Leibniz-Institute of Freshwater Ecology and Inland Fisheries
Recent publications
Angler satisfaction is a key consideration in the management of recreational fisheries. Anglers typically prefer high catch rates and large fish, but the importance of these catch outcomes for satisfaction may differ across angler types, target species, and other contextual conditions. We examined the relationships between catch outcomes and satisfaction using trip-level (n = 19,558) catch and harvest information from two fisheries with contrasting governance and cultural contexts within the same nation, a small club context of north-western Germany (Lower Saxony) and a regional context with largely open access in north-eastern Germany (Mecklenburg-Western Pomerania). Both fisheries are from the same eco-region and offer multi-species fisheries of a similar species mix (predominantly freshwater). Catch rate and size of fish were found to positively affect catch satisfaction in both social-ecological contexts. The catch rate-satisfaction relationship showed diminishing marginal returns (i.e., more catch is better, but the marginal benefits diminish as catch increases), and the maximum fish size-satisfaction relationship was positively exponential (i.e., larger maximum fish sizes make anglers increasingly more satisfied). Social-ecological context, trip context (e.g., season and previous catch outcomes) and angler specialization were all significant moderators of the importance of catch outcomes towards satisfaction with catch. Importantly, after controlling for catch outcomes and other contextual factors, anglers in the small-scale club context from north-western Germany (Lower Saxony) were, on average, more satisfied with their catch than anglers in a large-scale regional context from north-eastern Germany (Mecklenburg-Western Pomerania). These findings suggest that managers cannot expect anglers to be similarly satisfied at identical catch outcomes in different social-ecological contexts, even within the same nation. Managers may well be advised to manage for specific qualities of catch (e.g., regularity of catch and larger maximum size of fish) rather than attempting to manage for high catch rates alone as the latter might not contribute to more satisfied anglers after catch rate thresholds have been passed.
Freshwater microbes play a crucial role in the global carbon cycle. Anthropogenic stressors that lead to changes in these microbial communities are likely to have profound consequences for freshwater ecosystems. Using field data from the coordinated sampling of 617 lakes, ponds, rivers, and streams by citizen scientists, we observed linkages between microbial community composition, light and chemical pollution, and greenhouse gas concentration. All sampled water bodies were net emitters of CO2, with higher concentrations in running waters, and increasing concentrations at higher latitudes. Light pollution occurred at 75% of sites, was higher in urban areas and along rivers, and had a measurable effect on the microbial alpha diversity. Genetic elements suggestive of chemical stress and antimicrobial resistances (IntI1, blaOX58) were found in 85% of sites, and were also more prevalent in urban streams and rivers. Light pollution and CO2 were significantly related to microbial community composition, with CO2 inversely related to microbial phototrophy. Results of synchronous nationwide sampling indicate that pollution-driven alterations to the freshwater microbiome lead to changes in CO2 production in natural waters and highlight the vulnerability of running waters to anthropogenic stressors.
In this study, we used three plastic powders (polystyrene (PS), polyethylene terephthalate (PET) and polyurethane (PU)) to conduct micro-enrichments with deep-sea sediments from the Eastern Pacific. High-throughput sequencing of the ITS marker gene was performed during the enrichment process. The results showed that in comparison to culture time, plastic type significantly influenced the richness and diversity of the associated fungal community. The fungal community structures in PS and PET enrichments were similar, and there was no significant difference in fungal β diversity. Culture time, however, did not have any significant impact on the fungal community. On the other hand, based on FUNGuild analysis, we revealed that the fungal community compositions in PS and PET samples were highly similar, whereas PU enrichment was very different. The OTU network indicated more interactions between the different OTUs in the PU-enriched samples, demonstrating a highly complex interaction network. Fungal abundance, however, was not significantly affected by plastic type or culture time. In conclusion, compared to the original deep-sea sediments, addition of microplastics results in changes of the fungal community structure. Furthermore, different plastic types lead to different fungal communities, and compared with PS and PET, the enrichment effect of PU was stronger. Finally, rather than culture time, plastic type has a significant impact on fungal diversity and community composition.
Predicting future changes in interspecific interactions continues to be a challenge for environmental managers. This uncertainty is exacerbated by increasing biological invasions and the likelihood that the strength of trophic interactions among native species will change. Abiotic variables influence predator resource utilisation and abundance as well as resource population dynamics. Currently no practical metric or impact prediction methodology can adequately account for all of these factors. Functional Response (FR) methods successfully incorporate resource utilisation rates with regards to resource density to quantify consumer-resource interactions under varying abiotic contexts. This approach has been extended to create the Relative Impact Potential (RIP) metric to compare invader vs native impact. However, this does not incorporate resource abundance dynamics, which clearly can also change with abiotic context. We propose a Resource Reproduction Qualifier (RRQ) be incorporated into the RIP metric, whereby RRQ is the reciprocal of the fraction or proportion to which reproduction (e.g. of prey species) changes under an environmental context. This modifies the RIP score to give a more informative RIP q value, which may be contextually increased or decreased. We empirically demonstrate the utility and benefits of including RRQ into impact potential predictions with an invasive species (the lionfish Pterois volitans) and two European native species (shanny fish Lipophyris pholis and lesser spotted dogfish Scy-liorhinus canicula) under different abiotic contexts. Despite high FR and abundance, lionfish impacts were reduced by increasing prey recruitment at higher temperatures, however, remained high impact overall. Shanny predatory impact increased with increasing temperature and was exacerbated by decreasing prey fecundity. Two population increase scenarios (50% and 80%) were assessed for lesser spotted dogfish under predicted temperature increases, preying upon E. marinus. Both scenarios indicated heightened predatory impact with increasing predator FR and decreasing prey fecundity. Our new metric demonstrates that accounting for resource reproductive responses to abiotic drivers, in tandem with the consumer per capita and abundance responses, better estimate the magnitudes of predicted inter-species interactions and ecological impacts. This can be used in stock assessments and predictions, as well as invasive species risk assessments in a comprehensive yet user-friendly manner..
Chytrid parasites are increasingly recognized as ubiquitous and potent control agents of phytoplankton, including bloom-forming toxigenic cyanobacteria. In order to explore the fate of the cyanobacterial toxin microcystins (MCs) and assess potential upregulation of their production under parasite attack, a laboratory experiment was conducted to evaluate short- and long-term variation in extracellular and intracellular MC in the cyanobacteria Planktothrix agardhii and P. rubescens, both under chytrid infection and in the presence of lysates of previously infected cyanobacteria. MCs release under parasite infection was limited and not different to uninfected cyanobacteria, with extracellular toxin shares never exceeding 10%, substantially below those caused by mechanical lysis induced by a cold-shock. Intracellular MC contents in P. rubescens under infection were not significantly different from uninfected controls, whereas infected P. agardhii showed a 1.5-fold increase in intracellular MC concentrations, but this was detected within the first 48 hours after parasite inoculation and not later, indicating no substantial MC upregulation in cells being infected. The presence of lysates of previously infected cyanobacteria did not elicit higher intracellular MC contents in exposed cyanobacteria, speaking against a putative upregulation of toxin production induced via quorum sensing in response to parasite attack. These results indicate that chytrid epidemics can constitute a bloom decay mechanism that is not accompanied by massive release of toxins into the medium.
Inland recreational fisheries, found in lakes, rivers, and other landlocked waters, are important to livelihoods, nutrition, leisure, and other societal ecosystem services worldwide. Although recreationally-caught fish are frequently harvested and consumed by fishers, their contribution to food and nutrition has not been adequately quantified due to lack of data, poor monitoring, and under-reporting, especially in developing countries. Beyond limited global harvest estimates, few have explored species-specific harvest patterns, although this variability has implications for fisheries management and food security. Given the continued growth of the recreational fishery sector, understanding inland recreational fish harvest and consumption rates represents a critical knowledge gap. Based on a comprehensive literature search and expert knowledge review, we quantified multiple aspects of global inland recreational fisheries for 81 countries spanning ~192 species. For each country, we assembled recreational fishing participation rate and estimated species-specific harvest and consumption rate. This dataset provides a foundation for future assessments, including understanding nutritional and economic contributions of inland recreational fisheries.
If life exists on Mars, it would face several challenges including the presence of perchlorates, which destabilize biomacromolecules by inducing chaotropic stress. However, little is known about perchlorate toxicity for microorganism on the cellular level. Here we present the first proteomic investigation on the perchlorate‐specific stress responses of the halotolerant yeast Debaryomyces hansenii and compare these to generally known salt stress adaptations. We found that the responses to NaCl and NaClO4‐induced stresses share many common metabolic features, e.g., signaling pathways, elevated energy metabolism, or osmolyte biosynthesis. Nevertheless, several new perchlorate‐specific stress responses could be identified, such as protein glycosylation and cell wall remodulations, presumably in order to stabilize protein structures and the cell envelope. These stress responses would also be relevant for life on Mars, which ‐ given the environmental conditions ‐ likely developed chaotropic defense strategies such as stabilized confirmations of biomacromolecules and the formation of cell clusters. This article is protected by copyright. All rights reserved.
Growing population and urbanization challenge water resources sustainability and require stringent solutions in terms of emission measurements and pollution controls. Advancements in observation techniques have improved the availability of impervious surface data that cover both urban and non-urban areas to assess the impacts of urbanization. However, most models used in macroscale studies continue to derive surface imperviousness based on land-use classes and population data, and the contributions of non-urban impervious surfaces to runoff and nutrient emissions remain largely ignored. Effects of different impervious surface data on the predicted runoff and nutrient emissions is investigated in this study for macroscale urban and non-urban areas in tandem by means of an extended urban module MONERIS - PCRaster to enable scenarios with high-resolution imperviousness data. The results showed that approximately 70% of the total runoff and nutrient emissions nationwide originated from low-to-medium populated impervious surfaces rather than from major urban catchments. Using high-resolution imperviousness data at various aggregation levels resulted in lower biased outputs of predicted runoff and nutrient emissions when compared to results using the estimated impervious data from land-use and population information. The impervious surface shares between urban and non-urban lands revealed the opposite trends of urbanization developments in the less populated areas versus an increasing contribution of emissions from non-urban areas rather than urban centers in densely populated municipalities. Overall, the non-urban impervious surface areas contributed 5–20% of the “hidden” runoff volumes and nutrient emissions from all impervious areas. The results of this study highlight the need of model adaptations regarding the increased availability of high-resolution imperviousness data and the trend of urbanization development beyond urban areas for more accurate quantification of potential flood risks and emission hotspots of macroscale urbanized areas for sustainable water resources management.
Savannahs are often branded by livestock grazing with resulting land degradation. Holistic management of livestock was proposed to contribute to biodiversity conservation by simulating native wildlife grazing behaviour. This study attempts the comparison of the impact of a holistic management regime to a wildlife grazing management regime on grass and ground-dwelling beetle species diversity on neighboring farms in Namibian rangeland. Results show that the response of biodiversity in species richness and composition to holistic management of livestock differs substantially from wildlife grazing with a positive impact. From a total of 39 identified species of ground-dwelling beetles (Coleoptera: Tenebrionidae, Carabidae) from 29 genera, eight species were found to be indicators for holistic management of livestock and three were found to be indicators for wildlife grazed rangeland. Observations suggest that holistic management of livestock may contribute to biodiversity conservation, but the differential effect of grazing management on species assemblages suggests that livestock grazing cannot replace native wildlife herbivory. Implications for insect conservation An adaptive management strategy such as holistic management used in this study shows the potential to support high beetle biodiversity. Holistic management of livestock thus aspects in favour for a sustainable form of grazing management for insect conservation even though it does not functionally replace grazing by native wildlife.
Distributed models have been increasingly applied at finer spatiotemporal resolution. However, most diagnostic analyses aggregate performance measures in space or time, which might bias subsequent inferences. Accordingly, this study explores an approach for quantifying the parameter sensitivity in a spatiotemporally explicit way. We applied the Morris method to screen key parameters within four different sampling spaces in a grid‐based model (mHM‐Nitrate) for NO3‐N simulation in a mixed landuse catchment using a 1‐year moving window for each grid. The results showed that an overly wide range of aquatic denitrification rates could mask the sensitivity of the other parameters, leading to their spatial patterns only related to the proximity to outlet. With adjusted parameter space, spatial sensitivity patterns were determined by NO3‐N inputs and hydrological transport capacity, while temporal dynamics were regulated by annual wetness conditions. The relative proportion of parameter sensitivity further indicated the shifts in dominant hydrological/NO3‐N processes between wet and dry years. By identifying not only which parameter(s) is(are) influential, but where and when such influences occur, spatial sensitivity analysis can help evaluate current model parameterization. Given the marked sensitivity in agricultural areas, we suggest that the current NO3‐N parameterization scheme (land use‐dependent) could be further disentangled in these regions (e.g., into croplands with different rotation strategies) but aggregated in non‐agricultural areas; while hydrological parameterization could be resolved into a finer level (from spatially constant to land use‐dependent especially in nutrient‐rich regions). The spatiotemporal sensitivity pattern also highlights NO3‐N transport within soil layers as a focus for future model development.
Creatine is an amino acid derivate commonly found in vertebrate muscle tissue. Creatine facilitates the recycling of adenosine triphosphate and thus contributes to the energy supply of the muscles as well as the brain. Creatine is used as a supplement for several reasons and its effects in humans, particularly in sports medicine, have been studied excessively. Also, creatine supplementation has been studied for its functions and benefits in terrestrial farm animals. Up to date, little is known about the use of creatine as a supplement in fish nutrition. Yet, due to its many physiological functions, creatine may serve as a valuable supplement in aquafeeds of farmed aquaculture species. Indeed, creatine plays a pivotal role in the fish's muscle and may help to enhance performance of fish reared in aquaculture systems. With regard to swimming exercise, creatine may even amplify its metabolic effects. Upon supplementation, creatine stimulates muscle growth increasing body mass and it has the potential to improve feed utilisation particularly of plant‐based diets. Also, creatine plays a part in osmoregulation when fish adapt to changes in salinity. Furthermore, it may improve product quality upon slaughter. Here, we compile what is known about the many functions of creatine as well as its physiological effects in fish in comparison to mammals. We also highlight its potential beneficial effects as a supplement in aquaculture and infer why creatine can help increase the sustainability of fish feeds.
In nearly every ecosystem, human predators (hunters and fishers) exploit animals at extraordinarily high rates, as well as target different age classes and phenotypes, compared to other apex predators. Demographically decoupled from prey populations and technologically advanced, humans now impose widespread and significant ecological and evolutionary change. In this paper, we investigate whether there is evidence that humans provide complementary services and whether ecosystem services of predators can be maintained by humans where wild predators are lost. Our objective is to contribute to two key ecological themes: the compatibility of human harvesting within ecosystems and management approaches in consideration of the intentional or unintentional loss of predators. We reviewed evidence for five key effects of predators: natural selection of prey, disease dynamics, landscape effects, carbon cycling and human well‐being. Without carefully designed management strategies, such changes can impose harm to ecosystems and their constituents, including humankind. Ultimately, we applied this information to consider management paradigms in which humans could better support the role of, and potentially behave more like, apex predators and discuss the challenges to such coexistence. Read the free Plain Language Summary for this article on the Journal blog. Read the free Plain Language Summary for this article on the Journal blog.
Research on Plant Growth-Promoting Bacteria (PGPB) has focused much more on rhizospheric bacteria. However, PGPB associated with toxic cyanobacterial bloom (TCB) could enter the rhizosphere through irrigation water, helping plants such as Pisum sativum L. (pea) overcome oxidative stress induced by microcystin (MC) and improve plant growth and nutritional value. This study aimed to isolate bacteria associated with toxic cyanobacteria, test PGPB properties, and inoculate them as a consortium to pea seedlings irrigated with MC to investigate their role in plant protection as well as in improving growth and nutritional value. Two bacterioplankton isolates and one rhizosphere isolate were isolated and purified on a mineral salt medium supplemented with 1000 μg/L MC and identified via their 16S rRNA gene. The mixed strains were inoculated to pea seedlings in pots irrigated with 0, 50, and 100 μg/L MC. We measured the morphological and physiological parameters of pea plants at maturity and evaluated the efficiency of the plant’s enzymatic and non-enzymatic antioxidant responses to assess the role and contribution of PGPB. Both bacterioplankton isolates were identified as Starkeya sp., and the rhizobacterium was identified as Brevundimonas aurantiaca. MC addition significantly (p < 0.05) reduced all the growth parameters of the pea, i.e., total chlorophyll content, leaf quantum yield, stomatal conductance, carotenoids, and polyphenol contents, in an MC concentration-dependent manner, while bacterial presence positively affected all the measured parameters. In the MC treatment, the levels of the pea’s antioxidant traits, including SOD, CAT, POD, PPO, GST, and ascorbic acid, were increased in the sterile pots. In contrast, these levels were reduced with double and triple PGPB addition. Additionally, nutritional values such as sugars, proteins, and minerals (Ca and K) in pea fruits were reduced under MC exposure but increased with PGPB addition. Overall, in the presence of MC, PGPB seem to positively interact with pea plants and thus may constitute a natural alternative for soil fertilization when irrigated with cyanotoxin-contaminated water, increasing the yield and nutritional value of crops.
Understanding the impact of long-term exposure of microorganisms to space is critical in understanding how these exposures impact the evolution and adaptation of microbial life under space conditions. In this work we subjected Nostoc sp. CCCryo 231-06, a cyanobacterium capable of living under many different ecological conditions, and also surviving in extreme ones, to a 23-month stay at the International Space Station (the Biology and Mars Experiment, BIOMEX, on the EXPOSE-R2 platform) and returned it to Earth for single-cell genome analysis. We used microfluidic technology and single cell sequencing to identify the changes that occurred in the whole genome of single Nostoc cells. The variant profile showed that biofilm and photosystem associated loci were the most altered, with an increased variant rate of synonymous base pair substitutions. The cause(s) of these non-random alterations and their implications to the evolutionary potential of single bacterial cells under long-term cosmic exposure warrants further investigation.
Polygonal networks occur on various terrestrial and extraterrestrial surfaces holding valuable information on the pedological and climatological conditions under which they develop. However, unlike periglacial polygons that are commonly used as an environmental proxy, the information that polygons in the hyper‑arid Atacama Desert can provide is little understood. To promote their use as a proxy, we investigated a polygonal network within an inactive channel that exhibits uncommonly diverse surface morphologies and mineral compositions, using geochemical and remote sensing techniques. Our findings show that the polygons belong to a continuous network of the same genetic origin. Their differences result from post‑formational differential eolian erosion up to 50 cm depth, exposing indurated subsurface horizons rich in sulfate or nitrate and chloride. Their location in an ancient channel could lead to the misinterpretation of fluvial polygon erosion, however, we find no such signs but evidence for aqueous resurfacing of microtopography by fog and minimal rainwater infiltration. Our findings extend the use of polygons as proxies in the Atacama Desert, indicating saline soils and hyper‑arid conditions. We conclude that this example of polygon erosion can guide future polygon research, especially regarding the use of erosional surfaces on Earth and beyond to gain valuable subsurface insights.
The extent and impacts of biological invasions on biodiversity are largely shaped by an array of socio-economic and environmental factors, which exhibit high variation among countries. Yet, a global analysis of how these factors vary across countries is currently lacking. Here, we investigate how five broad, country-specific socio-economic and environmental indices (Governance, Trade, Environmental Performance, Lifestyle and Education, Innovation) explain country-level (1) established alien species (EAS) richness of eight taxonomic groups, and (2) proactive or reactive capacity to prevent and manage biological invasions and their impacts. These indices underpin many aspects of the invasion process, including the introduction, establishment, spread and management of alien species. They are also general enough to enable a global comparison across countries, and are therefore essential for defining future scenarios for biological invasions. Models including Trade, Governance, Lifestyle and Education, or a combination of these, best explained EAS richness across taxonomic groups and national proactive or reactive capacity. Historical (1996 or averaged over 1996–2015) levels of Governance and Trade better explained both EAS richness and the capacity of countries to manage invasions than more recent (2015) levels, revealing a historical legacy with important implications for the future of biological invasions. Using Governance and Trade to define a two-dimensional socio-economic space in which the position of a country captures its capacity to address issues of biological invasions, we identified four main clusters of countries in 2015. Most countries had an increase in Trade over the past 25 years, but trajectories were more geographically heterogeneous for Governance. Declines in levels of Governance are concerning as they may be responsible for larger levels of invasions in the future. By identifying the factors influencing EAS richness and the regions most susceptible to changes in these factors, our results provide novel insights to integrate biological invasions into scenarios of biodiversity change to better inform decision-making for policy and the management of biological invasions.
Understanding genome evolution of polyploids requires dissection of their often highly similar subgenomes and haplotypes. Polyploid animal genome assemblies so far restricted homo-logous chromosomes to a 'collapsed' representation. Here, we sequenced the genome of the asexual Prussian carp, which is a close relative of the goldfish, and present a haplotype-resolved chromosome-scale assembly of a hexaploid animal. Genome-wide comparisons of the 150 chromosomes with those of two ancestral diploid cyprinids and the allotetraploid goldfish and common carp revealed the genomic structure, phylogeny and genome duplication history of its genome. It consists of 25 syntenic, homeologous chromosome groups and evolved by a recent autoploid addition to an allotetraploid ancestor. We show that de-polyploidization of the alloploid subgenomes on the individual gene level occurred in an equilibrated fashion. Analysis of the highly conserved actinopterygian gene set uncovered a subgenome dominance in duplicate gene loss of one ancestral chromosome set.
Understanding how individual differences arise and how their effects propagate through groups are fundamental issues in biology. Individual differences can arise from indirect genetic effects (IGE): genetically based variation in the conspecifics with which an individual interacts. Using a clonal species, the Amazon molly ( Poecilia formosa ), we test the hypothesis that IGE can propagate to influence phenotypes of the individuals that do not experience them firsthand. We tested this by exposing genetically identical Amazon mollies to conspecific social partners of different clonal lineages, and then moving these focal individuals to new social groups in which they were the only member to have experienced the IGE. We found that genetically different social environments resulted in the focal animals experiencing different levels of aggression, and that these IGE carried over into new social groups to influence the behaviour of naive individuals. These data reveal that IGE can cascade beyond the individuals that experience them. Opportunity for cascading IGE is ubiquitous, especially in species with long-distance dispersal or fission–fusion group dynamics. Cascades could amplify (or mitigate) the effects of IGE on trait variation and on evolutionary trajectories. Expansion of the IGE framework to include cascading and other types of carry-over effects will therefore improve understanding of individual variation and social evolution and allow more accurate prediction of population response to changing environments.
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251 members
Hans-Peter Grossart
  • Department of Experimental Limnology
Robert Arlinghaus
  • Department of Biology and Ecology of Fishes
Ramsy Agha
  • Department of Ecosystem Research
Martin Pusch
  • Department of Ecosystem Research
Information
Address
Müggelseedamm 301 und 310, 12587, Berlin, Berlin, Germany
Head of institution
Prof. Dr. Luc De Meester
Website
http://www.igb-berlin.de/
Phone
+49 (0)30 641 81 5
Fax
+49 (0)30 641 81 600