How do macroalgae colonize newly ice-free areas in Potter Cove?

MARIA LILIANA QUARTINO; GABRIELA LAURA CAMPANA; DOLORES DEREGIBUS; GUSTAVO EDGAR JUAN LATORRE; FERNANDO ROBERTO MOMO; KATHARINA ZACHER

Bremerhaven

Workshop; IMCOAST Workshop 2012; 2012

Alfred Wegener Institute

Benthic macroalgal communities of Potter Cove have been studied regularly for more than 20 years. These studies revealed a complex community with high biomass production, considered to be one of the main carbon sources in the system. Until 1993 the inner cove was completely devoid of macroalgae and only rare exceptions were found on few boulders and stones of moraine deposits, which occurred in front of the glacier cliffs. Over the last years Fourcade glacier retreat has exposed newly ice-free areas, providing a substrate for macroalgal colonization. However, simultaneously an alteration of the water column (due to an increase of sediment input and salinity changes) and on the ice disturbance patterns are expected to influence the structure of the algal communities developing in these areas. In order to get an understanding of the structure and functioning of the macroalgal communities established in these areas: community structure, patterns of early colonization and succession and ecophysiological studies of key macroalgal species have been analysed in six newly ice-free areas, with different degree of glacial influence. Simultaneously, physical and optical properties of the water column have been monitored and related to the observed biological patterns.Macroalgae were found colonizing all the newly ice-free studied areas, even in close proximity to the retreating glacier. The complexity of macroalgal communities, the colonization and succession patterns, and the vertical distribution were site-specific and related to the degree of glacial influence. Considering that the spatial distribution of the macroalgal community is expanding to the inner cove, changes in the structure and function of the benthic system are expected. Furthermore, a higher macroalgal primary production in this area could lead to modifications of the energy and matter flows through the coastal food web.