Shared Flashcard Set


Ch 7 Exam
Environmental Studies
12th Grade

Additional Environmental Studies Flashcards





Aquatic Life Zones


1. saltwater/marine (estuaries,coastlines, coral reeds, coastal marshes, mangrove swamps, oceans)


2. freshwater (lakes, ponds, streams, rivers, inland wetlands)


cover about 71% of the earth's surface


giant circulatory system transporting water from one place to another as part of the earth's water cycle


play vital roles in biological productivity, climate, biogeochemical cycles, biodiversity

Four Major types of Organisms

1. Plankton: free-floating; 3 types

-phtyoplankton/plant plankton: producers that support aquatic food chains/webs

-zooplanktion/animal plankton: primary consumers that feed on phytoplankton and seconday consumers that feed on other zooplankton

 -ultraplankton: much smaller; photosynthetic bacteria responsible for 70% of primary productivity near ocean surface


2. nekton: strongly swimming consumers (fish turtles whales)


3. benthos: dwell at bottom (oysters, worms, lobsters)


4. decomposers: bacteia that break down waster into sumple nutrient compounds


Aquatic vs. Terrestrial Systems


Aquatic Systems...


-have less pronounced and fixed boundaries

-have more complex/longer food chains/webs

-more difficult to monitor and study



Depths of Aquatic Life Zones


*temp, access to sunlight, dissolved oxygen, nutrients are factors that determine the types/#s of organims found in layers


1. Upper/Euphotic Zone: sunlight can penetrate through; more photosynthesis; dissolved O2 is higher; low levels of CO2


2. Deeper zones: Oxygen levels fall ans carbon dioxide levels rise due to aerobic respiration by animals and oxygen gas dissolves less in deep cold water


Coastal Zone


warm nutrient-rish, shallow water that extends from the high-tide mark on land to the gently-sloping, shallow edge of the continental shelf; contains 90% of all marine species; high net primary productivity per unit of area due to ample sunlight and plant nutrients


estuaries, coastal wetland, mangrove swamps


estuaries/coastal wetlands/mangrove swamps


estuary: partially enclosed area of coastal water where seawater mixes with freshwater and nutrients from rivers, streams and runoff from land


Temperature and salinity levels vary widely in estuaries and coastal wetlands due to tides/seasonal variations in the flow of freshwater into the estuary / unpredictable flows of freshwater after heavy rains and salt water after storms/hurricanes


constant water movement stirs up nutient-rich silt; filter toxic pollutants, excess plant nutrients, sediments and other pollutants


 Mangrove forest swamps: dominant organisms: trees that can grow in salt water; extensive roots that extend about water to get O2 and for support; nutrient rich forests in sheltered regions along tropical coasts




Intertidal Zone


area of shoreline between low and high tides


its organisms must be able to deal with tides and varying salinity; either hold on, dig in or hide in shells

Barrier Islands

low, narrow, sandy islands that form offshore from coastline; help protect mainland, estuaries, and coastal wetlands from storm waves


have one or more rows of natural sand dunes held in place my grass roots which serve as first line of defense against waves

Coral Reefs

form on clear, warm coastal waters; ecologically complex interactions among diverse organisms


vulnerable to damage because they grow slowly & disrupted easily; thrive only in clear warm fairly shallow water of constant high salinity


sediment runoff and human activities are biggest threats

Open ocean

sharp increase in water depth at the edge of the continental shelf separates coastal zone from vast volume of the ocean


divided into three vertical zones


1. euphotic zone:lighted upper zone where phytoplanktion photosynthesize; high oxygen low nutrients


2. bathyal zone: dimly lit middle zone; zooplankton and smaller fish


3. abyssal zone: dark, cold and little O2; enough nutrients on the ocean floor to support 98% of species living in the ocean


deposit feeders: take mud in and extract nutrients


filter feeders: pass water through/over bodies and extract nutrients


average primary productivity and NPP per unit are low except at an occasional equatorial upwelling

Freshwater Life Zones

water with a dissolved salt concentration of less than 1%


-standing (lentic) bodies (lakes, ponds, inland wetlands)


-flowing (lotic) bodies (streams, rivers)


less than 1% of earth's surface


large natural bodies of standing fresh water formed when precipitaion, runoff or groundwater seepage fill depressions in the earth's surface


depression can be caused by glaciation, crustal displacement, and volcanic activity


four distinct zones


1. littoral zone: shallow sunlit waters near shore to the depth at which rooted plants stop growing, high biological diversity; adequate nutrients from bottom sediments


2. limnetic zone: open sunlit water surface away from the shore that extensd to the depth penetrated by sunlight; main photosynthetic body of the lake


3. profundal zone: deep, open water where it is too dark for photosynthesis; low oxygen levels


4.benthic zone: bottom of the lake; decomposers, detritus feeders


-during the summer and winter the water in deep temperate zone lakes become stratified into different temperature layers which do not mix


-fall and spring the waters mix in overturns  that equalize the temp

types of lakes

-oligotropic lake: newly formed; small supply of plant nutrients; deep, steep banks; clear water; low net primary productivity


- eutropic lake: large or excessive supply of nutrients; murky water; high net primary productivity; bottom layer is depleted of dissolved oxygen in warm months


cultural eutrophication


mesotropic lakes: between two extremes

freshwater streams and rivers

surface water: precipitation that dusnt sink/evaporate


runoff: flows into streams


watershed/drainage basin: land area that delivers runoff, sediment to a stream


downward flow of surface water to sea has three dif zones


1. source zone:headwaters rush  downwards dissolving oxygen; not productive due to lack of nutrients


2. transition zone: wider, deeper streams that flow down gentler slopes; more producers(phytoplankton) and fish


3. floodplain zone: wider deeper rivers over flat valleys; higher temperature and less oxygen than first two zones; large amount of producers; muddy and lots of silt


inland wetlands

lands covered with fresh water and located away from coastal area

 (marshes, swamps, prairie potholes, floodplains)

human impacts on freshwater systems

1. dams, diversions, canals fragment 60% of worlds largest rivers


2. floor control levees alter and destroy habitats


3. cities and farmlands add pollutants and exess plant nutrients to streams/rivers


4. many inland wetlands have been drained

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