Aquatic Ecology Chapter 6

Coral Reefs What do coral reefs require? Answer – dissolved oxygen, light and nutrients What threatens coral reefs? (3) Chemical pollution, global warming, extra UV from ozone hole, excess sediment from rivers (soil erosion), human contact

Coral Reefs What percent of reefs is estimated to be destroyed by human intervention? 10 percent What about estuaries and wetlands? About 50%(US) through filling, sewage, runoff pollution, and diversion

Categories of organisms Floating algae – phytoplankton Swimming microscopic and macroscopic organisms – zooplankton Fish – nekton Tube worms, crabs - benthos

Reasons oxygen varies in water Number of consumers (respiration) Number of producers (photosynthesis) Temperature (cold holds more) Turgidity (rough water dissolves more) Number of decomposers (bacteria can take up a lot of oxygen)

Salt water areas What zone is on the continental shelf? - the coastal zone What area exhibits variable temperature and salinity - Estuaries Where would you find a mangrove? - tropical coastal estuaries

Fig. 7.7, p. 157

Salt water areas What is the dim or twilight area of the open sea called? - bathyal zone What is the area with the highest photosynthetic rate in the sea called? - euphotic zone

Fresh water areas Where does photosynthesis take place in lakes? - the limnetic zone, of course! Where do fish who like cool, dark water reside? - the profundal zone Where do the worms live? -the benthic zone

Sunlight Painted turtle Green frog Blue-winged teal Muskrat Pond snail Littoral zone Limnetic zone Diving beetle Plankton Profundal zone Benthic zone Bloodworms Yellow perch Northern pike Fig. 7.14, p. 165

Nutrient levels in lakes A newly formed, nutrient poor lake is? - Oligotrophic A mature and nutrient rich lake is? - eutrophic A middle aged and moderately nutrient rich (normal) lake is? - mesotrophic

Limnetic zone Dense fish population Sunlight Much shore vegetation Much shore vegetation Wide littoral zone High concentration of nutrition and plankton Limnetic zone Dense fish population Gently sloping shorelines Salt, sand, clay bottom Eutrophic Lake Fig. 7.15b, p. 166

nutrition and plankton Sunlight Little shore vegetation Narrow littoral zone Low concentration of nutrition and plankton Limnetic zone Profundal zone Steeply sloping shorelines Sparce fish population Sand, gravel, rock bottom Oligotrophic Lake Fig. 7.15a, p. 166

Overturn When does overturn happen is a lake? When the weather changes from warm to cold, or cold to warm, so in spring and fall Which season produces the most profound thermoclines? summer

Dissolved O2 concentration 22˚ 4˚ 20˚ Epilimnion 4˚ 18˚ 4˚ 8˚ 4˚ 6˚ 4˚ Hypolimnion 5˚ 4˚C 4˚C Thermocline Summer Fall overturn 0˚ 4˚ 2˚ 4˚ 4˚ 4˚ 4˚ 4˚ 4˚ 4˚ 4˚C 4˚C Winter Spring overturn Dissolved O2 concentration High Medium Low Fig. 7.16, p. 167

It’s okay to destroy when? If you ruin a wetland for agriculture (the number one reason), what says you have to build a new one somewhere else? Mitigation banking – it is an agreement to restore or create new in another location whatever wetlands you ruin

Rain and snow Lake Rapids Glacier Waterfall Tributary Flood plain Oxbow lake Salt marsh Delta Ocean Deposited sediment Source Zone Transition Zone Water Flood-Plain Zone Sediment Fig. 7.17, p. 168

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