impoverished or even annihilated the soft-bottom
macrofauna.
Eutrophication of surface waters accompanied by
oxygen-deficient bottom waters can lead to a shift in
dominance from demersal fishes to pelagic fishes. In
the Baltic Sea and Kattegatt where eutrophicationrelated ecological changes occurred mainly after
World War II, changes in fish stocks have been both
positive (due to increased food supply; e.g., pike
perch in Baltic archipelagos) and negative (e.g.,
oxygen deficiency reducing Baltic cod recruitment
and eventual harvest). Similar shifts are inferred with
limited data on the Mississippi River-influenced shelf
with the increase in two pelagic species in bycatch
from shrimp trawls and a decrease in some demersal
species. Commercial fisheries in the Black Sea declined as eutrophication led to the loss of macroalgal
habitat and oxygen deficiency, amid the possibility of
overfishing. After the mid-1970s, benthic fish populations (e.g., turbot) collapsed, and pelagic fish
populations (small pelagic fish, such as anchovy and
sprat) started to increase. The commercial fisheries
diversity declined from about 25 fished species to
about five in 20 years (1960s to 1980s), while anchovy stocks and fisheries increased rapidly. The
point on the continuum of increasing nutrients versus
fishery yields remains vague as to where benefits are
subsumed by environmental problems that lead to
decreased landings or reduced quality of production
and biomass.
Future Expectations
The continued and accelerated export of nitrogen
and phosphorus to the world’s coastal ocean is the
trajectory to be expected unless societal intervention
takes place (in the form of controls or changes in
culture). The largest increases are predicted for
southern and eastern Asia, associated with predicted
large increases in population, increased fertilizer use
to grow food to meet the dietary demands of that
population, and increased industrialization. The implications for coastal eutrophication and subsequent
ecosystem changes such as worsening conditions of
oxygen depletion are significant.
Further Reading
Dı ´az RJ, Nestlerode J, and Dı ´az ML (2004) A global
perspective on the effects of eutrophication and hypoxia
on aquatic biota. In Rupp GL and White MD (eds.)
Proceedings of the 7th International Symposium on Fish
Physiology, Toxicology and Water Quality, EPA 600/
R-04/049, pp. 1–33. Tallinn, Estonia, 12–15 May 2003.
Athens, GA: Ecosystems Research Division, US EPA.
Dı ´az RJ and Rosenberg R (1995) Marine benthic hypoxia:
A review of its ecological effects and the behavioural
responses of benthic macrofauna. Oceanography and
Marine Biology Annual Review 33: 245--303.
Gray JS, Wu RS, and Or YY (2002) Review. Effects of
hypoxia and organic enrichment on the coastal marine
environment. Marine Ecology Progress Series 238:
249--279.
Hagy JD, Boynton WR, and Keefe CW (2004) Hypoxia in
Chesapeake Bay, 1950–2001: Long-term change in
relation to nutrient loading and river flow. Estuaries 27:
634--658.
Helly J and Levin LA (2004) Global distributions of
naturally occurring marine hypoxia on continental
margins. Deep-Sea Research 51: 1159--1168.
Mee LD, Friedrich JJ, and Gomoiu MT (2005) Restoring
the Black Sea in times of uncertainty. Oceanography 18:
100--111.
Rabalais NN and Turner RE (eds.) (2001) Coastal and
Estuarine Studies 58: Coastal Hypoxia – Consequences
for Living Resources and Ecosystems. Washington, DC:
American Geophysical Union.
Rabalais NN, Turner RE, and Scavia D (2002) Beyond
science into policy: Gulf of Mexico hypoxia and the
Mississippi River. BioScience 52: 129--142.
Rabalais NN, Turner RE, Sen Gupta BK, Boesch DF,
Chapman P, and Murrell MC (2007) Characterization
and long-term trends of hypoxia in the northern Gulf of
Mexico: Does the science support the Action Plan?
Estuaries and Coasts 30(supplement 5): 753--772.
Turner RE, Rabalais NN, and Justic ´ D (2006) Predicting
summer hypoxia in the northern Gulf of Mexico:
Riverine N, P and Si loading. Marine Pollution Bulletin
52: 139--148.
Tyson RV and Pearson TH (eds.) Geological Society Special
Publication No. 58: Modern and Ancient Continental
Shelf Anoxia, 470pp. London: The Geological Society.
Relevant Websites
http://www.gulfhypoxia.net
– Hypoxia in the Northern Gulf of Mexico.
314 HYPOXIA
macrofauna.
Eutrophication of surface waters accompanied by
oxygen-deficient bottom waters can lead to a shift in
dominance from demersal fishes to pelagic fishes. In
the Baltic Sea and Kattegatt where eutrophicationrelated ecological changes occurred mainly after
World War II, changes in fish stocks have been both
positive (due to increased food supply; e.g., pike
perch in Baltic archipelagos) and negative (e.g.,
oxygen deficiency reducing Baltic cod recruitment
and eventual harvest). Similar shifts are inferred with
limited data on the Mississippi River-influenced shelf
with the increase in two pelagic species in bycatch
from shrimp trawls and a decrease in some demersal
species. Commercial fisheries in the Black Sea declined as eutrophication led to the loss of macroalgal
habitat and oxygen deficiency, amid the possibility of
overfishing. After the mid-1970s, benthic fish populations (e.g., turbot) collapsed, and pelagic fish
populations (small pelagic fish, such as anchovy and
sprat) started to increase. The commercial fisheries
diversity declined from about 25 fished species to
about five in 20 years (1960s to 1980s), while anchovy stocks and fisheries increased rapidly. The
point on the continuum of increasing nutrients versus
fishery yields remains vague as to where benefits are
subsumed by environmental problems that lead to
decreased landings or reduced quality of production
and biomass.
Future Expectations
The continued and accelerated export of nitrogen
and phosphorus to the world’s coastal ocean is the
trajectory to be expected unless societal intervention
takes place (in the form of controls or changes in
culture). The largest increases are predicted for
southern and eastern Asia, associated with predicted
large increases in population, increased fertilizer use
to grow food to meet the dietary demands of that
population, and increased industrialization. The implications for coastal eutrophication and subsequent
ecosystem changes such as worsening conditions of
oxygen depletion are significant.
Further Reading
Dı ´az RJ, Nestlerode J, and Dı ´az ML (2004) A global
perspective on the effects of eutrophication and hypoxia
on aquatic biota. In Rupp GL and White MD (eds.)
Proceedings of the 7th International Symposium on Fish
Physiology, Toxicology and Water Quality, EPA 600/
R-04/049, pp. 1–33. Tallinn, Estonia, 12–15 May 2003.
Athens, GA: Ecosystems Research Division, US EPA.
Dı ´az RJ and Rosenberg R (1995) Marine benthic hypoxia:
A review of its ecological effects and the behavioural
responses of benthic macrofauna. Oceanography and
Marine Biology Annual Review 33: 245--303.
Gray JS, Wu RS, and Or YY (2002) Review. Effects of
hypoxia and organic enrichment on the coastal marine
environment. Marine Ecology Progress Series 238:
249--279.
Hagy JD, Boynton WR, and Keefe CW (2004) Hypoxia in
Chesapeake Bay, 1950–2001: Long-term change in
relation to nutrient loading and river flow. Estuaries 27:
634--658.
Helly J and Levin LA (2004) Global distributions of
naturally occurring marine hypoxia on continental
margins. Deep-Sea Research 51: 1159--1168.
Mee LD, Friedrich JJ, and Gomoiu MT (2005) Restoring
the Black Sea in times of uncertainty. Oceanography 18:
100--111.
Rabalais NN and Turner RE (eds.) (2001) Coastal and
Estuarine Studies 58: Coastal Hypoxia – Consequences
for Living Resources and Ecosystems. Washington, DC:
American Geophysical Union.
Rabalais NN, Turner RE, and Scavia D (2002) Beyond
science into policy: Gulf of Mexico hypoxia and the
Mississippi River. BioScience 52: 129--142.
Rabalais NN, Turner RE, Sen Gupta BK, Boesch DF,
Chapman P, and Murrell MC (2007) Characterization
and long-term trends of hypoxia in the northern Gulf of
Mexico: Does the science support the Action Plan?
Estuaries and Coasts 30(supplement 5): 753--772.
Turner RE, Rabalais NN, and Justic ´ D (2006) Predicting
summer hypoxia in the northern Gulf of Mexico:
Riverine N, P and Si loading. Marine Pollution Bulletin
52: 139--148.
Tyson RV and Pearson TH (eds.) Geological Society Special
Publication No. 58: Modern and Ancient Continental
Shelf Anoxia, 470pp. London: The Geological Society.
Relevant Websites
http://www.gulfhypoxia.net
– Hypoxia in the Northern Gulf of Mexico.
314 HYPOXIA