Associations among temperature, sea ice and phytoplankton bloom dynamics in the Barents Sea

Abstract

Variations in physical conditions caused by climate change are likely to have large influences on marine organisms, including phytoplankton. Here, we investigated associations between satellite-derived chlorophyll a data from the Barents Sea and 2 key abiotic factors: sea surface temperature and sea-ice concentration. Specifically, we investigated how climate variability, through the measured physical factors, associated with phytoplankton phenology between 1998 and 2014. Associations between sea surface temperature and phytoplankton bloom dynamics differed depending on the area. The spring phytoplankton bloom occurred earlier and had higher magnitude in warm compared to cold years in the northern part of the Barents Sea, but there was no significant association in the southern part. In seasonally ice-covered regions, the association between the timing of the sea-ice retreat and the phytoplankton peak was nonlinear: sea-ice retreat time before mid-May was not associated with bloom timing, whereas the phytoplankton bloom occurred before or immediately following the ice retreat when the ice retreated after mid-May. Although drivers that are relatively constant across years, such as insolation, probably influenced the spatial gradient in chlorophyll, a space-for-time substitution captured the predicted effects of sea-ice retreat on the timing and magnitude of the phytoplankton bloom quite well.

Meroplankton Diversity, Seasonality and Life-History Traits Across the Barents Sea Polar Front Revealed by High-Throughput DNA Barcoding

“…A secondary peak in abundance also occurred in April to the north of the Polar Front. This peak, largely driven by the ophiuroids O. gracilis and O. sericeum as well as the polychaete Spio sp., may represent a real surge in abundance just prior to the phytoplankton bloom (in May, Dalpadado et al, 2020;Dong et al, 2020). However, it could also be an artifact of the closer proximity to the Polar Front compared to other months, given that plankton often accumulate in patches around fronts (Trudnowska et al, 2016) and adult benthic invertebrates on the seafloor also occur in higher densities near the Polar Front (Carroll et al, 2008).…”

“…The spring phytoplankton bloom is broadly found to occur in May in the southern Barents Sea, when sufficient light and stratification of the water column favor bloom development. In ice-covered waters of the northern Barents Sea, however, the phenology of the phytoplankton bloom is more variable, occurring anytime from May to July depending on timing of sea ice retreat (Dalpadado et al, 2020;Dong et al, 2020). In these seasonally ice-covered waters, an ice algal bloom as well as an under-ice phytoplankton bloom can contribute primary production to the system prior to ice melt, extending the duration of the productive period (Syvertsen, 1991;Leu et al, 2015;Ardyna et al, 2020).…”

Multiple Trophic Markers Trace Dietary Carbon Sources in Barents Sea Zooplankton During Late Summer

“…Such environmental changes have major impacts on primary producers (algae) and their interactions with consumers in the Barents Sea ecosystem (Wassmann et al, 2006;Stige et al, 2019;Dalpadado et al, 2020;Dong et al, 2020). Zooplankton are key components of marine ecosystems, transferring energy from algae to fish and ultimately to top predators (Wassmann et al, 2006;Hop and Gjøsaeter, 2013;Planque et al, 2014).…”

Taxonomic and genetic confirmed findings of snow crab (Chionoecetes opilio) larvae in the Barents Sea

“…In the Barents Sea, the stabilization of the upper water mass layer established in late April or early May stratification usually is strengthened in March and April due to solar heating which results in onset of the phytoplankton bloom (Loeng 1991;Dong et al 2020). In a study using data from the Central Barents Sea from August to September in the period 1970 to 2016, temperatures in the upper water masses roughly ranged from 1 to 3.5 °C and the pycnocline generally establishes around 50 m (Lind et al 2018).…”