CHAPTER 11 The Coastal Ocean

CHAPTER 11The Coastal Ocean

Overview • 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%20trawler2.jpg

Ocean ownership • 1609 sea is free to all (mare liberum = free) • Assumed fish resources are inexhaustible • 1702 territorial sea under coastal nation’s sovereignty (3 nautical miles from shore) • Distance of cannon shot

United Nations and ocean laws • 1958-1982 United Nations Law of the Sea Conferences • National sovereignty extends 12 nautical miles • Exclusive Economic Zone (EEZ)200 nautical miles (370 km) from land (mineral and fishing resources) • Right of free passage for ships • Open ocean mining regulated by International Seabed Authority • This has changed, still very contentious • United Nations arbitrates disputes

EEZ of the U.S.--about 30% more than land area of entire U.S. Fig. 11.1

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 • Shallow, low volume • Salinity uniform • Slightly stratified • Deeper than previous • Upper layer less salty; lower layer more salty • Estuarine circulation • Highly stratified • Deep, relatively strong halocline • Salt wedge • Deep, high volume • Strong halocline • Typical at mouths of deep, high volume rivers

Figure 11.8 Severely effected by human activity, freshwater wedge can be traceable far out to sea

Chesapeake Bay Estuary • Anoxic conditionsbelow pycnocline in summer • Runoff of sewage and fertilizer cause algae bloom • when these organisms die, increased decomposition causes anoxic conditions • Decrease in oxygen levels in water • Major kills of commercially important marine animals

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

Sebastian Inlet http://www.indianriverlagoon.org/docs/irlmap.html

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/PBATHY1.GIF

Mediterranean Sea • Remnant of Tethys Sea – when all the continents were together • Deeper than usual marginal sea • Underlain by oceanic crust • Thick salt deposits – almost dried up about 6 million years ago Fig. 11.14a

Mediterranean circulation Fig. 11.14b • High rates of evaporation • Mediterranean Intermediate Water very salty

Coastal Wetlands - Types of coastal wetlands • Ecosystems that are saturated with water • Swamps, tidal flats, coastal marshes, bayous • Salt marsh • Any latitude • Mangroves • 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/WetlandLG.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.

Petroleum • Biodegradable hydrocarbons • Recovery faster than expected • Exxon Valdez oil spill, 1989 • But many organisms killed outright • Long-term consequences uncertain • Research is still being done in this area, some animal populations have not completely recovered Fig. 11.16

BP Deepwater Horizon Oil Spill in Gulf of Mexico • April 20, 2010 • 4.9 MILLION barrels of oil were leaked • What are future effects?

Cleaning oil spills • Natural processes • Volatilization • Photo oxidation • Emulsification • Biodegration by pelagic organisms • Biodegration by benthic organisms • Artificial processes • Oil dispersants • Isolate spill with booms • Skimming or absorbing surface oil slick • Bioremediation by “hydrocarbon-eating” bacteria

Preventing oil spills • Double hulled oil tankers by 2015 • 1990 Oil Pollution Act • Burn oil before it spreads • 1999 M/V New Carissa http://www.ec.gc.ca/EnviroZine/images/aerial.jpg http://www.modelshipmaster.com/products/ocean_liners/tube.jpg

Sewage sludge • Semisolid material after treatment • No dumping of sludge in ocean after 1981 • Clean Water Act, 1972 • HOWEVER - many exceptions/waivers

New York’s sewage sludge disposal Fig. 11.25 • First, shallow water sites • Then (1986), deeper water site • Adverse effects on fish • 1993 all sewage disposed on land

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 • Decline in bird populations and thin eggshells • 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

Bioaccumulation and biomagnification • Safe levels of mercury determined by • Rate of fish consumption by people • Mercury concentration in fish consumed • Minimum ingestion rate of mercury to cause damages

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/v5/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. 11.32a,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, pH, 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 are 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.

CHAPTER 11 The Coastal Ocean