Late winter coccolithophore bloom off central Portugal in response to river discharge and upwelling

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

“…7). Higher cell densities of E. huxleyi, as well as the small Gephyrocapsa group, appeared highly related to the upwelling regime, in agreement with other studies carried out in the central Iberian Margin and other coastal upwelling regions (Ziveri et al, 1995;Baumann et al, 2008;Silva et al, 2008;Guerreiro et al, 2013;Narciso et al, 2016), where both taxa are proposed as indicators of productive periods. Despite this common affinity for the upwelling regime, temporal variability of their absolute abundance and the CCA (Figs.…”

“…2 and 3c). Indeed, despite the general association of coccolithophores with weak upwelling and nutrient depletion, our results show that these phytoplankton groups may follow diverse life strategies, as demonstrated for this region by Guerreiro et al (2013).…”

“…As a consequence, discernment between autochthonous and allochthonous coccolithophore signals in the water column was not possible for these periods, preventing application of CCA to the RAIA data set. Guerreiro et al (2013) have observed a rapid increase in coccolithophore production at the inner shelf of the central Iberian Margin influenced by a nutrient-rich buoyant plume resulting from intense river runoff. However, our results give no conclusive evidence as to whether freshwater lenses advected to RAIA station influenced the total coccosphere abundance (Figs.…”

“…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.…”

“…Fossil coccolith records are being extensively used for climatic reconstructions along the western Iberian Margin (Parente et al, 2004;Flores et al, 2010;Incarbona et al, 2010;Amore et al, 2012;Palumbo et al, 2013). However, the few existing studies characterizing living coccolithophore community, distribution, abundance, and ecology in the water column are mostly based on central and southern areas (Cachão and Moita, 2000;Ferreira and Cachão, 2005;Silva et al, 2008;Moita et al, 2010;Guerreiro et al, 2013;Guerreiro et al, 2014), being scarce for northern locations (Abrantes and Moita, 1999;Moita, 2001). In this context, we present a year-long data set of coccospheres and free coccoliths based on monthly sampling at several depths at two different stations (one on the inner shelf and one on the outer shelf) across the NW Iberian Margin.…”