The trophic ecology of Antarctic anthozoans and their role in benthic−pelagic coupling processes is poorly understood. We studied 7 gorgonian species (Primnoisis sp., Fannyella nodosa, Ainigmaptilon antarcticum, Notisis sp., Primnoella sp., Dasystenella sp. and Thouarella sp.) in 2 Antarctic regions: the Eastern Weddell Sea and the Bransfield Strait (Antarctic Peninsula) in austral autumn 2000, a period in which primary productivity drastically decreases. We aimed at finding the main food sources for these gorgonians and to elucidate the strategies of the 7 species in this season, relating the obtained data with their biology and ecology. Stable isotope data of the 7 gorgonian species was virtually the same as that measured in the phytodetritus of the so called 'green carpets' and in microzooplankton (δ 13 C from −27.7 to −24.8 ‰; δ 15 N from 4.1 to 7.5 ‰). A large proportion of the gorgonian's diet seems to be based on sedimented and resuspended material, which supports the hypothesis that some suspension feeders deal successfully with the Antarctic winter by consuming phytoplankton sedimented in the 'green carpets'. While stable isotope analysis suggested similar food sources for 7 species, the biochemical balance indicated different energy storage as lipid values (mean ± SD) ranged from 105.1 ± 99 to 776.4 ± 354.1 µg lipids mg −1 organic matter depending on the species. Our results contribute to a better understanding of the trophic ecology of benthic Antarctic gorgonians and their strategies for coping with autumn conditions in this polar environment.

In the Southern Ocean, the trophic ecology of deep-sea communities is probably one of the most neglected fields in the discipline. In the present study, the trophic position and energy storage-mobilization of 3 different deep-sea echinoderms living in the Weddell Sea (around 1500 m depth) were investigated with indirect tools (i.e. stable isotopes, carbohydratelipid-protein balance, and free fatty acid [FFA] contents). The stalked crinoid Dumetocrinus antarcticus, the holothurian Rhipidothuria racovitzai, and the ophiuroid Ophiura carinifera were sampled in spring 2003 during a Polarstern cruise. We found that stable isotopes were in line with previous results of other species ( 13 C ranging from-24.3‰ to-26.5‰;  15 N ranging from 6.8‰ to 7.9‰), showing similarities in the trophic position of the 3 echinoderms. The capability to store energy by these 3 organisms is conspicuous and different, e.g. from 18 to 45% of the organic matter (OM) consists of lipids. The capability to mobilize energy in the form of carbohydrates and FFAs among species was also very different (e.g. biomolecules ranging from 9 to 22 µg carbohydrates mgOM-1 and from 4 to 39 µg FFA mgOM-1). It is suggested that even if the trophic level is similar in the 3 echinoderms, the strategies to invest the energy inputs in these deep-sea organisms in polar environments may be quite different.

<p>A Associação de Pesquisadores e Educadores em Início de Carreira sobre o Mar e os Polos (APECS-Brasil), comitê brasileiro da <em>Association of Polar Early Career Scientists </em>(APECS)<em>, </em>vem desenvolvendo, no Brasil, atividades de divulgação da ciência polar de forma direta e contínua, reflexo das ações e projetos desenvolvidos no contexto do Ano Polar Internacional (2007-2009). A APECS-Brasil, no contexto das Semanas Polares Internacionais (SPIs), promove desde 2008 a integração de escolas de todo o Brasil. Nossos objetivos são: incentivar a comunicação, divulgação e compreensão da ciência em sala de aula e em ambientes não formais de educação e; aproximar educadores, cientistas e estudantes da ciência polar, trazendo conhecimentos para o dia-a-dia da sala de aula. A ideia é de preparar o professor, agente direto de construção do conhecimento dentro da sala de aula, como disseminador do conhecimento sobre o mar e os polos através da troca de informações entre pesquisadores e professores. Para facilitar a inclusão destas atividades e auxiliar os professores foi desenvolvido um tutorial que apresenta ideias de abordagem da ciência antártica em sala de aula, despertando o interesse dos estudantes pela pesquisa científica e aproximando a ciência da realidade local e possibilitando um diálogo interdisciplinar e multidisciplinar em sala de aula.</p>

No abstract

The amphipod Gondogeneia antarctica is among the most abundant benthic organisms, and a key food web species along the rapidly warming West Antarctic Peninsula (WAP). However, little is known about its trophic strategy for dealing with the extreme seasonality of Antarctic marine primary production. This study, using trophic markers, for the first time investigated seasonal dietary shifts of G. antarctica in a WAP fjord. We analyzed δ13C and δ15N in G. antarctica and its potential food sources. The isotopic signatures revealed a substantial contribution of red algae to the amphipod diet and also indicated a significant contribution of benthic diatoms. The isotope results were further supported by fatty acid (FA) analysis, which showed high similarities in FA composition (64% spring–summer, 58% fall–winter) between G. antarctica and the red algal species. G. antarctica δ13C showed a small shift seasonally (−18.9 to −21.4‰), suggesting that the main diets do not change much year-round. However, the relatively high δ15N values as for primary consumers indicated additional dietary sources such as animal parts. Interestingly, G. antarctica and its potential food sources were significantly enriched with δ15N during the fall–winter season, presumably through a degradation process, suggesting that G. antarctica consumes a substantial portion of its diets in the form of detritus. Overall, the results revealed that G. antarctica relies primarily on food sources derived from benthic primary producers throughout much of the year. Thus, G. antarctica is unlikely very affected by seasonal Antarctic primary production, and this strategy seems to have allowed them to adapt to shallow Antarctic nearshore waters.