| 43261. |
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| 43262. |
- Ragazzola, Federica, et al.
(författare)
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An intertidal life : Combined effects of acidification and winter heatwaves on a coralline alga (Ellisolandia elongata) and its associated invertebrate community
- 2021
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Ingår i: Marine Environmental Research. - : Elsevier. - 0141-1136 .- 1879-0291. ; 169
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Tidskriftsartikel (refereegranskat)abstract
- In coastal marine ecosystems coralline algae often create biogenic reefs. These calcareous algal reefs affect their associated invertebrate communities via diurnal oscillations in photosynthesis, respiration and calcification processes. Little is known about how these biogenic reefs function and how they will be affected by climate change. We investigated the winter response of a Mediterranean intertidal biogenic reef, Ellissolandia elongata exposed in the laboratory to reduced pH conditions (i.e. ambient pH – 0.3, RCP 8.5) together with an extreme heatwave event (+1.4 °C for 15 days). Response variables considered both the algal physiology (calcification and photosynthetic rates) and community structure of the associated invertebrates (at taxonomic and functional level). The combination of a reduced pH with a heatwave event caused Ellisolandia elongata to significantly increase photosynthetic activity. The high variability of calcification that occurred during simulated night time conditions, indicates that there is not a simple, linear relationship between these two and may indicate that it will be resilient to future conditions of climate change.In contrast, the associated fauna were particularly negatively affected by the heatwave event, which impoverished the communities as opportunistic taxa became dominant. Local increases in oxygen and pH driven by the algae can buffer the microhabitat in the algal fronds, thus favouring the survival of small invertebrates.
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| 43263. |
- Ragazzola, Federica, et al.
(författare)
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Structural and elemental analysis of the freshwater, low-Mg calcite coralline alga Pneophyllum cetinaensis
- 2020
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Ingår i: PLANTS. - : MDPI. - 2223-7747. ; 9:9
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Tidskriftsartikel (refereegranskat)abstract
- Coralline algae are one of the most diversified groups of red algae and represent a major component of marine benthic habitats from the poles to the tropics. This group was believed to be exclusively marine until 2016, when the first freshwater coralline algae Pneophyllum cetinaensis was discovered in the Cetina River, southern Croatia. While several studies investigated the element compositions of marine coralline algal thalli, no information is yet available for the freshwater species. Using XRD, LA-ICP-MS and nano indentation, this study presents the first living low-Mg calcite coralline algae with Mg concentrations ten times lower than is common for the average marine species. Despite the lower Mg concentrations, hardness and elastic modulus (1.71 ± 1.58 GPa and 29.7 ± 18.0 GPa, respectively) are in the same range as other marine coralline algae, possibly due to other biogenic impurities. When compared to marine species, Ba/Ca values were unusually low, even though Ba concentrations are generally higher in rivers than in seawater. These low values might be linked to different physical and chemical characteristics of the Cetina River.
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| 43264. |
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Raggbock (Tragosoma depsarium) och skrovlig flatbagge (Calitys scabra) i Södermanlands län 2006-2009 – Förekomst, hotstatus samt förslag till skötselåtgärder
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Som ett led i arbetet med åtgärdsprogrammet för skalbaggar på äldre tallved har inventering av raggbock och skrovlig flatbagge bedrivits under 2006-2008 i Södermanlands och angränsande del av Stockholms län. Dessa är de arter i åtgärdsprogrammet som är aktuella för Sörmland (även en tredje art i åtgärdsprogrammet, gulfläckig praktbagge, finns uppgiven för landskapet, men inga nyare fynd har rapporterats). Arterna har eftersökts på både nya och tidigare kända lokaler med syfte att avgränsa förekomstområden, bedöma populationsstatus och substrattillgång och, vad gäller raggbock, även antalet kläckta individer på vissa lokaler. Rapporten redovisar kunskapsläget våren 2009 avseende arternas förekomst i delar av Södermanlands och angränsande län och ger förslag till prioriteringar och konkreta bevarandeåtgärder för olika delområden. Huvuddelen av åtgärdsförslagen ägnas raggbocken, eftersom den bedöms vara den mest hotade arten. Skrovlig flatbagge är vitt spridd i landskapet och dess fortlevnad verkar vara relativt tryggad.
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| 43265. |
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Raggbocken Tragosoma depsarium i Norra Ny socken Värmland
- 2000
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Förekomsten av den starkt hotade raggbocken Tragosoma depsarium L. (familjen långhorningar) som utvecklas i äldre tallågor undersöktes i Norra Ny socken, norra Värmland. Inventeringen gjordes i tre rumsliga skalor (5x5 km, 1x1 km, och beståndsnivå). Fyra 1x1-km rutor i vardera fem 5x5-km rutor (sammanlagt 2000 hektar) tillsammans med två större naturreservat (ca 100 hektar vardera), inventerades noggrant. Inom de utvalda rutorna ingick ett tiotal som låg i rutornas närhet.Totalt gjordes 123 fynd av lågor med pågående eller avslutade gnag av raggbock. Norra Ny har idag sannolikt en av de största populationerna av raggbock i landet, och därmed i Europa utanför Ryssland. Andelen av olika beståndstyper (hyggen, röjningsskog, gallringsskog, myr etc.) korrelerades med fynden, varvid mängden avverkningsmogen skog föll ut som den viktigaste faktorn på båda landskapsskalorna. Sambandet är dock förmodligen starkare för den större skalan, där de två storrutor med flest fynd hade över 30 % avverkningsmogen skog (baserat på skogsmarksareal). Ofta var förekomsterna klumpade inom varje 1x1-km ruta, vilket inte enbart kunde förklaras med utbredningen av lämpliga lågor. Detta kan, trots artens vida utbredning i socknen, tyda på att arten idag är spridningsbegränsad.Flest fynd (65 st.) av raggbock gjordes på äldre hyggen, speciellt hyggen med kvarlämnade fröträd, tillsammans med sydvända kanter mellan äldre skog och hyggen (29). Fynd inuti skog (12) gjordes uteslutande i mer öppna skogstyper, Inget fynd gjordes i de två naturreservaten eller i någon av de mer än 20 inventerade nyckelbiotoper som låg i eller strax intill rutorna. Däremot hittades arten ibland i deras sydvända kanter. Två mindre (1 och 1,5 hektar) brandfält inkluderas av en slum i studien, och båda hyste raggbock. Detta och tidigare studier pekar på att raggbocken är brandgynnad.För varje fynd noterades olika variabler om raggbock och andra insekters antal och utbredning i lågan, lågans egenskaper, och dess läge. Raggbocken är en specialiserad art med stora krav på sina lågor (grova träd med hög kärnvedsandel som snabbt måste förlora barken efter träddöd för att den för raggbocken lämpliga rötan ska uppstå) och deras lägen (solexponerade med markkontakt). Arten har två olika slags dynamik i lågorna. I den brukade skogen utnyttjas normalt endast lågans splintved (den yttre mjukare veden) som koloniseras snabbt (tre till fem år efter träddöd) och även förbrukas snabbt (framkläckta individer hinner ej själva kolonisera lågan på nytt). I lågor av gamla grova träd i optimala lägen kan däremot även kärnveden utnyttjas. Sådana "buffertlågor" utnyttjas sannolikt under många decennier och kan därmed bidra till att stabilisera populationen genom att individer kontinuerligt kläcks ut från dessa under en lång tidsperiod.Fem andra rödlistade insekter påträffades i lågorna, men dessa arter föredrog annorlunda lågor och/eller bestånd än raggbocken. I ett landskap kan dock en god förekomst av raggbock antas indikera en hög artrikedom av tallberoende insekter, Rovlevande insekter såsom knäpparlarver och hästmyror var vanligare på hyggen, där predationen på raggbockslarver kan vara större. Den viktigaste anledningen till att raggbocken är hotad är dock att arealen äldre skog med gamla grova tallar snabbt minskar, samt att bränderna upphört. De sista tio åren har mängden avverkningsmogen skog minskat med 25 % i undersökningsområdet. Dessutom blir den återstående skogen allt yngre. Detta innebär att raggbocken, och andra arter beroende av äldre tallskog, snabbt kommer att minska och på sikt försvinna från Norra Ny. Detta skulle kunna motverkas genom bildande av stora naturreservat (>500 hektar) på produktiv skogsmark i vilka elden återinförs, samt genom en betydligt med omfattande och funktionell avverkningshänsyn i skogsbruket.
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| 43266. |
- Raghunatha, Aishwarya, et al.
(författare)
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Addressing the emergence of drones – A policy development framework for regional drone transportation systems
- 2023
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Ingår i: Transportation Research Interdisciplinary Perspectives. - : Elsevier. - 2590-1982. ; 18
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Tidskriftsartikel (refereegranskat)abstract
- The climate crisis demands an energy transition away from fossil fuels, and for the transport sector, this implies finding more electric or hydrogen-fuelled solutions. An emerging disruptive solution with high potential for improved sustainability is using drones as a mode of transport, i.e., Advanced Air Mobility for passenger and freight transport in urban and rural areas,fuelled by electricity or green hydrogen. As drones are being rapidly commercialized, there is a need for a policy framework for local and regional actors to address this in decision-making. This paper aims to develop a policy framework through a systematic literature review where findings have been validated by experts from industry and appropriate governance bodies. The results reveal three conceptual elements in the Advanced Air Mobility system where policy actions are needed: 1) primary technology, including vehicle-related aspects; 2) functionality, including infrastructure and operations; and 3) adoption, including the environment, market, and society. The overall lack of a multi-level governance model for Advanced Air Mobility and the scarcity of knowledge of the topic within vital fields such as energy systems and regional planning are also addressed. The findings are discussed in light of regulatory frameworks for drone transportation in Europe. The paper concludes with a policy development framework for regional Advanced Air Mobility deployment and provides policy implications.
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| 43267. |
- Raghunatha, Aishwarya, et al.
(författare)
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Critical assessment of emissions, costs, and time for last-mile goods delivery by drones versus trucks
- 2023
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Ingår i: Scientific Reports. - : NATURE PORTFOLIO. - 2045-2322. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Electric drones as an autonomous mode of transport are scaling up to transform last-mile goods delivery, raising an urgent need for assessing impacts of drone transport from a systems perspective. In this paper, we conduct systems analyses to assess the environmental, economic, and delivery time impact of large drones for delivery scenarios to pick-up centers between mid-size cities predominantly in rural areas, and deliveries within city limits compared with electric and diesel trucks. Results show that large drones have lower emissions than diesel trucks for deliveries in rural areas and that drones dont compete with electric trucks, mainly due to the high energy demand required for take-off and landing for each delivery. Furthermore, we show that electric drones are an economically more cost-effective option than road-bound transport modes such as diesel and electric trucks due to the high degree of automation, and also provide the fastest delivery times. Our analysis provides unique insights that drones can address rapid electrification and emergency applications due to low costs, high flexibility, and fast operations. However, for regulators and practitioners to realize it as an emission-friendly option it is necessary to determine the optimal size of drones, particularly for use cases in urban areas, avoid very low landings for deliveries, and have home deliveries instead of pick-up points.
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| 43268. |
- Ragnarsson Stabo, Henrik, et al.
(författare)
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Kvantifiering av stora djurplankton i de stora sjöarna
- 2012
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Ingår i: Rapport - Vänerns vattenvårdsförbund. - 1403-6134. ; , s. 89-106
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Large zooplankton (>2 mm) are important for the functioning of the ecosystem in many large lakes. In several cases they have severely altered the food web where they have invaded. Most are predatory, which makes them both direct competitors to, and the dominant food of, many planktivorous fish species. In addition, juveniles of several predatory species, such as zander (Sander lucioperca) have been reported to utilize them extensively. In this case study we used different methods to map the spatial patterns in abundance of the large zooplankton in Lake Vänern, Lake Vättern and Lake Mälaren. The cladocerans Leptodora kindtii and Bythotrephes longimanus are predators whereas the copepod Limnocalanus macrurus is an omnivore. Generally, quantitative measurements of large zooplankton in large volumes of water are difficult to obtain with traditional sampling methods. In this case study we sampled plankton with a large plankton net - to obtain biovolume estimates horizontally, and with a tucker trawl for the vertical distribution[TA1]. A total of 58 samples were collected. In addition, multi-frequency hydroacoustics was tested as a monitoring method, with the tucker trawls as ground truth. Two frequencies were used to separate the acoustic backscattering from fish, mysids and plankton. The plankton communities were very heterogenous both within and among the lakes. Both Lake Vänern and Lake Mälaren were dominated by Leptodora, whereas Lake Vättern was dominated by Limnocalanus. The depth at the sample site was most important for the structure of the community, with Limnocalanus predominantly present below the thermocline. The hydroacoustics showed some potential for sampling the species that do not share habitat with mysids. The high densities of predatory zooplankton found in all lakes indicate that they have the potential of being important prey species for fish as well as competitors, and thus any ecosystem models in these lakes should include them. Our results indicate that large predatory zooplankton are found in the same amount (biomass) as planktivorous fish. Consequently, they are important in the food web of all three lakes. Hydroacoustic monitoring of some of the species show promising results and with some alterations in the sampling methods this could be a useful addition to the regular zooplankton monitoring of the large lakes.
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| 43269. |
- Ragnvaldsson, Daniel, et al.
(författare)
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Applying Generic Water Quality Criteria to Cu and Zn in a Dynamic Aquatic Environment-The Case of the Brackish Water Formation Strommen-Saltsjon
- 2022
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Ingår i: Water. - : MDPI AG. - 2073-4441. ; 14:6
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Tidskriftsartikel (refereegranskat)abstract
- The EU Water Framework Directive stipulates that all EU waterways shall have good chemical and ecological status by 2027. Methodologies are described for how to assess and classify waterbodies and make 7-year management plans. Aquatic risk assessment methodologies and environmental quality standards are defined and a biotic ligand model methodology is available to assess the influence of water chemistry on the ability of aquatic organisms to take up metals. Aquatic status classification practices of naturally occurring river basin-specific metals are discussed, specifically how Cu and Zn water quality criteria guideline values have been adopted and defined for Swedish coastal and estuarine waters and how well they represent possible ecological risks. Calculations of bioavailability and ecotoxicity are conducted using recognised models for the Strommen-Saltsjon water body in Stockholm, in which naturally occurring metals, especially Cu, have among the highest background concentrations of Sweden. Proposals are made to improve risk assessment methodologies to better reflect the vitality of living organisms, and to what extent current levels of these metals in Swedish waterways may influence their welfare. The study concludes that a more local assessment including, e.g., studies of the benthic fauna would be relevant for ecological status classification.
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| 43270. |
- Ragnvaldsson, Daniel, 1976-
(författare)
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Hazard screening of contaminated sites : bioavailable fractions and biological in vitro tools
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The environmental bioavailability of contaminants, rather than their total concentrations in the soil compartment play a decisive role for the risks associated with contaminated sites. Various soil constituents and abiotic conditions have strong influence on bioavailability, which may vary substantially between different locations. It is therefore necessary to site-specifically use tools that reflect the fractions of contaminants that are available to biota and pose the highest potential environmental risks. Bioassays provide integrated toxic responses which include effects from unknown contaminants or combinatory toxic effects from mixtures of contaminants. Thus, biological effect data greatly contribute to establish more realistic exposure and risk-scenarios at contaminated sites. The work underlying this thesis presents possible techniques for high capacity screening for site-specific hazards at contaminated areas. By combining rapid water extractions and cell-based in vitro designs measures of the toxic potential in soils was obtained. Toxicologically bioavailable fractions of mixed metal pollution, including arsenic, were primarily investigated in this thesis. In two of the studies, environmental availability and toxicological bioavailability of arsenic was explored in CCA-contaminated soils. Application of cell-based in vitro screening techniques was also conducted at a metal contaminated industrial site to obtain spatial distribution of toxicity. Multivariate association techniques were employed in the interpretation of environmental exposure and cytotoxicity data. It was shown that cell-based in vitro systems for both basal cytotoxicity and specific end-points targeting arsenic could assess the toxic potential from extracts obtained by several water-based extraction techniques including Pressurised Liquid Extraction (PLE). The cell-based in vitro systems were found to add important information on the site-specific differences in arsenics genotoxic potential from CCA-contaminated soils. The results highlight the importance of taking speciation and toxicological bioavailability into account in the risk analysis, rather than to base risk estimates on total load of contaminants. The presented screening approach was successfully applied at a metal polluted industrial site where spatial distribution of toxicity was obtained. PLE extraction also provided means for combined toxicological and chemical screening of explosives in soils from live-fire training ranges. Multivariate association techniques highly facilitated the interpretation of complex environmental data. The PLE was found to be a rapid extraction technique that has sufficient environmental relevance to be used in environmental impact analyses. It was also concluded that other cell-based in vitro systems that target specific toxic effects have large potential for being used in screening for a variety of environmental chemicals. Keywords: Environmental availability, Environmental bioavailability, Toxicological bioavailability, mixture toxicity, hazard screening, contaminated soils, heavy metals, arsenic, CCA, explosives, soil extraction, water extracts, cell-based in vitro tests, cytotoxicity, genotoxicity, PLE, MVDA, PCA, PLS.
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