation to B. P. Horton (Award #0842728 and 1419824) and to S. E. Engelhart (Award #1419844). Chris Vane publishes with permission of theExecutive Director British Geological Survey and wassupported by the Climate and Landscape Change researchprogramme at the BGS. Research by Alan Nelson and RobWitter was supported by the Earthquake Hazards Programof the U.S. Geological Survey. Any use of trade, product,or firm names is for descriptive purposes only and does notimply endorsement by the U.S. Government. This paper isa contribution to IGCP project 588 ‘Preparing for coastalchange’ and PALSEA 2.

REFERENCES

Allen, J. R. L., Lamb, A. L., and Dark, P., 2007, Seasonality of d13Cand C/N ratios in modern and mid-Holocene sediments inthe Severn Estuary Levels, SW Britain: The Holocene, v. 17,p. 139–144.

Alve, E., and Murray, J. W., 1994, Ecology and taphonomy of benthicforaminifera in a temperate mesotidal inlet: Journal of Forami-niferal Research, v. 24, p. 18–27.

Alve, E., and Nagy, J., 1986, Estuarine foraminiferal distribution inSandebukta, a branch of the Oslo Fjord: Journal of ForaminiferalResearch, v. 16, p. 261–284.

Benner, R., Fogel, M. L., Sprague, E. K., and Hodson, R. E., 1987,Depletion of 13C in lignin and its implications for stable carbonisotope studies: Nature, v. 329, p. 708–710.

Berkeley, A., Perry, C. T., Smithers, S. G., Horton, B. P., and Taylor,K. G., 2007, A review of the ecological and taphonomic controlson foraminiferal assemblage development in intertidal environ-ments: Earth-Science Reviews, v. 83, p. 205–230.

Berkeley, A., Perry, C. T., Smithers, S. G., and Horton, B. P., 2008,The spatial and vertical distribution of living (stained) benthicforaminifera from a tropical, intertidal environment, northQueensland, Australia: Marine Micropalaeontology, v. 69,p. 240–261.

Birks, H. J. B., 1995, Quantitative palaeoenvironmental reconstruc-tions, in Maddy, D., and Brew, J. S. (eds.), Statistical Modelling ofQuaternary Science Data: Cambridge University Press, Cam-bridge, p. 1–271.

Bolker, B. M., Brooks, M. E., Clark, C. J., Geange, S. W., Poulsen,J. R., Stevens, M. H. H., and White, J.-S. S., 2009, Generalizedlinear mixed models: a practical guide for ecology and evolution:Trends in Ecology & Evolution, v. 24, p. 127–135.

Bray, J. R., and Curtis, J. T., 1957, An ordination of the upland forestcommunities of southern Wisconsin: Ecological Monographs,v. 27, p. 325–349.

Brophy, L., and van de Wetering, S., 2012, Ni-les’tun Tidal WetlandRestoration Effectiveness Monitoring: Baseline (2010–2011),Green Point Consulting, The Institute for Applied Ecology, andthe Confederated Tribes of Siletz Indians Corvallis, Oregon, 114 p.

Buzas, M. A., 1965, The distribution and abundance of foraminifera inLong Island Sound: Smithsonian Miscellaneous Collections,Smithsonian Institution, Washington, 89 p.

Buzas, M. A., 1968, On the spatial distribution of foraminifera:Contributions from the Cushman Foundation for ForaminiferalResearch, v. 19, p. 1–11.

Buzas, M. A., Hayek, L.-A. C., Reed, S. A., and Jett, J. A., 2002,Foraminiferal densities over five years in the Indian river lagoon,Florida: a model of pulsating patches: Journal of ForaminiferalResearch, v. 32, p. 68–92.

Byrne, R., Ingram, B. L., Starratt, S., Malamud-Roam, F., Collins,J. N., and Conrad, M. E., 2001, Carbon-Isotope, diatom, and pollenevidence for late Holocene salinity change in a brackish marsh in theSan Francisco estuary: Quaternary Research, v. 55, p. 66–76.

Cearreta, A., Alday, M., Conceicao Freitas, M., Andrade, C., andCruces, A., 2002, Modern foraminiferal record of alternating openand restricted environmental conditions in the Santo Andrelagoon, SW Portugal: Hydrobiologia, v. 475–476, p. 21–27.

Cearreta, A., Alday, M., Conceicao Freitas, M., and Andrade, C.,2007, Postglacial foraminifera and paleoenvironments of theMediles lagoon (SW Portugal): Towards a regional model ofcoastal evolution: Journal of Foraminiferal Research, v. 37,p. 125–135.

Chmura, G. L., and Aharon, P., 1995, Stable carbon isotope signaturesof sedimentary carbon in coastal wetlands as indicators of salinityregime: Journal of Coastal Research, v. 11, p. 124–135.

Chmura, G. L., Aharon, P., Socki, R. A., and Abernethy, R., 1987, Aninventory of 13C abundances in coastal wetlands of Louisiana,USA: Vegetation and sediments: Oecologia, v. 74, p. 264–271.

Cisternas, M., Atwater, B. F., Torrejon, F., Sawai, Y., Machuca, G.,Lagos, M., Eipert, A., Youlton, C., Salgado, I., Kamataki, T.,Shishikura, M., Rajendran, C. P., Malik, J. K., Rizal, Y., andHusni, M., 2005, Predecessors of the giant 1960 Chile earthquake:Nature, v. 437, p. 404–407.

Clarke, K. R., 1993, Non-parametric multivariate analyses of changesin community structure: Australian Journal of Ecology, v. 18,p. 117–143.

Cloern, J. E., Canuel, E. A., and Harris, D., 2002, Stable carbon andnitrogen isotope composition of aquatic and terrestrial plants ofthe San Francisco Bay estuarine system: Limnology andOceanography, v. 47, p. 713–729.

Culver, S. J., and Horton, B. P., 2005, Infaunal marsh foraminiferafrom the Outer Banks, North Carolina, U.S.A.: Journal ofForaminiferal Research, v. 35, p. 148–170.

Debenay, J.-P., Bicchi, E., Goubert, E., and Armynot du Chatelet, E.,2006, Spatio-temporal distribution of benthic foraminifera inrelation to estuarine dynamics (Vie estuary, Vendee, W France):Estuarine, Coastal and Shelf Science, v. 67, p. 181–197.

de Rijk, S., 1995, Salinity control on the distribution of salt marshforaminifera (Great Marshes, Massachusetts): Journal of Fora-miniferal Research, v. 25, p. 156–166.

Dura, T., Rubin, C. M., Kelsey, H. M., Horton, B. P., Hawkes, A. D.,Vane, C. H., Daryono, M., Pre, C. G., Ladinsky, T., and Bradley,S., 2011, Stratigraphic record of Holocene coseismic subsidence,Padang, West Sumatra: Journal of Geophysical Research: SolidEarth, 116, B11306.

Edwards, R. J., and Horton, B. P., 2000, Reconstructing relative sea-level change using UK salt-marsh foraminifera: Marine Geology,v. 169, p. 41–56.

Ember, L. M., Williams, D. F., and Morris, J. T., 1987, Processes thatinfluence carbon isotope variations in salt marsh sediments:Marine Ecology–Progress Series, v. 36, p. 33–42.

Engelhart, S. E., Horton, B. P., Nelson, A. R., Hawkes, A. D., Witter,R. C., Wang, K., Wang, P.-L., and Vane, C. H., 2013a, Testing theuse of microfossils to reconstruct great earthquakes at Cascadia:Geology, v. 41, p. 1067–1070.

Engelhart, S. E., Horton, B. P., Vane, C. H., Nelson, A. R., Witter,R. C., Brody, S. R., and Hawkes, A. D., 2013b, Modernforaminifera, d13C, and bulk geochemistry of central Oregon tidalmarshes and their application in paleoseismology: Palaeogeogra-phy, Palaeoclimatology, Palaeoecology, v. 377, p. 13–27.

Faith, D. P., Minchin, P. R., and Belbin, L., 1987, Compositionaldissimilarity as a robust measure of ecological distance: Vegetatio,v. 69, p. 57–68.

Frenkel, R. E., Eilers, H. P., and Jefferson, C. A., 1981, Oregon coastalsalt marsh upper limits and tidal datums: Estuaries, v. 4,p. 198–205.

Fu, L., and Moncher, R. B., 2004, Severity distributions for GLMs:Gamma or lognormal? Evidence from Monte Carlo simulations:Casualty Actuarial Society Discussion Paper Program, p. 149–230.

Gehrels, W. A., 2000, Using foraminiferal transfer functions toproduce high-resolution sea-level records from salt-marsh depos-its, Maine, USA: The Holocene, v. 10, p. 367–376.

Goldstein, S. T., and Watkins, G. T., 1999, Taphonomy of salt marshforaminifera: an example from coastal Georgia: Palaeogeography,Palaeoclimatology, Palaeoecology, v. 149, p. 103–114.

Goni, M. A., and Thomas, K. T., 2000, Sources and transformations oforganic matter in surface soils and sediments from a tidal estuary(North Inlet, South Carolina, USA): Estuaries, v. 23, p. 548–564.

Green, M. A., Aller, R. C., and Aller, J. Y., 1993, Carbonatedissolution and temporal abundances of foraminifera in Long



Island Sound sediments: Limnology and Oceanography, v. 38,p. 331–345.

Guilbault, J.-P., Clague, J. J., and Lapointe, M., 1995, Amount ofsubsidence during a late Holocene earthquake - evidence fromfossil tidal marsh foraminifera at Vancouver Island, west coast ofCanada: Palaeogeography, Palaeoclimatology, Palaeoecology,v. 118, p. 49–71.

Hammer, O., Harper, D. A. T., and Ryan, P. D., 2001, PAST:Palaeontological STatistics package for education and dataanalysis: Palaeontologica Electronica, v. 4, p. 1–9. (http://palaeo-electronica.org/2001-1/past/past.pdf).

Hawkes, A. D., Horton, B. P., Nelson, A. R., and Hill, D. F., 2010,The application of intertidal foraminifera to reconstruct coastalsubsidence during the giant Cascadia earthquake of AD 1700 inOregon, USA: Quaternary International, v. 122, p. 116–140.

Hawkes, A. D., Horton, B. P., Nelson, A. R., Vane, C. H., and Sawai,Y., 2011, Coastal subsidence in Oregon, USA, during the giantCascadia earthquake of AD 1700: Quaternary Science Reviews,v. 30, p. 364–376.

Hippensteel, S. P., Martin, R. E., Nikitina, D., and Pizzuto, J. E., 2002,Interannual variation of marsh foraminiferal assemblages (Bom-bay Hook National Wlidlife Refuge, Smyrna, De): Do foraminif-eral assemblages have a memory?: Journal of ForaminiferalResearch, v. 32, p. 97–109.

Hoffman, J. C., and Bronk, D. A., 2006, Interannual variation in stablecarbon and nitrogen isotope biogeochemistry of the MattaponiRiver, Virginia: Limnology and Oceanography, v. 51, p. 2319–2332.

Horton, B. P., 1999, The distribution of contemporary intertidalforaminifera at Cowpen Marsh, Tees Estuary, UK: implicationsfor studies of Holocene sea-level changes: Palaeogeography,Palaeoclimatology, Palaeoecology, v. 149, p. 127–149.

Horton, B. P., and Edwards, R. J., 2003, Seasonal distributions offoraminifera and their implications for sea-level studies, CowpenMarsh, U.K: SEPM (Society for Sedimentary Geology), Specialpublication no. 75, p. 21–30.

Horton, B. P., and Edwards, R. J., 2006, Quantifying Holocene sea-level change using intertidal foraminifera: Lessons from the BritishIsles: Cushman Foundation for Foraminiferal Research, SpecialPublication No. 40, p. 1–97.

Horton, B. P., and Murray, J. W., 2006, Patterns in cumulativeincrease in live and dead species from foraminiferal time series ofCowpen Marsh, Tees Estuary, UK: Implications for sea-levelstudies: Marine Micropalaeontology, v. 58, p. 287–315.

Horton, B. P., and Murray, J. W., 2007, The roles of elevation andsalinity as primary controls on living foraminiferal distributions:Cowpen Marsh, Tees Estuary, UK: Marine Micropalaeontology,v. 63, p. 169–186.

Horton, B. P., Edwards, R. J., and Lloyd, J. M., 1999, UK intertidalforaminiferal distributions: implications for sea-level studies:Marine Micropalaeontology, v. 36, p. 205–223.

Hunger, A. A., 1966, Distribution of foraminifera, Netarts Bay,Oregon: Oregon State University, Masters thesis, 112 p.

Jennings, A. E., and Nelson, A. R., 1992, Foraminiferal assemblagezones in Oregon tidal marshes - relation to marsh floral zones andsea level: Journal of Foraminiferal Research, v. 22, p. 13–29.

Jennings, A. E., Nelson, A. R., Scott, D. B., and Aravena, J. C., 1995,Marsh foraminiferal assemblages in the Valdivia Estuary, south-central Chile, relative to vascular plants and sea level: Journal ofCoastal Research, v. 11, p. 107–123.

Jonasson, K. E., and Patterson, R. T., 1992, Preservation potential ofsalt marsh foraminifera from the Fraser River delta, BritishColumbia: Micropaleontology, v. 38, p. 289–301.

Jones, G. D., and Ross, C. A., 1979, Seasonal distribution offoraminifera in Samish Bay, Washington: Journal of Paleontol-ogy, v. 53, p. 245–257.

Kemp, A. C., Horton, B. P., and Culver, S. J., 2009, Distribution ofmodern salt-marsh foraminifera in the Albemarle–Pamlico estu-arine system of North Carolina, USA: Implications for sea-levelresearch: Marine Micropaleontology, v. 72, p. 222–238.

Kemp, A. C., Vane, C. H., Horton, B. P., and Culver, S. J., 2010,Stable carbon isotopes as potential sea-level indicators in saltmarshes, North Carolina, USA: The Holocene, v. 20, p. 623–636.

Kemp, A. C., Vane, C. H., Horton, B. P., Engelhart, S. E., andNikitina, D., 2012, Application of stable carbon isotopes for

reconstructing salt-marsh floral zones and relative sea level, NewJersey, USA: Journal of Quarternary Sciences, v. 27, p. 404–414.

Kemp, A. C., Horton, B. P., Vane, C. H., Bernhardt, C. E., Corbett,D. R., Engelhart, S. E., Anisfeld, S. C., Parnell, A. C., and Cahill,N., 2013a, Sea-level change during the last 2500 years in NewJersey, USA: Quaternary Science Reviews, v. 81, p. 90–104.

Kemp, A. C., Engelhart, S. E., Culver, S. J., Nelson, A. R., Briggs,R. W., and Haeussler, P. J., 2013b, Modern salt-marsh and tidal-flat foraminifera from Sitkinak and Simeonof Islands, southwest-ern Alaska: Journal of Foraminiferal Research, v. 43, p. 83–94.

Khan, N. S., Vane, C. H., and Horton, B. P., 2015, The application ofstable carbon isotope and C/N geochemistry of coastal wetlandsediments as sea-level indicator, in Shennan, I., et al. (eds.),Handbook of Sea-Level Research: Wiley-Blackwell, Hoboken,p. 295–311.

Lamb, A. L., Wilson, G. W., and Leng, M. J., 2006, A review ofpalaeoclimate and relative sea-level reconstruction using d13C and C/N ratios in organic material: Earth Science Reviews, v. 75, p. 29–57.

Lamb, A. L., Vane, C. H., Wilson, G. P., Rees, J. G., and Moss-Hayes,V. L., 2007, Assessing d13C and C/N ratios from organic materialin archived cores as Holocene sea level and palaeoenvironmentalindicators in the Humber Estuary, UK: Marine Geology, v. 244,p. 109–128.

Le Cadre, V., Debenay, J.-P., and Lesourd, M., 2003, Low pH effectson Ammonia beccarii test deformation: Implications for using testdeformations as a pollution indicator: Journal of ForaminiferalResearch, v. 33, p. 1–9.

Legendre, P., and Birks, H. J. B., 2012, Clustering and Partitioning, inBirks, H. B. J., et al. (eds.), Tracking Environmental ChangeUsing Lake Sediments: Developments in PaleoenvironmentalResearch: Springer, Dordrecht, p. 167–200.

Leorri, E., Gehrels, W. R., Horton, B. P., Fatela, F., and Cearreta, A.,2010, Distribution of foraminifera in salt marshes along theAtlantic coast of SW Europe: Tools to reconstruct past sea-levelvariations: Quaternary International, v. 221, p. 105–155.

Malamud-Roam, F., and Ingram, B. L., 2001, Carbon isotopiccompositions of plants and sediments of tide marshes in the SanFrancisco Estuary: Journal of Coastal Research, v. 17, p. 17–29.

Meyers, P. A., 1994, Preservation of elemental and isotopic sourceidentification of sedimentary organic matter: Chemical Geology,v. 114, p. 289–302.

Murray, J. W., 1982, Benthic foraminifera: The validity of living, deador total assemblages for the interpretation of palaeoecology:Journal of Micropalaeontology, v. 1, p. 137–140.

Murray, J. W., 1991, Ecology and distribution of benthic foraminifera,in Lee, J. J., and Anderson, O. R. (eds.), Biology of Foraminifera:Academic Press, London, p. 221–253.

Murray, J. W., and Alve, E., 1999, Natural dissolution of modernshallow water benthic foraminifera: taphonomic effects on thepalaeoecological record: Palaeogeography, Palaeoclimatology,Palaeoecology, v. 146, p. 195–209.

Murray, J. W., and Alve, E., 2000, Major aspects of foraminiferalvariability (standing crop and biomass) on a monthly scale in anintertidal zone: Journal of Foraminiferal Research, v. 30,p. 177–191.

Murray, J. W., and Bowser, S. S., 2000, Mortality, protoplasm decayrate, and reliability of staining techniques to recognize ‘living’foraminifera: a review: Journal of Foraminiferal Research, v. 30,p. 66–70.

Nelder, J. A., and Wedderburn, R. W. M., 1972, Generalized LinearModels: Journal of the Royal Statistical Society (Series A), v. 135,p. 370–284.

Nelson, A. R., and Kashima, K., 1993, Diatom zonation in southernOregon tidal marshes relative to vascular plants, foraminifera, andsea level: Journal of Coastal Research, v. 9, p. 673–697.

Nelson, A. R., Shennan, I., and Long, A. J., 1996, Identifiyingcoseismic subsidence in tidal-wetland stratigraphic sequences atthe Cascadia subduction zone of western North America: Journalof Geophysical Research, v. 101, p. 6115–6135.

Nelson, A. R., Sawai, Y., Jennings, A. E., Bradley, L.-A., Gerson, L.,Sherrod, B. L., Sabean, J., and Horton, B. P., 2008, Great-earthquake paleogeodesy and tsunamies of the past 2000 years atAlsea Bay, central Oregon coast, USA: Quaternary ScienceReviews, v. 27, p. 747–768.



Overpeck, J. T., Webb, T., III, and Prentice, I. C., 1985, Quantitativeinterpretation of fossil pollen spectra: Dissimilarity coefficientsand the method of Modern Analogs: Quaternary Research, v. 23,p. 87–108.

Park, J., and Shin, Y., 2010, East Asian Monsoon history as indicatedby C/N ratios and d13C - evidence from the estuarine tidal flatsediments in the west coast of Korea: Journal of KoreanGeographical Society, v. 45, p. 541–552.

Patterson, R. T., 1990, Intertidal benthic foraminiferal biofacies on theFraser River delta, British Columbia: Modern distribution andpaleoecological importance: Micropaleontology, v. 36, p. 229–244.

Patterson, R. T., Guilbault, J.-P., and Clague, J. J., 1999, Taphonomyof tidal marsh foraminifera: implications of surface samplethickness for high-resolution sea-level studies: Palaeogeography,Palaeoclimatology, Palaeoecology, v. 149, p. 199–211.

Peel, M. C., Finlayson, B. L., and McMahon, T. A., 2007, Updatedworld map of the Koppen-Geiger climate classification: Hydrol-ogy and Earth System Sciences, v. 11, p. 1633–1644.

Phleger, F. B., and Walton, W. R., 1950, Ecology of marsh and bayforaminifera, Barnstable, Massachusetts: American Journal ofScience, v. 248, p. 274–294.

Reaves, C. M., 1986, Organic matter metabolizability and calciumcarbonate dissolution in nearshore marine muds: Journal ofSedimentary Research, v. 56, p. 486–494.

Sanders, D., 2003, Syndepositional dissolution of calcium carbonate inneritic carbonate environments: geological recognition, processes,potential significance: Journal of African Earth Science, v. 36,p. 99–134.

Sawai, Y., Satake, K., Kamataki, T., Nasu, H., Shishikura, M.,Atwater, B. F., Horton, B. P., Kelsey, H. M., Nagumo, T., andYamaguchi, M., 2004, Transient uplift after a 17th-centuryearthquake along the Kuril Subduction Zone: Science, v. 306,p. 1918–1920.

Schnitker, D., Mayer, L. M., and Norton, S., 1980, Loss of calcareousmicrofossils from sediments through gypsum formation: MarineGeology, v. 36, p. M35–M44.

Scott, D. B., and Medioli, F. S., 1978, Vertical zonations of marshforaminifera as accurate indicators of former sea-levels: Nature,v. 272, p. 528–531.

Scott, D. B., and Medioli, F. S., 1980, Living vs. total foraminiferalpopulations: Their relative usefulness in paleoecology: Journal ofPaleontology, v. 54, p. 814–831.

Scott, D. B., and Hermelin, J. O. R., 1993, A device for precisionsplitting of micropaleontological samples in liquid suspension:Journal of Paleontology, v. 67, p. 151–154.

Simpson, G. L., 2012, Analogue methods in palaeolimnology, in Birks,H. J. B., et al. (eds.), Tracking Environmental Change Using LakeSediments: Developments in Paleoenvironmental Research:Springer, Dordrecht, p. 495–522.

Smith, B. N., and Epstein, S., 1970, Biogeochemistry of the stableisotopes of hydrogen and carbon in salt marsh biota: PlantPhysiology, v. 46, p. 738–742.

Smith, B. N., and Epstein, S., 1971, Two categories of 13C/12C ratios forhigher plants: Plant Physiology, v. 47, p. 380–384.

Swallow, J. E., 2000, Intra-annual variability and patchiness in livingassemblages of salt-marsh foraminifera from Mill Rythe Creek,Chichester Harbour, England: Journal of Micropalaeontology,v. 19, p. 9–22.

Tyson, R. V., 1995, Sedimentary Organic Matter: Organic Facies andPalynofacies: Chapman and Hall, London, 615 p.

Vane, C. H., Rawlins, B. G., Kim, A. W., Moss-Hayes, V. L.,Kendrick, C. P., and Leng, M. J., 2013, Sedimentary transportand fate of polycyclic aromatic hydrocarbons (PAH) frommanaged burning of moorland vegetation on a blanket peat,South Yorkshire, UK: Science of The Total Environment, v. 449,p. 81–94.

Walton, W. R., 1952, Techniques for recognition of living foraminif-era: Contributions of the Cushman Foundation for ForaminiferalResearch, v. 3, p. 56–60.

Wang, P., and Chappell, J., 2001, Foraminifera as Holoceneenvironmental indicators in the South Alligator River, NorthernAustralia: Quaternary International, v. 83–85, p. 47–62.

Wang, P.-L., Engelhart, S. E., Wang, K., Hawkes, A. D., Horton,B. P., Nelson, A. R., and Witter, R. C., 2013, Heterogeneousrupture in the great Cascadia earthquake of 1700 inferred fromcoastal subsidence estimates: Journal of Geophysical Research:Solid Earth, v. 118, p. 2460–2473.

Wentworth, C. K., 1922, A scale of grade and class terms for clasticsediments: Journal of Geology, v. 30, p. 377–392.

Williams, H. F. L., 1989, Foraminiferal zonations on the Fraser Riverdelta and their application to paleoenvironmental interpretations:Palaeogeography, Palaeoclimatology, Palaeoecology, v. 73,p. 39–50.

Williams, H. F. L., 1999, Foraminiferal distributions in tidal marshesbordering the Strait of Juan de Fuca: Implications for paleoseis-micity studies: Journal of Foraminiferal Research, v. 29,p. 196–208.

Wilson, G. P., Lamb, A. L., Leng, M. J., Gonzalez, S., and Huddart,D., 2005a, Variability of organic d13C and C/N in the MerseyEstuary, U.K. and its implications for sea-level reconstructionstudies: Estuarine, Coastal and Shelf Science, v. 64, p. 685–698.

Wilson, G. P., Lamb, A. L., Leng, M. J., Gonzalez, S., and Huddart,D., 2005b, d13C and C/N as potential coastal palaeoenvironmentalindicators in the Mersey Estuary, UK: Quaternary ScienceReviews, v. 24, p. 2015–2029.

Wright, A. J., Edwards, R. J., and van de Plassche, O., 2011,Reassessing transfer-function performance in sea-level reconstruc-tion based on benthic salt-marsh foraminifera from the Atlanticcoast of NE North America: Marine Micropaleontology, v. 81,p. 43–62.

Zheng, S., and Shangguan, Z., 2006, Spatial patterns of foliar stablecarbon isotope compositions of C3 plant species in the LoessPlateau of China: Ecological Research, v. 22, p. 342–353.




APPENDIX 1. Location and mean elevation (NAVD88) of BandonMarsh stations.

Latitude LongitudeMean elevation (m)

NAVD88

Station 1 43u7.9669 N 124u24.1389 W 1.29Station 2 43u7.9399 N 124u24.1319 W 1.34Station 3 43u7.9399 N 124u24.1199 W 1.43Station 4 43u7.9569 N 124u24.1199 W 1.48Station 5 43u8.6859 N 124u23.8169 W 2.08Station 6 43u8.6979 N 124u23.7829 W 2.14Station 7 43u8.7239 N 124u23.7939 W 2.29Station 8 43u8.6749 N 124u23.7699 W 2.29Station 9 43u8.5969 N 124u23.8569 W 2.33Station 10 43u8.6629 N 124u23.7619 W 2.42



APPENDIX 2. Census counts of live and dead foraminifera.

Dead specimens

No Sam

pli

ng

date

(mo

nth

/day/y

ear)

Sam

ple

IDu

sed

inth

isst

ud

y

Sa

mp

leco

de

Mil

iam

min

afu

sca

Haynes

ina

sp.

Reo

phax

monil

iform

is

Am

mobacu

lite

ssp

p.

Tro

cham

min

ain

flata

Haplo

phra

gm

oid

esm

anil

aen

sis

Haplo

phra

gm

oid

esw

ilber

ti

Haplo

phagm

oid

essp

p.

Jadam

min

am

acr

esce

ns

Balt

icam

min

apse

udom

acr

esce

ns

Tro

cham

min

ita

irre

gula

ris

juven

ile

tro

cha

mm

inid

s

ind

eter

min

ate

1 08/16/11 2A BM/11/St.1 081611 246 0 0 0 0 0 0 0 0 0 0 0 22 08/16/11 3A BM/11/St.2 081611 314 3 0 3 0 0 0 0 2 0 0 0 13 08/16/11 1A BM/11/St.3 081611 286 0 0 1 0 0 0 0 0 0 0 0 64 08/16/11 4A BM/11/St.4 081611 369 0 0 1 32 27 1 0 4 0 0 0 35 08/16/11 9A BM/11/St.5 081611 5 0 0 0 3 1 1 0 16 279 70 0 36 08/16/11 5A BM/11/St.6 081611 123 0 0 0 141 82 27 0 27 131 2 0 07 08/16/11 8A BM/11/St.7 081611 40 0 0 0 31 18 3 0 253 1 3 20 48 08/16/11 6A BM/11/St.8 081611 176 0 0 0 140 41 22 11 212 16 12 9 149 08/16/11 7A BM/11/St.9 081611 127 0 0 0 44 15 4 0 299 182 44 29 25

10 08/16/11 10A BM/11/St.10 081611 10 0 0 0 16 5 1 0 25 63 124 9 1911 10/14/11 2B BM/11/St.1 101411 345 0 0 0 0 0 0 0 0 0 0 0 012 10/14/11 3B BM/11/St.2 101411 416 12 2 5 0 0 0 0 1 0 0 0 313 10/14/11 1B BM/11/St.3 101411 283 1 2 0 0 0 0 0 0 0 0 0 014 10/14/11 4B BM/11/St.4 101411 209 0 0 0 2 0 0 0 2 0 0 0 215 10/14/11 9B BM/11/St.5 101411 34 0 0 0 8 6 0 0 62 60 17 15 016 10/14/11 5B BM/11/St.6 101411 96 0 0 0 131 25 16 0 198 19 5 24 317 10/14/11 8B BM/11/St.7 101411 8 0 0 0 11 0 3 0 120 5 5 20 218 10/14/11 6B BM/11/St.8 101411 46 0 0 0 143 13 40 0 115 12 5 12 419 10/14/11 7B BM/11/St.9 101411 33 0 0 0 11 16 3 0 83 109 80 14 620 10/14/11 10B BM/11/St.10 101411 2 0 0 0 3 2 0 0 6 85 108 0 221 07/24/12 2C BM/11/St 1 072312 288 0 5 3 0 0 0 0 0 0 0 0 022 07/24/12 3C BM/11/St 2 072312 436 0 5 4 0 0 0 0 0 0 0 0 123 07/24/12 1C BM/11/St 3 072312 431 0 2 2 0 0 0 0 0 0 0 0 024 07/24/12 4C BM/11/St 4 072312 251 0 0 1 3 8 0 0 9 0 0 0 625 07/24/12 9C BM/11/St 5 072312 15 0 0 0 7 26 0 0 53 244 247 7 026 07/24/12 5C BM/11/St 6 072312 140 0 0 0 149 96 8 0 149 21 5 16 327 07/24/12 8C BM/11/St 7 072312 14 0 0 0 113 15 0 0 364 9 14 26 028 07/24/12 6C BM/11/St 8 072312 193 0 0 0 94 164 0 0 165 15 4 11 429 07/24/12 7C BM/11/St 9 072312 279 0 0 0 105 117 0 0 273 50 37 30 330 07/24/12 10C BM/11/St 10 072312 0 0 0 0 0 0 0 0 0 1 3 0 031 10/12/12 2D BM/11/St.1 101212 606 0 0 1 0 0 0 0 0 0 0 0 032 10/12/12 3D BM/11/St.2 101212 229 6 4 5 0 0 0 0 1 0 0 0 333 10/12/12 1D BM/11/St.3 101212 637 1 4 0 0 0 0 0 0 0 0 0 134 10/12/12 4D BM/11/St.4 101212 501 0 11 4 5 10 0 0 0 0 0 0 335 10/12/12 9D BM/11/St.5 101212 111 0 0 0 0 0 0 0 150 60 13 28 236 10/12/12 5D BM/11/St.6 101212 115 0 0 0 240 31 33 0 228 34 6 30 1037 10/12/12 8D BM/11/St.7 101212 44 0 0 0 146 13 17 0 380 13 12 44 1238 10/12/12 6D BM/11/St.8 101212 265 0 0 0 153 141 33 0 158 3 5 31 039 10/12/12 7D BM/11/St.9 101212 175 0 0 0 236 9 6 0 124 9 41 40 140 10/12/12 10D BM/11/St.10 101212 8 0 0 0 0 1 0 0 21 102 383 0 0



Live specimens

Mil

iam

min

afu

sca

Haynes

ina

sp.

Reo

phax

monil

iform

is

Am

mobacu

lite

ssp

p.

Tro

cham

min

ain

flata

Haplo

phra

gm

oid

esm

anil

aen

sis

Haplo

phra

gm

oid

esw

ilber

ti

Haplo

phagm

oid

essp

p.

Jadam

min

am

acr

esce

ns

Balt

icam

min

apse

udom

acr

esce

ns

Tro

cham

min

ita

irre

gula

ris

juven

ile

tro

cham

min

ids

ind

eter

min

ate

sum

dea

dsp

ecim

ens

sum

live

spec

imen

s

Sa

mp

lev

olu

me

(cm

3)

Sp

lit

69 0 0 0 0 0 0 0 0 0 0 0 1 248 70 15.3 1/8135 29 0 3 0 0 0 0 0 0 0 0 0 323 167 14.8 1/8151 0 0 0 0 0 0 0 0 0 0 0 0 293 151 23.3 1/869 0 0 0 5 1 1 0 0 0 0 0 0 437 76 18.5 3/81 0 0 0 0 0 0 0 0 102 9 0 1 378 113 41.5 1

15 0 0 0 34 27 1 0 2 48 0 0 0 533 127 41.4 1/83 0 0 0 1 8 4 0 67 2 0 3 3 373 91 46.8 1

66 0 0 0 54 15 10 5 69 7 1 3 28 653 258 40.3 1/818 0 0 0 13 2 0 0 25 37 20 6 6 769 127 42.7 1/80 0 0 0 2 0 0 0 0 5 8 0 0 272 15 34.4 1/4

130 0 0 0 0 0 0 0 0 0 0 0 0 345 130 25.6 1/8163 172 3 16 0 0 0 0 0 0 0 0 3 439 357 27.7 1/8312 15 0 0 0 0 0 0 0 0 0 0 0 286 327 22.8 1/849 0 0 0 0 0 0 0 0 0 0 0 1 215 50 29.6 1/296 0 0 0 2 2 1 0 10 38 15 28 1 202 193 35.0 1/432 0 0 0 152 21 1 0 92 27 4 34 5 517 368 29.7 1/811 0 0 0 37 3 0 0 126 19 12 49 8 174 265 26.0 1/833 0 0 0 46 6 18 0 28 4 0 8 5 390 148 26.5 1/81 0 0 0 2 1 1 0 10 108 65 10 2 355 200 32.7 1/40 0 0 0 0 0 0 0 0 35 13 0 0 208 48 20.7 1/4

153 3 0 0 0 0 0 0 0 0 0 0 0 296 156 20.0 1/8100 0 0 0 0 0 0 0 0 0 0 0 0 446 100 19.8 1/8132 0 0 0 0 0 0 0 0 0 0 0 0 435 132 16.8 2/810 0 0 1 0 0 0 0 0 0 0 0 0 278 11 19.3 2/85 0 0 0 0 6 0 0 6 87 41 0 0 599 145 28.5 1/4

24 0 0 0 17 3 0 0 11 4 1 0 0 587 60 16.8 1/84 0 0 0 22 0 0 0 11 1 1 0 0 555 39 15.5 3/8

30 0 0 0 17 33 0 0 13 7 0 1 0 650 101 30.6 1/825 0 0 0 9 12 0 0 25 5 2 1 2 894 81 35.6 2/80 0 0 0 0 0 0 0 0 0 0 0 0 4 0 23.0 1

76 0 0 1 0 0 0 0 0 0 0 0 0 607 77 22.0 1/4112 28 1 4 0 0 0 0 0 0 0 0 0 248 145 18.5 1/8170 4 0 0 0 0 0 0 0 0 0 0 0 643 174 16.8 1/416 0 0 0 0 0 0 0 0 0 0 0 0 534 16 18.0 1/455 0 0 0 0 0 0 0 18 33 2 6 1 364 115 37.3 1/45 0 0 0 17 12 1 0 3 1 0 0 1 727 40 25.3 1/8

16 0 0 0 46 7 3 0 22 2 2 4 2 681 104 20.8 1/422 0 0 0 63 26 0 0 2 0 1 4 0 789 118 20.0 1/816 0 0 0 9 1 0 0 7 1 1 0 0 641 35 24.5 1/81 0 0 0 0 0 0 0 0 2 16 0 0 515 19 18.3 1

APPENDIX 2. Extended.


REFERENCES

Hawkes, A. D., Horton, B. P., Nelson, A. R., and Hill, D. F., 2010,The application of intertidal foraminifera to reconstruct coastalsubsidence during the giant Cascadia earthquake of AD 1700 inOregon, USA: Quaternary International, no. 1–2, p. 116–140.

Horton, B. P., and Edwards, R. J., 2006, Quantifying Holocene sea-level change using intertidal foraminifera: Lessons from the BritishIsles: Cushman Foundation for Foraminiferal Research, Specialpublication no. 40, p. 1–97.

Loeblich, A. R., and Tappan, H., 1988, Foraminiferal genera and theirclassification: Van Nostrand Reinhold Company, New York,1694p.

Wright, A. J., Edwards, R. J., and van de Plassche, O., 2011,Reassessing transfer-function performance in sea-level reconstruc-tion based on benthic salt-marsh foraminifera from the Atlanticcoast of NE North America: Marine Micropaleontology, v. 81,p. 43–62.


APPENDIX 3. Grain size data, d13C values and C/N ratios.

station IDID used in

Milker et al. d13C (per mil) C/N TOC (%) TN (%) Clay (%) Silt (%) Sand (%)

BM/11/St.1 081611 2A 220.66 8.42 0.40 0.05 1.13 8.52 90.35BM/11/St.2 081611 3A 221.63 8.26 0.60 0.07 2.04 14.98 82.98BM/11/St.3 081611 1A 220.73 7.65 0.51 0.07 2.85 16.19 80.97BM/11/St.4 081611 4A 223.83 10.40 4.98 0.48 9.09 70.24 20.67BM/11/St.5 081611 9A 228.26 21.75 38.86 1.79 9.98 58.31 31.71BM/11/St.6 081611 5A 222.88 17.02 23.35 1.37 20.01 77.63 2.36BM/11/St.7 081611 8A 224.35 15.49 14.17 0.92 8.57 72.33 19.10BM/11/St.8 081611 6A 222.56 14.69 14.75 1.00 17.04 71.73 11.24BM/11/St.9 081611 7A 227.14 15.23 26.91 1.77 16.31 77.32 6.37BM/11/St.10 081611 10A 229.84 18.65 40.14 2.15 16.12 76.65 7.23BM/11/St.1 101411 2B 221.08 8.28 0.47 0.06 6.07 26.34 67.58BM/11/St.2 101411 3B 221.26 8.86 0.86 0.10 3.87 28.27 67.87BM/11/St.3 101411 1B 220.56 8.01 0.63 0.08 2.02 12.97 85.01BM/11/St.4 101411 4B 223.56 11.00 5.03 0.46 8.93 64.30 26.77BM/11/St.5 101411 9B 228.01 22.69 38.50 1.70 11.31 50.93 37.76BM/11/St.6 101411 5B 225.11 17.09 19.30 1.13 22.94 74.58 2.48BM/11/St.7 101411 8B 223.87 14.37 17.57 1.22 15.63 79.24 5.13BM/11/St.8 101411 6B 224.26 12.95 12.40 0.96 18.77 80.88 0.35BM/11/St.9 101411 7B 228.09 21.05 30.69 1.46 11.22 53.91 34.87BM/11/St.10 101411 10B 229.13 17.96 40.78 2.27 18.42 75.55 6.03BM/11/St 1 072312 2C 222.49 9.01 0.77 0.09 2.53 15.77 81.70BM/11/St 2 072312 3C 221.30 7.73 0.43 0.06 3.09 21.43 75.49BM/11/St 3 072312 1C 221.45 8.19 0.51 0.06 3.15 21.15 75.70BM/11/St 4 072312 4C 224.32 12.57 3.66 0.29 6.86 48.64 44.50BM/11/St 5 072312 9C 228.05 16.47 28.67 1.74 15.63 73.14 11.23BM/11/St 6 072312 5C 227.71 19.61 36.17 1.84 23.42 73.69 2.89BM/11/St 7 072312 8C 223.55 14.28 14.60 1.02 17.28 69.51 9.98BM/11/St 8 072312 6C 224.05 15.37 6.55 0.43 15.52 81.49 3.00BM/11/St 9 072312 7C 225.96 14.49 13.42 0.93 14.91 73.87 11.22BM/11/St 10 072312 10C 227.79 19.39 42.49 2.19 19.88 71.14 8.98

APPENDIX 4. Taxonomic list of mentioned species in the text.

Ammobaculites spp. Wright et al., 2011, p. 59, Fig. A2/4

Balticammina pseudomacrescens Bronnimann,Lutze & Whittaker, 1989

Horton & Edwards, 2006, p. 63, Pl. 1, fig. 1a–d; Hawkes et al., 2010, p. 18, Pl. 1, fig. 5a–c;Wright et al., 2011, p. 58, Fig. A1/1

Haplophragmoides manilaensis (Anderson, 1953) Hawkes et al., 2010, p. 18, Pl. 1, fig, 1Haplophragmoides wilberti (Anderson, 1953) Hawkes et al., 2010, p. 18, Pl. 1, fig. 2a–bHaynesina sp. Test is planispiral, involute and biumbilicate with depressed umbilici and gradually

increasing height of chambers. Sutures are radial curved and deeply incised. Wall iscalcareous and perforate. It differs from H. germanica, often reported from marshenvironments, by the more deeply incised sutures and more prominently developedtubercles.

Jadammina macrescens (Brady, 1870) Horton & Edwards, 2006, p. 65, Pl. 1, fig. 4a–d; Hawkes et al., 2010, p. 18, Pl. 1, fig, 7a–d;Wright et al., 2011, p. 58, Fig. A1/5

Miliammina fusca (Brady, 1870) Horton & Edwards, 2006, p. 67, Pl. 1, fig. 5a–b; Wright et al., 2011, p. 59, Fig. A2/2Reophax moniliformis Siddall, 1886 Horton & Edwards, 2006, p. 67, Pl. 1, fig. 6a–cTrochammina inflata (Montagu, 1808) Horton & Edwards, 2006, p. 68, Pl. 2, fig. 8a–d; Wright et al., 2011, p. 58, Fig. A1/9Trochamminita irregularis Cushman & Bronnimann,

1948Loeblich & Tappan, 1988, p. 67, Pl. 51, fig. 1–5; Hawkes et al. 2010, p. 18, Pl. 1, fig. 3a–b


annual and seasonal distribution of intertidal...

Documents