delineation of irzs and przs in the german license area (ccz): … · 2019. 1. 7. · prz is a...

ISA workshop on the design of IRZs and PRZs, 27.09.2017

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Delineation of IRZs and PRZs in the German

license area (CCZ): Criteria and characteristics

Annemiek Vink, Carsten Rühlemann, Thomas Kuhn – BGR Hannover, GermanyAnnika Janssen, Katja Uhlenkott – DZMB Wilhelmshaven, Germany

Mexico

Hawaii

► Exploration contract July 2006 – July 2021► 8 expeditions (2008 – 2016); next expedition spring 2018

Nodule license areas in the CCZ


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Large nodules (9%)

Prospective areas (18%)

PA1

PRZ

Small nodules (64%)

0 50 km

Hard rock, slope > 3° (27%)

IRZ

PA2

Prospective mining areas


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BGR ADCP mooringsIRZ: Bottom current data

2013 2014 2015 2016

April 2013 – May 2014

May 2014 – June 2015

June 2015 – May 2016


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BGR ADCP mooringsIRZ: Plume modelling

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10 mm

1 mm

0.1 mm

For PA1 (70 x 70 km):

3D hydrodynamic Ocean model +

Sediment-transport model

Sediment mobilisation: 1000 t/h


Box core samples

IRZ

PRZ

PA1

PA2


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Macrofauna IRZ vs. PRZ

► Significantly higher densities in the PRZ

► Small but siginificant differences in macrobenthic community composition

total densities in eastern German license area: 37 - 202 ind./ 0.25 m²

IRZPRZNorth


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nMDS based on Bray-Curtis Similarity

► No significant differences in community structure between IRZ and PRZ at higher taxonomic level

Macrofauna IRZ vs. PRZ

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a

a2013 2014 2015 2016 2013 2014 2015 2016

a

100

80

60

40

20

0

Impact Reference Zone (IRZ) Preservation Reference Zone (PRZ)


Isopoda

Maxillopoda

Polychaeta

Bivalvia

Ophiuroidea

Peracarida

PRZ IRZ

Small-scale connectivity

Janssen et al. (in prep.): nMDS based on BrayCurtis Similarity

Polychaeta*:

► 550 sequences – 147 MOTUs

► 67 MOTUs singletons (46%)

► 40 MOTUs shared (27%)

► 35 MOTUs in PRZ

► 5 MOTUs in IRZ

* Mitochondrial CytochromoxidaseSubunit 1 (COI) gene

Raschka (2014), Master thesis


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Small-scale connectivity

Janssen et al. (in prep.): nMDS based on BrayCurtis Similarity

Isopods:

► 349 sequences – 83 MOTUs

► 45 MOTUs singletons (54%)

► 11 MOTUs shared (13%)

► 15 MOTUs PRZ

► 12 MOTUs IRZ

Raschka (2014), Master thesis

• Max. one-third of the putative species live in both areas

• phylogenetic differences within one

area are almost as high as between areas


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► No geographic population structure:- hardly divergence- sufficient gene flow

Genetic structure between populations


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Janssen et al. (submitted)

Multicorer samples

PRZ IRZ

PA2


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Meiofauna IRZ vs. PRZ

► Significantly higher densities in the PRZ

► No siginificant differences in meiobenthiccommunity structure at higher taxonomic

level

IRZ PRZ


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Meiofauna total abundance

Mapping based on:

• Bathymetry• Backscatter

• Mn-nodule coverage

0.44 of variation explained


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…from point sampling tospatial mapping…

R-Package Random-Forest

(machine-learningalgorithm)

PRZ PA1

PA2

Meiofauna diversity (Simpson Index)

Mapping based on:• Bathymetry• Backscatter

• Mn-nodule coverage

0.32 of variation explained


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PA2

PRZ PA1

Nodule size variability

PA1 PA2 PRZ

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BGR ADCP mooringsGeochemical variability of nodules

PRZ

PA1

PA2


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Geochemical variability of nodules

PA1 PA2 PRZ

Cu > Ni

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TOC concentrations

PA1 PA2PRZ

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MnO2 content

PA1 PA2PRZ


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What have we learnt?

PRZ is a functional area for:

• ensuring representative and stable biota of the seabed

• as a protected area with a wide range of nodule facies and habitats

But:

high degree of spatial variability in geological, geochemical and ecological

conditions (topography, nodule composition, size, coverage, biodiversity)

between and within reference areas at small scales

So at the size scales of IRZs and PRZs (> 50 km apart), the definition of a PRZ as

being “…as ecologically similar as possible to the impact zone, and …removed from

potential mining impacts…” (CCZ EMP) may be a difficult goal to reach!

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delineation of irzs and przs in the german license area (ccz): … · 2019. 1. 7. · prz is a...

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