574 resultados para western gulf


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EXTRACT (SEE PDF FOR FULL ABSTRACT): The suppression of primary productivity observed in eastern boundary ecosystems of the Pacific during El Nino episodes does not occur throughout the Gulf of California. On the contrary, analysis of the modern siliceous phytoplankton record from annually layered sediments and compilation of available primary productivity measurements indicate that production is significantly increased in the central Gulf during El Nino years compared to anti-El Nino years. Integrated observations of biological and physical variability during the spring of 1983, under the influence of the strong El Nino, show that very high primary productivity occurred along the eastern margin of the central Gulf. This resulted from the upwelling of a nutrient rich source provided by the locally formed Gulf water mass originating in the northern Gulf. Lower productivity and phytoplankton biomass were associated with the anomalous penetration of Tropical Surface Water along the western side of the Gulf.

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Western Atlantic synodontid species were studied as part of an ongoing effort to reanalyze Caribbean shorefish diversity. A neighbor-joining tree constructed from cytochrome c oxidase I (COI) data revealed 2 highly divergent genetic lineages within both Synodus intermedius (Agassiz, 1829) (Sand Diver) and S. foetens (Linnaeus, 1766) (Inshore Lizardfish). A new species, Synodus macrostigmus, is described for one of the S. intermedius lineages. Synodus macrostigmus and S. intermedius differ in number of lateral-line scales, caudal pigmentation, size of the scapular blotch, and shape of the anterior-nostril flap. Synodus macrostigmus and S. intermedius have overlapping geographic and depth distributions, but S. macrostigmus generally inhabits deeper water (>28 m) than does S. intermedius and is known only from coastal waters of the southeastern United States and the Gulf of Mexico, in contrast to those areas and the Caribbean for S. intermedius. Synodus bondi Fowler, 1939, is resurrected from the synonymy of S. foetens for one of the S. foetens genetic lineages. The 2 species differ in length and shape of the snout, number of anal-fin rays, and shape of the anterior-nostril flap. Synodus bondi and S. foetens co-occur in the central Caribbean, but S. bondi otherwise has a more southerly distribution than does S. foetens. Redescriptions are provided for S. intermedius, S. foetens, and S. bondi. Neotypes are designated for S. intermedius and S. foetens. A revised key to Synodus species in the western Atlantic is presented.