The UK government is committed to the long-term protection of over four million square kilometres of the world oceans that fall within the UK’s Overseas Territories. Prioritising which parts of the ocean are most important to protect depends on scientific information to help decide upon the size and location of these marine protected areas (MPAs). However, many of the UK Overseas territories such as the sub-Antarctic island of South Georgia are very remote and have limited scientific data. Very often habitat maps made using large-scale physical environmental data (such as depth, submarine terrain and water temperature) are used to help predict patterns in marine biodiversity where biological records are either poor or lacking.

Remotely-sensed data collected over decades of collaborative research in Antarctic can be compiled to help create maps of the physical environment on the seabed around South Georgia. (Credit: British Antarctic Survey)
Remotely-sensed data collected over decades of collaborative research in Antarctic can be compiled to help create maps of the physical environment on the seabed around South Georgia. (Credit: British Antarctic Survey)

A new publication in the journal Science of the Total Environment, from British Antarctic Survey, the National Oceanography Centre and University of Southampton, is the first attempt to see how well these large habitat maps help us understand the distribution patterns in the unique biodiversity of one of the world’s largest marine protected areas (1.07 million km2) at South Georgia. Lead author and marine ecologist Oliver Hogg says: “The waters surrounding the island of South Georgia teem with incredibly rich marine life; many species living there are found nowhere else on earth”.

A Blackbrowed Albatross soars in front of the mountain ranges of South Georgia. The waters surrounding the island are rich in nutrients and attract an abundance of wildlife. (Credit: Katja Riedel)
A Blackbrowed Albatross soars in front of the mountain ranges of South Georgia. The waters surrounding the island are rich in nutrients and attract an abundance of wildlife. (Credit: Katja Riedel)

The study found a distinct collection of marine animals associated with each of the different habitat regions, such as slow-growing cold-water corals found in complete darkness at depths of over a thousand metres and basket stars, a close relative of the starfish, which have spaghetti-like arms to grasp at food in South Georgia’s nutrient-rich waters. Regions sharing similar environmental conditions were shown to share more of the same species than regions with contrasting condition. This means that on very-large scales, habitat mapping could be meaningfully used to assist with planning and conservation in this important fisheries region.  It could also be a useful tool for other areas of the World that do not have enough available biological data.

Elephant seals give birth to their young on South Georgia beaches. Seal babies, so called weaners, litter the beached in December. (Credit: Katja Riedel)
Elephant seals give birth to their young on South Georgia beaches. Seal babies, so called weaners, litter the beached in December. (Credit: Katja Riedel)

Oliver Hogg concludes: “Through better understanding the link between the marine environment and the biological communities which live there, we are better placed to protect some of the rare, unique and fascinating marine life that inhabits these icy Antarctic waters”.

South Georgia and the South Sandwich Islands is a British Overseas Territory in the southern Atlantic Ocean. South Georgia is 165 kilometres long and 1 to 35 km wide. The seas around South Georgia have one of the highest bio diversities among all the ecosystems on Earth. (Credit: Stamp World History)
South Georgia and the South Sandwich Islands is a British Overseas Territory in the southern Atlantic Ocean. South Georgia is 165 kilometres long and 1 to 35 km wide. The seas around South Georgia have one of the highest bio diversities among all the ecosystems on Earth. (Credit: Stamp World History)

Source: British Antarctic Survey (BAS)