Wetlands 012
Dec 18, 2015
Wetlands
012
Coastal wetlands are coastal watersheds that drain to the ocean or to an estuary or bay.
• Intertidal zones• Estuaries• Salt marshes• Seagrass beds• Muddy & sandy bottom
communities• Mangroves• Coral Reefs
Open ocean <50 g C/m2/year Coral reefs 1000 g C/m2/yearMangroves 500 g C/m2/year Continental Shelf: Nonupwelling 200 g C/m2/year Coastal upwelling 300 g C/m2/yearSeagrass beds 1000 g C/m2/yearEstuaries and salt marshes 800 g C/m2/yearUpwelling 300 g C/m2/year
• The transition between terrestrial and marine environments
• Zonation is a vertical banding of the organisms living on the rocky coastline.
• The area between the highest high tide and lowest low tide.
• 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
opihi
Mussels & starfish
periwinkles
ulva
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.
Oahu Watershed
Traditional Hawaiian Uses of WetlandsTraditional Hawaiian Uses of Wetlands
Seaweedslimu
Seaweedslimu
Hooks andLures
Hooks andLures
Octopus Lure
Fishing Shrinesko‘a
Fishing Shrinesko‘a
Hawaiian Fish Pondsloko i‘a
Hawaiian Fish Pondsloko i‘a
Ahupua’a
1. Upland2. Plains3. Ocean
Ranges from the tip of the mtn to the reef area
TheAhupua‘a
TheAhupua‘a
Salt Marsh
Salt Marsh
• 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.
• Vegetation zones due to tides and salinity• Wet grasses lands that grow along
estuarine shores• 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.
600 species worldwide
Wetlands at the upstream side of Ka’elepulu Fish Pond, looking towards Kailua Bay
Pacific Golden Plover
Hawaiian StiltHawaiian Coot
Hawaiian Duck
Black crowned night heron
Northern Pintail Duck
Sanderling
Wanderling tattler
Rudy Turnstone
Tilapia Milkfish
Mullet‘O‘opu akupa
Opae ula
Anchialine ponds
mangrove
aki'aki akulikuli
bullrush
Waikiki & Diamond HeadWaikiki & Diamond Head
1934
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
Current distribution of wetlands and deepwater habitats
• 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
Natural Threats
• Erosion
• Subsidence
• Sea level rise
• Droughts
• Hurricanes and other storms
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
Examples of estuaries
Pu‘uloa
Classifying estuaries by water mixing
• Vertically mixed
• Slightly stratified
• Highly stratified
• Salt wedge
57 species worldwide
Classification
Five kingdom system:
Monera Protista FungiPlantae Animalia
Angiosperms Gymnosperms
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
Halophila hawaiiana- only form of seagrass in Hawaii
Turtle grass
Eel grass
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
Mangrove Distribution
• There are approximately 40 species of mangroves distributed worldwide
A diverse group of trees that are salt tolerant (halophyte) and are viviparous .
• shallow and protected tropical and subtropical regions (25oN and 25oS latitude)• restricted to intertidal and adjacent marine habitats • temperature range: 10oC to 20oC
Mangrovesreplace salt marshes in tropical regions
develop where wave action is absent, sediments accumulate, mud is anoxic
have prop roots and pneumatophores
mangrove removal in Kailua
A few mangrove species can survive in freshwater, but are not good competitors with other species.
Mangroves have a high salt tolerance. They can survive well in 90%o soil salinity. The ocean averages 35 %o.
They need to prevent water loss by either:1. excrete salt at leaves 2. exclude salt at roots 3. salt excretion and abscission (remove of salt laden
organs)
Salt Tolerance:
What would happen if you watered your garden with salt water?
Stresses: 1. Channelization, drainage, and siltation
2. Hurricane
3. Shrimp & fish farms
4. Herbicides and defoliants
5. Pesticides and pollution
6. Thermal loading (heat)
Prop roots:• help support the tree
Pneumatophores:• respiratory function– take in O2
• push nutrients to the upper soil layer
Propagule: • fruiting body (a seedling) • most mangroves are viviparous• propagules drop from branches and are carried
away by waves.
Physiology:
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
Coral Reef Communities
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
Inquiry
1. What features make mangroves so successful?
2. Identify biotic and abiotic factors affecting animals in the intertidal zone.
3. Discuss zonation of mangroves, corals, and intertidal communities