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Dead phytoplankton and other organisms sink to the bottom giving rise to large numbers of decomposers due to increased food supply (dead organisms, phytoplankton). Due to the increased number of decomposers that use more oxygen, fish and shrimp at the lower layers of the ocean become oxygen-starved, resulting in the creation of hypoxic zones.
Since the tundra has such a harsh environment, the animals who live here have adapted in a way to call the tundra their home. The keystone species of the tundra can be as small as a lemming to as large as a musk ox. The low biodiversity means that fluctuation in individual animals can substantially affect the entire ecosystem.
Land ecosystems are thought to be the main sources of this asymmetry, although it has been suggested in 2007 that "the role of the Arctic Ocean is significantly underestimated." [20] Soil temperature and moisture levels are important variables in soil methane fluxes in tundra environments. [21] [22]
East Antarctic tundra: Eastern Antarctica: Ellsworth Land tundra: Ellsworth Land: Ellsworth Mountains tundra: Ellsworth Mountains: Enderby Land tundra: Enderby Land: Marie Byrd Land tundra: Marie Byrd Land: North Victoria Land tundra: Victoria Land: Northeast Antarctic Peninsula tundra: Antarctic Peninsula: Northwest Antarctic Peninsula tundra ...
In 2008, Molnar et al. documented the pathways of hundreds of marine invasive species and found shipping was the dominant mechanism for the transfer of invasive species in the ocean. The two main maritime mechanisms of transporting marine organisms to other ocean environments are via hull fouling and the transfer of ballast water. [20]
While marine pollution can be obvious, as with the marine debris shown above, it is often the pollutants that cannot be seen that cause most harm.. Marine pollution occurs when substances used or spread by humans, such as industrial, agricultural and residential waste, particles, noise, excess carbon dioxide or invasive organisms enter the ocean and cause harmful effects there.
At a certain stage, such shifts could become effectively irreversible, making them tipping points in the climate system, and a major assessment designated both processes - reversion of southern boreal forests to grasslands and the conversion of tundra areas to boreal forest - as separate examples of such, which would likely become unstoppable ...
Concern among experts has grown since the 2000s that some organisms have adapted to live on [139] floating plastic debris, allowing them to disperse with ocean currents and thus potentially become invasive species in distant ecosystems. [140]