ALBERT

Beschreibung: Barnacle cypris larvae respond to many cues when selecting a settlement site. The settlement of over a million larvae on tiles of different textures, orientations and densities of incumbent settlers was measured on the rocky intertidal at Great Cumbrae, Scotland. Half of the tiles were replaced every tide whereas the others simultaneously accumulated settlers. Factor effects varied on each tide, and converged in the accumulating deployment. Increasing incumbent density led to net loss of settlement, which was less probable on the textures on which fastest settlment occurred ('very fine'), and more probable on those on which settlement was slowest ('smooth'). More settlement occurred on down-facing orientations during daylight and vice versa. Cue ranks were non-linear, so a path analysis model quantified the relative influence of each factor. Gregariousness was the most influential cue measured, although unmeasured factors had greater effects, highlighting the complexity of settlement influences in this species.

Beschreibung: Glacial meltwater discharge from Antarctica is a key influence on the marine environment, impacting ocean circulation, sea level, and productivity of the pelagic and benthic ecosystems. The responses elicited depend strongly on the characteristics of the meltwater releases, including timing, spatial structure and geochemical composition. Here we use isotopic tracers to reveal the time-varying pattern of meltwater during a discharge event from the Fourcade Glacier into Potter Cove, northern Antarctic Peninsula. The discharge is strongly dependent on local air temperature, and accumulates into an extremely thin, buoyant layer at the surface. This layer showed evidence of elevated turbidity, and responded rapidly to changes in atmospherically-driven circulation to generate a strongly pulsed outflow from the cove to the broader ocean. These characteristics contrast with those further south along the Peninsula, where strong glacial frontal ablation is driven oceanographically by intrusions of warm deep waters from offshore. The Fourcade Glacier switched very recently to being land-terminating; if retreat rates elsewhere along the Peninsula remain high and glacier termini progress strongly landward, the structure and impact of the freshwater discharges are likely to increasingly resemble the patterns elucidated here.

Beschreibung: King George Island (KGI, Isla 25 de Mayo) is located within one of the most rapidly warming regions on Earth at the north-western tip of the Antarctic Peninsula. Since 1991 hydrographical characteristics and phytoplankton dynamics were monitored at two stations in Potter Cove, a fjord-like environment on the south-eastern KGI coastline. Seawater temperature and salinity, total suspended particulate matter (TSPM) and chlorophyll-a (Chl-a, a proxy for phytoplankton biomass) concentrations were measured in summer and winter over a 19 year period, together with local air temperature. Mean air temperatures rose by 0.39 and 0.48 ºC per decade in summer and winter, respectively. Positive anomalies characterised wind speeds during the decade between the mid ’90 and the mid 2000 years, whereas negative anomalies were observed from 2004 onwards. Day of sea ice formation and retreat, based on satellite data, did not change, although total sea ice cover diminished during the studied period. Surface water temperature increased during summer (0.36 ºC per decade), whereas no trend was observed in salinity. Summer Chl-a concentrations were around 1 mg m-3 Chl-a with no clear trend throughout the study period. However, summer Chl-a correlates positively with water column stratification, which in turn resulted from high air temperature and lower salinity in front of the melting glacier. TSPM increased in surface waters of the inner cove during the spring-summer months. The Southern Annular Mode (SAM) climate signal was apparent in the fluctuating interannual pattern of the hydrographic variables in the outer Potter Cove and bottom waters whereas surface hydrography was strongly governed by the local forcing of glacier melt. The results show that global trends have significant effects on local hydrographical and biological conditions in the coastal marine environments of Western Antarctica.

Beschreibung: A long-term environmental data set from King George Island, Western Antarctic Peninsula, was analysed using statistical approaches that can deal with missing values. Since the WAP region belongs to the most rapidly warming regions on earth it is vital to find methods that take into account the incompleteness of Antarctic time series, but are still applicable to analyze general patterns in the series to arrive to conclusions on long term trends and inter-annual variability in the face of the rapidly changing climate in Western Antarctica. We applied U statistics after Pettit and Buishand to detect sudden changes over time, a dynamic factor analysis as well as additive modelling to detect common trends and patterns related to climatic cycles such as the Southern Annular Mode and El Niño Southern Oscillation. Our results not only reveal sudden changes for sea surface temperature and salinity, but also clear patterns in all investigated variables (sea surface temperature, salinity, suspended particulate matter and Chlorophyll a) that can be directly be assigned to climatic cycles. Hence, our statistical analyses may prove valuable for other polar environmental data sets and contribute to a better understanding of the regional variability of climate change and its impact on coastal systems.

Beschreibung: Benthic habitat mapping is an important first step towards ecosystem-based management. In a top-down approach, benthic mapping of a semi-enclosed bay in south-eastern Brazil was performed using a combined approach of acoustic RoxAnn survey and benthic samples. An inventory of the benthic macrofauna as well as unsupervised classifications of the acoustic data provided information about sediment patterns and potential areas of ecological importance, and a new zoning scheme is suggested based on the macrofauna analysis. The RoxAnn survey proved suitable to determine sediment characteristics, however, species-environment relationships cannot be revealed by acoustic techniques only. Based on the data presented here, acoustic surveys could become an important tool in future monitoring programmes following the bottom-up approach of seabed classification protocols for an ecosystem-based management to improve existing coastal ecosystem management strategies in Brazil.

Beschreibung: IMCOAST is an international research program that features a multidisciplinary approach involving geo and biological sciences, field investigations, remote sensing and modeling and knowledge into the hydrographical and biological history of the marine coastal ecosystems of the Western Antarctic Peninsula region.