13 research outputs found
Historien upprepar sig - Rapport från havsbotten
No full textVi oroas eller förundras ständigt över att havsmiljön visar nya sidor, plötsligt och dramatiskt eller smygande. Ingenting tycks bestå. Alla kan vi minnas att det var annorlunda förr. Men var det egentligen det? Var det bättre och vad menar vi i så fall med bättre? Sedimenten på havsbotten ger oss svar
Recent oxygen depletion and benthic faunal change in shallow areas of Sannäs Fjord, Swedish west coast
No full textSannäs Fjord is a shallow fjord (<. 32. m w.d.) with a sill depth of 8. m, located at the Swedish west coast of the Skagerrak (North Sea). The anthropogenic impact on the fjord represents combination of sewage from the local village of Sannäs and land run-off from agricultural areas. Sewage impact has been reduced since 1991 and today the fjord is included into several nature conservation programs administrated by the European Union. Yet, observations during the summers of 2008-2011 show that the shallow inner fjord inlet experiences severe oxygen depletion at 5-12. m water depth. To explore if the oxygen depletion is only a recent phenomenon and to evaluate the potential of fjord sediments to archive such environmental changes, in 2008 and 2009 seven sediment cores were taken along a transect oriented lengthwise in the fjord. The cores were analysed for organic carbon, C/N, benthic foraminifera and lead pollution records (as relative age marker). Carbon content increases in most of the cores since the ~. 1970-80s, while C/N ratio decreases from the core base upward since ~. 1995. Foraminiferal assemblages in most core stratigraphies are dominated by agglutinated species. Calcareous species (mainly elphidiids) have become dominant in the upper part of the records since the ~. late 1990s or 2000 (the inner fjord and the deepest basin) and since the ~. 1950-70s (the outer fjord). In the inner Sannäs Fjord, an increase of agglutinated foraminiferal species (e.g. Eggerelloides scaber) and organic inner linings occurred since the ~. 1970s, suggesting an intensification of taphonomic processes affecting postmortem calcareous shell preservation. A study of living vs. dead foraminiferal assemblages undertaken during June-August 2013 demonstrates that in the shallow inner fjord, strong carbonate dissolution occurs within 1-3. months following the foraminiferal growth. The dissolution is linked to corrosive conditions present within the sediment - bottom water interface, and is likely caused by the organic matter decay, resulting in severe hypoxia to anoxia. Oxygen depletion at <. 10. m w.d. develops fast due to the small water volume and limited bottom water exchange caused by a close proximity of pycnocline to the fjord bottom. Sediment cores from the deep fjord basin and the outer fjord are, on the contrary, characterized by good to excellent preservation of foraminiferal shells, higher sediment accumulation rates, and the greatest potential for high-resolution paleoenvironmental studies. Increased frequencies of low-oxygen tolerant species (e.g. Stainforthia fusiformis) in the outer fjord after ~ the 1970s suggests that increased primary productivity and seasonal oxygen deficiency have existed in the area over the last century.Recent milder winters, absent sediment reworking by freezing and grounding of sea-ice, increased nutrient load due to higher precipitation and land run-off, and the luxuriant growth of filamentous green algae followed by the organic matter decay are discussed among the mechanisms driving formation of recent oxygen deficiency in the shallow fjord inlets
Mikroplast från gjutet gummigranulat och granulatfria konstgräsytor
No full textProjektet syftade till att öka kunskapen om spridningen av mikroplaster från gjutna gummiytor och granulatfria konstgräsytor genom att komplettera tidigare studier med nya mätningar och beräkningar. Ett mål var att komma närmare en kvantifiering av dessa källors bidrag till mikroplaster nationellt, samt att få en bättre förståelse för hur man kan förhindra att spridning av mikroplaster från dessa ytor sker. Spridningen av mikroplast från dessa material per ytenhet uppskattades till 0,4-20 g/m2 per år för konstgräs utan granulat och 0,6-48 g/m2 per år för gummiytor. Variationen mellan olika ytor är mycket stor och osäkerheten i både mätningar och analys hög. Detta är en spridning i samma nivå som en vägyta med en årsmedeldygnstrafik på 5,500–13,000 fordon, som beräknas sprida 56 g mikroplast/m2. Vissa konstgräsplaner släpper sina konstgräsfiber betydligt lättare än andra (ca 50 ggr lättare) och av denna anledning bör standardiserade metoder för att identifiera högutsläppande konstgräsplaner utvecklas. Välkonstruerade och välskötta granulatfria konstgräsytor har goda möjligheter att klara EUs kommande gränsvärde för spridning av mikroplast på 7 g/m2 per år. Utifrån kommunenkäter, leverantörsdata och GIS-analyser har Sveriges totala area platsgjutet gummi uppskattats till 1 200 000 m2, varav ca 550 000 m2 på lekplatser + ca 650 000 m2 på idrottsplatser. Sveriges totala yta konstgräs utan granulat har i tidigare studie undersökts i 15 städer och har i detta projekt utifrån befolkning uppskattats till totalt ca 447 000 m2. Med utgångspunkt från den beräknade gummiarean på lekplatser och idrottsplatser kombinerat med de uppmätta mikroplastutsläppen per år och kvadratmeter uppskattas de totala årliga utsläppen från Sveriges gummiytor till ca 16 ton/år. Motsvarande beräkning för konstgräsytor utan granulat ger ca 2 ton/år. Detta är sålunda avsevärt mindre utsläppskällor än t ex vägtrafiken (8 190 ton/år) eller konstgräsplaner med infill (676 ton/år) och ligger snarare i nivå med uppskattade mikroplastutsläpp från fiskenät och andra fiskeredskap (4-46 ton/år). Projektet tog också fram tekniska specifikationer för att begränsa spridningen av mikroplaster från ytor med gummigranulatPå uppdrag av Naturvårdsverket har IVL i samarbete med KTH och företaget Sandmaster undersökt spridningen av mikroplast från utomhusytor med gummi och konstgräs utan granulat. Projektet tog också fram tekniska specifikationer för att begränsa spridningen av mikroplaster från gummiytor
Microplastic fromcast rubber granulate andgranulate-free artificial grass surfaces
No full textThis assignment, commissioned by the Swedish Environmental Protection Agency, focused on expanding knowledge about the dispersion of microplastics from cast rubber and granulate-free artificial grass surfaces by supplementing previous studies with new measurements and calculations. The goal was to improve estimates of how much these sources contribute to microplastics nationally and to identify strategies to better prevent leakage into the environment.To our knowledge, this is the first time this method has been used. The method allowed us to quantify the leakage of microplastics from cast rubber surfaces and granulate-free artificial grass surfaces in wash water from cleaning machines specifically adapted for these types of surface. By analysing a well-mixed subset of wash water and using information on the size of cleaned surface areas, the leakage of microplastics from these materials per unit area was determined to be 0.4–20 g/m2per year for granulate-free artificial grass and 0.6–48 g/m2 per year for rubber surfaces. The variation between different surfaces is, however, very high and the uncertainty in both measurements and analysis is high. This is a level of dispersion on par with a road surface with an annual mean daily traffic of 5,500–13,000 vehicles, which is estimated to be 56 g microplastic/m2. Some artificial grass surfaces release their artificial grass much more easily than others (about 50 times easier). This is why standardised methods for identifying high-emission artificial grass surfaces should be developed. Well-designed and well-maintained granulate-free artificial grass surfaces are likely to meet the EU’s proposed threshold limit for dispersion of microplastics at 7 g/m2 per year.Based on municipal surveys, supplier data and GIS analyses, Sweden’s total area of cast rubber surface is estimated to be 1,200,000 m2 in 2020, of which approx. 550,000 m2 is on playgrounds and approx. 650,000 m2 is on sports pitches. Previous studies looked at Sweden’s total area of granulate-free artificial grass in 15 cities, which this project estimates, based on population, to total about 447,000 m2.Based on the estimated rubber area on playgrounds and sports pitches combined with the measured microplastic emissions per year and square metre, total emissions from Sweden’s rubber surfaces are estimated to be about 16 tonnes/year. The equivalent estimate for artificial grass surfaces without granulates is about 2 tonnes/year. These are thus considerably smaller sources of emissions than such sources as road traffic (8,190 tonnes/year) and artificial grass with infill (676 tonnes/year), and in line with estimated microplastic emissions from fishing nets and other fishing implements (4–46 tonnes/year). The relatively low values are attributable to the total area of these surfaces being significantly smaller compared with the total area of roads in Sweden. Measures to reduce microplastic emissions from car traffic can thus reduce Swedish microplastic emissions more than measures for rubber surfaces. However, the latter measures are also important because they are relatively easy and cost-efficient to implement.The project developed technical specifications to limit the leakage of microplastics from surfaces with cast rubber granules. These include making good material choices, such as recycled SBR (styrene-butadiene rubber), choosing European tyres newer than 2010 which do not contain hazardous HA oils, and using 10–20 % PUR binder if casting occurs outdoors. Always consider the use of natural materials, which do not generate microplastics, such as grass, wood chips or sand. Available cork products on the market have the same function and appearance as rubber materials. Though these still contain PUR binders, they are considered a more environmental-friendly alternative from a microplastic perspective and probably from a climate perspective as well.Construction (environment, substrate and design) is another important aspect for reducing the leakage of microplastics from rubber surfaces and artificial grass surfaces. Open street drains near these surfaces should be avoided, and in exposed places these should be fitted with filters. Good drainage should be ensured by using stable draining substrate, such as crushed stones and stone dust. Sand on granular surfaces increases wear and should be avoided by separating with edges and spacing. Trees, particularly fruit trees, and berry bushes should be avoided next to rubber surfaces due to bird droppings and troublesome soiling that can require expensive maintenance.Maintenance is crucial for long lifespan and reduced leakage of microplastics from rubber materials. Prepare a maintenance plan together with the supplier and the maintenance contractor. Check the surfaces regularly (approx. 3–10 times/season) and repair damage as soon as possible so that it does not worsen. Pick, vacuum, brush and/or blow off debris and leaves from the surfaces regularly (3–10 times/season). Do not plough and clear snow on granulate surfaces and avoid using the surfaces for dumping snow. Empty any microplastic filters regularly, at least once a season and more often as needed. Do a deep clean with a cleaning machine if necessary, about once per every 1–4 years, depending on how dirty the surface becomes. It is important that the wash water be treated properly, so that it does not contribute to emissions of microplastics. Standardised methods for identifying and addressing high-emission artificial grass pitches and rubber surfaces should be developed to cost-effectively reduce the dispersion of microplastics from these surfaces
Seasonal oxygen depletion in a shallow sill fjord on the Swedish west coast
No full textDuring the summer of 2008, oxygen depleted water, between 5 and 12 m depth, was discovered in Sannasfjord on the Swedish west coast. The resulting sediments were black, benthic macrofauna were absent and Beggiatoa bacterial mats were a characteristic feature. This phenomenon, which was observed several years in a row, appears to be a relatively new phenomenon starting in the mid-1980s. In this study we attempt to find the underlying causes by investigating climatic effects (temperature, wind and precipitation), the local supply of nutrients from land, ecosystem change and the supply of organic material from the open Skagerrak. An analysis of long meteorological time series indicates that climatic effects are contributory, but probably not a dominating factor leading to hypoxia. Results from an advection-diffusion model solving for oxygen show that the observed increase in the river supply of nutrients has a high potential to generate hypoxia. Although complex and more difficult to quantify, it appears that ecosystem changes, with higher abundance of filamentous algae, may have played an important role. It is also possible that an enhanced supply of organic material from the open Skagerrak has contributed.</p
Present and past flow regime on contourite drifts west of Spitsbergen: preliminary results from Eurofleet 2 PREPARED cruise (June 2014).
No full textEurofleets-2 PREPARED cruise was conducted during June 5–15, 2014 on board the Norwegian R/V G.O. Sars to investigate the present and past oceanographic flow regime and patterns around two contourite drifts located in the eastern side of the Fram Strait (south-western margin of Spitsbergen). To achieve the main objective of the project, a full range of time scaled measurements was planned, from instantaneous (CTD) and seasonal (moorings) oceanographic measurements, to the recent (Box corer) and geologic (Calypso core) past record. The successful cruise recovered about 2780 km of underway measurements (hull-mounted ADCP and thermosalinograph); 60 CTD sites along 5 main transects; 22 sites for water sampling at different depths for biogeochemical characterization of water masses; 13 meso-zooplankton samplings carried out by vertical hauls (WP2 net) and 20 by horizontal hauls (Manta net) for the study of the present biological productivity of the area; about 120 km of site survey including high-resolution multibeam map and sub-bottom profiles for the identification of current related structures; 5 Box cores; and 2 Calypso piston cores 19.67 and 17.37 m long with an excellent sediment recovery up to 92%. In addition, 3 moorings were deployed for seasonal measurements of water currents direction and velocity, water mass temperature and salinity and to determine the annual amount of local sediment input. Preliminary onboard analyses outlined the presence of a cold-oxygenated and low salinity water mass moving in the deep northern part of the Storfjorden Trough under the effect of the Corilis force and tide configuration considerably affecting the velocity and bottom distribution of the cold water mass. The long Calypso cores contain the record of the past 20 ka with an exceptionally expanded Holocene sequence (over 5 m-thick) that will allow us to obtain very-high resolution palaeoceanographic and palaeoenvironmental reconstructions in the area
Dead Cores in a Convection-Diffusion Problem
No full textMathematics, AppliedMathematicsSCI(E)0ARTICLE155-7518
Eko Marina III - Inventering, kartläggning och miljömärkning av Sveriges fritidsbåtshamnar : Inventering av Sveriges fritidsbåtshamnar, kartläggning av fritidsbåtshamnars uppbyggnad samt utvecklig av prototyp för Eko Marinas miljömärkningssystem
No full textEko Marina III är den tredje delen av ett projekt som påbörjades i oktober 2019, med övergripande syfte att undersöka förutsättningarna för att utveckla en miljömärkning för fritidsbåtshamnar för att minska deras negativa miljöpåverkan. Denna del av projektet har fokuserat på tre primära områden: 1. en inventering av Sveriges fritidsbåtshamnar, 2. en kartläggning över hur fritidbåtshamnarna ser ut samt 3. utvecklingen av ett digitalt verktyg som kan bära miljömärkningsindexet, men också utgöra en stödplattform för fritidsbåtshamnarna i deras miljöarbete. Inventeringen resulterade i att 2 654 fritidsbåtshamnar listades. Det tidigare antagandet om att omkring 1 500 fritidsbåtshamnar finns i Sverige har därmed visat sig vara en kraftig underskattning. För att undersöka hur intresset bland fritidsbåthamnarna såg ut för ett digitalt verktyg för stöd i sitt miljöarbete tillfrågades även hamnrepresentanterna i enkätundersökning om vilka olika digitala funktioner de hade ett intresse av. Projektgruppen valde att arbeta vidare med att utveckla ett stödsystem för egenkontroll, vilket 73 procent av respondenterna svarade att de hade ett medel- till stort intresse av. Detta beslut grundade sig dels på respondenternas svar, men även på de intervjuer med fritidsbåtshamnar som har gjorts under projektet, där det blivit tydligt att många hamnar saknar kunskap och förståelse för sitt miljöansvar och behöver stöd för att upprätta en systematisk egenkontroll för att undvika att utsläpp sker. För att illustrera hur den digitala stödplattformen (verktyget) som utvecklats i detta projekt kan användas i olika typer av verksamheter och vilka funktioner som kan ingå, valdes exemplet båtbottentvätt, där en stegvis genomgång av egenkontrollen presenteras i bilaga 5. Det digitala verktygets övergripande syfte är att hjälpa fritidsbåtshamnar att upprätta ett systematiskt egenkontrollarbete där risker identifieras, rutiner och åtgärder tas fram, arbetet dokumenteras och följs upp för att säkerställa att hamnens miljöpåverkan på havsmiljön minimeras. En prototyp av det digitala verktyget har under projektet visats upp för en arbetsgrupp och referensgrupp bestående av branschorganisationer, hamnar, myndigheter och forskare. Överlag var mottagandet positivt – deltagarna såg många möjligheter för effektivisering av den egna verksamheten, driva miljöengagemang hos klubbmedlemmar samt stöd för att prioritera utvecklingen av miljöarbetet hamnarna. Däremot uppfattades komplexiteten och detaljnivån som ett potentiellt hinder för hamnar som inte har kommit långt i miljöarbetet. En utmaning i det framtida utvecklingsarbetet blir att hitta ett sätt att möta och kunna hantera fritidsbåtshamnarnas heterogenitet, där variation av hamnarnas finansiella förutsättningar, kunskap i miljöbalken samt kommunernas fokus på tillsyn är så olika
