ORCID Profile
0000-0002-1580-4875
Current Organisation
Aarhus University
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Publisher: Elsevier BV
Date: 2022
Publisher: Springer Science and Business Media LLC
Date: 20-06-2012
DOI: 10.1038/NATURE11205
Abstract: Ecosystem respiration is the biotic conversion of organic carbon to carbon dioxide by all of the organisms in an ecosystem, including both consumers and primary producers. Respiration exhibits an exponential temperature dependence at the subcellular and in idual levels, but at the ecosystem level respiration can be modified by many variables including community abundance and biomass, which vary substantially among ecosystems. Despite its importance for predicting the responses of the biosphere to climate change, it is as yet unknown whether the temperature dependence of ecosystem respiration varies systematically between aquatic and terrestrial environments. Here we use the largest database of respiratory measurements yet compiled to show that the sensitivity of ecosystem respiration to seasonal changes in temperature is remarkably similar for erse environments encompassing lakes, rivers, estuaries, the open ocean and forested and non-forested terrestrial ecosystems, with an average activation energy similar to that of the respiratory complex (approximately 0.65 electronvolts (eV)). By contrast, annual ecosystem respiration shows a substantially greater temperature dependence across aquatic (approximately 0.65 eV) versus terrestrial ecosystems (approximately 0.32 eV) that span broad geographic gradients in temperature. Using a model derived from metabolic theory, these findings can be reconciled by similarities in the biochemical kinetics of metabolism at the subcellular level, and fundamental differences in the importance of other variables besides temperature—such as primary productivity and allochthonous carbon inputs—on the structure of aquatic and terrestrial biota at the community level.
Publisher: Springer Science and Business Media LLC
Date: 09-06-2004
Publisher: Springer Science and Business Media LLC
Date: 11-11-2008
Publisher: Walter de Gruyter GmbH
Date: 19-01-2001
DOI: 10.1515/BOT.2001.005
Publisher: Public Library of Science (PLoS)
Date: 29-03-2016
Publisher: Wiley
Date: 18-05-2010
DOI: 10.1111/J.1461-0248.2010.01466.X
Abstract: Successful mitigation of negative effects of global warming will depend on understanding the link between physiological and ecological responses of key species. We show that while metabolic adjustment may assist Australasian kelp beds to persist and maintain abundance in warmer waters, it also reduces the physiological responsiveness of kelps to perturbation, and suppresses canopy recovery from disturbances by reducing the ecological performance of kelp recruits. This provides a warning not to rely solely on inventories of distribution and abundance to evaluate ecosystem function. The erosion of resilience is mediated by a shift in adult-juvenile interactions from competitive under cool to facilitative under warm conditions, supporting the prediction that positive interactions may become increasingly important in a warmer future. Kelp beds may remain intact but with a lower threshold for where additional impacts (e.g., extreme storms or reduced water quality) will lead to persistent loss of habitat and ecological function.
Publisher: Wiley
Date: 05-2013
Publisher: American Geophysical Union (AGU)
Date: 05-2012
DOI: 10.1029/2012GL051886
Publisher: Wiley
Date: 02-2009
DOI: 10.1111/J.1529-8817.2008.00635.X
Abstract: We tested the ability of sporophytes of a small kelp, Ecklonia radiata (C. Agardh) J. Agardh, to adjust their photosynthesis, respiration, and cellular processes to increasingly warm ocean climates along a latitudinal gradient in ocean temperature (∼4°C). Tissue concentrations of pigment and nutrients decreased with increasing ocean temperature. Concurrently, a number of gradual changes in the metabolic balance of E. radiata took place along the latitudinal gradient. Warm-acclimatized kelps had 50% lower photosynthetic rates and 90% lower respiration rates at the optimum temperature than did cool-acclimatized kelps. A reduction in temperature sensitivity was also observed as a reduction in Q10 -values from cool- to warm-acclimatized kelps for gross photosynthesis (Q10 : 3.35 to 1.45) and respiration (Q10 : 3.82 to 1.65). Respiration rates were more sensitive to increasing experimental temperatures (10% higher Q10 -values) than photosynthesis and had a higher optimum temperature, irrespective of s ling location. To maintain a positive carbon balance, E. radiata increased the critical light demand (Ec ) exponentially with increasing experimental temperature. The temperature dependency of Ec was, however, weakened with increasing ocean temperature, such that the critical light demand was relaxed in kelp acclimated to higher ocean temperatures. Nevertheless, calculations of critical depth limits suggested that direct effects of future temperature increases are unlikely to be as strong as effects of reduced water clarity, another globally increasing problem in coastal areas.
Publisher: Elsevier BV
Date: 11-2023
Publisher: Wiley
Date: 02-12-2022
DOI: 10.1002/IEAM.4552
Abstract: Coastal waters are highly productive and erse ecosystems, often dominated by marine submerged aquatic vegetation (SAV) and strongly affected by a range of human pressures. Due to their important ecosystem functions, for decades, both researchers and managers have investigated changes in SAV abundance and growth dynamics to understand linkages to human perturbations. In European coastal waters, monitoring of marine SAV communities traditionally combines er observations and/or video recordings to determine, for ex le, spatial coverage and species composition. While these techniques provide very useful data, they are rather time consuming, labor‐intensive, and limited in their spatial coverage. In this study, we compare traditional and emerging remote sensing technologies used to monitor marine SAV, which include satellite and occupied aircraft operations, aerial drones, and acoustics. We introduce these techniques and identify their main strengths and limitations. Finally, we provide recommendations for researchers and managers to choose the appropriate techniques for future surveys and monitoring programs. Integr Environ Assess Manag 2022 :892–908. © 2021 SETAC
Publisher: Elsevier BV
Date: 09-2005
Publisher: Regional Euro-Asian Biological Invasions Centre Oy (REABIC)
Date: 06-2008
Publisher: American Chemical Society (ACS)
Date: 29-09-2016
Abstract: Recent technological developments have increased the number of variables being monitored in lakes and reservoirs using automatic high frequency monitoring (AHFM). However, design of AHFM systems and posterior data handling and interpretation are currently being developed on a site-by-site and issue-by-issue basis with minimal standardization of protocols or knowledge sharing. As a result, many deployments become short-lived or underutilized, and many new scientific developments that are potentially useful for water management and environmental legislation remain underexplored. This Critical Review bridges scientific uses of AHFM with their applications by providing an overview of the current AHFM capabilities, together with ex les of successful applications. We review the use of AHFM for maximizing the provision of ecosystem services supplied by lakes and reservoirs (consumptive and non consumptive uses, food production, and recreation), and for reporting lake status in the EU Water Framework Directive. We also highlight critical issues to enhance the application of AHFM, and suggest the establishment of appropriate networks to facilitate knowledge sharing and technological transfer between potential users. Finally, we give advice on how modern sensor technology can successfully be applied on a larger scale to the management of lakes and reservoirs and maximize the ecosystem services they provide.
Publisher: Wiley
Date: 13-01-2023
DOI: 10.1002/LNO.12299
Abstract: The ability of seagrass meadows to filter nutrients and capture and store CO 2 and nutrients in the form of organic carbon (OC) and nitrogen (N) in their sediments may help to mitigate local eutrophication as well as climate change via meadow restoration and protection. This study assesses OC and N sediment stocks (top 50 cm) and sequestration rates within Danish eelgrass meadows. At four locations, eelgrass‐vegetated and nearby unvegetated plots were studied in protected and exposed areas. The average OC and N sediment 50 cm stocks were 2.6 ± 0.3 kg OC m −2 and 0.23 ± 0.01 kg N m −2 , including vegetated and unvegetated plots. In general, OC and N stocks did not differ significantly between eelgrass meadows and unvegetated sediments. Lack of accumulation of excess 210 Pb suggested sediment erosion or low rates of sediment accumulation at most sites. OC accumulation rates ranged from 6 to 134 g m −2 yr −1 and N from 0.7 to 14 g m −2 yr −1 . Generalized additive models showed that ≥ 80% of the variation in sediment OC and N stocks was explained by sediment grain size, organic matter source, and hydrodynamic exposure. Long cores, dated with 210 Pb, showed declining OC and N densities toward present time, suggesting long‐term declines in eelgrass OC and N pools. Estimates of potential nation‐wide OC and N accumulation in eelgrass sediments show that they could annually capture up to 0.7% ± 0.5% of CO 2 emissions and 6.9% ± 5.2% of the total terrestrial N load.
Publisher: Elsevier BV
Date: 2022
Publisher: Frontiers Media SA
Date: 04-04-2019
Publisher: Informa UK Limited
Date: 20-04-2007
Publisher: Springer Science and Business Media LLC
Date: 22-10-2005
No related grants have been discovered for Peter Anton Upadhyay Stæhr.