TY - JOUR
T1 - An under‑ice bloom of mixotrophic haptophytes in low nutrient and freshwater‑influenced Arctic waters
AU - Søgaard, Dorte
AU - Sorrell, Brian Keith
AU - Sejr, Mikael Kristian
AU - Andersen, Per
AU - Rysgaard, Søren
AU - Hansen, Per Juel
AU - Skyttä, Annaliina
AU - Lemcke, Signe
AU - Lund-Hansen, Lars Chresten
PY - 2021/2
Y1 - 2021/2
N2 - The pelagic spring bloom is essential for Arctic marine food webs, and a crucial driver of carbon transport to the ocean depths. A critical challenge is understanding its timing and magnitude, to predict its changes in coming decades. Spring bloom onset is typically light-limited, beginning when irradiance increases or during ice breakup. Here we report an acute 9-day under-ice algal bloom in nutrient-poor, freshwater-influenced water under 1-m thick sea ice. It was dominated by mixotrophic brackish water haptophytes (Chrysochromulina/ Prymnesium) that produced 5.7 g C m
−2 new production. This estimate represents about half the annual pelagic production, occurring below sea ice with a large contribution from the mixotrophic algae bloom. The freshwater-influenced, nutrient-dilute and low light environment combined with mixotrophic community dominance implies that phagotrophy played a critical role in the under-ice bloom. We argue that such blooms dominated by potentially toxic mixotrophic algae might become more common and widespread in the future Arctic Ocean.
AB - The pelagic spring bloom is essential for Arctic marine food webs, and a crucial driver of carbon transport to the ocean depths. A critical challenge is understanding its timing and magnitude, to predict its changes in coming decades. Spring bloom onset is typically light-limited, beginning when irradiance increases or during ice breakup. Here we report an acute 9-day under-ice algal bloom in nutrient-poor, freshwater-influenced water under 1-m thick sea ice. It was dominated by mixotrophic brackish water haptophytes (Chrysochromulina/ Prymnesium) that produced 5.7 g C m
−2 new production. This estimate represents about half the annual pelagic production, occurring below sea ice with a large contribution from the mixotrophic algae bloom. The freshwater-influenced, nutrient-dilute and low light environment combined with mixotrophic community dominance implies that phagotrophy played a critical role in the under-ice bloom. We argue that such blooms dominated by potentially toxic mixotrophic algae might become more common and widespread in the future Arctic Ocean.
U2 - 10.1038/s41598-021-82413-y
DO - 10.1038/s41598-021-82413-y
M3 - Journal article
C2 - 33536514
SN - 2045-2322
VL - 11
JO - Scientific Reports
JF - Scientific Reports
M1 - 2915
ER -