Aquatic Sciences Meeting, Albuquerque 2001

SS16 Iron Bioavailability and Limitation to Primary Production (Disciplinary Connections)

Date: Monday, February 12, 2001, Time: 11:15:00 AM

Location: Mesilla

Rue, E, L, Institute of Marine Sciences, UC Santa Cruz, Santa Cruz, CA, USA, elrue@cats.ucsc.edu

Smith, G, J, Institute of Marine Sciences, UC Santa Cruz, Santa Cruz, CA, USA, geosmit@cats.ucsc.edu

Lessin, L, , Institute of Marine Sciences, UC Santa Cruz, Santa Cruz, CA, USA,

Bruland, K, W, Institute of Marine Sciences, UC Santa Cruz, Santa Cruz, CA, USA, bruland@cats.ucsc.edu

The influence of iron and macronutrients in coastal upwelling regimes off Peru.

During September 2000 we participated in a major field study of upwelling regimes off Peru to examine the influence of iron and macronutrients on diatom blooms developing in these areas. We predicted we would find regions off Peru representing a mosaic of iron limitation regimes ranging from iron replete to iron deplete conditions similar to what has been previously observed for upwelling regimes off California. In the northern coastal regions of Peru, where the upwelling occurred over a wide continental shelf, we observed upwelling waters with extremely high iron concentrations (iron replete conditions) and observed exceptionally high chlorophyll a concentrations resulting from extensive blooms of large diatoms. In offshore regions, we observed iron deplete conditions, with the existence of large areas with high residual macronutrient concentrations, but low iron and chlorophyll a concentrations. In the southern coastal regions of Peru, where the upwelling occurred over a narrow shelf, we observed low concentrations of iron in the upwelling waters and did not observe extensive blooms of large diatoms. Surface transects and data from various regions of the dynamic Peruvain upwelling regime will be presented.

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Aquatic Sciences Meeting, Albuquerque 2001

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