Abiotic+and+Biotic+Factors

Abiotic and Biotic Factors!!!!  Many environmental factors have an effect on estuaries; they are a combination of living and non-living factors. All of the non-living factors are called the abiotic factors and the living factors are the biotic factors. Together these factors affect the productivity and diversity of life in the estuary.

Some of the abiotic factors that affect the San Francisco Bay Estuary are the salinity of the water, amount of sunshine available, nutrient concentration, and dissolved oxygen concentration. The salinity of the estuary is very important and varies across the estuary from almost no salt, near the river mouths to near seawater salinity of 3.5%, or 35 grams of salt per liter. Many plants and other organisms in the estuary rely on the sunshine to photosynthesize. The primary producers take advantage of the 160 sunny days on average a year to support the biodiversity of life in the estuary. Additionally the dissolved oxygen concentration is a vital abiotic factor in the San Francisco Bay estuary. All of the fish and other marine heterotrophs directly rely on the oxygen to survive and furthermore, the organisms that prey on those marine heterotrophs need the dissolved oxygen because without the oxygen then there would be no prey for them. The nutrient content of the estuary is a very important abiotic factor. With the increased usage of fertilizer, rains can cause the nutrients to flow into the rivers and then the bay. The addition of too much nutrients, called eutrophication, can cause algae blooms, which then cause the O2 concentration to drop because of the decomposers use the oxygen.

Biotic factors are also very important to the San Francisco Bay Estuary. The biotic factors are the primary producers, consumers, and predators. Phytoplanktons play a major role in the estuary because they are the main producers and without them, the entire ecosystem would fall apart. The Zooplankton that eat the Phytoplanktons and then are subsequently eaten by grass shrimp, herring, smelt, which are then eaten by the larger striped bass and lastly by predatory birds, fish, otters, seals and humans. All of these organisms rely on each other and without one; the whole balance of the estuary would be thrown off. media type="file" key="Threats_to_Estuaries__Bays.wmv" width="300" height="300"

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