Antarctic marine mammals and ocean acoustics

Marine mammals rely on sound and hearing as their primary means of communication and sensing their world. Concerns that anthropogenic sound in the ocean could infer their sensing, cause stress or even damage their hearing physically rose a controversial discussion and triggered a worldwide boost in marine bioacoustic research. Innovative acoustic technologies and field methods are required to provide a basis for carefully designed and technically challenging research projects on free-ranging marine mammals, especially under the harsh environmental conditions of polar regions. The Ocean Acoustics group within the Marine Observing Systems section endeavors multidisciplinary research of environmental scientists, geophysicists, oceanographers, physicists, physiologists, and biologists to investigate the need and scope of mitigation measures for the effects of man-generated sound in the ocean, develop acoustic census techniques, explore marine mammal responses to various anthropogenic sounds, and study the vocal behaviour and hearing physiology of Antarctic marine mammals

Foraging movements of emperor penguins at Pointe Géologie, Antarctica.

International audienceThe foraging distributions of 20 breeding emperor penguins were investigated at Pointe Ge´ologie, Terre Ade´lie, Antarctica by using satellite telemetry in 2005 and 2006 during early and late winter, as well as during late spring and summer, corresponding to incubation, early chick-brooding, late chick-rearing and the adult pre-moult period, respectively. Dive depth records of three post-egg-laying females, two post-incubating males and four late chick-rearing adults were examined, as well as the horizontal space use by these birds. Foraging ranges of chick-provisioning penguins extended over the Antarctic shelf and were constricted by winter pack-ice. During spring ice break-up, the foraging ranges rarely exceeded the shelf slope, although seawater access was apparently almost unlimited. Winter females appeared constrained in their access to open water but used fissures in the sea ice and expanded their prey search effort by expanding the horizontal search component underwater. Birds in spring however, showed higher area-restricted-search than did birds in winter. Despite different seasonal foraging strategies, chick-rearing penguins exploited similar areas as indicated by both a high ‘Area-Restricted-Search Index' and high ‘Catch Per Unit Effort'. During pre-moult trips, emperor penguins ranged much farther offshore than breeding birds, which argues for particularly profitable oceanic feeding areas which can be exploited when the time constraints imposed by having to return to a central place to provision the chick no longer apply

Implementation barriers for management accounting in the public sector

The adaptation and implementation of management accounting/Controlling in the public sector was only partially carried out (this has been noted, e.g., by Hirsch, Nitzl & Schauß (2015); Nuhu, Baird & Appuhami, (2017)), and those implementations that were completed exhibited only limited success. In particular, in Germany, the impact of the implementation efforts of controlling has been disappointing. The complexity of implementations of management accounting/Controlling (as noted, e.g., by Granlund, 2001; Gosselin, 1997; Baxter & Chua, 2003) is even more pronounced in public institutions due to the social and political context than in private sector organisations (Hoque, 2014). Implementation barriers, particularly on a personal level in the form of resistance, persistently make an introduction more difficult. The underlying reasons for resistance have been studied just as little (Parvis-Trevisany, 2006; Agasiisti, Catalano & Erbacci, 2018) as the behavioural science aspects impacting the behaviour of actors in the implementation (Parvis-Trevisany, 2006). Hence, there is a need to study particularly the specific motives and behavioural aspects of actors in the public sector (Hoque, 2014); this thesis meets this demand and aims to examine implementation barriers as well as aspects of and reasons for resistance in greater depth. The empirical study is based on the introduction of a complete controlling concept during the refugee crisis. The empirical foundation of the case study involved a combination of interviews and participant observations. They were supplemented by expert interviews in order to increase the significance of the results and to make a comparison of a problematic with a successful introduction. The thesis examines resistance and its triggers on the basis of behavioural reasoning theory and combines it with behavioural science approaches, including cognitive limitations of the individual actors. The resistances and triggers identified in the case study extend the behavioural reasoning theory with additional 'reasons against' for the introduction of management accounting/Controlling. In the case study, the following 'reasons against' were identified: (1.) fear of transparency, (2.) faulty understanding of Controlling (Controlling as monitoring (‘Kontrolle’)), (3.) overwhelming due to insufficient learning process and (4.) overwhelming due to overambitious targets. The resistance behaviour can be explained by cognitive limitations. For example, the phenomena of overly ambitious targets is influenced by the cognitive limitations of the implementing actor in the form of availability and representativeness heuristics as well as anchor effects. In addition, the role of cognitive dissonance and information overload in the implementation process is highlighted and used as an explanatory approach for the resistance that occurs. The study shows also that different resistance behaviours occur under identical conditions. Further it shows the impact of resistance during a controlling implementation, in that the scope of top management support is limited due to resistance

Under-shelf ice foraging of Weddell seals

The Weddell seal (Leptonychotes weddellii) inhabits the Antarctic coastal ecosystem and aggregates in areas characterized by a stable fast ice layer. Due to their extreme diving capabilities, they are able to exploit both pelagic and benthic prey resources. They mainly feed on fishes but occasionally also take cephalopods and crustaceans. Weddell seals instrumented with still-picture camera loggers in the Drescher Inlet, eastern Weddell Sea, detected an unknown cryo-benthic community underneath the floating ice shelf. Images show dense aggregations of invertebrates that likely represent an attractive food horizon for Weddell seals. In this context, we conducted a retrospective analysis of dive profiles collected in the Drescher Inlet to identify favoured hunting depths of Weddell seals and correlate those to the local physical and biological environment. A total of 34 adult Weddell seals were instrumented with dive loggers in the course of six summer field campaigns between 1990 and 2016. An automated broken stick algorithm was used to separate each dive profile into different segments. Segments with a high sinuosity were considered to indicate hunting. Segments characterized by a straight dive trajectories (low sinuosity), were assumed to be transit phases with no hunting activities. A tri-modal distribution of mean hunting depths suggests that Weddell seals concentrated their foraging activities in three depth strata. A peak in hunting depths below 370 m corresponds to the sea floor of the Drescher Inlet, indicating demersal foraging. A second peak between 110 and 160 m matches with the depth of the underside of the floating ice shelf, which suggests shelf ice associated foraging. The third peak probably represents hunting in the pelagic realm. Our investigation highlights the importance of the shelf ice underside as an attractive food horizon for Weddell seals suggesting a re-evaluation of trophic interactions and bentho-pelagic processes in the coastal Antarctic ecosystem

Habitat modelling of crabeater seals (Lobodon carcinophaga) in the Weddell Sea using the multivariate approach Maxent

The crabeater seal (Lobodon carcinophaga) is the most abundant Antarctic seal and inhabits the circumpolar pack ice zone of the Southern Ocean. Until now, information on important environmental factors affecting its distribution as well as on foraging behaviour is limited. In austral summer 1998, 12 crabeater seals of both sexes and different age classes were equipped with satellite-linked dive recorders at Drescher Inlet (72.85°S, 19.26°E), eastern Weddell Sea. To identify suitable habitat conditions within the Weddell Sea, a maximum entropy (Maxent) modelling approach was implemented. The model revealed that the eastern and southern Weddell Sea is especially suitable for crabeater seals. Distance to the continental shelf break and sea ice concentration were the two most important parameters in modelling species distribution throughout the study period. Model predictions demonstrated that crabeater seals showed a dynamic response to their seasonally changing environment emphasized by the favoured sea ice conditions. Crabeater seals utilized ice-free waters substantially, which is potentially explained by the comparatively low sea ice cover of the Weddell Sea during summer 1998. Diving behaviour was characterized by short (>90 % = 0–4 min) and shallow (>90 % = 0–51 m) dives. This pattern reflects the typical summer and autumn foraging behaviour of crabeater seals. Both the distribution and foraging behaviour corresponded well with the life history of the Antarctic krill (Euphausia superba), the preferred prey of crabeater seals. In general, predicted suitable habitat conditions were congruent with probable habitats of krill, which emphasizes the strong dependence on their primary prey