Wetlands 012. Coastal wetlands are coastal watersheds that drain to the ocean or to an estuary or bay.

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