Spring transition in sea ice net community production

What is it about?

This study shows the potential for net heterotrophic conditions in the bottom of sea ice during the Arctic spring, despite sufficient light being available for photosynthesis and the moderate accumulation of carbon biomass. These findings highlight the importance of (i) species composition on productive state, (ii) community respiration on net oxygen fluxes between the ice and ocean, and (iii) the potential influences of facultative heterotrophy or sustained ice colonization by pelagic cells throughout the bloom. The occurrence of a net heterotrophic state at a time when algae dominate the ice community also challenges the common assumption that photosynthesis during the spring bloom will always result in positive net production (autotrophy).

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Why is it important?

Sea ice can be net heterotrophic during the Arctic spring, despite sufficient light being available for photosynthesis A rapid (within 1 week) switch from net heterotrophy to autotrophy coincided with a transition in the algal community from pennate to centric diatoms The potential for heterotrophy during the spring bloom highlights a complexity of carbon cycling in sea ice not previously anticipated