scholarly journals Hypoxic areas, density-dependence and food limitation drive the body condition of a heavily exploited marine fish predator

2016 ◽  
Vol 3 (10) ◽  
pp. 160416 ◽  
Author(s):  
Michele Casini ◽  
Filip Käll ◽  
Martin Hansson ◽  
Maris Plikshs ◽  
Tatjana Baranova ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Density Dependence ◽  
Body Condition ◽  
Food Limitation ◽  
Biological Data ◽  
The Body ◽  
The Baltic Sea ◽  
Fish Predator ◽  
The Past ◽  
The Baltic

Investigating the factors regulating fish condition is crucial in ecology and the management of exploited fish populations. The body condition of cod ( Gadus morhua ) in the Baltic Sea has dramatically decreased during the past two decades, with large implications for the fishery relying on this resource. Here, we statistically investigated the potential drivers of the Baltic cod condition during the past 40 years using newly compiled fishery-independent biological data and hydrological observations. We evidenced a combination of different factors operating before and after the ecological regime shift that occurred in the Baltic Sea in the early 1990s. The changes in cod condition related to feeding opportunities, driven either by density-dependence or food limitation, along the whole period investigated and to the fivefold increase in the extent of hypoxic areas in the most recent 20 years. Hypoxic areas can act on cod condition through different mechanisms related directly to species physiology, or indirectly to behaviour and trophic interactions. Our analyses found statistical evidence for an effect of the hypoxia-induced habitat compression on cod condition possibly operating via crowding and density-dependent processes. These results furnish novel insights into the population dynamics of Baltic Sea cod that can aid the management of this currently threatened population.

Whitefish (Coregonus lavaretus (L.)) landings in the Baltic Sea during the past 100 years: combining official datasets and grey literature

2013 ◽  
Vol 64 ◽  
pp. 133-152 ◽  
Author(s):  
Aare Verliin ◽  
Lauri Saks ◽  
Roland Svirgsden ◽  
Markus Vetemaa ◽  
Mehis Rohtla ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Grey Literature ◽  
Coregonus Lavaretus ◽  
The Baltic Sea ◽  
The Past ◽  
The Baltic

Screening the East, Probing the Past: The Baltic Sea in Contemporary German Cinema

2004 ◽  
Vol 22 (2) ◽  
pp. 27-48
Author(s):  
Alexandra Ludewig
Keyword(s):  
Gender Roles ◽  
Baltic Sea ◽  
Breeding Ground ◽  
Berlin Wall ◽  
The Baltic Sea ◽  
The Past ◽  
Traditional Gender Roles ◽  
German Cinema ◽  
The Baltic ◽  
Artistic Heritage

Since the fall of the Berlin Wall, unification, and the subsequent reinventionof the nation, German filmmakers have revisited theircountry’s cinematic traditions with a view to placing themselves creativelyin the tradition of its intellectual and artistic heritage. One ofthe legacies that has served as a point of a new departure has beenthe Heimatfilm, or homeland film. As a genre it is renowned for itsrestorative stance, as it often features dialect and the renunciation ofcurrent topicality, advocates traditional gender roles, has antimodernovertones of rural, pastoral, often alpine, images, and expressesa longing for premodern times, for “the good old days” that supposedlystill exist away from the urban centres. The Nazis used Heimatfilms in an effort “to idealize ‘Bauerntum’ as the site of desirable traditionsand stereotyped the foreign (most often the urban) as thebreeding ground for moral decay.”

Regional differences in winter sea level variations in the Baltic Sea for the past 200 yr

2008 ◽  
Vol 60 (2) ◽  
pp. 384-393 ◽  
Author(s):  
Birgit Hünicke ◽  
Jürg Luterbacher ◽  
Andreas Pauling ◽  
Eduardo Zorita
Keyword(s):  
Baltic Sea ◽  
Sea Level ◽  
Regional Differences ◽  
The Baltic Sea ◽  
The Past ◽  
Sea Level Variations ◽  
The Baltic

The three-spined stickleback (Gasterosteus aculeatus) infection with Schistocephalus solidus in Hel marina (Puck Bay, Baltic Sea, Poland)

2015 ◽  
Vol 44 (1) ◽  
Author(s):  
Zdeněk Mačát ◽  
Adam Bednařík ◽  
Martin Rulík
Keyword(s):  
Baltic Sea ◽  
Gasterosteus Aculeatus ◽  
The Body ◽  
Published Data ◽  
Body Width ◽  
The Baltic Sea ◽  
Schistocephalus Solidus ◽  
Total Prevalence ◽  
The Baltic ◽  
Puck Bay

AbstractParasitic relations between animals are very common in wild nature. In this paper, we studied levels of infection in three-spined stickleback with plerocercoids of Schistocephalus solidus from Puck Bay (Baltic Sea, Poland). The total prevalence of infection was 54.2%, while proportion of infected individuals was significantly higher for females than for males. The body width was found to be significantly positively correlated with the number and the weight of parasites. In spite of the increasing deterioration of the Baltic Sea ecosystem by excessive eutrophication and hypoxia, lower prevalence of infection compared to previous published data indicates that there are likely other factors than pollution affecting the life cycle of parasites and the level of parasitism.

scholarly journals Sedimentary alkalinity generation and long-term alkalinity development in the Baltic Sea

2018 ◽  
Author(s):  
Erik Gustafsson ◽  
Mathilde Hagens ◽  
Xiaole Sun ◽  
Daniel C. Reed ◽  
Christoph Humborg ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Reactive Transport ◽  
Total Alkalinity ◽  
Biogeochemical Model ◽  
Co2 Uptake ◽  
Low Oxygen ◽  
The Baltic Sea ◽  
The Past ◽  
Oxygen Conditions ◽  
The Baltic

Abstract. Enhanced release of alkalinity from the seafloor, principally driven by anaerobic degradation of organic matter under low-oxygen conditions and associated secondary redox reactions, can increase the carbon dioxide (CO2) buffering capacity of seawater and therefore oceanic CO2 uptake. The Baltic Sea has undergone severe changes in oxygenation state and total alkalinity (TA) over the past decades. The link between these concurrent changes has not yet been investigated in detail. A recent system-wide TA budget constructed for the past 50 years using BALTSEM, a coupled physical-biogeochemical model for the whole Baltic Sea area, revealed an unknown TA source. Here we use BALTSEM in combination with observational data and one-dimensional reactive transport modelling of sedimentary processes in the Fårö Deep, a deep Baltic Sea basin, to test whether sulfate reduction coupled to iron (Fe) sulfide burial can explain the missing TA source in the Baltic Proper. We calculated that this burial can account for 26 % of the missing source in this basin, with the remaining TA possibly originating from unknown river inputs or submarine groundwater discharge. We also show that temporal variability in the input of Fe to the sediments since the 1970s drives changes in sulfur burial in the Fårö Deep, suggesting that Fe availability is the ultimate limiting factor for TA generation under anoxic conditions. The implementation of projected climate change and two nutrient load scenarios for the 21st century in BALTSEM shows that reducing nutrient loads will improve deep water oxygen conditions, but at the expense of lower surface water TA concentrations, CO2 buffering capacities and faster acidification. When these changes additionally lead to a decrease in Fe inputs to the sediment of the deep basins, anaerobic TA generation will be reduced even further, thus exacerbating acidification. This work highlights that Fe dynamics play a key role in the release of TA from sediments where Fe sulfide formation is limited by Fe availability, as exemplified for the Baltic Sea. Moreover, it demonstrates that burial of Fe sulfides should be included in TA budgets of low oxygen basins.

scholarly journals Size matters: relationships between body size, dry weight and ash-free dry weight of common coastal, aquatic invertebrates in the Baltic Sea

2016 ◽  
Author(s):  
Johan Eklöf ◽  
Åsa Austin ◽  
Ulf Bergström ◽  
Serena Donadi ◽  
Britas D H K Eriksson ◽  
...  
Keyword(s):  
Body Size ◽  
Baltic Sea ◽  
Dry Weight ◽  
Negative Influence ◽  
The Body ◽  
Biologically Active ◽  
Power Relationship ◽  
Potential Influence ◽  
The Baltic Sea ◽  
The Baltic

Background. Organism biomass is one of the most important variables in ecological studies, making estimations of organism weight one of the most common laboratory tasks. Biomass of small macroinvertebrates is usually estimated as dry (DW) or ash-free dry weight (AFDW); a laborious and time consuming process, that often can be speeded up using easily measured and reliable proxy variables like wet/fresh weight and/or body size. Another common way of estimating AFDW - which is the most accurate but also time-consuming estimate of biologically active tissue weight - is the use of AFDW/DW ratios or conversion factors. So far, however, these ratios typically ignore the possibility that the relative weight of biologically active vs. non-active support tissue (e.g. protective exoskeleton or shell) - and therefore, also the AFDW/DW ratio - may change with body size, as previously shown for taxa like spiders, vertebrates and trees. Methods. We collected samples of aquatic, epibenthic macroinvertebrates (>1 mm) in 32 shallow bays along a 360 km stretch of the Swedish coast along the Baltic Sea; one of the largest brackish water bodies on Earth. We then estimated statistical relationships between the body size (length or height in mm), dry weight and ash-free dry weight for 14 of the most common taxa; five gastropods, three bivalves, three crustaceans and three insect larvae. Finally, we statistically estimated the potential influence of body size on the AFDW/DW ratio per taxon. Results. For most of the taxa, non-linear regression models describing the power relationship between body size and i) DW and ii) AFDW fit the data well (as indicated by low SE and high R2). Moreover, for more than half of the taxa studied (including the vast majority of the shelled molluscs), body size had a negative influence on organism AFDW/DW ratios. Discussion. The good fit of the modelled power relationships suggest that the constants reported here can be used to more quickly estimate organism dry- and ash-free dry weight based on body size, thereby freeing up considerable work resources. However, the considerable differences in constants between taxa emphasize the need for taxon-specific relationships, and the potential dangers associated with either ignoring body size or substituting relationships between taxa. The negative influence of body size on AFDW/DW ratio found in a majority of the molluscs could be caused by increasingly thicker shells with organism age, and/or spawning-induced loss of biologically active tissue in adults. Consequently, future studies utilizing AFDW/DW (and presumably also AFDW/wet weight) ratios should carefully assess the potential influence of body size to ensure more reliable estimates of organism biomass.

scholarly journals Sea Level Dynamics and Coastal Erosion in the Baltic Sea Region

2021 ◽  
Author(s):  
Ralf Weisse ◽  
Inga Dailidiene ◽  
Birgit Hünicke ◽  
Kimmo Kahma ◽  
Kristine Madsen ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Sea Level ◽  
Coastal Erosion ◽  
Data Availability ◽  
The Baltic Sea ◽  
Mean Sea Level ◽  
The Past ◽  
Coastline Change ◽  
Baltic Sea Region ◽  
The Baltic

Abstract. There are a large number of geophysical processes affecting sea level dynamics and coastal erosion in the Baltic Sea region. These processes operate on a large range of spatial and temporal scales and are observed in many other coastal regions worldwide. Together with the outstanding number of long data records, this makes the Baltic Sea a unique laboratory for advancing our knowledge on interactions between processes steering sea level and erosion in a climate change context. Processes contributing to sea level dynamics and coastal erosion in the Baltic Sea include the still ongoing visco-elastic response of the Earth to the last deglaciation, contributions from global and North Atlantic mean sea level changes, or from wind waves affecting erosion and sediment transport along the subsiding southern Baltic Sea coast. Other examples are storm surges, seiches, or meteotsunamis contributing primarily to sea level extremes. All such processes have undergone considerable variations and changes in the past. For example, over the past about 50 years, the Baltic absolute (geocentric) mean sea level rose at a rate slightly larger than the global average. In the northern parts, due to vertical land movements, relative sea level decreased. Sea level extremes are strongly linked to variability and changes in the large-scale atmospheric circulation. Patterns and mechanisms contributing to erosion and accretion strongly depend on hydrodynamic conditions and their variability. For large parts of the sedimentary shores of the Baltic Sea, the wave climate and the angle at which the waves approach the nearshore are the dominant factors, and coastline changes are highly sensitive to even small variations in these driving forces. Consequently, processes contributing to Baltic sea level dynamics and coastline change are expected to vary and to change in the future leaving their imprint on future Baltic sea level and coastline change and variability. Because of the large number of contributing processes, their relevance for understanding global figures, and the outstanding data availability, we argue that global sea level research and research on coastline changes may greatly benefit from research undertaken in the Baltic Sea.

scholarly journals Sedimentary alkalinity generation and long-term alkalinity development in the Baltic Sea

2019 ◽  
Vol 16 (2) ◽  
pp. 437-456 ◽  
Author(s):  
Erik Gustafsson ◽  
Mathilde Hagens ◽  
Xiaole Sun ◽  
Daniel C. Reed ◽  
Christoph Humborg ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Reactive Transport ◽  
Total Alkalinity ◽  
Biogeochemical Model ◽  
Co2 Uptake ◽  
Low Oxygen ◽  
The Baltic Sea ◽  
The Past ◽  
Oxygen Conditions ◽  
The Baltic

Abstract. Enhanced release of alkalinity from the seafloor, principally driven by anaerobic degradation of organic matter under low-oxygen conditions and associated secondary redox reactions, can increase the carbon dioxide (CO2) buffering capacity of seawater and therefore oceanic CO2 uptake. The Baltic Sea has undergone severe changes in oxygenation state and total alkalinity (TA) over the past decades. The link between these concurrent changes has not yet been investigated in detail. A recent system-wide TA budget constructed for the past 50 years using BALTSEM, a coupled physical–biogeochemical model for the whole Baltic Sea area revealed an unknown TA source. Here we use BALTSEM in combination with observational data and one-dimensional reactive-transport modeling of sedimentary processes in the Fårö Deep, a deep Baltic Sea basin, to test whether sulfate (SO42-) reduction coupled to iron (Fe) sulfide burial can explain the missing TA source in the Baltic Proper. We calculated that this burial can account for up to 26 % of the missing source in this basin, with the remaining TA possibly originating from unknown river inputs or submarine groundwater discharge. We also show that temporal variability in the input of Fe to the sediments since the 1970s drives changes in sulfur (S) burial in the Fårö Deep, suggesting that Fe availability is the ultimate limiting factor for TA generation under anoxic conditions. The implementation of projected climate change and two nutrient load scenarios for the 21st century in BALTSEM shows that reducing nutrient loads will improve deep water oxygen conditions, but at the expense of lower surface water TA concentrations, CO2 buffering capacities and faster acidification. When these changes additionally lead to a decrease in Fe inputs to the sediment of the deep basins, anaerobic TA generation will be reduced even further, thus exacerbating acidification. This work highlights that Fe dynamics plays a key role in the release of TA from sediments where Fe sulfide formation is limited by Fe availability, as exemplified by the Baltic Sea. Moreover, it demonstrates that burial of Fe sulfides should be included in TA budgets of low-oxygen basins.

scholarly journals New records from the southern North Sea and first records from the Baltic Sea of Kornmannia leptoderma

2019 ◽  
Vol 62 (1) ◽  
pp. 63-73
Author(s):  
Florian Weinberger ◽  
Sophie Steinhagen ◽  
Dmitry F. Afanasyev ◽  
Rolf Karez
Keyword(s):  
Life Cycle ◽  
Baltic Sea ◽  
North Sea ◽  
New Records ◽  
The Baltic Sea ◽  
The Past ◽  
The North ◽  
Green Algal ◽  
The North Sea ◽  
The Baltic

Abstract Combined genetic, morphological and ontogenetic observations show that the circumarctic boreal green algal macrophyte Kornmannia leptoderma has expanded its distribution range into the Baltic Sea, on a German coastal section of 220 km length. The species is also again (or still) established at its former extreme southern distribution limit in the North Sea, the German island of Helgoland, where it has not been detected during the last four decades. Macroscopic visible sporophytes of K. leptoderma are nowadays present in the Baltic Sea and at Helgoland from February to September, while they were in the past only detected from February to May at Helgoland. This capacity for formation of sporophytes in summer correlates with the circumstance that K. leptoderma from the Baltic Sea can complete its life cycle at 15°C while several studies conducted decades ago with material from Helgoland and from Pacific coasts consistently reported an inhibition of the algal gametogenesis at temperatures that exceed 12°C. Possibly K. leptoderma has undergone adaptations that facilitate its spread into warmer environments, unless the Kornmannia present in the Baltic Sea and on Helgoland today represents a newly introduced cryptic species.

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