Successional Processes in Antarctic Benthic Algae

Abstract

Despite the importance of benthic algal communities to Antarctic coastal ecosystems, much information about their dynamics is still needed. Primary succession processes in the Antarctic benthos are frequently initiated by ice-mediated disturbance and by the creation of denuded substrate following glacier retreat, both expected to increase in the future. Primary succession of benthic algae starts with rapid colonization by diatoms, ephemeral green algal filaments and propagules of annual and pseudoperennial macroalgae. Early stages of macroalgae can be particularly vulnerable to environmental stress factors, being critical for the structure of mature communities. The Antarctic environment is severely affected by global change, and successional patterns can change due to species-specific susceptibilities to abiotic and biotic drivers, introducing changes in the matter and energy flow in the coastal food webs. This chapter summarizes new advances in our knowledge on the successional dynamics of benthic primary producers in the Antarctic hard-bottom benthos. Manipulative experiments on the effects of grazing and ultraviolet (UV) radiation as drivers of the succession at early stages and long-term experiments carried out at sites with different environmental conditions are compiled. The gathered information can contribute to achieve a deeper knowledge of these key communities and their structure and functioning in a changing environment.