- Slides: 30
The Coastal Ocean
Coastal waters support about 95% of total biomass in ocean Most commercial fish caught within 320 km (200 m) from shore Important also for shipping, oil and gas production, and recreation Many pollutants found here – that’s a problem! http: //www. safmc. net/Portals/0/shrimp%20 trawler 2. jpg
Characteristics of coastal waters Adjacent to land (to edge of continental shelf) Influenced by river runoff, wind, tides Salinity variable Freshwater runoff Winds Mixing by tides
Characteristics of coastal waters Temperature variable Low-latitudes: restricted circulation, very warm High-latitudes: sea ice Mid-latitudes ○ Seasonal changes ○ Prevailing winds
Types of coastal waters Estuary Partially enclosed coastal area with ocean water and freshwater (runoff) mixing; mouths of rivers, bays, etc. Lagoon Shallow coastal water separated from ocean by barrier island Marginal sea Relatively large semi-isolated body of water
Estuaries - Origin of estuaries Rising sea level “drowns” what was once land Coastal plain estuary Former river valley now flooded with seawater Fjord Former glaciated valley now flooded with seawater Bar-built estuary Lagoon separated from ocean by sand bar or barrier island Tectonic estuary Faulted or folded down-dropped area now flooded with ocean
Estuaries - Classification of estuaries 4 types - Based on mixing of freshwater and saltwater Vertically mixed Slightly stratified Highly stratified Salt wedge Shallow, low volume Salinity uniform Deeper than previous Upper layer less salty; lower layer more salty Estuarine circulation Deep, relatively strong halocline Deep, high volume Strong halocline Typical at mouths of deep, high volume rivers
Lagoons Water isolated by barrier islands 3 main zones: ○ Freshwater zone ○ Transition zone of brackish water ○ Saltwater zone Hypersaline in arid regions
Indian River Lagoon Well-mixed due to winds and shallow depths Seasonal changes in salinity, temperature, dissolved oxygen Most biologically diverse estuary in north america…over 4, 000 species of plants and animals Threats: habitat destruction, stormwater runoff, and invasive exotic species
Marginal seas Mostly from tectonic events Ocean crust between continents, e. g. , Mediterranean Sea Behind volcanic island arcs, e. g. , Caribbean Sea Shallower than ocean Connected to ocean http: //www. shinesforall. com/images/Caribbeanmap. gif
Caribbean Sea On Caribbean plate defined by Greater and Lesser Antilles – volcanic island arc Relatively shallow marginal sea – deepest is Cancun Trough at 7, 686 m (25, 220 ft) Underlain by oceanic crust http: //woodshole. er. usgs. gov/project-pages/caribbean/images/PBATHY 1. GIF
Coastal Wetlands - Types of coastal wetlands o o o Ecosystems that are saturated with water o Swamps, tidal flats, coastal marshes, bayous Salt marsh o Any latitude Mangroves o Low latitude
Characteristics of coastal wetlands Efficiently cleanse polluted water Absorb water from coastal flooding during storms Protect shores from wave erosion http: //soundwaves. usgs. gov/2008/03/Wetland. LG. jpg
Coastal Wetlands - Loss of coastal wetlands Half of U. S. coastal wetlands lost to development (housing, industry, agriculture) U. S. Office of Wetland Protection, 1986 Minimize loss of wetlands Protect or restore wetlands http: //www. on. ec. gc. ca/wildlife/factsheets/images/glfs-coast-stress. jpg
Marine pollution Any harmful substance or energy put into the oceans by humans Harmful to living organisms ○ Standard laboratory bioassay – concentration of pollutant that causes 50% mortality among test organisms Hindrance to marine activities (e. g. , fishing) Reduction in quality of sea water
Waste disposal in ocean Diluting pollutants with huge volume of ocean water Long-term effects not known Debate about dumping wastes in ocean None at all ? ? Some, as long as properly disposed and monitored ? ?
Main types of marine pollution Petroleum Nutrient excess ○ Sewage sludge ○ Fertilizer runoff DDTs and PCBs Mercury Non-point-source pollution and trash ○ Drainage from roads, canals, etc.
DDT and PCBs Pesticide DDT and industrial chemicals PCBs (polychlorinated biphenyls) ○ DDT – pesticide that was widely used ○ PCBs – used in transformers and other areas of industry Widespread in oceans Persistent organic pollutants Toxic Long life dissolved in seawater Accumulated in food chain Bioaccumulation – it’s happening in us, also!
Bioaccumulation and biomagnification Bioaccumulation – organisms concentrate pollutant from seawater Biomagnification – organisms gain more pollutant by eating other organisms
DDT n Decline in bird populations and thin eggshells n n Long Island osprey California brown pelican DDT banned in U. S. in 1972 Some marine bird populations rebounded
Mercury and Minamata disease Methyl mercury toxic to most living organisms Chemical plants, Minamata Bay, Japan, released mercury in 1938 By 1950 first reported ecological changes By 1953 humans poisoned Neurological disorder – numbness, muscle weakness, paralysis, coma, congenital defects
Non-point-source pollution and trash Not from underwater pipelines Hard to regulate For example, from storm drains Pesticides and fertilizers Road oil Trash
Trash from dumping Some trash can be legally dumped far from shore Biodegradable (e. g. , food) or Sinkable (e. g. , glass, metal) Some trash cannot be dumped Plastic ○ Lightweight (floats) ○ Not easily biodegradable ○ Plastic can incorporate pollutants, such as DDT and PCBs http: //www. sciencepunk. com/v 5/gallery/greenpeace_table. JPG
It is up to us! Don’t throw trash out your car window Don’t leave trash on the beach Don’t throw trash off the side of your boat Don’t use fertilizers irresponsibly Don’t just dump things down the drain without reading about proper disposal Get onto people you know that do this! ○ Think of your kids and grandkids!
Problems with Contaminants in Oceans Research into immunosuppression and reproductive problems in many species Chemicals that are banned in US and other countries are still used in others – it is 1 ocean, doesn’t matter where it is dumped ○ It will effect us all! All drains lead to the ocean!
Fig. 11. 32 a, b
Misconceptions –What have we learned that make the following statements false? Science and technology can solve all of our problems. The Earth can absorb and neutralize any amount of waste and pollution over time. Dilution is the solution to the problem. Microorganisms are not important to human survival. Local people cannot improve their environments; it is out of their hands. If we run out of oil and gas we will just find more. Earth is both an endless supply of resources and a limitless sink for the waste products of our society.
Ocean Literacy Principles 1. d - Sea level is the average height of the ocean relative to the land, taking into account the differences caused by tides. Sea level changes as plate tectonics cause the volume of ocean basins and the height of the land to change. It changes as ice caps on land melt or grow. It also changes as sea water expands and contracts when ocean water warms and cools. 1. h - Although the ocean is large, it is finite and resources are limited. 5. f - Ocean habitats are defined by environmental factors. Due to interactions of abiotic factors such as salinity, temperature, oxygen, p. H, light, nutrients, pressure, substrate and circulation, ocean life is not evenly distributed temporally or spatially, i. e. , it is “patchy”. Some regions of the ocean support more diverse and abundant life than anywhere on Earth, while much of the ocean is considered a desert. 5. i - Estuaries provide important and productive nursery areas for many marine and aquatic species.
Sunshine State Standards SC. 6. E. 6. 1 - Describe and give examples of ways in which Earth's surface is built up and torn down by physical and chemical weathering, erosion, and deposition. SC. 6. E. 6. 2 - Recognize that there a variety of different landforms on Earth's surface such as coastlines, dunes, rivers, mountains, glaciers, deltas, and lakes and relate these landforms as they apply to Florida. SC. 912. E. 6. 6 - Analyze past, present, and potential future consequences to the environment resulting from various energy production technologies. SC. 912. L. 17. 2 - Explain the general distribution of life in aquatic systems as a function of chemistry, geography, light, depth, salinity, and temperature. SC. 912. L. 17. 3 - Discuss how various oceanic and freshwater processes, such as currents, tides, and waves, affect the abundance of aquatic organisms. SC. 912. L. 17. 8 - Recognize the consequences of the losses of biodiversity due to catastrophic events, climate changes, human activity, and the introduction of invasive, nonnative species. SC. 912. L. 17. 11 - Evaluate the costs and benefits of renewable and nonrenewable resources, such as water, energy, fossil fuels, wildlife, and forests. SC. 912. L. 17. 13 - Discuss the need for adequate monitoring of environmental parameters when making policy decisions. SC. 912. L. 17. 16 - Discuss the large-scale environmental impacts resulting from human activity, including waste spills, oil spills, runoff, greenhouse gases, ozone depletion, and surface and groundwater pollution. SC. 912. L. 17. 20 - Predict the impact of individuals on environmental systems and examine how human lifestyles affect sustainability.