Research on climate-change impact on Southern Ocean and Antarctic ecosystems after the UN Paris climate conference –"now more than ever" or "set sail to new shores"?

The Paris Agreement, being the main result of the COP21 UN climate conference in 2015, included the ever most clearly defined political statement on anthropogenic climate change and the need for it to be reduced. In an opinion survey, Antarctic ecosystem researchers expressed their views, in which direction science should develop, after their mission to provide evidence for the existence of anthropogenic climate change and its impacts is accomplished. Four options for answers were offered. The majority voted in support for research for a better ecosystem understanding under climate change, since overarching questions seem to not yet be sufficiently answered. Applied research for mitigation received an intermediate amount of support. Similar amount of support was received for no changes in research strategies. This might be a result of an already existing lively progression of new developments, but might also be due to some old and burning questions, which still remain unanswered, e.g. on the Southern Ocean acting as a biological CO2 sink. Fewest experts thought that scientists should define totally new scientific themes. The results were also analysed separately for different groups of respondents in terms of stage of career, employing institutions (mission orientated or independent), and terrestrial or marine scientists. New student courses and university degrees are proposed, since new requirements by stakeholders demand new research strategies but traditional academic education and creativity is also still needed

High environmental variability and steep biological gradients in the waters off the northern Antarctic Peninsula.

199 pagesInternational audienc

Biodiversidad y estructura del mega-epibentos en la región de Magallanes (América del Sur)

Epibenthic communites have been investigated at 55 stations in the Magellan region by underwater photogra-phy at water depths between 15 and 430m. Five species assemblages were identified of which the two shallow and the two deep ones in the channel system differed considerably in abundance, number of taxa, diversity and species composition. The dominant systematic group of the shallow assemblages were ascidians. In one of these assemblages decapod crustaceans, in the other mainly sessile suspension feeders e.g. sponges, anthozoans and bryozoans were the characteristic taxa. In the deeper assemblages echinoderms were most abundant. The fifth assemblage, consisting of several offshore stations south of the eastern entrance of the Beagle, was more similar to the shallow stations in the channel system in terms of dominant life forms. Various hypotheses were confirmed or rejected: The benthos at the deeper stations in the channel system was not more homogeneous than at the shallow stations. At both the channel and the offshore stations filter feeders were most dominant whereas at the bottom of the channels deposit feeders were more abundant. Differences between the wide Straits of Magellan and the narrow and steep Beagle Channel were not very distinct. The benthic assemblages inside the channel system did not differ considerably from the assemblage outside the channel system with the exception of the stations close to the continental slope of the Atlantic. Differences due to Pacific or Atlantic influences were not recognisable. The biological patterns could best be explained by the environmental parameters water depth, occurrence of soft sediment and biogenic debris.Se estudiaron las comunidades epibentónicas en 55 estaciones de la región de Magallanes en profundidades entre 15 y 430 m mediante fotografía subacuática. Se identificaron cinco comunidades distintas. Las dos comunidades someras y las dos profundas en el sistema de canales revelaron diferencias considerables en lo que se refiere a abundancia, número de taxones, diversidad y composición específica. Las ascidias predominaron en las comunidades someras. En una de ellas, los crustáceos decápodos fueron el taxón característico mientras en la otra lo fueron los suspensívoros sésiles tales como esponjas, antozoos o briozoos. En las comunidades de mayor profundidad los equinodermos fueron el grupo más notable. La quinta comunidad, compuesta por varias estaciones situadas al sur de la entrada este del Canal del Beagle, resultó ser muy parecida a la de las estaciones someras en el sistema de canales en términos de formas de vida dominantes. Se aceptaron o rechazaron varias hipótesis. El bentos en las estaciones más profundas del sistema de canales no se mostró más homogéneo que en las estaciones someras. Tanto en las estaciones cercanas como en las estaciones fuera de la costa predominaron los suspensívoros, mientras que los detritívoros fueron el grupo dominante en el fondo de los canales. No se detectaron diferencias muy marcadas entre el Estrecho de Magallanes, de configuración ancha, y el Canal del Beagle de forma estrecha y pendiente fuerte. Con excepción de las estaciones cercanas al talud continental atlántico, las comunidades fuera del sistema de canales no se distinguieron mucho de las de dentro. No se evidenciaron diferencias faunísticas causadas por influencia pacífica o atlántica. Los patrones biológicos se pueden explicar mejor por los parámetros ambientales profundidad del agua, presencia de sedimentos blandos y escombros biogénicos

Dynamic benthic communities: assessing temporal variations in benthic community structure, megafaunal composition and diversity at the Arctic deep-sea observatory HAUSGARTEN between 2004 and 2015

Established in the Fram Strait in 1999, the LTER (Long-Term Ecological Research) observatory HAUSGARTEN enables us to study changes on the deep Arctic seafloor. Repeated deployments of a towed camera system (Ocean Floor Observation System) along the same tracks allowed us to build a time series longer than a decade (2004 - 2015). Here, we present the first time-series results from a northern and the southernmost station of the observatory (N3 and S3, ~2650m and 2350m depth respectively) obtained via the analysis of still imagery. We assess temporal variability in community structure, megafaunal densities and diversity, and use a range of biotic and abiotic factors to explain the patterns observed. There were significant temporal differences in megafaunal abundances, diversity and abiotic factors at both stations. A particularly high increase in megafaunal abundance was recorded at N3 from 12.08 (±0.39; 2004) individuals m-2 to 35.21 (±0.97; 2007) ind. m-2 alongside a ten-fold increase in (drop-)stones. At S3, megafaunal densities peaked in 2015 (22.74 ±0.61 ind. m-2) after an increasing trend since 2004 (12.44 ±0.32 ind. m-2). Holothurians showed particularly striking temporal differences: densities of the small sea cucumber Elpidia heckeri densities rose ten-fold from 0.31 ind. m-2 (±0.04; 2004) to 3.74 ind. m-2 (±0.14; 2015) at S3, coinciding with a sustained increase in phytodetritial matter (chloroplastic pigment equivalents) at the seafloor. Initially entirely absent from N3, densities of the larger holothurian Kolga hyalina peaked in 2007 (5.87 ±0.22 ind. m-2) and declined continuously since then. Overall diversity (γ) increased at both stations over the course of the study, however, with varying contributions of α and β diversities. Our results highlight the importance of time-series studies as megafaunal community composition is characterised by continuous changes. This indicates that epibenthic communities from the deep seafloor are reactive and dynamic, with no “null” community state. To continue to monitor them is therefore crucial in understanding natural and anthropogenic impacts in an area exposed to the effects of climate change