Coastal OceanCoastal Ocean
• Intertidal Zone• Estuaries• Muddy bottom and sandy
bottom communities• Salt marshes and seagrass
beds• Mangroves• Coral reefs
Zonation is a vertical banding of the organisms living on the rocky coastline.
These distinct bands occur in part from many complex physical and biological factors that effect marine organisms.
Tidal Zones on a Rocky Ocean Shore
Splash Fringe Level
High Tide Level
Mid Tide Level
Low Tide Level
Low Fringe Level
Spray or Splash Zone
High Tide Zone
Middle Tide Zone
Low Tide Zone
Mostly shelled orgs
Many soft bodied orgs and algae
Biotic factors affecting organisms living in the intertidal zone:
• Competition for space and food• Predation• Reproduction• Substrate settlement preference• Osmoregulation
Abiotic factors affecting organisms living in the intertidal zone:• Salinity• Temperature • Air and light exposure• Tidal flow• Waves and current action• Substrate• Wind direction and strength• Dissolved O2• Storms• Natural Disasters
Estuaries are among the most productive marine ecosystems with high biomass of benthic algae, seagrass and phytoplankton
Wetlands in Hawaii• At one time contained an estimated 59,000 acres
of wetlands• Over the last 200 years Hawaii has lost
approximately 12 % of its original wetland acres. • The exact effect of the loss or degradation of
Hawaii's wetlands on local fisheries is unclear. • It is estimated that only 1% of the Pacific island
recreational and commercial species are estuarine-dependent.
• Economically important estuarine fish: mullet, milkfish, shrimp, and the nehu, a tropical anchovy used as live bait in the pole-and-line skipjack tuna fishery.
Estuaries• Estuaries are partially enclosed coastal bodies
of water• Examples of estuaries include:
– River mouths– Bays– Inlets– Gulfs– Sounds
• Formed by a rise in sea level after the last Ice Age
Classifying estuaries by water mixing
Salt wedgeHighly stratified
Slightly stratifiedVertically mixed
Coastal wetlands
• Coastal wetlands are saturated areas that border coastal environments
• Brackish water conditions• Two most important types of
coastal wetlands:1. Salt marshes (mid-latitudes)2. Mangrove swamps (low latitudes)
Infauna: • live within the sediment, mostly soft bottom; • mostly clams and worms (polychaetes) • burrow tubes for food scavenging and oxygen
supply• Primary producers: algae, mostly benthic
diatoms and dinoflagellates • cyanobacteria mats on mudflats • mud more productive than sand• macro- and meiobenthos, often detrivores,
living of deposits from seagrasses and marshes
• birds important grazers
Ecological Role:• clean sediments • aerate soil
32,000 polychaetes in sand/m2vs
50-500 earth worms in soil/m2
• Found from the Arctic to Southern Australia
• Salt marshes grow in muds and sands that are sheltered by barrier islands.
• Flood and ebb currents transport saltwater, nutrients, plankton and sediments in and out of the marsh.
Pacific Golden Plover
Hawaiian StiltHawaiian Coot
Hawaiian Duck
Black crowned night heron
Northern Pintail Duck
Sanderling
Wanderling tattler
Rudy Turnstone
The value of coastal wetlands• Highly productive food factory• Serves as fish nurseries • Acts as a giant sponge:
– The salt marsh absorbs large volumes of water, thus minimizing the impacts of flooding and erosion and recharging groundwater.
• Filters polluted runoff from land– absorbing toxins and in some cases metabolizing them into
harmless substances
Problem: – wetlands viewed as worthless land
Of the original 215 million acres of wetlands in the U.S. (excluding Alaska and Hawaii) , about 106
million acres remain.
distribution of wetlands in the U.S. in the 1780s
distribution of wetlands in the U.S. in the 1900s
• Drainage • Dredging and stream channelization • Deposition of fill material • Diking and damming • Tilling for crop production • Levees • Logging • Mining • Construction • Runoff • Air and water pollutants • Changing nutrient levels • Releasing toxic chemicals • Introducing non-native species to the ecosystem • Grazing by domestic animals
Major Causes of Wetlands Loss and DegradationHuman Actions
Prop roots:• help support the tree
Pneumatophores:• respiratory function– take
in O2
• push nutrients to the upper soil layer
Ecological Role of Mangroves:• Stabilize sediment
• Accumulate detrital or other foreign material
• Habitat for epiphytes
• Fish and invertebrate nursery
• Nesting/roosting sites for birds
• Limited role as a direct food source
• Major contributor to detrital food chain• Protect shoreline from erosion during tropical
storms
• fish and shrimp cultivation• food for people• firewood and boat building material• tanning material• finest honey
Mangrove Use:
Shrimp farm surrounded by degraded mangroves, Vietnam
Distribution: 12 genera of seagrasses (5 in the high latitude and 7 in the low latitude)
• True marine angiosperm• Evolved from shoreline Lillie-like plants~100
mya• Vascular plants reinvaded the seas 3 different
times (algae is nonvascular; i.e., no need for roots to transport water and nutrients)
• Can grow and reproduce while completely submerged under water
Develop in:• intertidal and shallow
subtidal areas on sands and muds
• marine inlets and bays
• lagoons and channels, which are sheltered from significant wave action
1. Help stabilize the sediment
2. Prevents resuspension of sediments in water (water is clearer)
3. Binds substratum, reduces turbidity, and reduces erosion
4. Sediment accumulation slows velocity of incoming water
5. Food for many organisms
6. Refuge for many organisms
Seagrass productivity is highly dependent on a number of factors:• salinity• water temperature• turbidity
This ecosystem is particularly sensitive to degradation due to:• agricultural pollution-run-off of
herbicides• industrial pollution• domestic pollution
Threats to Seagrass BedsThreats to Seagrass Beds
Hermatypic corals:• possess zooxanthellae• are reef builders
Light: Clear water Warm temperature: 18-32oCLow nutrientsLow productivity in water
Ahermatypic corals:• no zooxanthellae• rely on tentacular feeding• can live in aphotic zone
Cauliflower coral(Pocillopora meandrina)
6 m
0 m
25 m
13 m
Lobe coral(Porites lobata)
Finger coral(Porites compressa)
Plate coral(Porites rus)
High light levelsModerate wave energy
Moderate light levelsOccasional storm wave energy
Low light levelsLow wave energy
Very low light, Primarily downwelling No wave energy