Winter phytoplankton blooms in the offshore south Adriatic waters (1995–2012) regulated by hydroclimatic events: Special emphasis on the exceptional bloom of 1995

Abstract

<p><strong>Abstract.</strong> The characteristics and intensity of winter phytoplankton blooms in the open South Adriatic (OSA) were investigated by combining data on abundance and satellite-derived surface chlorophyll (1995–2012). Particular attention was paid to the different circulation regimes in the Ionian Sea, namely the anticyclonic and cyclonic Northern Ionian Gyres (NIG), both of which influence the physical and biochemical properties of the South Adriatic. Relatively high winter production was evident during both. Contrary to nutrient-poor cyclonic years, in nutrient-rich anticyclonic years, shallow vertical mixing is sufficient for enrichment of euphotic layers and bloom development. Moreover, intense blooms have occurred under certain hydroclimatic conditions: the East Mediterranean Transient (EMT), extreme winters, and reversal years that switch between anticyclonic and cyclonic circulation. Winter phytoplankton bloom in February 1995, with microphytoplankton abundance exceeding 105 cells<span class="thinspace"></span>L<sup>−1</sup>, was related to the phenomenon of EMT which produced dramatic changes in the East Mediterranean basin-wide circulation patterns. Dominance of a microphytoplankton species uncommonly encountered in the OSA may be related to strong inflow of Atlantic Water (AW) into the Adriatic during EMT and anticyclonic circulation in the NIG.</p>

Climate variability during MIS 20–18 as recorded by alkenone-SST and calcareous plankton in the Ionian Basin (central Mediterranean)

“…In the first case poornutrient LIW/CIW waters enter the north Ionian Sea and south Adriatic Sea, while the influx of MAW during anticyclonic phase favours upwelling events and nutrients supply at the periphery of the anticyclonic NIG along the southern Italian coasts before reaches the south Adriatic Sea (Civitarese et al, 2010). The alternating anticyclonic and cyclonic states are known as Adriatic-Ionian bimodal oscillation system (Civitarese et al, 2010;Gačić et al, 2010) that may influence nutrient distribution and phytoplankton growth (Civitarese et al, 2010;Batistić et al, 2017). Modern annual mean SSTs in the Gulf of Taranto are about 19.7 °C (Pujol and Vergnaud-Grazzini, 1995).…”

Paleoproductivity Modes in Central Mediterranean During MIS 20—MIS 18: Calcareous Plankton and Alkenone Variability

“…In this scenario, an increased influence of the WAC may have also contributed to the nutrient delivery in the study area. A contribution from local upwelling resulting from improved advection of Atlantic water during sea level rise that goes along with interstadials (Figure 1C), as occurs today at the periphery of the anticyclonic NIG (Batistić et al., 2014, 2017; Civitarese et al., 2010), cannot be also excluded.…”

“…A contribution from local upwelling resulting from improved advection of Atlantic water during sea level rise that goes along with interstadials (Figure 1C), as occurs today at the periphery of the anticyclonic NIG (Batistić et al, 2014(Batistić et al, , 2017Civitarese et al, 2010), cannot be also excluded.…”

The Ideale section at Montalbano Jonico (southern Italy): a Standard Auxiliary Boundary Stratotype (SABS) for the Middle Pleistocene Subseries of the Quaternary System

“…1D) . The alternating anticyclonic and cyclonic states are known as the Adriatic-Ionian bimodal oscillation system (Civitarese et al, 2010;Gačić et al, 2010) and they may influence nutrient distribution, water column structure and salinity, upwelling phenomena and phytoplankton growth (Civitarese et al, 2010;Batistić et al, 2017).…”