Coastal Ocean Coastal wetlands are coastal watersheds that drain to the ocean or to an estuary or bay.
Coastal Ocean • Intertidal Zone • Estuaries • Muddy bottom and sandy bottom communities • Salt marshes and seagrass beds • Mangroves • Coral reefs
Intertidal Zonation 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.
Which tidal cycle has the greatest effect on marine organisms living in the intertidal zone?
Tidal Zones on a Rocky Ocean Shore Splash Fringe Level High Tide Level Mid Tide Level Low Tide Level Low Fringe Level
Mostly shelled orgs Spray or Splash Zone High Tide Zone Middle Tide Zone Many soft bodied orgs and algae Low Tide Zone
periwinkles ulva opihi Mussels & starfish
What are some stresses that affect the organisms residing in the intertidal zone?
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
What are some adaptations to living in the intertidal zone?
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.
Ahupua’a Ranges from the tip of the mtn to the reef area • Upland • Plains • Ocean
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 origin • Coastal plain • Fjord • Bar-built • Tectonic
Examples of estuaries Pu‘uloa
Examples of estuaries Fjord estuary (Norway) Tectonic estuary (San Francisco, CA)
Classifying estuaries by water mixing Vertically mixed Slightly stratified Highly stratified Salt wedge
Coastal wetlands • Coastal wetlands are saturated areas that border coastal environments • Brackish water conditions • Two most important types of coastal wetlands: • Salt marshes (mid-latitudes) • Mangrove swamps (low latitudes)
Muddy bottom and sandy bottom communities • 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
Muddy bottom and sandy bottom communities 32,000 polychaetes in sand/m2 vs 50-500 earth worms in soil/m2 • Ecological Role: • clean sediments • aerate soil
Salt marshes • 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.
Wetland Birds Black crowned night heron Sanderling Rudy Turnstone Hawaiian Coot Hawaiian Stilt Pacific Golden Plover Northern Pintail Duck Hawaiian Duck Wanderling tattler
Wetland Fish Mullet Tilapia Milkfish
Wetland Inverts Anchialine ponds Opae ula
Wetland Plants aki'aki akulikuli mangrove bullrush
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
Major Causes of Wetlands Loss and Degradation Human Actions • 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
Natural Threats • Erosion • Subsidence • Sea level rise • Droughts • Hurricanes and other storms