The study, published by the scientific journal Biology, highlights new environments that could be refuge and breeding areas for countless marine organisms.
The detachment of icebergs in Antarctica has increased in recent years as a consequence of climate change that strongly affects high latitudes. Large expanses break away from the glaciers to float across the sea and run aground in coastal areas and erode everything in their path. This impact has been widely documented in the scientific literature and described as one of the most powerful disturbances at the ecosystem level.
However, the sinkholes generated by the ice in areas of soft bottoms (sand or mud) act as traps for drifting algae which, carried by marine currents or tides, are deposited in those depressions. The accumulation of this material in coastal areas of the Antarctic Peninsula generates a new habitat that is used by other organisms such as invertebrates and fish. The description of this new environment was published in the scientific journal Biology.
“We use the term ‘icepit,’ a technical concept used to describe depressions caused by ice erosion on the seabed at great depths, but until now it had not been applied or linked to an ecological process in the shallow waters of Antarctica” said Ignacio Garrido, a researcher at the Center for Dynamic Research in High Latitude Marine Ecosystems (IDEAL) at the Austral University of Chile (UACh) and director of the Calfuco Aquatic Resources Coastal Laboratory (LCRAC), who led the study.
“Historically, ecology of communities of soft (sand) and hard (rock) bottom environments has been done. However, these ‘icepits’ are mixed and this work is pioneer in analyzing their formation dynamics over time and the species of algae found there,” stated Dr. Luis Miguel Pardo, IDEAL Center researcher and director of the Graduate School of the Faculty of Sciences of UACh, co-author of the research.
The scientists carried out a characterization of these habitats in 17 sites in front of Fildes Bay. Although the ‘icepits’ only covered 4.2% of the seabed, they contained 98% of the biomass of drifting algae, considered true material “traps”.
In the study it was observed that the decomposition rate of the algae that stranded in these sinkholes is very slow, due to the low temperatures of Antarctica. Added to this is its ability to adapt to low light levels. For this reason, algal accumulations are usually colonized by amphipods, isopods, starfish, anemones and some fish.
“The algae accumulated in these tunnels are colonized by organisms that are tolerant of low oxygen levels, thus avoiding predation. Therefore, the ‘icepits’ become refuges for species in their adult and juvenile stages, acting as breeding areas. We are beginning to discover a habitat that may have an important role in the entire Antarctic benthic ecosystem,” said Dr. Pardo.
“Most of investigations speak of this type of disturbance as damage to the Antarctic benthos, but no one had highlighted that this erosion of the soft seabed also generates a window to create this new habitat,” concluded Garrido.
During this year’s Antarctic Scientific Expedition (ECA 59), the second part of this research will be carried out, which will include determining the ecological role of algal accumulations in these ‘icepits’, on the functioning of the ecosystem in this quick changing polar environment.
Read the research here.