Phytoplankton biomass and production in the Gulf of California: a review

Abstract

The Gulf of California has three main natural fertilization mechanisms: upwelling, tidal mixing, and water exchange with the Pacifi c Ocean. Waters high in nutrients occur at very shallow depths in the gulf, and little energy is required for these nutrients to reach the euphotic zone. Upwelling off the eastern coast is strong, chlorophyll a concentration (Chl) can exceed 10 mg m -3 , and because of eddy circulation it increases the phytoplankton biomass across the gulf. Because of strong stratifi cation during summer, upwelling off the western coast causes Chl to increase only to ∼ 0.5 mg m -3 . The annual cycle is the dominant mode of Chl variability in most of the gulf. El Ni ñ o events cause the suppression of Chl mostly in areas on the eastern side of the central and southern gulf, with the effect decreasing from the mouth to the central gulf. 14 C data show that highest productivities occur during winter -spring, and in the Guaymas Basin (up to > 4 g C m -2 day -1 ). Averages of total integrated production (P Tint ) for " winter " and for whole regions within the gulf estimated from satellite imagery are in good agreement with averages of 14 C estimates ( ∼ 1.8 g C m -2 day -1 ). P Tint values for " summer " are ∼ 30 % of those for " winter. "Keywords: 14 C incubations; El Ni ñ o effect; Gulf of California; phytoplankton biomass and production; satellite color imagery. Brought to you by | University of Virginia Authenticated | 128.143.23.241 Download Date | 10/4/12 8:04 AM

Variabilidad en el tamaño y alimentación de Acanthaster planci (Echinodermata: Asteroidea) en el sur del Golfo de California, México

“…del disco de A. planci y de su alimentación en cuatro sitios del sur del Golfo de California. Su tamaño se considera una variable relevante, ya que está relacionado con aspectos como la reproducción (mayor fecundidad) y alimentación, donde organismos grandes consumen más tejido, resultando en una mayor pérdida de cobertura coralina, cambios ecosistémicos y repercusiones en actividades económicas (Keesing & Lucas, 1992;De'ath & Moran, 1998;Reyes-Bonilla & Calderon-Aguilera, 1999;Uthicke et al, 2009;Kayal et al, 2011;2012;Babcock et al, 2016b).…”

Field and satellite observations on the seasonal variability of the surface chlorophyll-a in the Bay of La Paz, Gulf of California, Mexico

“…During the winter, strong and persistent winds induce strong mixing within the water column, which ensures high nutrient concentrations in the euphotic layer available for the phytoplankton where the highest values of CHLA were observed. In contrast, during the summer the low wind speed conditions associated with frequent calm periods inhibit mixing of the water column, and thus there are no nutrient fluxes in the euphotic layer, leading to the lowest values of CHLA [12]. Another mechanism that could be involved in determining the observed seasonal variability in the levels of CHLA is related to the heating and cooling of the surface layer throughout the annual cycle.…”

“…In the Bay of La Paz, CHLA variability has been associated with normal periods of surface layer heating and cooling, which in turn determine the mixed layer and the availability of nutrients that promote a high phytoplankton biomass [12]. Based on insitu observations, the seasonal variability of CHLA in the Bay of La Paz was evaluated by Martínez-López et al [13], who linked the physical forcing with the CHLA concentration, showing an inverse relationship with temperature and water column transparency; the lowest values were found during the warmest season as a result of strong water stratification while the highest values were observed during the coldest season as a result of mixing processes in the water column.…”

CRISPR-Cas systems in the marine actinomycete Salinispora: linkages with phage defense, microdiversity and biogeography

“…Location-specific spacers provide evidence of exposure to local virus populations [ 41 , 55 ], with the majority of localized spacers occurring in strains from the Sea of Cortez (Figure 4 A). This is a highly productive sea [ 56 ] enclosed by a distinct geographical barrier and the only site classified as a Coastal biome [ 54 ]. While these results are preliminary, it is intriguing to speculate that spacer sequences can be used to trace location-specific interactions with distinct MGE pools, as also observed in other ecosystems [ 23 , 57 , 58 ].…”