Alfred Wegener Institute for Polar and Marine Research
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Offshore wind turbines constitute benthic secondary production hotspots on and around constructions
Get PDFIn response to climate change, the expansion of renewable energies leads to an increasing number of offshore wind farms in the North Sea. This comes along with an increase in (artificial) hard substrates in a mainly soft-bottom dominated marine area with so far largely unknown consequences for the underlying ecosystem functioning. We used a large combined dataset (both hard- and soft-substrate data) to model the secondary production of fouling communities on turbine foundations and of soft-bottom fauna inside and outside offshore wind farms (OWF) in the southern North Sea (Belgium, the Netherlands, Germany). We demonstrate that (1) a large amount of energy is channelled through fouling fauna on turbines (i.e., secondary production of fouling communities was on average 80 times higher than of soft-substrate communities), (2) 71 % of fouling production on turbines is released to the surrounding sediment (annual release: −221 ± 825 gC m−2 y−1 (SD)), and that (3) local production of soft-bottom communities is elevated up to a distance of 150–250 m from turbines. Production impacted area (PIA) was determined from hard- and soft-substrate data independently: mechanistic modelling of hard-substrate production export showed a production increase of 5 % up to 150 m from the turbine and generalised additive mixed models (GAMMs) based on soft-bottom fauna data suggested an elevated production up to 250 m from turbines. Accordingly, on the scale of an OWF (distance between turbines ∼1000 m), the local production “halo” effect around turbines affects about 11 % of an OWF area (dependent on OWF configuration). The observed changes in benthic energy flow may lead to so far unknown changes at the ecosystem level from plankton communities to apex predators
Collaborative metabolic curation of an emerging model marine bacterium, Alteromonas macleodii ATCC 27126
Get PDFInferring the metabolic capabilities of an organism from its genome is a challenging process, relying on computationally-derived or manually curated metabolic networks. Manual curation can correct mistakes in the draft network and add missing reactions based on the literature, but requires significant expertise and is often the bottleneck for high-quality metabolic reconstructions. Here, we present a synopsis of a community curation workshop for the model marine bacterium Alteromonas macleodii ATCC 27126 and its genome database in BioCyc, focusing on pathways for utilizing organic carbon and nitrogen sources. Due to the scarcity of biochemical information or gene knock-outs, the curation process relied primarily on published growth phenotypes and bioinformatic analyses, including comparisons with related Alteromonas strains. We report full pathways for the utilization of the algal polysaccharides alginate and pectin in contrast to inconclusive evidence for one-carbon metabolism and mixed acid fermentation, in accordance with the lack of growth on methanol and formate. Pathways for amino acid degradation are ubiquitous across Alteromonas macleodii strains, yet enzymes in the pathways for the degradation of threonine, tryptophan and tyrosine were not identified. Nucleotide degradation pathways are also partial in ATCC 27126. We postulate that demonstrated growth on nitrate as sole nitrogen source proceeds via a nitrate reductase pathway that is a hybrid of known pathways. Our evidence highlights the value of joint and interactive curation efforts, but also shows major knowledge gaps regarding Alteromonas metabolism. The manually-curated metabolic reconstruction is available as a "Tier-2" database on BioCyc
Proactive assisted gene flow for Caribbean corals in an era of rapid coral reef decline
No full textRegulatory action could facilitate cross-border efforts to retain ecosystem function
Phase boundary dynamics for ice nucleation and growth processes in fresh and sea water
Get PDFIce crystals and snowflakes are out-of-equilibrium growth shapes which are a result of a nonlinear growth dynamics as a consequence of the extremal property of the associated thermodynamic potential. A special role during the pattern formation play kink solutions that represent the different state of order at the phase boundaries. The mechanisms of the kink formation give an insight into the dynamics of phase transitions in particular the formation and growth of ice nuclei. In this paper is described a relationship between the classical nucleation theory and Kobayashi’s phase field theory for ice crystal growth. The critical length of the nuclei is derived from the linear stability analysis for the phase field model and is identified with the result of the classical nucleation theory. We modify original Kobayashi’s phase field model by including freezing point depression due to salt in order to describe the phase boundary of the fine network and cavities filled with brine which are formed during the freezing process in sea ice
Investigating boreal forest successional stages in Alaska and Northwest Canada using UAV‐LiDAR and RGB and a community detection network
Get PDFAbstract Boreal forests are a key component of the global carbon cycle, forming North America's most extensive biome. Different successional stages in boreal forests have varying levels of ecological values and biodiversity, which in turn affect their functions. A knowledge gap remains concerning the present successional stages, their geographic patterns and possible successions. This study develops a novel application of UAV‐LiDAR and Red Green Blue (RGB) data and network analysis to enhance our understanding of boreal forest succession. Between 2022 and 2024, we collected UAV‐LiDAR and RGB data from 48 forested sites in Alaska and Northwest Canada to (i) identify present successional stages and (ii) deepen our understanding of successional trajectories. We first applied UAV‐derived spectral and structural tree attributes to classify individual trees into plant functional types representative of boreal forest succession, amely, evergreen and deciduous . Second, we built a forest‐patch network to characterize successional stages and their interactions and assessed future stage transitions. Finally, we applied a simplified forward model to predict future dynamics and highlight different successional trajectories. Our results indicate that tree height and spectral variables are the most influential predictors of plant functional type in random forest algorithms, and high overall accuracies were attained. The network‐based community detection algorithm reveals five interconnected successional stages that could be interpreted as ranging from early to late successional and a disturbed stage. We find that disturbed sites are mainly located in Interior and Southcentral Alaska, while late successional sites are predominant in the southern Canadian sites. Transitional stages are mainly located near the tundra‐taiga boundary. These findings highlight the critical role of disturbances, such as fire or insect outbreaks, in shaping forest succession in Alaska and Northwest Canada
The Natural History of the Crustacea Volume 10 Ecology and Conservation
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This is the last volume of a ten-volume series on The Natural History of the Crustacea. The chapters in this volume synthesize our current understanding of the diverse topics in ecology and conservation of crustaceans. The first section summarizes the role of crustaceans as food for higher trophic levels, as consumers of plant and animal prey, and it examines their contribution to the processing of dead organic material as scavengers and detritivores. The following chapters evaluate how crustaceans modify the structure of ecosystems and the availability of habitat and other resources as bioengineers through, for example, bioturbation. Non-trophic interactions involving crustaceans are synthesized in the following chapters, including parasitism and competition for space and food as well as the importance of crustacean biodiversity and disparity for the structure and functioning of ecosystems. The second section identifies threats to crustaceans in a changing world, such as the effects of habitat loss and fragmentation, global climate change, human land and water use, contaminants, and the impacts of species invasions. The third section of this volume summarizes conservation strategies for endangered crustacean species and habitats and how these strategies can benefit from modern molecular biological technologies and global digital databases. Examples will be given for the successful recovery of crustacean populations in protected areas and how crustaceans are considered in legislative frameworks in, for example, nature conservation and fishery policies. The fourth section addresses the role of crustaceans in human society as a species, as food but also in media and pop culture.</jats:p
East Siberian ice wedges recording dust transport variability during the Late Pleistocene
Get PDFDuring the Late Pleistocene, a severely cold and dry climate strengthened dust production across the Northern Hemisphere. Despite many studies examining aridification and dust production, there is a lack of understanding about dust transportation during global climate variability. Long-range transported (LRT) dust can be traced by comparing global geochemical signatures and constraining provenance relationships. Here we report rare earth element abundances and strontium, neodymium, and oxygen isotope compositions of inorganic substances in ice wedges from Batagay and Central Yakutia (Cyuie and Churapcha), which comprise Yedoma deposits that formed in unglaciated Beringia. Distinct geochemical properties reflect differences between local and LRT dust contributions. Particles in the Batagay ice wedges show higher similarities to Chinese aeolian deposits, while those in Central Yakutia indicate stronger local input. These provenance constraints highlight variability in atmospheric circulation transporting dust to the Arctic during the Late Pleistocene, linking climate changes to aerosol distribution
