Aquatic Habitats

Aquatic Habitats - Coral Reefs form in clear warm coastal...

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Coral Reefs form in clear, warm, coastal waters of tropics and subtropics with constant high salinity formed by colonies of polyps: o build reefs by secreting protective crust of limestone (calcium carbonate) o die and leave behind empty crusts platform for reef growth result from mutual relationship between polyps and zooxanthellae (algae) o algae provide polyps with color, food, and oxygen through photosynthesis o algae produce calcium carbonate which forms coral skeleton o polyps provide algae with well-protected home and nutrients account for 0.1% of ocean 25% of ocean’s species’ homes moderate atmospheric temperatures remove CO 2 from atmosphere act as barriers protect 15% of world’s coastline produce one-tenth global fish-catch one-fourth in developing countries provide jobs and building materials 20% of coral reefs have been lost due to stresses Coral bleaching – coral becomes stressed and the algae it lives off of dies, leaving underlying white skeleton of calcium carbonate. o Two causes are: increased water temp. and runoff of silt that covers coral and prevents photosynthesis Grow slowly and are disrupted easily vulnerable Need 18-30 o C temperatures, change of 1 o C can cause bleaching Biodiversity reduced by: o Severe storms o Freshwater floods o Invasions of predatory fish 20% of coral reefs are destroyed and won’t recover 2050 – another 30-50% of world’s coral reefs will be lost to: o Climate change o Habitat loss o Pollution (eroded sediment) o Over-fishing Only 300/6000 of coral reefs are protected on paper Worth $100,000-$600,000/square km/year Water Covers 71% of Earth’s surface Organisms determined by salinity Aquatic life zones classified into two types: saltwater/marine and freshwater Types of Organisms Plankton – weakly swimming, free-floating o Phytoplankton (plant plankton) - producers
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o Zooplankton (animal plankton) – primary consumers (herbivores that eat phytoplankton) and secondary consumers (feed on other zooplankton) o Consist of single-celled protozoa, jellyfish o Ultraplankton – small, photosynthetic bacteria responsible for 70% of primary productivity near ocean surface Nekton – strong swimming animals o Fish, turtles, whales Benthos – bottom dwellers o Barnacles, oysters, worms that burrow, lobsters, crabs Decomposers – bacteria o Breakdown stuff Layers Surface, middle, and bottom Types and number of organisms determined by: o Temperature o Access to sunlight for photosynthesis o Dissolved oxygen content o Availability of nutrients (Carbon, Nitrogen, Phosphorus) for producers Depth of Euphotic zone reduced by algal blooms (excessive algae growth) Dissolved oxygen o More near surface because photosynthesis occurs here o Less at depths because of aerobic respiration by aquatic animals and decomposers Shallow waters have lots of nutrients
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This note was uploaded on 06/26/2008 for the course ENV 1101 taught by Professor Don'tremember during the Spring '08 term at FSU.

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Aquatic Habitats - Coral Reefs form in clear warm coastal...

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