Benthic production and processes off Baja California, northwest Africa and Peru: a classification of benthic subsystems in upwelling ecosystems

Conference · Sat Jan 01 04:00:00 EST 1983

OSTI ID:5180684

Rowe, G T

Estimates of the standing stocks, secondary production and metabolism of the benthos have been compared in the coastal upwelling ecosystems off northwest Africa, Baja California, and southern Peru. Northwest Africa is characterized by shelf break upwelling and as a result standing stocks, macrobenthic production and sediment organic matter are highest out at the shelf-slope boundary. Sediment microbial activity and biomass on the other hand are highest nearshore in the dynamic zone where aeolian silt and sand are being blown into the sea from the Sahara Desert. Baja California is dominated by the red crab, Pleuroncodes planipes, having high rates of growth and metabolic utilization of organic matter, both on bottom and in the water. Peru benthos and metabolism are very different from the above areas because of the low oxygen concentrations in the bottom water. Organic matter is far higher in the sediment and heterotrophic metabolism is principally anaerobic rather than aerobic. A normal offshore benthic fauna is replaced by a mat of sulfur bacteria with unknown production and metabolic rates. Benthic subsystems in upwelling ecosystems can be placed in two categories: those overloaded with organic matter, depleted of oxygen and dominated by sulfate reduction and those that are not overloaded and remain aerobic. Peru and southwest Africa typify overloaded systems whereas NW Africa and Baja California are examples of aerobic systems. Although benthic metabolism and ionorganic nutrient regeneration are high in both types of subsystems, all upwelling ecosystems, with their dynamic open boundaries, export organic particulate matter and import inorganic nutrients at rates that are far in excess of that consumed or produced by benthic metabolism. 42 refs., 7 figs., 8 tabs.

• Research Organization: Brookhaven National Lab., Upton, NY (USA). Oceanographic Sciences Div.
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 5180684
• Report Number(s): BNL-38497; CONF-8311292-1; ON: DE86015079
• Country of Publication: United States
• Language: English

Related Subjects

520100* -- Environment
Aquatic-- Basic Studies-- (-1989)
54 ENVIRONMENTAL SCIENCES
AFRICA
ANIMALS
AQUATIC ECOSYSTEMS
AQUATIC ORGANISMS
ARTHROPODS
BENTHOS
BIOMASS
CRABS
CRUSTACEANS
DECAPODS
DEVELOPING COUNTRIES
ECOSYSTEMS
ENERGY SOURCES
GULF OF CALIFORNIA
INVERTEBRATES
LATIN AMERICA
PACIFIC OCEAN
PERU
RENEWABLE ENERGY SOURCES
SEAS
SEDIMENTS
SOUTH AFRICA
SOUTH AMERICA
SOUTH WEST AFRICA
SURFACE WATERS
UPWELLING