Alfred Wegener Institute for Polar and Marine Research
Electronic Publication Information CenterNot a member yet
52828 research outputs found
Sort by
Impacts of Reindeer on Soil Carbon Storage in the Seasonally Frozen Ground of Northern Finland: A Pilot Study
Get PDFTo test the effect of reindeer husbandry on soil carbon storage of seasonally frozen ground, we analysed soil and vegetation properties in peatlands and mixed pine and mountain birch forests. We analysed sites with no grazing and contrasting intensities of grazing, and associated trampling, in Northern Finland. With a pilot study approach, we optimised the study design to include several grazing class sites including grazing seasonality but omitting sample replication at one site. Soils were analysed for water content, bulk density, total organic carbon (TOC), total nitrogen, stable carbon isotopes and radiocarbon ages. We found that there was no significant difference between grazing intensities in terms of TOC, but that TOC mainly depended on the soils' TOC content present prior to intensive herbivory introduction. In contrast, understory vegetation was visibly transformed from dwarf shrub to graminoid-dominated vegetation with increasing grazing and trampling intensity. Also, we found a decrease in bulk density with increasing animal activity on soil sites, which most likely results from named vegetation changes and therefore different peat structures
Making the UN Ocean Decade work? The potential for, and challenges of, transdisciplinary research and real‐world laboratories for building towards ocean solutions
Get PDFDue to the strong interconnectedness between the ocean and our societies worldwide, improved ocean governance is essential for sustainable development in the context of the UN Ocean Decade. However, a multitude of different perspectives—ecological, societal, political, economic—and relations between these have to be understood and taken into consideration to foster transformative pathways towards marine sustainability. A core challenge that we are facing is that the ‘right’ response to complex societal issues cannot be known beforehand as abilities to predict complex systems are limited. Consequently, societal transformation is necessarily a journey towards the unknown and therefore requires experimental approaches that must enable the involvement of everyone with stakes in the future of our marine environment and its resources. A promising transdisciplinary research method that fulfils both criteria—being participatory and experimental—are real-world laboratories. Here, we discuss how real-world labs can serve as an operational framework in the context of the Ocean Decade by facilitating and guiding successful knowledge exchange at the interface of science and society. The core element of real-world labs is transdisciplinary experimentation to jointly develop potential strategies leading to targeted real-world interventions, essential for achieving the proposed ‘Decade Outcomes’. The authors specifically illustrate how deploying the concept of real-world labs can be advantageous when having to deal with multiple, overlapping challenges in the context of ocean governance and the blue economy. Altogether, we offer a first major contribution to synthesizing knowledge on the potentials of marine real-world labs, considering how they act as a way of exploring options for sustainable ocean futures. Indeed, in the marine context, real-world labs are still under-explored but are a tangible way for addressing the societal challenges of working towards sustainability transformations over the coming UN Ocean Decade and beyond. Read the free Plain Language Summary for this article on the Journal blog
A Review of Seismic Surveys on the Lomonosov Ridge: Conclusions on its Structural Segmentation and Influence on Arctic Ocean Paleoceanography
Get PDFThe Lomonosov Ridge presents a major morphologic feature in the Arctic Ocean. Its tectonic evolution influenced the development of the ocean current system, deposition realm, glacial processes and ecosystem essentially. Based on morphological differences, the Lomonosov Ridge can be divided into three segments: the North American leg north off Greenland, the central part, and the Siberian leg.
The contribution presents an overview on a set of seismic surveys along the Ridge, and across into the adjacent Eurasian and Amerasia Basins. The data image the entire sedimentary cover, as well as the ridge’s basement surface. Prominent reflectors, reflector configuration, as well as the reflection pattern of seismic units were correlated with coring information and magnetic anomalies to establish a seismostratigraphic model.
Aim of the study is to investigate if the structure of the sedimentary cover can be related to the segmentation of the Lomonosov Ridge, and thus, can provide information on the subsidence history of the different legs. Drift bodies, sediment waves, and erosional structures are examined for indications on the Paleoceanography, such as first passages for water mass exchanges between the Amerasia and Eurasia Basins, and the onset of a modern ocean circulation system and paleo-bottom current activity in the Arctic Ocean
Predictability of Coastal Boundary Layer Jets in South China Using Atmosphere–Ocean Coupling
Get PDFMost standalone atmospheric models do not perform well in simulations of coastal boundary layer jets (BLJs), important weather processes that can trigger heavy rain in coastal areas by supplying both moisture and dynamic lifting. We compared 33-year simulations with a coupled atmosphere–ocean model and its standalone atmospheric component, the REgional atmosphere MOdel (REMO), forced by the prescribed sea surface temperature (SST). We validated our results using the Tropical Rainfall Measuring Mission SST and the ERA5 hourly reanalysis data set. We found that the coupled model gave a more realistic SST standard deviation than the REMO on BLJ days and corrected the overestimated air temperature over land during the day. The coupled atmosphere–ocean model showed a lower land–sea thermal contrast in the boundary layer. This increased the effects of inertial oscillation, which caused the ageostrophic flows to veer southwest, which is the direction of the maximum wind speed on BLJ days. This reproduced a more reasonable land–sea thermal contrast in the boundary layer as a result of strong air–sea mixing in coastal weather processes, which led to a more robust inertial oscillation and a larger SST standard deviation over the central South China Sea. These findings deepen our understanding of the influence of a fully mixed air–sea boundary on coastal weather processes. These results show that operational numerical weather prediction models can be improved by applying atmosphere–ocean coupling to advance their ability to forecast the weather (e.g., BLJ events) in coastal areas
Levelling-up rhodolith-bed science to address global-scale conservation challenges
Get PDFGlobal marine conservation remains fractured by an imbalance in research efforts and policy actions, limiting progression towards sustainability. Rhodolith beds represent a prime example, as they have ecological importance on a global scale, provide a wealth of ecosystem functions and services, including biodiversity provision and potential climate change mitigation, but remain disproportionately understudied, compared to other coastal ecosystems (tropical coral reefs, kelp forests, mangroves, seagrasses). Although rhodolith beds have gained some recognition, as important and sensitive habitats at national/regional levels during the last decade, there is still a notable lack of information and, consequently, specific conservation efforts. We argue that the lack of information about these habitats, and the significant ecosystem services they provide, is hindering the development of effective conservation measures and limiting wider marine conservation success. This is becoming a pressing issue, considering the multiple severe pressures and threats these habitats are exposed to (e.g., pollution, fishing activities, climate change), which may lead to an erosion of their ecological function and ecosystem services. By synthesizing the current knowledge, we provide arguments to highlight the importance and urgency of levelling-up research efforts focused on rhodolith beds, combating rhodolith bed degradation and avoiding the loss of associated biodiversity, thus ensuring the sustainability of future conservation programs
pWCP is a widely distributed and highly conserved Wolbachia plasmid in Culex pipiens and Culex quinquefasciatus mosquitoes worldwide
Get PDFAbstract
Mosquitoes represent the most important pathogen vectors and are responsible for the spread of a wide variety of poorly treatable diseases. Wolbachia are obligate intracellular bacteria that are widely distributed among arthropods and collectively represents one of the most promising solutions for vector control. In particular, Wolbachia has been shown to limit the transmission of pathogens, and to dramatically affect the reproductive behavior of their host through its phage WO. While much research has focused on deciphering and exploring the biocontrol applications of these WO-related phenotypes, the extent and potential impact of the Wolbachia mobilome remain poorly appreciated. Notably, several Wolbachia plasmids, carrying WO-like genes and Insertion Sequences (IS), thus possibly interrelated to other genetic units of the endosymbiont, have been recently discovered. Here we investigated the diversity and biogeography of the first described plasmid of Wolbachia in Culex pipiens (pWCP) in several islands and continental countries around the world—including Cambodia, Guadeloupe, Martinique, Thailand, and Mexico—together with mosquito strains from colonies that evolved for 2 to 30 years in the laboratory. We used PCR and qPCR to determine the presence and copy number of pWCP in individual mosquitoes, and highly accurate Sanger sequencing to evaluate potential variations. Together with earlier observation, our results show that pWCP is omnipresent and strikingly conserved among Wolbachia populations within mosquitoes from distant geographies and environmental conditions. These data suggest a critical role for the plasmid in Wolbachia ecology and evolution, and the potential of a great tool for further genetic dissection and possible manipulation of this endosymbiont.</jats:p
Pan‐Arctic soil moisture control on tundra carbon sequestration and plant productivity
No full textLong-term atmospheric CO2 concentration records have suggested a reduction in the positive effect of warming on high-latitude carbon uptake since the 1990s. A variety of mechanisms have been proposed to explain the reduced net carbon sink of northern ecosystems with increased air temperature, including water stress on vegetation and increased respiration over recent decades. However, the lack of consistent long-term carbon flux and in situ soil moisture data has severely limited our ability to identify the mechanisms responsible for the recent reduced carbon sink strength. In this study, we used a record of nearly 100 site-years of eddy covariance data from 11 continuous permafrost tundra sites distributed across the circumpolar Arctic to test the temperature (expressed as growing degree days, GDD) responses of gross primary production (GPP), net ecosystem exchange (NEE), and ecosystem respiration (ER) at different periods of the summer (early, peak, and late summer) including dominant tundra vegetation classes (graminoids and mosses, and shrubs). We further tested GPP, NEE, and ER relationships with soil moisture and vapor pressure deficit to identify potential moisture limitations on plant productivity and net carbon exchange. Our results show a decrease in GPP with rising GDD during the peak summer (July) for both vegetation classes, and a significant relationship between the peak summer GPP and soil moisture after statistically controlling for GDD in a partial correlation analysis. These results suggest that tundra ecosystems might not benefit from increased temperature as much as suggested by several terrestrial biosphere models, if decreased soil moisture limits the peak summer plant productivity, reducing the ability of these ecosystems to sequester carbon during the summer
ULVA: Tomorrow's "Wheat of the sea", a model for an innovative mariculture
Get PDFA growing interest in the development of oceanic coastal shores has arisen over the past decade, seeking alternative sustainable food sources and other valuable products. Our initiative aims at exploiting the potential of marine seaweeds in Europe. Building on the successes of previous EU and pan-European projects on seaweeds, and due the unique characteristics of the genus Ulva (Linnaeus, 1753), we have identified these green algae as the most suitable candidate and model organism for a novel kind of European mariculture. Much of the knowledge on Ulva, generated in diverse scientific disciplines and different communities, is not easily comparable nor is it shared among scientists, stakeholders, end users and the public. This COST Action, "SeaWheat" (CA20106—TOMORROW'S 'WHEAT OF THE SEA': ULVA, A MODEL FOR AN INNOVATIVE MARICULTURE), proposes an innovative conceptual pathway to address these issues, significantly improving knowledge in the biology of the most promising Ulva spp., capitalising on their economic potential, and exploring commercial applications in the human food, animal feed, pharmaceutical industries and ecosystem service. The COST Action combines interdisciplinary approaches to the sustainable use of marine resources, encompassing all the facets of Ulva biology, ecology, aquaculture, engineering, economic and social sciences. This Action will lead to the development of advanced science, create business and job opportunities in the maritime and coastal economies, and have a significant impact on societal welfare. This COST Action fulfils the current ‘Societal Challenges Priorities’ of European Horizon 2020 strategy for food security, and its application will contribute to the UN Sustainable Development Goals 14 (UNSDG) to conserve and sustainably exploit natural resources
Introduction of the BiasAdjustCXX command-line tool for the application of fast and efficient bias corrections in climatic research
Get PDFBias correction algorithms for modeled climate variables such as temperature, precipitation, and barometric pressure are used to approximate certain aspects of the distribution characteristics to the actual observed values. Thus, modeled climate data estimating future climate scenarios can be bias-adjusted using data from past periods so that climate variables and their distribution, as well as their variability, can be represented more realistically within the bias-adjusted time series. This document aims to introduce the command-line tool BiasAdjustCXX that enables the application of different scaling- and distribution-based bias adjustment techniques to minimize bias which can be estimated from time-series climate data