Spatial distribution of living coccolithophores in the southwestern Gulf of Mexico

Abstract

Abstract. The present study was conducted to provide information about the upper water column distribution of living coccolithophores in the subtropical Gulf of Mexico. In total, 52 plankton samples from 6 stations collected in March 2006 were analysed. Coccolithophore standing crops range from zero in deep-water samples (200 m) to about 23 000 to 46 500 coccospheres per litre at intermediate water depths. From 39 identified taxa, only nine species contribute significant cell numbers of more than 1000 cells 1–1 and comprise more than 5 % of the communities in at least one sample. Emiliania huxleyi was the most abundant species throughout the stations with concentrations of up to 22 700 cells l–1. At all stations, a vertical succession of coccolithophore species was found. Umbellosphaera tenuis (type IV), Discosphaera tubifera, Rhabdosphaera clavigera and, as a minor component, species of the genus Syracosphaera, were mainly restricted to surface waters (≤50 m), all adapted to lower nutrient levels. The assemblage in the deep photic zone (50–150 m water depth) was composed mainly of abundant Florisphaera profunda, Gladiolithus flabellatus and Algirosphaera robusta indicating a tolerance of lower light availability. Thus, the vertical distribution of all coccolithophorid taxa, except the placolith-bearing species, in particular E. huxleyi, was probably controlled by upper photic-zone water temperature and stratification of the water column.

GDGT and alkenone flux in the northern Gulf of Mexico: Implications for the TEX86 and UK'37 paleothermometers

“…We consider the former possibility to the most likely explanation, as it has been observed in the Atlantic that deep production of alkenones below the mixed layer peaks during summer stratification [ Kinkel et al ., 2000]. A coccolithophorid assemblage study in the southwestern Gulf of Mexico likewise indicates that coccolithophorid abundance peaks between 50 and 100 m water depth with E. huxleyi dominating the assemblage down to 100 m [ Baumann and Boeckel , ]. The upper water column in the nGoM is highly stratified in the summer, with an integrated temperature of 28–29°C for the upper 75 m of the water column (based on August 2011 and 2012 CTD casts at the site).…”

Spatial and temporal variability in coccolithophore abundance and distribution in the NW Iberian coastal upwelling system

“…7 and 8). This species is regarded as a component of the lower limit of the photic zone in coastal settings (Baumann and Boeckel, 2013), and has been related to relatively nutrient-rich coastal waters in the SW Iberian Margin (Ferreira and Cachão, 2005;Silva et al, 2008;Guerreiro et al, 2013;Guerreiro et al, 2014). Its highest abundance coincides with maximum Chl a values and higher nutrient content (Figs.…”

Spatial variability of dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) in the southern Gulf of Mexico

“…[90] However, no studies refer to their spatio-temporal distribution. Studies have focussed only on the spring season, [91,92] and have mentioned that the highest phytoplankton abundance was dominated mainly by the species E. huxleyi and Gephyrocapsa oceanica in the stations near the Grijalva-Usumacinta and Coatzacoalcos rivers. A predominance of E. huxleyi and of the diatom Nitzschia bifurcata, of the Class Bacillariophyceae, which is also considered a producer of DMSP, has been recorded for the Campeche Canyon.…”

“…[93] In March 2006, coccolithophores were also found to play an important role in the structure of the phytoplankton communities of the southern GM (Bay of Campeche), with E. huxleyi the most abundant species throughout the area at concentrations of up to 22 700 cells L À1 . [92] Notwithstanding that the presence of coccolithophorids has not been reported for the study area during winter, there are studies in other parts of the world that report high concentrations during this season, mainly of E. huxleyi and G. oceanica, [94][95][96][97] indicating that these species are present in different oceans of the world throughout the year.…”