Chlorophyll-a vertical distribution patterns during summer in the Bay of La Paz, Gulf of California, Mexico

Abstract

An understanding of chlorophyll-a vertical distribution patterns is essential for evaluating the productive potential of the oceans and implications for food webs. Based on high-resolution in-situ observations for conductivity, temperature and fluorescence of chlorophyll-a made at 30 stations during a multidisciplinary research cruise, this paper aims to assess the vertical distribution of chlorophyll-a in the Bay of La Paz, Gulf of California, Mexico, during the summer of 2009. The maximum chlorophyll-a concentration was 3.03 mg m−3 with a vertical distribution consistent with two patterns: 1) a peak closely related with the seafloor at the stations in the shelf area, close to the coast, and 2) a peak related with the thermocline and pycnocline, either above or below, in the central region of the bay. These patterns might have several implications for food webs, particularly for grazers, recently reported in high abundances in the bay. On the basis of these observations, a zonal trend would be expected for summer, whereby the two vertical patterns described above can be observed.