Unit 4: Disruption & Homeostasis of Aquatic Communities PDF

Unit 4: Disruption & Homeostasis of Aquatic Communities Texas Aquatic Science: 1AB, 2E-J, 3ABDEF, 4B, & 11B All images from Google Images 4B: Positive & Negative Feedback Cycles Positive Feedback Cycles: Positive feedback cycles are responses t...

Unit 4: Disruption & Homeostasis of Aquatic Communities Texas Aquatic Science: 1AB, 2E-J, 3ABDEF, 4B, & 11B All images from Google Images 4B: Positive & Negative Feedback Cycles Positive Feedback Cycles: Positive feedback cycles are responses to changes that increase change in conditions (reinforcing). EX: Eutrophication - pollutants from runoff increase algal blooms in bodies of water; Algal Blooms - increased algal populations that cover the surface of bodies of water, blocking photosynthesis of producers, thus affecting the aquatic food chain; Invasive Population Growth - non-native species that can survive in a new ecosystem and outcompete native organisms for limited resources All images from Google Images  4B: Positive & Negative Feedback Cycles Negative Feedback Cycles: Negative feedback cycles are responses to change that reduce change in conditions towards the previous state (balancing). EX: Carrying Capacity - average population sizes are determined by the limited environmental factors (food, water, shelter, & mates); Community Dynamics - how members in an aquatic community interact and change over time (adapt). All images from Google Images  4B: Positive & Negative Feedback Cycles Cause & Effect: # If this happens… Then this might occur… 1 Too much rain at one time Bodies of water fill beyond capacity (FLOOD) 2 Not enough rain for extended amount of time Water is lost from soil and bodies of water (DROUGHT) 3 Increased water temperature and pollution in oceans Die off of coral reefs & ocean producers (ACIDIFICATION) 4 Zebra mussels introduced to ecosystem without predators Population growth of invasive species (EXPONENTIAL GROWTH) 5 Polluted and unhealthy bodies of water Gradual fall of ecosystem (DEAD ZONE) 6 Change in water temperature Die off of organisms not fit (THREATENED/ENDANGERED SPECIES) 7 Pollution introduction to a body of water Increased algal blooms (EUTROPHICATION) 8 Winters become too cold for some birds Movement of birds to warmer climate (MIGRATION) 9 Seasonal conditions are perfect for mating Specific fish lay eggs for spawning (SPAWNING MIGRATION)  11B: Factors Affecting Aquatic Population Cycles Precipitation Rate - amount of precipitation over a period of time; ex: heavy rains can cause washout of aquatic plant life. Evaporation Rate - water lost over a period of time; ex: increasing evaporation rate, due to global warming, is decreasing lake surface areas. Acidification - increased pollution, warming oceans, and reduction of pH causes decline of coral populations; ex: acidification causes bleaching of coral reefs, which creates habitat loss for many ocean organisms and also drastically alters ocean food chains. Exponential Growth - rapid growth of populations; invasive species (apple snail, zebra mussels) introduced to new ecosystems with no predators; water scarcity due to increased human population growth All images from Google Images  11B: Factors Affecting Aquatic Population Cycles Dead Zones - low oxygen (hypoxic) zones, caused by eutrophication, where little to no organisms can live; ex: Gulf Dead Zone, Baltic Sea, Lake Erie Water Temperature - global warming is slowly increasing water temperatures; increased water temps lead to melting of ice caps, changes in aquatic pH, increased evaporation, changes in metabolic rates of aquatic organisms Pollution - point and nonpoint source pollution affects water quality and aquatic food chains; sewage dumping directly in to bodies of water (point); runoff from agricultural land (nonpoint); pollution leads to eutrophication and dead zones Seasons - currents, weather, upwelling, and migration change with global seasonal weather patterns All images from Google Images