Beschreibung: Anthropogenic greenhouse gas emissions have been driving global climate change and they will continue to do so over the course of the 21st century. Most of the marine biosphere and especially coastal marine systems have suffered from high anthropogenic pressure per se and it is possible that the novel burden of very rapidly proceeding global climate change triggers shifts to alternative regimes and functioning in marine ecosystems. In the light of this background, my dissertation aims to contribute to the mechanistic understanding of global and local climate change effects on a common coastal marine seaweed (Fucus vesiculosus, Phaeophyceae) system of the Baltic Sea. The results of my experimental studies provide important mechanistic clues about the underlying direct and indirect effective pathways of environmental change in the studied seaweed system. To the best of my knowledge, it is one of the first studies which assess the seasonal variability of the same environmental factors on the same marine system over the course of one year. The detected context-dependency of global climate change effects within one ecosystem clearly shows that our understanding of the basic underlying ecosystem processes and patterns forms a prerequisite for testing, predicting and managing future ecological change in marine systems. Given that grazing forms a crucial ecological force in many coastal vegetated systems, the identified underlying mechanisms of change (top-down and bottom-up control) may allow reference to other similarly structured coastal systems. Importantly my findings point out, that ecological impacts of global climate change may be underestimated if local perturbation is disregarded and, thus, underline the chance and responsibility of local ecosystem management.

Beschreibung: Highlights: • Authors use inconsistent definitions of key terms like driver and pressure. • An imprecise wording could induce misunderstanding between science and policy. • We provide definitions of key terms compatible with the DPSIR approach. Abstract: In the marine sciences an increasing number of studies on environmental changes, their causes, and environmental assessments emerged in recent years. Often authors use non-uniform and inconsistent definitions of key terms like driver, threats, pressures etc. Although all of these studies clearly define causal dependencies between the interacting socio-economic and environmental systems in an understandable way, still an overall imprecise wording could induce misunderstanding at higher policy levels when it comes to integrated ecosystems assessments. Therefore we recommend using unified definitions for a better communication between science and management within national, regional and international environmental policies, for example the European Marine Strategy Framework Directive (MSFD). With this article we provide definitions compatible with the driver-pressure-state-impact-response (DPSIR) approach. Although most examples are MSFD related and thus have a marine focus the definitions are intended to be equally applicable for other systems and are usable world-wide. We suggest sticking to these definitions for an easy and simplified knowledge transfer from science to management, since DPSIR model is already accepted as a helpful tool for structuring and communicating ecosystem analyses.

Beschreibung: Multiple global and local stressors threaten populations of the bladderwrack Fucus vesiculosus (Phaeophyceae). Baltic F. vesiculosus populations presumably have a lower genetic diversity compared to other populations. I investigated the adaptive potential under multifactorial environmental change in F. vesiculosus germlings. Effects of warming and acidification were crossed during one year at the two levels “present” and “future” (according to the year 2110) at the “Kiel Outdoor Benthocosms” by applying delta-treatments. Effects of warming varied with season while acidification showed generally weak effects. The two factors “ocean acidification and warming” (OAW) and nutrients were crossed showing that nutrient enrichment mitigated heat stress. Germlings previously treated under the OAW x nutrient experiment were subsequently exposed to a simulated hypoxic upwelling. Sensitivity to hypoxia was enhanced by the previous OAW conditions. Difference in the performance of genetically different sibling groups and diversity level were observed indicating an increased adaptive potential at higher genetic diversity. Different sibling groups were analysed under multiple factors to test correlations of genotypic sensitivities. Sensitivity towards warming, acidification and nutrient enrichment correlated positively while sensitivities towards OAW and hypoxia showed a negative correlation demonstrating that genotypes previously selected under OAW are sensitive to hypoxic upwelling. In a literature review, responses of marine organisms to climate change were analysed through different levels of biological organisation showing that climate change has different effects on each single level of biological organisation. This study highlights that global change research requires an upscaling approach with regard to multiple factors, seasons, natural fluctuations, different developmental stages and levels of biological organisation in the light of the adaptive potential.

Beschreibung: Coastal ecosystems worldwide are experiencing increasing anthropogenic pressure, mainly caused by growing human populations in near-shore urban areas and by the rising number of megacities. One of the consequences of this process is the eutrophication of marine habitats that lie in the vicinity of rivers carrying high loads of nutrients that come from agriculture and human sewage. The capital of the Republic of Indonesia, Jakarta, is an example of a megacity impacting the adjacent marine ecosystems: In Jakarta Bay excessive loads of nutrients cause frequent phytoplankton blooms and the resulting microbial activity causes hypoxia events. One of the few species that copes well with these conditions is the Asian green mussel Perna viridis. It forms dense aggregations on bamboo settlement stakes in the bay located within the native distributional range of the mussel that is also a well-known invader of coastal habitats. Non-native populations of this species exist in southern Japan, at some Pacific islands and in the West Atlantic. In Indonesia, P. viridis is native to the western parts of the archipelago but non-native to the eastern parts and was found in the non-native range as fouling on ships that cross the Indonesian archipelago from west to east. One of the reasons for its invasion success is the ability of P. viridis to tolerate large fluctuations in abiotic environmental conditions. Therefore, understanding the factors influencing the mussel’s tolerance to environmental stress, should help to understand their invasion success. To address this question, I conducted three studies in which I exposed mussels to hypoxia in the laboratory under different scenarios. In the first study, I compared the hypoxia tolerance and nutritional status of mussels collected from a ship hull in the non-native range to those of mussels from Jakarta Bay in the native range. I found that the mussels collected from the ship hull were in a very poor nutritional status and tolerated hypoxia in the laboratory only half as long as mussels from the eutrophic Jakarta Bay. The finding suggests that transport on a ship hull may reduce the invasion potential of the species if the journey leads through areas of low food supply. The other two studies that comprise this thesis aim at assessing the potential roles of local adaptations (i.e. an irreversible modification that is manifested in the gene pool of a population), acclimation to stress (i.e. a reversible modification that is not genetically manifested) and a good nutritional status (caused by ample planktonic food supply in a eutrophic habitat) in determining the degree of tolerance to environmental stress in mussels. The idea of investigating this closer had arisen from a previous study, which found that individuals from Jakarta Bay are more tolerant to environmental stress (i.e. salinity, thermal and oxygen stress) than conspecifics from a more natural habitat in Indonesia. However, it remained unknown which mechanisms led to this difference. I approached this question by conducting a reciprocal transplantation experiment and subsequent hypoxia tests in the laboratory with P. viridis from the eutrophic Jakarta Bay and an oligotrophic habitat in West Java. The experiment showed that tolerance to hypoxia was rather determined by the conditions in the habitat where the mussels had lived for two months after transplantation before exposure to stress and not by the characteristics of the habitat where they originated from. This suggests that local adaptations to stress did not occur in Jakarta Bay mussels - although they have a long history of experiencing adverse conditions – or that they have been overwritten by other determinants of tolerance to hypoxia. The main determinant of stress tolerance again was the nutritional status. In the third study of this thesis, I conducted experiments that allowed establishing a causal relationship between a high nutritional status and hypoxia tolerance. Jakarta Bay mussels that had obtained more food supply in the laboratory had a better hypoxia tolerance than Jakarta Bay mussels that had obtained less food and were in a poor nutritional status. Furthermore, acclimation to low, non-lethal concentrations of dissolved oxygen enhanced hypoxia tolerance in mussels with low nutritional states. Taken together, these results show that a good nutritional status is the most relevant determinant of tolerance to environmental stress in P. viridis, which implies that the mussel can benefit from eutrophication caused by anthropogenic impact. Perna viridis may, therefore, be a species that can extend its distributional range if anthropogenic pressure in urban, near-shore areas is increasing and contributing to eutrophication. However, it may not succeed and establish in more non-native areas if conservation efforts apply that keep tropical and subtropical coastal ecosystems in an oligotrophic state and maintain high levels of biodiversity.

Beschreibung: Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere – the “global carbon budget” – is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and methodology to quantify all major components of the global carbon budget, including their uncertainties, based on the combination of a range of data, algorithms, statistics, and model estimates and their interpretation by a broad scientific community. We discuss changes compared to previous estimates and consistency within and among components, alongside methodology and data limitations. CO2 emissions from fossil fuels and industry (EFF) are based on energy statistics and cement production data, respectively, while emissions from land-use change (ELUC), mainly deforestation, are based on combined evidence from land-cover change data, fire activity associated with deforestation, and models. The global atmospheric CO2 concentration is measured directly and its rate of growth (GATM) is computed from the annual changes in concentration. The mean ocean CO2 sink (SOCEAN) is based on observations from the 1990s, while the annual anomalies and trends are estimated with ocean models. The variability in SOCEAN is evaluated with data products based on surveys of ocean CO2 measurements. The global residual terrestrial CO2 sink (SLAND) is estimated by the difference of the other terms of the global carbon budget and compared to results of independent dynamic global vegetation models. We compare the mean land and ocean fluxes and their variability to estimates from three atmospheric inverse methods for three broad latitude bands. All uncertainties are reported as ±1σ, reflecting the current capacity to characterise the annual estimates of each component of the global carbon budget. For the last decade available (2006–2015), EFF was 9.3 ± 0.5 GtC yr−1, ELUC 1.0 ± 0.5 GtC yr−1, GATM 4.5 ± 0.1 GtC yr−1, SOCEAN 2.6 ± 0.5 GtC yr−1, and SLAND 3.1 ± 0.9 GtC yr−1. For year 2015 alone, the growth in EFF was approximately zero and emissions remained at 9.9 ± 0.5 GtC yr−1, showing a slowdown in growth of these emissions compared to the average growth of 1.8 % yr−1 that took place during 2006–2015. Also, for 2015, ELUC was 1.3 ± 0.5 GtC yr−1, GATM was 6.3 ± 0.2 GtC yr−1, SOCEAN was 3.0 ± 0.5 GtC yr−1, and SLAND was 1.9 ± 0.9 GtC yr−1. GATM was higher in 2015 compared to the past decade (2006–2015), reflecting a smaller SLAND for that year. The global atmospheric CO2 concentration reached 399.4 ± 0.1 ppm averaged over 2015. For 2016, preliminary data indicate the continuation of low growth in EFF with +0.2 % (range of −1.0 to +1.8 %) based on national emissions projections for China and USA, and projections of gross domestic product corrected for recent changes in the carbon intensity of the economy for the rest of the world. In spite of the low growth of EFF in 2016, the growth rate in atmospheric CO2 concentration is expected to be relatively high because of the persistence of the smaller residual terrestrial sink (SLAND) in response to El Niño conditions of 2015–2016. From this projection of EFF and assumed constant ELUC for 2016, cumulative emissions of CO2 will reach 565 ± 55 GtC (2075 ± 205 GtCO2) for 1870–2016, about 75 % from EFF and 25 % from ELUC. This living data update documents changes in the methods and data sets used in this new carbon budget compared with previous publications of this data set (Le Quéré et al., 2015b, a, 2014, 2013). All observations presented here can be downloaded from the Carbon Dioxide Information Analysis Center (doi:10.3334/CDIAC/GCP_2016).

Beschreibung: The global methane (CH4) budget is becoming an increasingly important component for managing realistic pathways to mitigate climate change. This relevance, due to a shorter atmospheric lifetime and a stronger warming potential than carbon dioxide, is challenged by the still unexplained changes of atmospheric CH4 over the past decade. Emissions and concentrations of CH4 are continuing to increase, making CH4 the second most important human-induced greenhouse gas after carbon dioxide. Two major difficulties in reducing uncertainties come from the large variety of diffusive CH4 sources that overlap geographically, and from the destruction of CH4 by the very short-lived hydroxyl radical (OH). To address these difficulties, we have established a consortium of multi-disciplinary scientists under the umbrella of the Global Carbon Project to synthesize and stimulate research on the methane cycle, and producing regular (∼ biennial) updates of the global methane budget. This consortium includes atmospheric physicists and chemists, biogeochemists of surface and marine emissions, and socio-economists who study anthropogenic emissions. Following Kirschke et al. (2013), we propose here the first version of a living review paper that integrates results of top-down studies (exploiting atmospheric observations within an atmospheric inverse-modelling framework) and bottom-up models, inventories and data-driven approaches (including process-based models for estimating land surface emissions and atmospheric chemistry, and inventories for anthropogenic emissions, data-driven extrapolations). For the 2003–2012 decade, global methane emissions are estimated by top-down inversions at 558 Tg CH4 yr−1, range 540–568. About 60 % of global emissions are anthropogenic (range 50–65 %). Since 2010, the bottom-up global emission inventories have been closer to methane emissions in the most carbon-intensive Representative Concentrations Pathway (RCP8.5) and higher than all other RCP scenarios. Bottom-up approaches suggest larger global emissions (736 Tg CH4 yr−1, range 596–884) mostly because of larger natural emissions from individual sources such as inland waters, natural wetlands and geological sources. Considering the atmospheric constraints on the top-down budget, it is likely that some of the individual emissions reported by the bottom-up approaches are overestimated, leading to too large global emissions. Latitudinal data from top-down emissions indicate a predominance of tropical emissions (∼ 64 % of the global budget, 〈 30° N) as compared to mid (∼ 32 %, 30–60° N) and high northern latitudes (∼ 4 %, 60–90° N). Top-down inversions consistently infer lower emissions in China (∼ 58 Tg CH4 yr−1, range 51–72, −14 %) and higher emissions in Africa (86 Tg CH4 yr−1, range 73–108, +19 %) than bottom-up values used as prior estimates. Overall, uncertainties for anthropogenic emissions appear smaller than those from natural sources, and the uncertainties on source categories appear larger for top-down inversions than for bottom-up inventories and models. The most important source of uncertainty on the methane budget is attributable to emissions from wetland and other inland waters. We show that the wetland extent could contribute 30–40 % on the estimated range for wetland emissions. Other priorities for improving the methane budget include the following: (i) the development of process-based models for inland-water emissions, (ii) the intensification of methane observations at local scale (flux measurements) to constrain bottom-up land surface models, and at regional scale (surface networks and satellites) to constrain top-down inversions, (iii) improvements in the estimation of atmospheric loss by OH, and (iv) improvements of the transport models integrated in top-down inversions. The data presented here can be downloaded from the Carbon Dioxide Information Analysis Center (http://doi.org/10.3334/CDIAC/GLOBAL_METHANE_BUDGET_2016_V1.1) and the Global Carbon Project.

Beschreibung: Sharing and secondary analysis of data have become increasingly important for research. Especially in geography, the collection of digital data has grown due to technological changes. Responsible handling and proper documentation of research data have therefore become essential for funders, publishers and higher education institutions. To achieve this goal, universities offer support and training in research data management. This article presents the experiences of a pilot workshop in research data management, especially for geographers. A discipline-specific approach to research data management training is recommended. The focus of this approach increases researchers’ interest and allows for more specific guidance. The instructors identified problems and challenges of research data management for geographers. In regards to training, the communication of benefits and reaching the target groups seem to be the biggest challenges. Consequently, better incentive structures as well as communication channels have to be established.

Beschreibung: The ever-increasing complexity of in silico experiments in computational science is reflected in the growing complexity of the simulation software enabling these experiments. However, computational scientists rarely employ state-of-the-art software engineering methods, which negatively affects their productivity as well as the reliability of their scientific results. To tackle this challenge, this book introduces the Sprat Approach, which hierarchically integrates multiple domain-specific languages to facilitate the cooperation of scientists from different disciplines and to support them in creating well-engineered software without extensive software engineering training. To evaluate the Sprat Approach, it is applied to the implementation of the Sprat Marine Ecosystem Model in an exploratory case study. The Sprat Marine Ecosystem Model is a novel end-to-end ecosystem model based on population balance equations. In order to evaluate the Sprat Model, it is parametrized for the eastern Scotian Shelf ecosystem with its intertwined direct and indirect fish stock interactions, which previously could not be modeled satisfactorily. The simulation results described in this book provide new insights into the main drivers of regime shifts in marine ecosystems.