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Spreading dead zones and consequences for marine ecosystems
Robert J Diaz1, Rutger Rosenberg
1Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA 23062, USA. diaz@vims.edu
Science (New York, N.Y.)
|August 16, 2008
Summary
Coastal dead zones have expanded significantly since the 1960s, harming marine ecosystems. This expansion is driven by increased primary production and coastal eutrophication from nutrient runoff and fossil fuel burning.
Area of Science:
- Marine Biology
- Oceanography
- Environmental Science
Background:
- Coastal dead zones, characterized by low dissolved oxygen, have expanded exponentially since the 1960s.
- These zones negatively impact marine ecosystem functioning and biodiversity.
- Global expansion affects over 400 systems, totaling more than 245,000 square kilometers.
Purpose of the Study:
- To summarize the causes and consequences of expanding coastal dead zones.
- To highlight the role of anthropogenic activities in exacerbating dead zone formation.
Main Methods:
- Review of scientific literature on coastal dead zones and eutrophication.
- Analysis of data on the geographical spread and size of dead zones.
- Synthesis of information on primary production, nutrient runoff, and oxygen depletion.
Main Results:
- Dead zone formation is linked to increased primary production, primarily fueled by fertilizer runoff and fossil fuel combustion.
- Enhanced primary production leads to organic matter accumulation, promoting microbial oxygen consumption in bottom waters.
- The phenomenon is widespread, impacting numerous coastal systems globally.
Conclusions:
- Coastal dead zones are a significant and growing threat to marine ecosystems.
- Mitigation of nutrient pollution and fossil fuel emissions is crucial to combat dead zone expansion.
- Dead zones represent a key stressor on marine environments worldwide.
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