9.3 Coastal Environment

1. 9.3 Coastal Environment • Structure of Coastlines • Coastlines are constantly shaped by wind, rain, waves, tides, currents and sea spray • Dunes and Beaches • Sand dunes and beaches found anywhere there is a source of eroding mineral or place sediment can deposit • Rocky Cliffs • Rocky coastlines consisting of various cliff formations, platforms and intertidal rocks

2. Vegetation thriving on hard rock cliffs consists of species adapted to high salinity and rocky substrate • Habitat for many species of seabirds • Barrier Islands • Long narrow islands that run parallel along the coast • Formed by wind, waves and currents. Made mostly of sand • Constantly changing due to erosion and storms

4. Coral Reefs • Animals that have calcareous skeletons and algae that attach to the skeletons • The Great Barrier Reef – eastern coast of Australia • Found in tropical and subtropical waters • Estuarine Ecosystem • Estuaries are semi-enclosed inlets that form transitional zones between rivers and sea • Characteristics • Water level changes with the tide • Mixture of salt and freshwater • Dissolved oxygen is high • Turbidity is high

5. Nutrients are high, but photosynthesis is low due to turbidity • 2 food chains • Grazer – dissolved nutrients may be absorbed directly by phytoplankton and rooted plants; then passed to consumers • Decomposer – detritus is consumed by detritus feeders • Because of abundant nutrient supply and high oxygen levels, more organisms are produced than other ecosystems (except coral reefs) • Values • Important for commercial and recreational fishing industries • Food, shelter, and breeding sites for waterfowl and furbearers • Flood and erosion control • Natural pollution filtering system

7. 9.5 Oceans • General Features • Covers 70% of Earths surface • 3 main basins – Pacific, Atlantic, and Indian Oceans • Deepest part – Mariana Trench southeast of Japan • Atlantic is warmest • Ocean water is 96.5% water and 3.5% salt • Salts come from volcanic eruptions, chemical weathering of rocks • Na, Cl, Mg, SO4 • Ocean is contnuously circulating • Upwelling- the vertical movement of currents • Brings up nutrient rich cold water from bottom to surface

9. Ocean Zones • Neritic Zone – like littoral zone of a lake • Relatively warm, nutrient rich, shallow regions over continental shelf • Sunlight normally penetrates and oxygen depletion is not a problem • Biomass is greater per unit of volume than in any other part of the ocean • Euphotic Zone- open water, like limnetic zone of lake • Sufficient sunlight for photosynthesis • Normally only extends to 200 m deep

10. Bathyal Zone – semidark, no photosynthesis • Abyssal Zone – similar to profundal zone of lake • Just above the ocean floor • Animal life scarce – mostly scavengers or decomposers • Water is very cold, near freezing, low levels of oxygen, high water pressure, scarce food • Some have developed bioluminescence

12. Marine Food Chains • Solar energy is mainly trapped by phytoplankton

13. Ocean Resources • Water supply • CO2 absorption • Food supply • Transportation • Minerals and oil • Emerging source of energy from tides • Pg 224 #17, 18, 23, 24