Marine Biodiversity And Ecosystem Adaptability

Diverse Marine Ecosystems Best Survive Environmental Change

Feb 27, 2009 John Pohl

Marine ecosystems with a range of species and healthy populations prove most resilient and adaptable to environmental change. Here's why.

Marine biodiversity refers to the variety of life in the oceans and the natural patterns it forms. At present, scientists have identified approximately 200,000 marine species in a variety of environments: from polar seas to tropical reefs, coastal estuaries to pelagic deserts. However, with recent advances in both survey technology and genetic analysis, researchers believe there may be another 100 million species as yet undiscovered.

All of these species, the known and unknown, interact collectively as communities within their respective environments to form ecosystems. Ecosystems are dynamic and adaptable, just like organisms, as they are always pressured to some degree by changes in environmental conditions. No matter if the environmental changes stem from a turning of seasons, fishing pressure from commercial fleets, or significant climate variation, for an ecosystem to remain intact in the face of change requires adaptability.

Natural Selection and Three Levels Of Biodiversity

Biodiversity is the general foundation upon which an ecosystem’s adaptability is built. There are three levels at which scientists study biodiversity:

• genetic diversity, or the diversity of genes within a species. (Genes are the basic unit of heredity);

• species diversity, or diversity among species. (A species is the basic category of biological classification, composed of related individuals that resemble one another, are able to breed among themselves, but are not able to breed with members of another species);

• ecosystem diversity, or the diversity of systems and the richness of the different processes within a system to which genes and species ultimately contribute.

The force which interacts and shapes these levels of diversity is:

• Natural selection, or the process by which forms of life having traits that better enable them to adapt to specific environmental pressures, such as predators, changes in climate, or competition for food or mates, will tend to survive and reproduce in greater numbers than others of their kind, thus ensuring the perpetuation of those favorable traits in succeeding generations.

Biodiversity and Adaptability

When a ecosystem’s environment changes - either as a result of natural cycles or human impact - natural selection acts upon the genetic diversity inherent in the various species composing the affected ecosystem. Without genetic and species diversity, the options afforded natural selection are limited, and adaption is virtually impossible. Impoverished ecosystems consequently are “brittle” and can withstand very little force of change without crashing.

The opposite is also true. The more diverse an ecosystem is, the greater the range of genetic resources natural selection acts upon, and the greater the likelihood a survivable combination will arise in response to the change. Experiments have shown strong positive linkages between biodiversity, productivity, and stability across marine ecosystem trophic levels in the face of change. Biodiverse ecosystems are thus “flexible,” adaptable, and exhibit a greater ability to survive environmental shocks.

References

Worm, Boris et al. 2006. Impacts of Biodiversity Loss on Ocean Ecosystem Services. Science, vol. 314, 3 Nov 2006.

The copyright of the article Marine Biodiversity And Ecosystem Adaptability in Marine Biology & Oceanography is owned by John Pohl. Permission to republish Marine Biodiversity And Ecosystem Adaptability in print or online must be granted by the author in writing.

Marine Biodiversity

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