What do we know? What’s next?

The Southern Ocean is critical to the rest of the oceans, accounting for one-third of global carbon dioxide sequestration and playing an important role in mitigating climate change by lowering carbon dioxide levels in the atmosphere. The North Antarctic Peninsula (NAP), located in West Antarctica and inside Antarctica, is seeing the most rapid warming in ocean and air temperatures.

The pressures caused by climate change will shape the biological communities along the NAP. At the base of the food chain, the effects of the changes will have consequences on the phytoplankton morphology and could even alter the phytoplankton communities in the region under study.

Although the response of local phytoplankton communities is expected to vary in the short and long term, a general trend towards a smaller morphotype with flagella (tails) is expected. This may have consequences for the ecosystem (Figure 1), as the remaining elements, such as krill, may not be able to adjust to the changes. Climate change is projected to have a long-term impact on the community, potentially leading to further transformations.

Current knowledge of this region provides information on phytoplankton’s response to climate change and what may occur. To fully comprehend and predict the changes that will occur in the region’s communities, a combined effort is required.

The main knowledge gap in the NAP is the intrinsic and elusive link between anthropogenic climate change and natural climate variability. To assess the impact of climate change, we must distinguish between natural internal fluctuation and long-term changes.

To close this gap, several research directions must be taken in the future (Figure 2), as well as expanding the current sampling effort, for which we have various methods that could be used, such as animal-borne sensors, ocean colour satellites, biogeochemical floats, underwater gliders, and more expeditions on ships to collect in situ data.

It is critical to assess how potential changes in phytoplankton composition may impact well-being and normal ocean functions. Understanding phytoplankton responses to climate change will not be possible without a better understanding of phytoplankton physiology in the PNA, which requires conducting studies with various stressors such as light, salinity, and carbon dioxide, focusing on the responses of the main phytoplankton species to them. Obtaining this knowledge will require the collaboration of polar research programmes and the scientific community within a common research framework.

Reference: Ferreira A, Costa RR, Dotto TS, Kerr R, Tavano VM, Brito AC, Brotas V, Secchi ER and Mendes CRB (2020) Changes in Phytoplankton Communities Along the Northern Antarctic Peninsula: Causes, Impacts and Research Priorities. Front. Mar. Sci. 7:576254.


Author: G. Sofia Nunes