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- Lind, Ulrika, et al.
(författare)
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Analysis of aquaporins from the euryhaline barnacle Balanus improvisus reveals differential expression in response to changes in salinity
- 2017
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12:7
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Tidskriftsartikel (refereegranskat)abstract
- Barnacles are sessile macro-invertebrates, found along rocky shores in coastal areas worldwide. The euryhaline bay barnacle Balanus improvisus (Darwin, 1854) (= Amphibalanus improvisus) can tolerate a wide range of salinities, but the molecular mechanisms underlying the osmoregulatory capacity of this truly brackish species are not well understood. Aquaporins are pore-forming integral membrane proteins that facilitate transport of water, small solutes and ions through cellular membranes, and that have been shown to be important for osmoregulation in many organisms. The knowledge of the function of aquaporins in crustaceans is, however, limited and nothing is known about them in barnacles. We here present the repertoire of aquaporins from a thecostracan crustacean, the barnacle B. improvisus, based on genome and transcriptome sequencing. Our analyses reveal that B. improvisus contains eight genes for aquaporins. Phylogenetic analysis showed that they represented members of the classical water aquaporins (Aqp1, Aqp2), the aquaglyceroporins (Glp1, Glp2), the unorthodox aquaporin (Aqp12) and the arthropod-specific big brain aquaporin (Bib). Interestingly, we also found two big brain-like proteins (BibL1 and BibL2) constituting a new group of aquaporins not yet described in arthropods. In addition, we found that the two water-specific aquaporins were expressed as C-terminal splice variants. Heterologous expression of some of the aquaporins followed by functional characterization showed that Aqp1 transported water and Glp2 water and glycerol, agreeing with the predictions of substrate specificity based on 3D modeling and phylogeny. To investigate a possible role for the B. improvisus aquaporins in osmoregulation, mRNA expression changes in adult barnacles were analysed after long-term acclimation to different salinities. The most pronounced expression difference was seen for AQP1 with a substantial (>100-fold) decrease in the mantle tissue in low salinity (3 PSU) compared to high salinity (33 PSU). Our study provides a base for future mechanistic studies on the role of aquaporins in osmoregulation. © 2017 Lind et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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| 2. |
- Havenhand, Jon, et al.
(författare)
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Havsplanering med hänsyn till klimatförändringar : An Assessment of the Theoretical Basis, and Practical Options, for Incorporating the Effects of Projected Climate Change in Marine Spatial Planning of Swedish Waters
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Den globala klimatförändringen orsakar omfattande förändringar i arters utbredning, ekosystemens samhällsstruktur och ekosystemtjänster. Uppvärmningen av havsvattnet flyttar arters utbredning norrut, och stressar fastsittande arter som t.ex. koraller. Havsförsurning påverkar redan kallvattensarter och hotar många andra arter och ekosystem. Inom vår region har temperaturen i Östersjön under de senaste 150 åren stigit med 1-2 grader och årstidsväxlingar har förändrats, med tidigare (och längre) somrar med varma temperaturer under de senaste fyra decennierna. Andra beräkningar baserade på modeller visar på fortsatt ytterligare förändring mot slutet av detta sekel, med ytterligare genomsnittlig uppvärmning med 2-4 °C, genomsnittlig utsötning med upp till 2 salthaltsenheter, och genomsnittlig minskning av syrekoncentrationer i djupvattnet med 0,5-4 mgO2 .ml-1. Dessa modeller visar också att förändringar kommer att variera mycket över rumsskalor från 10 till 100 kilometer. Modellprognoser indikerar också att 50-80% av havsisen i norra Östersjön kommer att gå förlorad i slutet av seklet. Även om litteraturen om klimatförändringseffekter i svenska kustvatten fortfarande är relativt liten är det tydligt att klimatförändringarna redan har effekter på svenska marina arter, och att prognoserna indikerar större effekter under de kommande årtiondena. Förutom direkta effekter på enskilda arter har klimatförändringar också indirekta effekter, och potentiellt också kaskadeffekter, på nyckelarter i ekosystemet, vilket för Östersjön kan vara betydande. Sannolikheten för stora förändringar i marina ekosystem och den biologiska mångfalden i hela svenska kustvatten är således hög. Dessa förändringar i ekosystemets sammansättning och mångfald är kritiska eftersom många skyddade områden är etablerade för att bevara viktiga arter och eftersom ekosystemets funktion och motståndskraft mot klimatförändringarna är starkt relaterade till biologisk mångfald. Förlust av biologisk mångfald har visat sig minska ekosystemets funktion, vilket leder till förlust av produktivitet, resurskollaps och ökad känslighet för störningar. Att införliva relevant teori i havsplanering för att behålla viktiga ekosystemtjänster under ett förändrat klimat är givetvis klok resursanvändning. Vi vill dock påpeka att teori så väl som empirisk kunskap – särskilt när det gäller biologisk mångfald, ekosystemets funktion och klimatets konsekvenser för tillhandahållandet av marina ekosystemtjänster – fortskrider snabbt. För att behålla det framtida värdet av våra marina resurser bör kunskapen uppdateras regelbundet. I detta PM sammanfattar vi relevant teori och kunskap för att ta itu med åtgärder som inriktar sig mot målarter, biologisk mångfald, populationers avgränsningar och potentialen för att arter kan få skydd mot miljöförändringarna i sk ”klimatrefuger”.
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| 3. |
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Scientific considerations of how Arctic Marine Protected Area (MPA) networks may reduce negative effects of climate change and ocean acidification : Report from the Third Expert Workshop on Marine Protected Area networks in the Arctic, organised by Sweden and Finland under the auspices of the PAME working group of the Arctic Council in Helsinki, Finland, 21-22 September 2017
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Rapid environmental changes in the ArcticDuring the last two decades, the Arctic region has become an area of international strategic importance for states, businesses, NGOs and other stakeholders. The rapid environmental changes in the Arctic create new opportunities for different actors that may impact negatively on ecological and social values. Global climate change and ocean acidification change the habitats of the cold-adapted organisms living in the Arctic, with the risk of exterminating unique biodiversity. Human-induced emissions of greenhouse gases (primarily carbon dioxide, methane and nitrous oxide) affect the balance between energy entering and leaving the Earth’s system resulting in global warming, melting of sea-ice (which increases heat absorption by the Arctic Ocean), and associated climate change. Approximately 27 % of the carbon dioxide released to the atmosphere every year is absorbed by the oceans. This keeps the atmosphere from warming as much as it otherwise would, but creates ocean acidification. In the Arctic region climate change and ocean acidification take place 10-100 times faster than at any time in the last 65 million years.Intention of the workshopThis third expert workshop on Marine Protected Area (MPA) networks in the Arctic, organised by Sweden and Finland, was held in Helsinki (Finland) and its outcome is a contribution to the ‘‘PAME MPA-network toolbox’’ project. An MPA, as defined by PAME, is ‘‘a clearly defined geographical space recognized, dedicated, and managed, through legal or other effective means, to achieve the long-term conservation of nature with associated ecosystem services and cultural values’. An MPA network is a collection of individual MPAs or reserves operating cooperatively and synergistically, at various spatial scales, and with a range of protection levels that are designed to meet objectives that a single reserve cannot achieve. During this third expert workshop the scientific basis of how MPA networks may reduce negative effects of climate change and ocean acidification in the Arctic region was discussed. Workshop participants were mainly scientists with expertise on Arctic marine ecosystems, climate change, ocean acidification and/or MPAs. The intention of the workshop was not to reach consensus and provide a fixed list of recommendations, but rather to summarize: (1) the best available knowledge that can already be applied to the planning of a pan-Arctic MPA network, and (2) the primary uncertainties and, hence, what necessary scientific knowledge is still lacking. As such, the six main outcomes from the workshop below contribute to the scientific basis for the potential of MPAs as a tool to meet the threats posed by climate change and ocean acidification to Arctic ecosystems and livelihoods.A paradigm shift for establishing MPAs is necessaryGiven the rapid environmental changes and unprecedented rate of loss of Arctic sea ice there is an urgency to protect habitats that are essential for ecosystem functioning and to link MPAs in an international network. Humanity has now the opportunity of a pro-active and precautionary approach vis-à-vis the largely intact, highly sensitive and unique cold-adapted Arctic marine ecosystems. The current paradigm for the creation of MPAs seems to be that a direct regional or local threat needs to be proven before an MPA can be designated. However, climate change and ocean acidification are global processes that operate across the whole Arctic, and therefore this paradigm should be shifted towards one that establishes MPA networks to protect what is valued and cherished before it is harmed. This calls for applying the precautionary principle and creating Arctic MPA networks that will support resilience of biodiversity and ecosystem services to climate change and ocean acidification. Scientists are aware that not all desired knowledge for planning such networks is available at this time. This includes uncertainty associated with projecting the consequences of climate change across the physical (e.g. climate models), ecological (e.g. species diversity, ecosystem processes) to the human domain (e.g. ecosystem services, human well-being). Uncertainty about the effects of climate change and ocean acidification grows when moving from physical processes to ecology and finally to human well-being. Nonetheless, general ecological principles and additional experience from other regions (e.g. Antarctica, Baltic Sea) provide sufficient basic understanding to start designing a robust pan-Arctic MPA network already now and to develop and implement the necessary connected management measures.Existing MPA criteria need to be adapted to Arctic conditionsCreating an MPA network for the Arctic will require adaptation of established criteria to the unique, and rapidly changing, character of the region. For example, optimal MPA locations for some MPAs in the Arctic Ocean may not be stationary in space and time; e.g. high-biodiversity marginal ice zone (MIZ) ecosystems will become more dynamic in time and space, contracting in winter and expanding in summer, with climate change. In order to account for the migration of species with moving physico-chemical conditions (so-called ‘climate tracking’) creating dynamic MPAs along oceanographic and climatic gradients may be a feasible and effective approach. Such focus on ocean features, the integration of other effective area-based measures next to MPAs, as well as the systematic integration of traditional and local knowledge (TLK), will be essential in the process of designating MPA networks. In so doing, the vulnerability and status of Arctic ecosystems to cumulative drivers and pressures from not only regional and local scales (fishing, tourism, pollution, etc.) but also global scales (climate change and ocean acidification) should be monitored and reviewed on a regular basis.Arctic MPAs should be located in areas that are expected to become refugiaClimate change and ocean acidificationdo not operate in isolation but combine with regional and local environmental stressors to affect Arctic species, habitats, and ecosystems. It is possible to lessen the total stress burden and increase the resilience of biodiversity to the impacts of climate change and ocean acidification by mitigating stresses from direct anthropogenic pressures, such as habitat destruction, fishing, shipping, discharges of hazardous substances, etc., through establishing MPA networks. This will not ‘solve’ the underlying problems of climate change and ocean acidification, which can only be done by reducing atmospheric greenhouse gas emissions, but it will ‘buy time’ during which the underlying problems are addressed globally.Additional stresses should be targetedA key aspect is how to identify the location of prospective MPAs within a network. Since the effects of climate change and ocean acidification are unevenly distributed across the Arctic Ocean, it would be recommended to protect habitats that will act as refugia for Arctic biodiversity. For example, protecting the areas north of Greenland, where summer sea ice is projected to be most long-lasting, or parts of the Arctic Ocean where the supply of organic matter through permafrost melt, glacier melt, higher precipitation and higher river runoff (with increasing coastal CO2 concentrations through microbial activity) will be lowest. The 18 Arctic large marine ecosystems (LMEs) reflect the marine ecosystem variability in the region, and should be used to draft plans for MPA networks to more effectively consider representativeness.The scientific knowledge basis must be improvedThe workshop highlighted the need for a dedicated group to compile relevant geophysical and biological data for the purpose of MPA network planning. These data should include the changing environment, ‘spatial adaptation planning’, biochemical gradients, and identification of areas of high and low impact of climate change and ocean acidification. There is a wealth of information available (both reviews and analyses of knowledge gaps from CAFF, AMAP and others), that can be used for MPA planning but this information is highly scattered and needs to be collated and made spatially explicit, when possible. While the planning for MPA networks can start already now, there remains a large need for monitoring and relevant scientific research. This would require not only improved scientific cooperation between countries but also truly integrated international monitoring and research to decrease fragmentation and duplication of research.Identification of research prioritiesGaps in knowledge identified by the workshop participants mainly concern the winter season, the vulnerability and resilience of the Arctic marine ecosystems and the need to support sustainable development. With respect to climate change much more is known about species higher up in the food web (seabirds, marine mammals, some fish) than about species lower in food web. For ocean acidification, most of the experimental work has been done on lower trophic levels. Much uncertainty surrounds the fate of Arctic ecosystems in a future world and how to deal with uncertainties is an issue that should be addressed in scientific studies. For example, the disappearance of strongly ice-associated species in many places will likely lead to a state-change in the associated ecosystem, yet the timing and nature of that change is currently unpredictable. While the basic drivers of the Arctic shelf-sea ecosystems are quite well understood, there is a massive lack of information at all trophic levels for the Central Arctic Ocean LME, i.e. the deep central basin, and key species are difficult to identify. Presently, this high-latitude ecosystem is ice-bound, but climate projections indicate that it will become ice-free during summer within decades; the projected spatial and temporal variability is however very large and i
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