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Mikroalger : – vår tids miljöhjältar
- 2020
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Konstnärligt arbeteabstract
- Utställningen Mikroalger - vår tids miljöhjältar visade forskningen inom projektet ALGOLAND ett projekt inom Linnéuniversitetets spetsforskning inom ekologi och evolutionsforskning. Inom Algoland undersöker forskare mikroalgers potential att rena luft och vatten som kommer från industrier. I projektet kombineras marinekologisk forskning med kompetens från industrin för att nå innovativa, hållbara lösningar som minskar utsläpp av koldioxid och närsalter. Samtidigt produceras viktiga produkter som djurfoder och biobränslen. Metoden har potential att bidra till sänkta växthusgasutsläpp i framtiden. Syftet med utställningen var att sprida kunskap om mikroalgers förmåga att rena luft och vatten samt bidra till en större medvetenhet kring vatten generellt. Målgrupper var befintliga och presumtiva studenter, anställda på Linnéuniversitetet, allmänhet samt skolbarn.
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- Alegria Zufia, Javier, Ph.D. 1992-, et al.
(författare)
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Seasonal dynamics in picocyanobacterial abundance and clade composition at coastal and offshore stations in the Baltic Sea
- 2022
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Ingår i: Scientific Reports. - London : Nature Publishing Group. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Picocyanobacteria (< 2 um in diameter) are significant contributors to total phytoplankton biomass. Due to the high diversity within this group, their seasonal dynamics and relationship with environmental parameters, especially in brackish waters, are largely unknown. In this study, the abundance and community composition of phycoerythrin rich picocyanobacteria (PE-SYN) and phycocyanin rich picocyanobacteria (PC-SYN) were monitored at a coastal (K-station) and at an offshore station (LMO; similar to 10 km from land) in the Baltic Sea over three years (2018-2020). Cell abundances of picocyanobacteria correlated positively to temperature and negatively to nitrate (NO3) concentration. While PE-SYN abundance correlated to the presence of nitrogen fixers, PC-SYN abundance was linked to stratification/shallow waters. The picocyanobacterial targeted amplicon sequencing revealed an unprecedented diversity of 2169 picocyanobacterial amplicons sequence variants (ASVs). A unique assemblage of distinct picocyanobacterial clades across seasons was identified. Clade A/B dominated the picocyanobacterial community, except during summer when low NO3, high phosphate (PO4) concentrations and warm temperatures promoted S5.2 dominance. This study, providing multiyear data, links picocyanobacterial populations to environmental parameters. The difference in the response of the two functional groups and clades underscore the need for further high-resolution studies to understand their role in the ecosystem.
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- Anonym, .
(författare)
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Alger sprids med vinden
- 2016
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Ingår i: Barometern. ; :11 Juli, s. 12-
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Tidskriftsartikel (populärvet., debatt m.m.)
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- Attayde, José Luiz
(författare)
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Direct and indirect effects of fish predation and excretion in aquatic food webs
- 2000
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis was to elucidate the mechanisms by which planktivorous fish can affect planktonic communities in lakes and how they may affect benthic communities through their effects on planktonic communities. In a laboratory experiment, nutrients released by fish increased algal biomass and altered phytoplankton community structure, suggesting that fish can affect phytoplankton by directly releasing nutrients. The effects of fish on planktonic communities through predation on zooplankton and nutrient excretion were experimentally separated and their relative importance quantified in a eutrophic humic lake. Results show that fish predation on zooplankton was the most important mechanism accounting for the increase in nutrient concentrations, phytoplankton and microzooplankton abundance in the presence of fish. However, nutrient excretion by fish had important indirect effects on zooplankton which, for some small cladocerans and copepods, were even stronger than the effects of fish predation. Fish affected phytoplankton through nutrient recycling by directly releasing nutrients and by changing the rates and ratios at which zooplankton recycled nutrients. These effects of fish on cyanobacteria and chlorophytes through nutrient recycling were stronger than those through zooplankton grazing, suggesting that fish-mediated nutrient recycling may explain most of the "trophic cascade" effects of planktivorous fish when the phytoplankton community is dominated by cyanobacteria or chlorophytes. Results also indicate that the effects of fish on planktonic communities were more predictable in direction as the taxonomic resolution of the data decreased and the experimental duration increased. The analysis of a general food web model suggest that in systems where autochthonous production is the dominant source of detritus, planktivorous fish may have an important effect on benthic communities by reducing zooplankton grazing on phytoplankton and thereby increasing the proportion of primary production that enters benthic habitats through sedimentation. Results also suggest that fish should have weaker effects (per unit of biomass) on pelagic food chains when subsidized by prey from benthic food chains and vice-versa.
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- Carlsson, Christel
(författare)
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Limitations and possibilities for microbial degradation of organic contaminants in aquifers
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Many factors can influence the rate of microbial degradation of organic contaminants in aquifers. Some of these factors, e.g. sorption, the presence of dissolved organic matter (DOM), biomass, redox conditions, cometabolism, microbial community composition, and activity of degrading microorganisms, are addressed in the thesis, with the ambition to gain insights for bioremediation in aquifers, and to prevent contaminants from spreading to drinking water supplies. The influence of sorption of organic contaminants and bacteria on biodegradation was investigated under both diffusion limited and advective flow conditions. The results demonstrated that degradation by suspended bacteria of dissolved aniline and 2,4-dichlorophenol (2,4-DCP) was faster than the degradation of the same compounds sorbed to the solids. Nevertheless, sorption to the solids was not sufficient to exclude trace contaminants from degradation. In another investigation, the main effect of DOM on microbial phenanthrene degradation in groundwater was stimulation of microbial growth and activity of degrading populations, with hydrophilic DOM having a better effect than hydrophobic. In another study, glyphosate degradation was different in a mixture of sediment and groundwater from two aquifers (Vejen, Denmark and Vomb, Sweden). Laboratory experiments excluded sorption and organic carbon limitation as major sources of the observed differences. Glyphosate degradation was positively correlated to the density of bacteria, but the difference in density between the two sites was too small to account for the degradation difference. Instead, it was found that the differences in metabolic activity of the degrading strains and the microbial community composition of the aquifers were large and coincided with differences in rates of biodegradation. Glyphosate sorption was lower and biodegradation was slower under anaerobic conditions compared with aerobic, and most of the degraded glyphosate was not mineralized but cometabolized to AMPA. The thesis pin-points to the possibilities to increase contaminant biodegradation in aquifers by the addition of i) oxygen to stimulate aerobic degradation, ii) a primary growth substrate, e.g. DOM, to increase biomass and thereby stimulate metabolic or cometabolic degradation, and iii) microorganisms to increase the degrading population and/or genetic capacity.
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- Daniel, Cesar Bolivar
(författare)
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The importance of terrestrial carbon in plankton food webs
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Allochthonous substances, i.e. produced in terrestrial ecosystems, are known to fuel bacterial production in humic lakes. I observed that allochthonous carbon subsidizes bacteria even at high levels of phytoplankton biomass. In line with that, my results also show that dissolved organic carbon is largely constituted of terrestrial substances irrespective of lake characteristics. Since bacteria constitute a quantitatively important food source for lake zooplankton, zooplankton growth can be subsidized by allochthonous carbon. Moreover, in the absence of phytoplankton derived substances I observed bacteria to grow and sustain the microbial food web. This was demonstrated by increasing populations of copepods in the absence of any input of newly produced algal carbon after a period of 1.5 years. Photochemical breakdown of organic substances, affects utilization of detrital carbon by bacteria and consequently the contribution of terrestrial carbon to food webs in humic lakes. Increase of bacterial production following abiotic cleavage of dissolved organic matter stimulated biomass production of lake zooplankton. Stimulation of zooplankton may depend on a direct trophic coupling to bacteria and flagellates, which is probably stronger in rotifers and cladocerans than in copepods. Mixotrophic flagellates can feed large zooplankton as much as heterotrophic flagellates. The flux of allochthonous substances and photosynthetic production to zooplankton is strongly coupled when bacterivorous algae dominates the flagellated community. I observed that ingestion rates of bacteria by the mixotrophic chrysophyte Poterioochromonas malhamensis is as high as for the heterotrophic Spumella elongata, whereas photosynthesis plays an important role on P. malhamensis nutrition. I conclude that allochthonous energy sources have great ecological relevance in terms of zooplankton nutrition, not only in special circumstances found in humic lakes.
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- Ekstam, Börje
(författare)
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Åtgärdsprogram för skaftslamkrypa : Elatine hexandra [Lapierre] DC.
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Det här är ett vägledande men inte legalt bindande aktionsprogram för att förbättra situationen för den starkt hotade (EN) kärlväxten skaftslamkrypa (Elatine hexandra).Skaftslamkrypa är en i Sverige primärt ettårig, vattenlevande kärlväxt inom familjen slamkrypeväxter (Elatinaceae). Skaftslamkrypa växer oftast på sorterad sandig-moig mineraljord med ett tunnare lager av gyttja eller ävja. Arten påträffas i regel på grunda sötvattenstränder med måttlig exponering av våg- och vattenrörelser. Skaftslamkrypans kärnförekomst är sjöar med klart vatten och nära neutralt pH-värde (mineralfattiga och oligo – mesotrofa klarvattenssjöar). Arten är påträffad i cirka 55 sjöar och vattendrag efter 1980 och klassas som starkt hotad i den senaste svenska rödlistan. Under senare årtionden är skaftslamkrypa i huvudsak funnen i avrinningsområden som mynnar i Västerhavet, i Värmlands, Västra Götalands, Jönköpings, Hallands och Kronobergs län.Det största hotet mot skaftslamkrypa är försämrad vattenkvalitet. Försurning, eutrofiering och brunifiering är tre faktorer som påverkar skaftslamkrypa negativt. Andra allvarliga hot är strandnära markexploatering, som en konsekvens av ändringar i lagstiftning (strandskyddslagen), och vattenregleringar vilka på olika sätt påverkar populationernas reproduktionsförmåga. Åtgärdsprogrammet föreslår åtgärder vars syfte är att motverka försurning, brunifiering, eutrofiering och vattengrumling samt åtgärder vilka syftar till att naturvårdens intressen i högre omfattning beaktas vid omprövning av vattenregleringar. Flera av de föreslagna åtgärderna syftar till att sprida kännedom om skaftslamkrypa. Här ingår framtagande av en informationsfolder, information till naturvårdshandläggare och planeringskontor på berörda kommuner samt att tillgängliggöra bevaranderelevant kunskap om arten i VISS (Vatteninformationssystem Sverige).Fältstudier rörande hur reproduktion och överlevnad påverkas av vattenregleringar samt artens nuvarande utbredning i form av plantor och fröbanker föreslås också i åtgärdsprogrammet. Resultatet av de föreslagna inventeringarna avses ligga till grund för förslag på vilka sjöar som skulle kunna vara aktuella för restaureringsåtgärder. Åtgärdsprogrammets giltighetstid är 2013-2018 och kostnaden är beräknad till 1 430 000 kronor.
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