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Perception of climate change-related forest dieback in mountain forests among the local population
(2023)
Mountain forests provide multiple benefits but are threatened by climate change-induced forest dieback. Although many studies summarize perceptions of forest ecosystem services, relatively few deal with mountain forests. The local population’s perception of forest dieback in mountain forests in relation to climate change has rarely been investigated so far. Their perspective is relevant as local people are often deeply attached to “their” forests, they actively use forest ecosystems and—as voters and taxpayers—they need to support the state’s adaptation and funding measures. Therefore, this study investigates the climate change and forest dieback perception of local inhabitants in two mountain areas of Southern Germany (the German Alps and the Bavarian Forest) with a quantitative survey based on representative online samples (n = 709). Relying conceptually on van der Linden’s (J Environ Psychol 41:112–124, 2015. https://doi.org/10.1016/j.jenvp.2014.11.012) climate change risk perception model, the results show that experiential processing, cognitive and socio-cultural factors are related to locals’ forest dieback and climate change perception, while socio-demographics show no or few connections. Nearly two-thirds (64.7%) of the respondents perceive moderate to strong forest dieback, while more than half (55.0%) of the respondents already observe consequences of climate change. The perceptions of climate change and forest dieback are positively correlated with medium to high strength. This shows that forest dieback could be interpreted as an indicator of climate change, which is difficult to observe due to its long-term nature. We identify three groups of respondents regarding preferred forest adaptation strategies to climate change. In general, respondents support nature-based forest adaptation strategies over intense measures.
Toarciconiopteryx dipterosimilis gen. et sp. nov. is described from the Lower Toarcian of Grimmen (Western Pomerania, Germany) based on a hind wing. This enigmatic wing superficially resembles a dipteran forewing, but analysis in detail establishes that it belongs to the Neuroptera. We assign it to the Coniopterygidae with great confidence by its great concordance with the hind wings of that family, but a small possibility remains that it might belong to the Dipteromantispidae, although the very derived haltere-like hind wings of all its known members are entirely unlike it. We, therefore, consider it to be the oldest record of Coniopterygidae. We create the new subfamily Toarciconiopteryginae subfam. nov. for it, which is distinguished from other Coniopterygidae by its hind wings possessing two branches of RP and a proximal forking of M. These conditions are also known in some Sialidae (Megaloptera), supporting the hypothesis that Coniopterygidae is the sister group of all other Neuroptera, as Megaloptera is considered by most authors to be sister to Neuroptera. New interpretations of some aspects of the Coniopterygidae venation are proposed.
Peatlands contribute to a wide range of ecosystem services. They play an important role as carbon sinks in their natural state, but when they are drained, they cause carbon emissions. Rewetting drained peatlands is required to reduce carbon emissions and create new carbon sinks. However, drained peatlands are commonly used as grassland or croplands; therefore, alternative agriculture schemes are required following rewetting. Paludiculture, i.e., agriculture on wet and rewetted peatlands, is an option in these areas after rewetting to produce biomass sustainably. Monitoring of peatland management is challenging, yet needed to ensure a successful rewetting and plantation of, e.g., Phragmites australis and Typha spp., two plants which are commonly used in paludiculture. Remote sensing is an excellent tool for monitoring the vegetation composition of vast rewetted peatland regions. However, because many peatland species have similar spectral characteristics, such monitoring is ideally based on high-spatial, high-temporal hyperspectral images. Data that complies with all these requirements does not exist on a regular basis. Therefore, we assessed the potential for mapping peatland vegetation communities in the Peene and Trebel river basins of the federal state of Mecklenburg-Western Pomerania, Germany, using multi-date hyperspectral (PRISMA) data. We used regression-based unmixing to map fractions of different peatland vegetation classes. Results were analyzed with regard to the contribution of multi-date observations and, in comparison, to multispectral datasets (Landsat-8/Sentinel-2). Our results showed that different classes are best mapped at different observation dates. The multi-date hyperspectral datasets produced less Mean Absolute Error (MAE = 16.4%) than the single-date hyperspectral images (ΔMAE + 1%), with high accuracies for all classes of interest. Compared to the results obtained with multispectral data from similar acquisition dates and annual spectral-temporal metrics (STM), the results from hyperspectral data were always clearly superior (ΔMAE + 4%). Besides the superior performance during comparisons, our results also indicate that information that can be derived from the hyperspectral data with the regression-based unmixing goes clearly beyond that of discrete classification. With more hyperspectral sensors coming up and an expected higher availability of multi-data hyperspectral imagery, these data can be expected to play a bigger role in the future monitoring of peatlands.
Monitoring and assessing groundwater quality according to European directives and national regulations is usually based on interpolation techniques, e.g. Kriging. However, contour maps of hydrochemical parameters often suggest a spurious local accuracy and can therefore lead to inappropriate action measures. Here, the early concept of extension variance combined with the Voronoi tessellation regionalization is proposed. The mosaic-like representation of pollutant concentrations in Voronoi polygons avoids misinterpretations caused by interpolation. The additional calculation of the extension variance, which is based on fundamental geostatistical assumptions, allows for estimating the probability that a given threshold is exceeded. This concept is further extended to hydraulically delimitable groundwater bodies, thus ensuring that hydraulic boundaries are considered. A method is here described for the assessment of groundwater quality with respect to nitrate concentration in the principal aquifer of the state Mecklenburg-Western Pomerania in Germany.
The reduction of individual carbon consumption could make an important contribution to the worldwide effort to limit global warming. Based on Bandura’s theory of moral disengagement, we hypothesized that the propensity to morally disengage concerning high-carbon behaviors (e.g., eating meat or traveling by plane) is one important factor that prevents individuals from reducing their carbon footprint. To measure the propensity to morally disengage in high-carbon-related behavior contexts, a questionnaire (MD-HCB) was developed and psychometrically validated in an online study with a German sample (N = 220). Confirmatory factor analyses revealed that the final nine-item scale had a one-dimensional structure, as intended. The internal consistency of the scale was excellent (Cronbach’s α = 0.94) and the scale interpretation had predictive validity for both past low-carbon consumption behavior and the intention to engage in such behavior in the future. Correlational analyses with relevant existing instruments confirmed the construct validity of the interpretations that can be drawn from the MD-HCB, as its resulting score is related to, yet separable from, the general tendency to morally disengage and is meaningfully connected to related constructs. A pre-study with a student sample (N = 89) not only helped to identify limitations in the study design but also showed a weak predictive ability of moral competence concerning high-carbon consumption behavior and intention to change. Based on our findings, future media campaigns designed to increase people’s intention to reduce high-carbon behavior could focus on the modification of common cognitive disengagement strategies.
The multi-level perspective has been criticized for being functionalistic and paying little attention to actor-based perspectives. Nevertheless, for the identification and assessment of potential change agents in a sustainability transition, a clear conceptual and methodological approach is necessary. This paper, thus, develops a multi-dimensional typology of niche, regime, and hybrid actors, which is conceptually grounded in transition studies and empirically illustrated by a cluster analysis based on a survey of pig and poultry farmers in Germany, France, and the Netherlands. Animal husbandry is chosen as a case study because a significant share of the environmental impact within the agri-food system is attributed to this sector and there is evidence for resistance to change by mainstream actors. Conceptually, the paper provides a framework of constitutive elements for different kinds of actors and contributes to an extension of the niche–regime dichotomy by adding the group of hybrid actors. The empirical results show that cluster analysis is a suitable approach to identify conceptually meaningful differences among interviewed farmers. Among pig and poultry farmers, the regime actors are by far the largest group. The smaller group of hybrid actors, however, has large potential to act as boundary spanners. A particularly interesting finding is that several larger farms are among the group of niche actors which hints at the possibility that larger farms are not necessarily resistant to change.
The occurrence and distribution of organochlorine pesticides (OCPs) in aquatic systems is a matter of global concern and poses significant toxicological threats to both organisms and human health. Despite the extensive use of OCPs for pest and disease control in southern Africa, relatively few studies have examined the occurrence and toxicological risks of OCP residues in the region. This study investigates the composition, distribution, and potential sources of OCP contamination in sediments from Richards Bay, a rapidly developing industrial port on the northeast coast of South Africa. Surface sediments collected from Richards Bay Harbour and surrounding areas indicate that OCP contamination in the region is widespread. Total concentrations (∑OCP) in surface samples ranged from 135 to 1020 ng g−1, with hexachlorocyclohexanes (∑HCH; 35–230 ng g−1) and dichlorodiphenyltrichloroethanes (∑DDT; 12–350 ng g−1) the dominant contaminant groups detected. Metabolite isomeric compositions indicate that the presence of aldrin and endosulfan likely result from historical agricultural usage, while recent input of γ-HCH, heptachlor, and endrin may be linked to the illegal use of old pesticide stockpiles. Total DDT concentrations were dominated by p,p′-DDT (80 ± 64 ng g−1), which was attributed to its ongoing use in malaria vector control in the region. A 210Pb-dated sediment core revealed that OCP input to the local environment increased dramatically from relatively low concentrations in the mid-1940s (∑OCP, 355 ng g−1) to peak levels (∑OCP, 781 ng g−1) in the 1980s/1990s. An overall decrease in ∑OCP concentration from the mid-2000s is likely related to restrictions on use following the Stockholm Convention in 2004. Despite current restrictions on use, OCP concentrations exceeded sediment quality guidelines in the vast majority of cases, raising concerns for protected estuarine and mangrove habitats in the area, as well as for local fishing and farming communities.
Thermally treated kaolinite is used to develop a range of alumino‐silicate‐based precursor materials but its behavior during plasma spraying has not been well‐researched. In this study, two types of kaolinite samples were investigated in the form of low defect (KGa‐1b) and high defect (KGa‐2) varieties. The extreme temperatures of the plasma stream (up to 20 000 K) induced flash melting to produce a highly porous alumino‐silicate glass without any crystallization of new Al−Si oxide minerals. The glass is comprised largely of intact or deformed spheres (average diameters 1.14–1.44 μm), which indicates rapid quenching and solidification before impact. The subspherical structures contain up to 40 % closed pore space caused by the rapid escape of water during melting. The low‐density, porous alumino‐silicate glass coatings with predicted specific surface areas (>0.95 m2/g) and hardnesses >1.8 GPa represent a potentially reactive but physically stable substrate ideal for further chemical functionalization.
Late Pleistocene glacitectonism at the southern Scandinavian Ice Sheet margin caused folding and thrusting of Upper Cretaceous chalk layers and Pleistocene glacial deposits in parts of the southwestern Baltic Sea area in Europe. Beside Møns Klint (SE Denmark), the Jasmund Glacitectonic Complex (JGC) on Rügen Island (NE Germany) is a similar striking example of glacitectonic deformation creating large composite ridges. In spite of a long research history and new results from modern datasets, the structural development of the JGC is still poorly understood, especially the detailed evolution of the southern JGC and its relationship to the northern JGC remain enigmatic. In this contribution, we demonstrate how the understanding of the JGC benefits from the application of established structural geological methods comprehending the formation of fold-and-thrust belts. The methods include cross-section balancing of the eastern coast (southern JGC) and quantification of the amount of folding and faulting. The proposed geometric model shows the current fold-and-thrust stack of glacially deformed sedimentary strata ca. 5720 m in length evolved by shortening from the original length (11,230 m) by 5510 m (49.1%). We present a spatial and temporal development of fault-related folding with a transition from detachment folds through fault-propagation folds to fault-bend folds. Together with morphological information from a digital elevation model, the thrust faults mapped in the cliff section are mainly inclined towards the S to SW and imply that a local glacier push occurred from the south. These results highlight the complexity and individual architecture of the JGC when compared to other Pleistocene and modern glacitectonic complexes. Resolving its structural development provides new insight into the deformation history and shortening of this spectacular glacitectonic complex lying in the southwestern Baltic Sea region.
There is a current need for developing improved synthetic porous materials for better constraining the dynamic and coupled processes relevant to the geotechnical use of underground reservoirs. In this study, a low temperature preparation method for making synthetic rocks is presented that uses a geopolymer binder cured at 80 °C based on alkali-activated metakaolin. For the synthesised sandstone, the key rock properties permeability, porosity, compressive strength, and mineralogical composition, are determined and compared against two natural reservoir rocks. In addition, the homogeneity of the material is analysed structurally by micro-computed tomography and high-resolution scanning electron microscopy, and chemically by energy dispersive X-ray spectroscopy. It is shown that simple, homogenous sandstone analogues can be prepared that show permeability-porosity values in the range of porous reservoir rocks. The advance in using geopolymer binders to prepare synthetic sandstones containing thermally sensitive minerals provides materials that can be easily adapted to specific experimental needs. The use of such material in flow-through experiments is expected to help bridge the gap between experimental observations and numerical simulations, leading to a more systematic understanding of the physio-chemical behaviour of porous reservoir rocks.
Calcitic valves of non-marine ostracodes are important geochemical archives. Investigations of the relationship between the ranges of oxygen and carbon isotope values of modern ostracode populations and their host water provide important information on local or regional conditions and influences. Here we present the first δ18Oostracode and δ13C of the freshwater ostracode species Cytheridella ilosvayi along with the isotopic composition of the waters in which the ostracodes calcified, δDwater, δ18Owater, δ13CDIC values—covering a large geographical range (Florida to Brazil). With this data we extended a newly developed approach based on the estimation of δ18O values of monthly equilibrium calcites as references for the interpretation of δ18Oostracode values. The expected apparent oxygen isotope fractionation between CaCO3 and H2O is correlated with temperature with smaller values occurring at higher temperatures as valid at isotope equilibrium (δ18Ocalcite_eq). Uncertainties about the expected equilibrium calcites derive from incomplete knowledge of high-frequency variations of the water bodies caused by interplay of mixing, evaporation, and temperature. Coincidence between δ18Oostracode and δ18Ocalcite_eq is restricted to few months indicating a seasonal calcification of Cytheridella. There is a characteristic pattern in its difference between mean δ18Oostracode and δ18Ocalcite_eq which implies that Cytheridella provides a synchronous life cycle in its geographical range with two calcification periods in spring (May, June) and autumn (October). This ubiquitous life cycle of Cytheridella in the entire study area is considered to be phylogenetically inherited. It might have originally been adapted to environmental conditions but has been conserved during the migration and radiation of the group over the Neotropical realm.
There is broad scientific consensus that current food systems are neither sustainable nor resilient: many agricultural practices are very resource-intensive and responsible for a large share of global emissions and loss of biodiversity. Consequently, current systems put large pressure on planetary boundaries. According to economic theory, food prices form when there is a balance between supply and demand. Yet, due to the neglect of negative external effects, effective prices are often far from representing the ‘true costs’. Current studies show that especially animal-based foodstuff entails vast external costs that currently stay unaccounted for in market prices. Against this background, we explore how informational campaigning on agricultural externalities can contribute to consumer awareness and tolerance of this matter. Further, we investigate the socially just design of monetary incentives and their implementation potentials and challenges. This study builds on the informational campaign of a German supermarket displaying products with two price tags: one of the current market price and the other displaying the ‘true’ price, which includes several environmental externalities calculated with True Cost Accounting (TCA). Based on interpretations of a consumer survey and a number of expert interviews, in this article we approach the potentials and obstacles of TCA as a communication tool and the challenges of its factual implementation in agri-food networks. Our results show that consumers are generally interested in the topic of true food pricing and would to a certain extent be willing to pay ‘true prices’ of the inquired foods. However, insufficient transparency and unjust distribution of wealth are feared to bring about communication and social justice concerns in the implementation of TCA. When introducing TCA into current discourse, it is therefore important to develop measures that are socially cautious and backed by relevant legal framework conditions. This poses the chance to create a fair playing (‘polluter pays’) with a clear assignment of responsibilities to policy makers, and practitioners in addition to customers.
Circular economies are an important pillar of sustainable production and consumption. This particularly applies to the agri-food industry, which is characterised by large amounts of organic waste and by-product streams posing a serious challenge for many food producers. Therefore, respective firms increasingly adopt circular economy business models (CEBMs) to manage these resource flows effectively. However, there is only little knowledge on the functioning of CEBMs in bio-based industries, especially from a socio-economic perspective. We address this gap by exploring enablers and motivations behind such business models as well as the institutional contexts they are embedded in. In methodological terms, we adopt a case study approach using the example of potato production in Lower Saxony (northwest Germany). The core of the paper is a qualitative in-depth analysis of four potato processors, adopting varying business models to valorise their by-product streams (e.g. peels, scraps, pulp) either ‘in-house’ or in partnerships with external partners. The findings show that the implementation of CEBMs results from a complex interplay of internal and external enablers, with economic considerations as the main impetus for the management of biological reverse cycles. Thereby, we found a shifting economic logic in the assessment of potato by-products from disposable waste to valuable resources for other sectors (e.g. livestock farming, bioenergy, biofuels). While being encouraged by targeted policies, the companies studied feel increasingly affected by emerging sustainability discourses, prompting them to (re)design and (re)frame their CEBMs in view of environmental and societal issues.
Thyreophora is a clade of globally distributed herbivorous ornithischian dinosaurs. The earliest forms are known from the Early Jurassic, and their latest surviving representatives witnessed the end-Cretaceous mass extinction. Throughout their evolutionary history, these ‘shield bearers’ became lumbering quadrupeds, evolved a wide array of bony armor, plates and spikes, as well as sweeping tail weapons in the form of tail clubs and thagomizers. An isolated new thyreophoran osteoderm from a Lower Jurassic Konservatlagerstätte near Grimmen is described and, with the aid of micro-CT data, compared to an osteoderm of the early diverging thyreophoran Emausaurus ernsti from a different stratigraphic horizon at the same locality.
Diagenetic illite growth in porous sandstones leads to significant modifications of the initial pore system which result in tight reservoirs. Understanding and quantifying these changes provides insight into the porosity-permeability history of the reservoir and improves predictions on petrophysical behavior. To characterize the various stages of diagenetic alteration, a focused ion beam – scanning electron microscopy (FIB-SEM) study was undertaken on aeolian sandstones from the Bebertal outcrop of the Parchim Formation (Early Permian Upper Rotliegend group). Based on 3D microscopic reconstructions, three different textural types of illite crystals occur, common to many tight Rotliegend sandstones, namely (1) feldspar grain alterations and associated illite meshworks, (2) tangential grain coats, and (3) pore-filling laths and fibers. Reaction textures, pore structure quantifications, and numerical simulations of fluid transport have revealed that different generations of nano-porosity are connected to the diagenetic alteration of feldspars and the authigenic growth of pore-filling illites. The latter leads to the formation of microstructures that range from authigenic compact tangential grain coatings to highly porous, pore-filling structures. K-feldspar replacement and initial grain coatings of illite are composed primarily of disordered 1Md illite whereas the epitaxially grown illite lath- and fiber-shaped crystals occurring as pore-filling structures are of the trans-vacant 1Mtv polytype. Although all analyzed 3D structures offer connected pathways, the largest reduction in sandstone permeability occurred during the initial formation of the tangential illite coatings that sealed altered feldspars and the subsequent growth of pore-filling laths and fibrous illites. Analyses of both illite pore-size and crystallite-size distributions indicate that crystal growth occurred by a continuous nucleation and growth mechanism probably controlled by the multiple influx of potassium-rich fluids during late Triassic and Jurassic times. The detailed insight into the textural varieties of illite crystal growth and its calculated permeabilities provides important constraints for understanding the complexities of fluid-flow in tight reservoir sandstones.
Ocean literacies: the promise of regional approaches integrating ocean histories and psychologies
(2023)
The current concept of ocean literacy reflects a prerequisite for achieving ocean sustainability. Existing ocean literacy reflects a fundamentally western view of oceans that works in tension with ocean literacy goals. Although ocean literacy practitioners and researchers are, laudably, starting to incorporate Indigenous knowledges and perspectives from BIPOC communities, attention to historical change continues to be left out of ocean literacy, to the detriment of ocean literacy goals. This article points out that, given the reality that human-ocean relationships have changed over time, and differed among cultural groups in the past as well as in the present, ocean literacy needs to incorporate ocean history at a foundational level. Because there are historical differences in human relationships with oceans, it stands to reason that regional ocean literacies must be more effective than a universal and timeless ocean literacy framework. Following the logical efficacy of a regional approach to ocean literacy, this article further argues that regional ocean literacies should involve the systematic inclusion of emotional elements. Regional ocean literacies should be constructed through knowledge co-production, involving diverse types of expertise, knowledge and actors to produce context-specific knowledge and pathways towards a sustainable future. To fully exploit the potential of ocean literacy, there is a need for the UN Ocean Decade to work towards regional and place-based approaches that incorporate history as well as culture in an iterative and collaborative process involving diverse types of expertise, knowledge and actors.
Giant clam (Tridacna) distribution in the Gulf of Oman in relation to past and future climate
(2022)
The Oman upwelling zone (OUZ) creates an unfavorable environment and a major biogeographic barrier for many coral reef species, such as giant clams, thus promoting and maintaining faunal differences among reefs on the east and west side of the Arabian Peninsula. We record the former existence of Tridacna in the Gulf of Oman and review its stratigraphic distribution in the Persian Gulf to provide new insights on the connectivity of coral reef habitats around southern Arabia under changing climate and ocean conditions. Fossil shells were carbon-14 dated and employed as sclerochronological proxy archives. This reveals that the Omani population represents a last glacial colonization event during the Marine Isotope Stage 3 interstadial under colder-than-present temperatures and variable upwelling intensity linked to Dansgaard-Oeschger climate oscillations. It was favored by temperatures just above the lower threshold for the habitat-forming reef coral communities and instability of the upwelling barrier. We conclude that the distribution of Tridacna in the northern Arabian Sea is generally limited by either strong upwelling or cool sea surface temperature under gradually changing climate conditions at the interglacial-glacial scale. Opportunities for dispersal and temporary colonization existed only when there was a simultaneous attenuation of both limiting factors due to high-frequency climate variability. The OUZ will unlikely become a future climate change refuge for giant clams because they will be exposed either to thermal stress by rapid anthropogenic Indian Ocean warming or to unfavorable upwelling conditions.
Global change is one of the major challenges our society faces in recent times and is becoming increasingly noticeable in all aspects of our lives. In the last ten years, reports about droughts in Europe increased, contrary to expected natural climate variations and are attributed as indicators of climate change. Droughts resulted in a severe decrease in water levels of lakes, rivers and reservoirs, posing socio-economic and environmental challenges. Climate scenarios by the Intergovernmental Panel on Climate Change (IPCC) project increasing temperatures, more frequent, longer and/or more intense heat waves and warm spells, and an increase in aridity with short-term droughts in the upcoming decades for Western and Central Europe. Some areas – such as Northeast Germany – are already affected by negative water balances and the lowering of lake and groundwater levels. Additionally to possible challenges in water availability, excess nutrients and heavy metals from industrial emissions, agricultural fertilisers and land use changes lead to declining water quality. In the past century, extensive eutrophication and environmental pollution have become major water quality issues in many freshwater bodies.
Nonetheless, water and its availability in a sufficient quantity and quality are prerequisites for life and must be prioritised in future development. The European Union aims for a good status in all surface and groundwater bodies by 2027 regarding their ecological, chemical and quantitative status. However, a profound understanding of eutrophication, pollution sources, and water bodies' reference conditions – referring to pre-anthropogenic conditions – should be available for each system to apply integrated restoration strategies. Moreover, an in-depth understanding of long-term climate variability and its dynamics is indispensable to approach these climate change challenges and reliably predict water availability.
During the past decades, numerous paleoenvironmental studies have been carried out on Northern German sediment archives, using mainly lacustrine sediments to reconstruct hydroclimatic variability, often inferring lake-level variations as key indicators. However, most studies were carried out in areas affected by more maritime or continental climate. Studies from the transition zone are rare. Only few existing studies offer high-resolution records and/or robust chronologies, which limits the understanding of past environmental changes significantly. Besides, the Northern German lowlands have been anthropogenically affected since at least the Neolithic (~5.6 ka cal BP) and, in particular, forest composition and density have recently been shown to have at least partially an impact on lake-level variations. However, a reliable distinction between climatic impacts and anthropogenic interferences is widely missing, which is a problem because many studies were conducted on rather small lacustrine systems in which expected anthropogenic signals are higher, and single events may overprint the climatic signals. These biases lead to an incoherent picture of the past hydroclimatic variability in Northern Germany during the Holocene. To overcome this situation, it is inevitable to identify a suitable sedimentary archive from the transition zone – preferably a large lacustrine system in which natural (supra-)regional paleoenvironmental signals are expected to be not overprinted by single events. Moreover, it is necessary to establish robust chronologies and apply high-resolution methods to infer past environmental changes in a high temporal resolution. Taken together, this could contribute to an enhanced understanding of past environmental and climatic changes in Northern Germany.
This thesis consolidates the evidence for Schweriner See to act as a suitable sedimentary archive in Northern Germany for (supra-)regional climate reconstructions. Schweriner See is a large lowland lake in Northern Germany located within the transition zone from maritime to continental climate. In the first step, (paleo)lacustrine landforms, i.e. beach ridges, subaerial nearshore bar, and a silting-up sequence, are investigated along the north-eastern shoreline using a combined approach of sedimentology (e.g. grain size variations) and the relatively novel method of luminescence profiling offering relative age determinations to understand depositional processes and their chronological framework. Absolute age information is mainly inferred by OSL dating. Secondly, an important prerequisite to interpreting information obtained from lacustrine sediment archives is a thorough understanding of processes controlling sedimentation. Schweriner See is characterized by a complex morphometry, which influences in-lake processes, i.e. i) in-lake productivity, ii) carbonate precipitation and iii) wind- and wave-induced processes, resulting in a distinct spatial heterogeneity. This thesis shows that it is crucial first to understand sedimentary depositional processes and controlling mechanisms to i) select suitable coring location(s) and ii) reconstruct paleoenvironmental and hydroclimatic variations reliably.
Based on bathymetric considerations and inferred in-lake processes, two main coring locations were identified to infer i) the anthropogenic impacts and ii) hydroclimatic variations. Short sediment records from the shallow water areas (< 15 m water depth) cover the most recent environmental history of Schweriner See. A well-dated sedimentary record (210Pb/137Cs and 14C dating) links distinct sedimentary and geochemical changes with historical events. Schweriner See was extensively affected by lake-wide eutrophication and contamination, closely related to sewage and population dynamics within the catchment. The water quality only improved after the German Reunification in 1990 CE when sewage was precluded from Schweriner See. Contamination trends at Schweriner See showed similar trends to different archives along the southern Baltic Sea, implying a common regional driving mechanism, e.g. environmental legalisation.
A well-dated sediment record from the profundal zone (52 m water depth) allowed the reconstruction of large-scale atmospheric conditions during the past 3 ka cal BP by inferring winter temperature variability, the moisture source region and/or evaporative lake water enrichment, which resemble variations in the North Atlantic Oscillation (NAO). The NAO greatly influences the Central European climate, affecting, for example, surface air temperature, precipitation or storm tracks. During 3-2.8 ka and 2.1-0.8 ka cal BP, predominantly positive NAO conditions are reconstructed, which are characterized by warmer winter temperatures, moisture conditions bringing isotopically enriched precipitation from the southern/central North Atlantic to Northern Central Europe and/or warmer temperatures that may result in a higher evaporative isotopic lake water enrichment as a result of northwards displaced westerlies. Conversely, during 2.8-2.1 ka and 0.8-0.1 ka cal BP, results correspond to predominantly negative NAO phases influenced by southwards displaced westerlies. Frequent atmospheric blocking allows for the intrusion of northerly or easterly winds, resulting in colder winter temperatures, isotopically depleted precipitation from the Northern Atlantic and Arctic region and/or a lower evaporative lake water enrichment. In addition to these long-term changes in atmospheric conditions, short-term hydroclimatic variations have been reconstructed, mainly reflecting lake-level variations in conjunction with precipitation variability, with the proxy signal being additionally amplified by wind speed and wave motion. Comparisons with other archives support these results.
So far, the paleoenvironmental reconstruction is limited to the Late Holocene, but initial dating results imply possible interferences until the Late Pleistocene. Therefore, future studies should focus on extending the profundal record from Schweriner See further back in time, providing a high-resolution record covering both the Holocene and possibly the Late Pleistocene.
Based on extensive investigations along the coast and in the coastal waters of NE Germany, a lithostratigraphic classification of the Holocene coastal deposits is presented. Their characteristics, i.e. the lithofacies, reflect the spatial change in hydrodynamics, sediment supply, salinity, bioproduction, etc. in the accumulation space. The displacement of the facies associated with the sea-level rise of the Baltic Sea led to the formation of regularly occurring vertical depositional sequences. From these regular profiles, four lithostratigraphic formations and two subformations of the coastal deposits can be delineated as approximately homogeneous sedimentary bodies, which are described in detail, defined in terms of their spatial extent and classified with regard to the time of accumulation.
The exchange of water and dissolved elements between the continents and the oceans occurs via different routes in the hydrological cycle, such as rivers, atmospheric exchange, and submarine groundwater discharge (SGD). In addition, the elemental fluxes in the coastal waters may strongly depend on benthic water-solid-microbe interactions close to the sediment-water interface. It is becoming increasingly recognized that SGD can impact diagenesis and act as a source of water and dissolved substances for coastal ecosystems. The qualitative and quantitative assessment of SGD is still challenging as it requires the identification of suitable geochemical tracers for the complex hydrological and biogeochemical processes in the subterranean estuary. In this study, geochemical analyses were combined with geophysical, hydrological, and biological investigations to gain insights into the mechanisms driving SGD in coastal waters. In addition, onshore ground and surface waters were evaluated to identify the processes controlling the potential end member. The surveys were performed along the Baltic Sea coast: Warnow River and Wismar Bay in Germany, the Gulf of Gdańsk and Puck Bay in Poland, and Hanko Bay in Finland. The results suggest that the analyzed surface water system was strongly impacted by seasonal variations, while SGD displayed a much more stable composition throughout the year. New areas of SGD were also identified along the Baltic Sea. It was also observed that anthropogenic coastal infrastructures could promote SGD affecting the water balance and the benthic fluxes. At other sites, the SGD was associated with natural structures such as pockmarks. The stable isotopic composition of the fresh component of SGD was close to the meteoric water at most sites; however, old groundwaters from distinct aquifers were identified. Combining all sites, SGD showed high variability, ranging from near 0 to up to 300 L m-2 d-1, and the saline SGD was more dominant than the fresh component. The fluxes obtained at one site were even higher than the surface runoff. SGD was higher on sandy sediments, but the elemental fluxes were relatively low. Despite low SGD at muddy sites, interfacial elemental fluxes, enhanced by intense diagenesis in the top sediments, resulted in higher chemical fluxes to the water column. The sediment porewater gradients at the SGD impacted sites suggest that the advective upward flow of groundwater increased the elemental fluxes across the sediment-water interface. Therefore, the dissolved substances of SGD are partly impacted by the processes in the soil zone and aquifer during groundwater development, and partly impacted by the early diagenetic process in the surface sediments. Overall, this study shows the importance of SGD for the biogeochemical cycles of coastal waters. Moreover, 6 it can be concluded that a combination of interdisciplinary approaches can provide a better understanding and assessment of SGD in a specific environment. Although all the studies presented here are local, the methodology and results presented in this thesis can be replicated and thus provide assistance in other coastal areas.