Biological effects of El Niño 1997-98 on a shallow subtropical ecosystem: Bahía Magdalena, Mexico
Sea surface temperature (SST), zooplankton biomass and chlorophyll a concentration, along with abundance of four copepodspecies: Acartia clausi, Acartia lilljeborgii, Paracalanus parvus and Calanus pacificus, and eggs and larvae of small pelagicfishes: Sardinops caeruleus, Scomber japonicus, Opistho...
| Autores: | , , , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2003 |
| País: | México |
| Institución: | Instituto Politécnico Nacional |
| Repositorio: | Redalyc-IPN |
| OAI Identifier: | oai:redalyc.org:56842317 |
| Acceso en línea: | https://www.redalyc.org/articulo.oa?id=56842317 |
| Access Level: | acceso abierto |
| Palabra clave: | Ciencias de la Tierra 98 copepods El Niño 97 Chlorophyll a Bahía Magdalena |
| Sumario: | Sea surface temperature (SST), zooplankton biomass and chlorophyll a concentration, along with abundance of four copepodspecies: Acartia clausi, Acartia lilljeborgii, Paracalanus parvus and Calanus pacificus, and eggs and larvae of small pelagicfishes: Sardinops caeruleus, Scomber japonicus, Opisthonema spp. and Anchoa spp., were measured and estimated from May1997 to December 1998 in Bahía Magdalena, Mexico. In order to study response of these species to seasonal environmentalconditions and to the anomalous warming conditions driven by the 1997-98 El Niño event. Positive SST anomalies were presentduring 15 months with a maximum value of +4.4 °C recorded during summer of 1997. Zooplankton biomass was lower by halfthan the previous El Niño 1982-83, but the seasonal pattern was maintained. A chlorophyll concentration maximum of 9.2 mg/m3was observed in late spring to early summer, with a minimum of 0.2 mg/m3 in winter. Copepod abundance changes and an increaseof tropical species were registered during the most intense phase of the warming. The temperate copepod Calanus pacificusassociated with the California Current, was recorded only during the cold period before the onset of El Niño. The seasonalabundance of autochtonous species followed the pattern previously recorded in the bay, but decreased by about one third, comparedto El Niño 1982-83. The abundance of temperate and tropical small pelagic fishes showed important changes related to theintense warming effect, with half the abundance of previous reports for temperate Sardinops caeruleus while, tropical Opisthonemaspp abundance increased by up to an order of magnitud in 1997-98. |
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