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Chapter 7-10&26-28

ES101 Chapters 7-10 & 26-28.pdf

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Environmental Studies
Robert Mc Leman

ES101 Chapters 7102628Chapter 7 Aquatic Biodiversity Why Should We Care About Coral Reefs Found in the shallow coastal zones of warm tropical and subtropical oceans Formed by massive colonies of tiny animals called polyps When they die they form more reef to grow Zooxanrhellae live in the tissues of the polyps The formation of limestone shells they remove carbon from the air Coral Bleaching occurs when a coral becomes stressed and expels most of its colourful algae leaving an underlying ghostly white skeleton of calcium carbonate If water temperature rises too high or if water becomes cloudy from sediment corals die off and bleach 71 Aquatic Environments Aquatic Life Zones Saltwater and freshwater aquatic life zones cover almostof the earths surface 2 Categories of aquatic environments are saltwater marine and freshwater Water covers 71 of earths surface Organisms Living in Zones Aquatic systems contain floating drifting swimming bottomdwelling and decomposer organisms Plankton weak swimmers carried by the current Four types Phytoplankton larger freedrifting photosynthesizing plantlike organisms algae Zooplankton freefloating includes primary consumers herbivores and secondary consumers carnivores vary in size from microscopic to jellies Ultraplankton freefloating microscopic bacteria that photosynthesize collectively make a significant contribution to global primary productivity Nekton freeswimming consumers including fish reptiles mammals and large invertebrates Benthos bottom dweller examples are shellfish worms lobsters Decomposers break down the organic compounds in the dead bodies and wastes of aquatic organisms into simple nutrient compounds for use by producers bacteria Aquatic Systems vs Terrestrial Systems 1Aquatic aTemperatures fluctuate slowly bLow availability of oxygen cNo shortage of water dBuoyancy makes for easy locomotion dispersal eFewer edges niches and boundaries fComplex food chains ES101 Chapters 71026282Terrestrial Environment aLarge dailyseasonal temperature range bOxygen is plentiful cWater unevenly distributed dLocomotion dispersal more constrained eLots of edges niches and boundaries fSimpler food chains Factors Limiting Life at Different Depths in Aquatic Zones Life in aquatic systems is found in surface middle and bottom layers Key influences access to sunlight temperature dissolved oxygen availability dissolved nutrients carbon nitrogen phosphorus Euphotic Zone upper layer of the ocean where sunlight can penetrate and create photosynthesis Dissolved O2 levels are higher near the surface because this water is exposed to the action of wind and waves at the airwater interface and giving the ability to create photosynthesis In shallow areas nutrients are more available 90 of species are found near coastal waters Dissolved CO2 levels are higher in deeper darker layers where animals and decomposers produce it through aerobic respiration Once you drop below the surface primary productivity diminishes Oxygen becomes scare with increasing depth Nutrients are scare except at upwelling zones and at the bottom benthic environment Upwelling winds currents lead water from deep to ride toward surface upwelling water often brings additional nutrients WhaleFalls when a dead whale sinks to floor of deep ocean it brings a sudden influx of nutrients creates its own miniecosystem 72 Saltwater Life Zones Why Care About the Oceans Although oceans occupy most of the earths surface and provide many ecological and economic services we know less about them than we do about the mood Costal Zones Makes up less than 10 of the worlds ocean area but contains 90 of the species Warm nutrient rich shallow water that extends from the hightide mark on land to the gently sloping shallow edge of the continental shelf Marine Biodiversity Greatest Points of Contact Between ocean and shore At oceanair boundary Along benthic boundary ES101 Chapters 7102628Where different temperature waters mix Where freshwater mixes with saltwater Estuaries Coastal Wetlands and Mangrove Swaps Estuary highly productive area in the coastal zone a partially enclosed area of coastal water where seawater mixes with freshwater and nutrients from rivers streams and runoff from land Coastal Wetlands land areas covered with water all or part of the year Temperature and salinity levels vary widely in estuaries and coastal wetlands because of the daily rhythms of the tides and seasonal variations in the flow of freshwater into the estuary Dominant organisms in mangrove forest swamp are trees that can grow in salt water often mud and anaerobic sediments These systems filter toxic pollutants excess plant nutrients sediments and other pollutants by absorbing waves and storing excess water produced by storms Mangrove a mix of shrubs and tress common in coastal areas of the tropics can stand to have roots in water Human Alterations of Marine Environments 45 of humans live within 100km of the ocean 10 of humans live within 10m elevation above sea level Human impacts are greatest where marine productivity and biodiversity is highest Human Disturbances of Marine Systems at Contact Points At oceanshore contact zone littoral zone Chemical nutrient pollutants runoff land Humans remove coastal forests and mangroves leading to erosion loss of fishbreeding areas Beaches and shorelines converted to human use removing nesting sites for sea turtles shorebirds Where freshwater mixes with saltwater Large amounts of pollution nutrients are discharged into ocean Anoxic dead zones are developing At OceanAir Interface humans are Altering sea surface temperatures Altering marine chemistry Both are consequences of anthropogenic greenhouse gas emissions Along Benthic Margins humans Dump solid waste damage coral reefs bottomtrawl for fish shellfish drill for oil Niches Provided by Rocky and Sandy Shores
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