ecosystems

(noun)

Communities of living organisms (plants, animals and microbes) in conjunction with the nonliving components of their environment (things like air, water, and mineral soil), interacting as a system; linked together through nutrient cycles and energy flows.

Related Terms

Examples of ecosystems in the following topics:

  • Hydrothermal Vent Microbial Ecosystems

    • Hydrothermal vents are home to chemosynthetic bacteria, which are the basis of a unique ecosystem that thrives in total darkness.
    • In most shallow water and terrestrial ecosystems, energy comes from sunlight, but in the deep ocean there is total darkness.
    • These bacteria form the basis of the entire hydrothermal vent ecosystem.
    • The ecosystems around hydrothermal vents rely on mats chemosynthetic bacteria, and many species feed on the bacteria.
    • Hydrothermal vents are some of the most unique ecosystems in the world

  • Organization of Ecosystems

    • Although ecologists tend to regard ecosystems as basic structural units, it can be difficult (if not impossible) to formally define the boundaries of a given ecosystem.
    • As such, ecosystems are better thought of as conceptual rather than actual geographical locations.
    • These interactions may be best described by detailing feeding connections (what eats what) among biota in an ecosystem, thereby linking the ecosystem into a unified system of exchange.
    • All life forms in an ecosystem can be broadly grouped into one of two categories (called trophic levels):
    • This image shows a simplified food web model of energy and mineral nutrient movement in an ecosystem.

  • Microbes and Ecosystem Niches

    • Every ecosystem on Earth contains microorganisms that occupy unique niches based on their specific metabolic properties.
    • The ability of microbes to contribute substantially to the function of every ecosystem is a reflection their tremendous biological diversity .
    • Microbes are vital to every ecosystem on Earth and are particularly important in zones where light cannot approach (that is, where photosynthesis cannot be the basic means to collect energy).
    • They can also have additional indirect effects on the ecosystem through symbiotic relationships with other organisms.
    • Each species in an ecosystem is thought to occupy a separate, unique niche.

  • Microorganisms and Water Quality

    • Microorganisms from sewage can cause human disease, but can also negatively affect important ecosystems on which humans rely.
    • All healthy ecosystems have their own communities of bacteria that decompose biological matter.
    • However, contamination by sewage and human waste can disrupt the natural balance of bacteria and affect aquatic ecosystems.
    • An influx of human pathogens can cause problems for ecosystems in several ways.
    • First, sewage bacteria can cause hypoxic "dead zones" in aquatic ecosystems.

  • Viral Roles in Ecosystems

    • Viruses are immensley important to the turnover of biomass in many ecosystems.
    • Viruses are essential to the regulation of saltwater and freshwater ecosystems.

  • The Phosphorus Cycle

    • Phosphorous levels follow a seasonal pattern in aquatic ecosystems.
    • Later in the summer, the plants and algae begin to die off, and bacteria decompose them, and inorganic phosphorus is released back into the ecosystem.
    • Run-off and drainage from farms can flood aquatic ecosystems with excess phosphorus.
    • However, overgrowth of algae due to phosphorous fertilizer is called "cultural eutrophication" or "hypertrophication," and is generally negative for ecosystems .

  • Role of Microbes in Biogeochemical Cycling

    • Nutrients move through the ecosystem in biogeochemical cycles.
    • A biogeochemical cycle is a pathway by which a chemical element (such as carbon or nitrogen) circulates through the biotic (living) and the abiotic (non-living) factors of an ecosystem.
    • The elements that move through the factors of an ecosystem are not lost but are instead recycled or accumulated in places called reservoirs (or "sinks") where they can be held for a long period of time.
    • Ecosystems have many biogeochemical cycles operating as a part of the system.
    • A good example of a molecule that is cycled within an ecosystem is water, which is always recycled through the water cycle.

  • The Iron Cycle

    • The Terrestrial Iron Cycle: In terrestrial ecosystems, plants first absorb iron through their roots from the soil.
    • The role of iron in ocean ecosystems was first discovered when English biologist Joseph Hart noticed "desolate zones," which are regions that lacked plankton but were rich in nutrients.
    • Scientists hoped that by adding iron to ocean ecosystems, plants might grown and sequester atmospheric CO2.

  • Nitrate Reduction and Denitrification

    • Denitrification takes place under special conditions in both terrestrial and marine ecosystems.
    • This is a less common method of nitrate reduction than denitrification in most ecosystems.
    • Denitrification is an important process in maintaining ecosystems.

  • Microbial Environments and Microenvironments

    • In addition to occupying a unique niche within an ecosystem, microbes are potentially sensitive to subtle environmental differences between adjacent areas.
    • Microbes, therefore, are not only adapted to their habitat, but also to the immediate environment, thus promoting increased diversity among microbial species within an ecosystem.