Through predictive models, research published in the scientific journal Progress in Oceanography revealed that by the end of the century there will be a decrease in the biomass of this organism. This will also mean a displacement of species that depend on it, such as penguins and crabeater seals.
Antarctic krill (Euphasia superba,) a small crustacean that is between 6 and 7 centimeters long, is an essential food source for whales, penguins, seals, squid and fish, among other marine organisms. It is considered the key link in the food webs of the white continent and, despite its abundant biomass, it is also vulnerable to the effects of climate change and the action of man.
A group of scientists from various Chilean institutions, including the University of Concepción (UdeC) and the Center for Dynamic Research of High Latitude Marine Ecosystems (IDEAL) of the Austral University of Chile (UACh), developed a study to determine what happens with this species under future climatic conditions. The team of researchers implemented a new version of a predictive model to learn how environmental variables will affect krill biomass from now to 2100.
The professionals used a trophic model called Ecopath. With it, they made three environmental climate projections under parameters such as the extent of sea ice and the concentration of chlorophyll; in addition to analyzing anthropogenic variables related to the krill fishery (no capture, constant fishing and increase in this activity.) The sampled area covered the western part of the Antarctic Peninsula, from Alexander Island to the eastern part of Elephant Island.
The study reflected the importance of environmental variables in the evolution of this organism, with special emphasis on chlorophyll-a, a photosynthetic pigment that is produced by phytoplankton, food for krill. The quantity of this element strongly influenced the variability of the Antarctic food web in the future, generating changes towards the end of the century. The research also detected a decrease in E. superba and an increase in other zooplanktonic organisms, such as salps.
The decline in krill biomass will also mean a displacement of species that depend on it, such as penguins and crabeater seals. “With this we are not talking about a collapse in the food web, but it will mean an important restructuring, not only regarding those who go up or down in the food web, but at a spatial level, because it will force those who depend on this resource to move around to find it,” commented Dr. Andrea Piñones, oceanographer at the IDEAL Center and co-author of the study.
Regarding the impact of the fishery on the quantity of krill, the results of the predictive model consider a low influence on the biomass of this organism. However, the absence of studies that chart its spatial and seasonal variability could cause an underestimation of its real impacts on the ecosystem.
“The results of this research suggest a strong decline in Antarctic krill biomass by the end of the century under all climate scenarios and independent of fishing pressure. The next steps will be to corroborate the results obtained in the field and improve the model so that it better represents the life cycle of the species and the distribution of fisheries, in order to obtain more representative projections,” concluded Dr. Giovanni Testa, oceanographer of the UdeC and leader of the investigation.
The work published in the scientific journal Progress in Oceanography provides information on the response and dynamics that the species would have in the future. Studying krill biomass will provide evidence of real impacts on climate, fisheries, biodiversity and tourism.
Check the research here.