Climatic factors and their robust evidences controlling phytoplankton biomass in the Bransfield Strait

Abstract

The long-term variability of chlorophyll a (Chl-a) was analyzed during a 12year period (2002 -2014) in the Bransfield Strait, Antarctica, to assess the interannual variability of the Chl-a and its main regulating environmental variables. We found that Chl-a was significantly correlated with the El Niño Southern Oscillation (ENSO) phase (r = -0.65), sea surface temperature (SST) (r = 0.70), and wind speed (r = 0.72), and changes in these factors preceded the Chl-a change by 0 -4 months. High phytoplankton blooms (indicated by Chl-a levels) tended to coincide with higher SSTs, and lagged with wind speed variation during La Niña periods. This suggests that atmospheric teleconnections with ENSO-related processes, SST, and wind speed could have a direct impact on phytoplankton biomass in the Bransfield Strait in short-term (< 4 months) scales. Furthermore, our simple multivariable regression analysis showed the prominent possibility of using the three variables to predict Chla in the Bransfield Strait region. Overall, this study will help us to understand how atmospheric and oceanic fluctuations could affect phytoplankton dynamics in the Southern Ocean.

Biophysical coupling of seasonal chlorophyll-a bloom variations and phytoplankton assemblages across the Peninsula Front in the Bransfield Strait

“…The resulting time-series (2002-2010) displays a strong interannual variability, with summertime values ranging from ~ 1.1 mg m -3 (2006) to 0.37 mg m -3 (2003; their Figure 9). In the second study, the authors placed a slanted rectangular box parallel to the SSI coastline, and similar to our two boxes south of the SSI, but in their case extended towards Elephant Island (La et al, 2019). The resulting monthly climatology of the chl-a over the period 2002-2014 (12-year mean) displays the cycle from October to April.…”

“…The chl-a bloom develops then from baseline concentrations below 0.2 mg m -3 in October to peak concentrations ranging from ~ 1.75-1.95 mg m -3 (their Figure 2) through February to March. We attribute the higher climatological values in La et al (2019), occurring about one month later than in our boxes along the SSI, to the different choice of the study area. In their case the northward extension of the box may be including dynamics out of the Bransfield Strait, from the confluence zone with the Weddell Sea.…”

Biophysical coupling of seasonal chlorophyll-a bloom variations and phytoplankton assemblages across the Peninsula Front in the Bransfield Strait

“…The resulting time series(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010) displays a strong interannual variability, with summertime values ranging from ∼ 1.1 mg m −3 (2006) to 0.37 mg m −3 (2003; their Fig.9). In the second study,La et al (2019) placed a slanted rectangular box parallel to the SSI coastline and similar to our two boxes south of the SSI, but in their case it extended towards Elephant Island. The resulting monthly climatology of the chl a over the period 2002-2014 (12-year mean) displays the cycle from October to April.…”