Interplay between ocean circulation and sea ice extent determines the breeding success of some key plankton populations. These in turn are the food for predators, and at some locations the changes in food supply give rise to dramatic changes in population dynamics. These changes can be traced back to the 1920s, again suggesting that the observed changes are natural. One of the plankton species affected by the sea-ice variability is the Antarctic krill. This is the subject of one of the largest Southern Ocean fisheries but also forms the food supply for several other exploited species.
Plankton also play a role in regulating the carbon dioxide concentration in the atmosphere.
A fraction of this is removed permanently as it sinks to the seabed but the rest is recycled and the carbon dioxide returns to the atmosphere. The composition of the plankton community ultimately regulates how much of this carbon is recycled, but could itself be regulated by changing environmental factors such as the alterations in incident ultra-violet light. The science bites that have emerged from BAS since then have radically altered this public perception. BAS is now well known to be a world-leader in environmental research. But behind each newsworthy science story, a team of scientists labour for the insight from which a science bite is distilled.