Freshwater Life Zones Melissa Eng, Martha Holland, Conner Martin, Colin Ng, and David Wright

Aquatic Environments Water covers 71% of the Earth's surface Saltwater Freshwater Four Groups of organisms o Plankton o Nekton o Benthos o Decomposers Euphotic Zone Bottom of the Ocean

Climate Lakes Very low salt content Largely varying temperature Zonated, often with varying degrees of water clarity Rivers Often cooler temperatures, warming as the river nears the ocean Murky water, progessively more so as the river nears the ocean High oxygen content Wetlands Higher salt content Wide variety of plant life

Plant Life Why are there so many plants? lots of carbon dioxide sunlight and nutrients What kinds of plants? surface: duckweed water column: floating strands of waterweed water surface: water lilies shallow water at edge: reed varieties Limiting growth factors? pressure light intensity

Effects of Plant Nutrients on Lakes: Too Much of a Good Thing... Nutrients affect the types and numbers of organisms the lake can support lakes are classified by:  nutrient content  primary productivity o oligotrophic: poorly nourished o eutrophic: well nourished o mesotrophic: between these extremes Cultural eutrophication: human inputs of nutrients from atmosphere and nearby urban/agricultural areas (accelerates eutrophication)

Animal Life 10,000 species of fish Less than 5,000 species of amphibians Few hundred types of reptiles/mammals/birds o newts and salamanders, frogs and toads, turtles, crocodiless, snakes, birds, beavers/otters/hippopotamus/sea cows Invertebrates: land-living but live in freshwater early on, adult freshwater stages, bottom-living community Vertebrates: fish!  40% of all fish species live in freshwater

Lakes: Water-filled Depressions What are lakes? Large bodies of standing freshwater formed when precipitation, runoff, and groundwater seepage fill depressions in the earth's surface What causes these depressions? - glaciation - crustal displacement - volcanic activity Where do lakes get their water? - rainfall - melting snow - streams that drain surrounding watersheds

Freshwater Lakes: The Littoral Zone The littoral zone is the top layer near the shore sunlight penetrates all the way to sediment most productive zone biodiversity: algae, rooted plants, animals (turtles, frogs, crayfish), fish(bass, perch, carp)

Freshwater Lakes: The Limnetic Zone The limnetic zone is the surface layer away from shore that extends to depth penetrated by sun photosynthetic body of the lake organisms:  microscopic phytoplankton (floating microorganisms) and zooplankton  nekton (actively swimming animals)  large fish

Freshwater Lakes: The Profundal Zone The profundal zone (also known as the euphotic zone) is the section of water too dark for photosynthesis low oxygen levels fish! primary consumers  attached or at bottom of lake  benthos: bottom-dwelling animals

Freshwater Lakes: The Benthic Zone The benthic zone is the bottom of the lake inhabitants: decomposers, detritus feeders, fish nourished by dead matter from:  littoral and limnetic zones  sediment

Lakes and the Seasons What happens during summer and winter? water stratified in different temperature layers no mixing! What happens during fall and spring? overturns: all layers mix  temperature equalizes throughout  oxygen: surface to bottom  nutrients: bottom to surface

Littoral Zone Limnetic Zone Profundal Zone Benthic Zone Sunlight Painted Turtle Green Frog Pond Snail Diving Beetle Yellow Perch Bloodworms Northern Pike Plankton Muskrat Blue-winged Teal Textbook Figure 6.15

Water travelling from mountains to the sea creates different aquatic conditions and habitats! Terms to know: Surface water is precipitation that does not sink into the ground or evaporate. When surface water flows into streams, it becomes runoff. A watershed (or drainage basin) is the land area that carries runoff, sediment, and dissolved substances to a stream. Small streams form rivers; rivers travel downhill to the ocean. Streams shape the land and receive nutrients from bordering land ecosystems. Freshwater Streams and Rivers; From the Mountains to the Oceans

Freshwater Streams and Rivers... The Source Zone Streams often begin in mountainous or hilly areas at the source zone. Source zone headwaters typically: are shallow, cold, clear, and swiftly flowing dissolve large amounts of oxygen from the air (high DO content) lack nutrients/phytoplankton; streams are not very productive Most nutrients at the source zone come from the organic matter (leaves, branches, bodies of living and dead insects) that falls into streams. The zone is populated by cold water fish with compact, flattened bodies that allow them to live under stones; algae/mosses; organisms that require high levels of DO to survive

Freshwater Streams and Rivers... The Transition Zone Headwater streams merge to form wider, deeper, and warmer streams at the transition zone. At the transition zone, water flows down gentler slopes with fewer obstacles. The transistion zone is characterized by water that: is cloudier due to suspended sediment slowelowing contains less dissolved oxygen is warmer in temperatuer, supporting producers - higher productivity

Freshwater Streams and Rivers... The Floodplain Zone At the floodplain zone, streams join into wider and deeper rivers that flow across broad, flat valleys. The floodplain zone is characterized by: higher temperatures less dissolved oxgen slow moving water that supports a fairly large populations of producers increased erosion/run off muddy water containing high oncentrations of silt At the mouth, the river may divide into channels as it flows through deltas.

Freshwater Inland Wetlands: Vital Sponges Marshes, swamps, bogs Not considered to be freshwater ecosystems, due to higher salt content Support many terrestrial and aquatic species Home to over one third of endangered species in the United States Most biologically productive ecosystems in the world Act as a filter for poll

Case Study: Inland Wetland Losses in the United States Causes of Wetland loss o 80% caused by crop growth o Mining o Forestry o Oil and Gas extraction Other countries o Ex. German and France 80% loss 95% of wetlands are inland freshwater wetland o Alaska has many wetlands The loss of natrual capital

Impacts of Human Activities on Freshwater Systems humans disrupt many freshwater systems o through pollution of watersheds o both irrigation and industrial byproducts can effect freshwater  farm land runoff  waste from factories o hydroelectricity or dams o filling in wetlands

This is an example of a watershed

Current Event: India and Pakistan at Odds Over Shrinking Indus River pakistan-indus-river-water/ India and Pakistan's major industries use billions of gallons of water each year (on average, 737 billion gallons of water withdrawn from the Indus River annually to grow cotton) Irrigation and hydroelectric projects are draining the river's flow; glaciers are melting in Kashmir which will increase flooding and eventually drain the water supply Downstream provinces are drying out, coastal districts becoming "economically orphaned" Competition for water is provoking conflict between the two nations More conservation and adaptation is necessary!

To Do List Note sheet for class Assessment Video clips/visual representations - everyone look for videos/photos to enhance slides! (give link to Baxley prior to class) students.discovery.education.com Code: GHS2010 Password: research Current Event for discussion All slides: Martha - freshwater streams/rivers, current event Melissa - lakes, effects of plant nutrients Colin - impacts of human activities, aquatic environment Connor - freshwater inland wetlands, freshwater systems David - case study

Works Consulted Day, Trevor. Lakes and Rivers. New York: Chelsea House, Print. Hicks, Sarah. "Pollution." Lake Scientist. Web. 19 Oct "Humans and the Water Cycle | Sciencelearn Hub." Home | Sciencelearn Hub. Web. 18 Oct Ruzycki, Elaine, and Lindsay Anderson. "Lake Ecology -- Lake Zones." Lake Access: Real Time and Historical Water Quality Data for Lake Users. Natural Resources Research Institute. Web. 19 Oct Smith, David K. "The Freshwater Biome." University of California Museum of Paleontology. California Academy of Sciences, Web. 19 Oct