| 1. |
- Sjöstedt, Victoria, et al.
(author)
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Klimatanpassning av bostäder och bostadsområden : resultat från ett samarbetsprojekt mellan CEC och Riksbyggen
- 2016
-
Reports (other academic/artistic)abstract
- Denna rapport är en sammanställning av kunskap som genererats inom ramen för ett samarbetsprojekt mellan Centrum för miljö- och klimatforskning (CEC) vid Lundsuniversitet och Riksbyggen om klimatanpassning av bostäder och bostadsområden iSverige. Samarbetsprojektet byggde på utveckling och handledning av fem styckenmasteruppsatser vid Tillämpad klimatstrategi-programmet vid Lunds universitet,mellan november 2014 och juni 2015. De deltagande studenterna utvecklade sinauppsatser i dialog med Riksbyggen, och ett flertal av studenterna använde Riksbyggensbostadsbestånd som konkreta fallstudier. I denna rapport diskuteras de resultatsom framkommit i masteruppsatserna, med fokus på klimatrelaterad riskkartering,metoder för klimatanpassningsåtgärder, kunskapsunderlag, samt samverkan ochdeltagande. Syntesrapporten levererar inspirationsmaterial för Riksbyggens vidarearbete med klimatanpassning av bostadsrättsföreningar. Förslag på sätt att hantera klimatanpassningsproblematik i bostadssektorn läggs fram, vilka inkluderar utökad klimatrelaterad riskkartering, skräddarsydda åtgärdspaket, intern och externkommunikation av klimatrelaterade risker och anpassningsåtgärder, samt nya samarbetskonstellationer. Samarbetet mellan CEC och Riksbyggen tog tillvara på denpotential som finns i studentarbeten och skapade länkar mellan utbildning, forskningoch näringsliv. I rapporten förs en diskussion kring sätt att vidareutveckla dennasamarbetsmodell för att förnya och verka kvalitetshöjande för grundutbildningen.Rapporten identifierar även relevanta teman för nya masterprojekt, samt konkretaforskningsbehov kring kunskapsöverföring mellan aktörer och nivåer; samarbetemellan boende, fastighetsägare, myndigheter, konsulter och försäkringsbolag kringriskkartering och anpassningsåtgärder; kommunikationsinsatser för ökad acceptans föranpassningsåtgärder; samt juridiska och ekonomiska incitamentsstrukturer. Dessa ärviktiga områden att adressera i framtida forskningsinsatser för att stödja implementeringav utökad klimatrelaterad riskkartering och anpassningsåtgärder i bostadssektorn.
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| 2. |
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| 3. |
- Borgström, Anna, et al.
(author)
-
Wetlands as a Local Scale Management Tool to Reduce Algal Growth Potential
- 2022
-
In: Wetlands. - : Springer Science and Business Media LLC. - 0277-5212 .- 1943-6246. ; 42
-
Journal article (peer-reviewed)abstract
- Recent land-use changes have led to a significant loss of natural wetlands worldwide resulting in increased amounts of organic and inorganic compounds reaching lakes and coastal areas. In turn, this has led to an increased algal growth, and subsequently the risk of algal blooms and deteriorated water quality. The capacity of wetlands to retain nutrients is well-known, suggesting that constructed wetlands may be a potential management strategy to mitigate algal blooms in downstream waters, although little is known about seasonal variation in reduction of algal growth potential. Therefore, in a long-term study, we experimentally evaluated the efficiency of seven wetlands to reduce the algal growth potential by comparing the growth in cultures containing 50:50 wetland water from the inlet or outlet and water from a eutrophic lake as a standard inoculum. We show that the majority of the wetlands have a considerable potential to reduce algal growth potential, with up to 89% for cyanobacteria and 73% for green algae. However, there were strong temporal variations in efficiency within, as well as between wetlands. Specifically, we show that the potential to reduce algal growth (standardized conditions) was generally higher in winter than in summer. In addition, the wetlands showed different efficiency in reducing the growth potential of cyanobacteria and green algae. Taken together, our results show that wetlands have a considerable potential to reduce algal growth potential, suggesting that they are an efficient local-scale tool in reducing the risk of algal blooms especially from a future climate change perspective.
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| 4. |
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| 5. |
- Borgström, Anna, et al.
(author)
-
Wetlands as a potential multifunctioning tool to mitigate eutrophication and brownification
- 2024
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In: Ecological Applications. - 1051-0761 .- 1939-5582.
-
Journal article (peer-reviewed)abstract
- Eutrophication and brownification are ongoing environmental problems affecting aquatic ecosystems. Due to anthropogenic changes, increasing amounts of organic and inorganic compounds are entering aquatic systems from surrounding catchment areas, increasing both nutrients, total organic carbon (TOC), and water color with societal, as well as ecological consequences. Several studies have focused on the ability of wetlands to reduce nutrients, whereas data on their potential to reduce TOC and water color are scarce. Here we evaluate wetlands as a potential multifunctional tool for mitigating both eutrophication and brownification. Therefore, we performed a study for 18 months in nine wetlands allowing us to estimate the reduction in concentrations of total nitrogen (TN), total phosphorus (TP), TOC and water color. We show that wetland reduction efficiency with respect to these variables was generally higher during summer, but many of the wetlands were also efficient during winter. We also show that some, but not all, wetlands have the potential to reduce TOC, water color and nutrients simultaneously. However, the generalist wetlands that reduced all four parameters were less efficient in reducing each of them than the specialist wetlands that only reduced one or two parameters. In a broader context, generalist wetlands have the potential to function as multifunctional tools to mitigate both eutrophication and brownification of aquatic systems. However, further research is needed to assess the design of the generalist wetlands and to investigate the potential of using several specialist wetlands in the same catchment.
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| 6. |
- Broman, Elias, 1985-, et al.
(author)
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Shifts in coastal sediment oxygenation cause pronounced changes in microbial community composition and associated metabolism.
- 2017
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In: Microbiome. - : Springer Science and Business Media LLC. - 2049-2618. ; 5:1, s. 96-
-
Journal article (peer-reviewed)abstract
- BACKGROUND: A key characteristic of eutrophication in coastal seas is the expansion of hypoxic bottom waters, often referred to as 'dead zones'. One proposed remediation strategy for coastal dead zones in the Baltic Sea is to mix the water column using pump stations, circulating oxygenated water to the sea bottom. Although microbial metabolism in the sediment surface is recognized as key in regulating bulk chemical fluxes, it remains unknown how the microbial community and its metabolic processes are influenced by shifts in oxygen availability. Here, coastal Baltic Sea sediments sampled from oxic and anoxic sites, plus an intermediate area subjected to episodic oxygenation, were experimentally exposed to oxygen shifts. Chemical, 16S rRNA gene, metagenomic, and metatranscriptomic analyses were conducted to investigate changes in chemistry fluxes, microbial community structure, and metabolic functions in the sediment surface.RESULTS: Compared to anoxic controls, oxygenation of anoxic sediment resulted in a proliferation of bacterial populations in the facultative anaerobic genus Sulfurovum that are capable of oxidizing toxic sulfide. Furthermore, the oxygenated sediment had higher amounts of RNA transcripts annotated as sqr, fccB, and dsrA involved in sulfide oxidation. In addition, the importance of cryptic sulfur cycling was highlighted by the oxidative genes listed above as well as dsvA, ttrB, dmsA, and ddhAB that encode reductive processes being identified in anoxic and intermediate sediments turned oxic. In particular, the intermediate site sediments responded differently upon oxygenation compared to the anoxic and oxic site sediments. This included a microbial community composition with more habitat generalists, lower amounts of RNA transcripts attributed to methane oxidation, and a reduced rate of organic matter degradation.CONCLUSIONS: These novel data emphasize that genetic expression analyses has the power to identify key molecular mechanisms that regulate microbial community responses upon oxygenation of dead zones. Moreover, these results highlight that microbial responses, and therefore ultimately remediation efforts, depend largely on the oxygenation history of sites. Furthermore, it was shown that re-oxygenation efforts to remediate dead zones could ultimately be facilitated by in situ microbial molecular mechanisms involved in removal of toxic H2S and the potent greenhouse gas methane.
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| 7. |
- Bruhn, Anders Dalhoff, et al.
(author)
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Terrestrial Dissolved Organic Matter Mobilized From Eroding Permafrost Controls Microbial Community Composition and Growth in Arctic Coastal Zones
- 2021
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In: Frontiers in Earth Science. - : Frontiers Media SA. - 2296-6463. ; 9
-
Journal article (peer-reviewed)abstract
- Climate warming is accelerating erosion along permafrost-dominated Arctic coasts. This results in the additional supply of organic matter (OM) and nutrients into the coastal zone. In this study we investigate the impact of coastal erosion on the marine microbial community composition and growth rates in the coastal Beaufort Sea. Dissolved organic matter (DOM) derived from three representative glacial deposit types (fluvial, lacustrine, and moraine) along the Yukon coastal plain, Canada, were used as substrate to cultivate marine bacteria using a chemostat setup. Our results show that DOM composition (inferred from UV-Visible spectroscopy) and biodegradability (inferred from DOC concentration, bacterial production and respiration) significantly differ between the three glacial deposit types. DOM derived from fluvial and moraine types show clear terrestrial characteristics with low aromaticity (Sr: 0.63 ± 0.02 and SUVA254: 1.65 ± 0.06 L mg C−1 m−1 & Sr: 0.68 ± 0.01 and SUVA254: 1.17 ± 0.06 L mg C−1 m−1, respectively) compared to the lacustrine soil type (Sr: 0.71 ± 0.02 and SUVA254: 2.15 ± 0.05 L mg C−1 m−1). The difference in composition of DOM leads to the development of three different microbial communities. Whereas Alphaproteobacteria dominate in fluvial and lacustrine deposit types (67 and 87% relative abundance, respectively), Gammaproteobacteria is the most abundant class for moraine deposit type (88% relative abundance). Bacterial growth efficiency (BGE) is 66% for DOM from moraine deposit type, while 13 and 28% for DOM from fluvial and lacustrine deposit types, respectively. The three microbial communities therefore differ strongly in their net effect on DOM utilization depending on the eroded landscape type. The high BGE value for moraine-derived DOM is probably caused by a larger proportion of labile colorless DOM. These results indicate that the substrate controls marine microbial community composition and activities in coastal waters. This suggests that biogeochemical changes in the Arctic coastal zone will depend on the DOM character of adjacent deposit types, which determine the speed and extent of DOM mineralization and thereby carbon channeling into the microbial food web. We conclude that marine microbes strongly respond to the input of terrestrial DOM released by coastal erosion and that the landscape type differently influence marine microbes.
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| 8. |
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| 9. |
-
Feminist Philosophy : Time, history and the transformation of thought
- 2023. - 1
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Editorial collection (peer-reviewed)abstract
- What is the relationship between feminism and philosophy today? Although feminist philosophy is now a recognized field in the institution of philosophy, a tension between the terms feminism and philosophy persists. From the perspective of philosophy, feminist philosophy may seem too committed to political change. From the perspective of feminism, the practice of philosophy may seem too far removed from the pressing concerns of injustice in ordinary life.This volume is an interdisciplinary initiative at the intersection of philosophy, the history of ideas, and feminist theory, where philosophy is scrutinized from a feminist perspective and asks questions about what philosophy has to offer feminism.
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| 10. |
- Figueroa, Daniela, 1980-, et al.
(author)
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Selective degradation of different dissolved organic matter compounds by regionally transplanted bacteria.
-
Other publication (other academic/artistic)abstract
- Climate change projections indicate that precipitation will increase by ~30% in the Baltic Sea within the next hundred years. This will lead to lowered salinity and increased inputs of dissolved organic matter (DOM) to the sea. The interactive effects of these changes on bacterial communities and DOM degradation are virtually unknown. We studied the selective degradation of different DOM compounds by regionally transplanted bacterial communities. Bacteria from the northern Baltic Sea were transplanted and re-transplanted to the southern Baltic Sea and vice versa. Three fractions of DOM were identified; two allochthonous fractions, originating from terrestrial systems and one autochthononous constituting the protein building blocks tryptophan/tyrosine. The largest decrease of dissolved organic carbon was observed in seawater from the Bothnian Sea (northern Baltic Sea), and the bacteria performing this degradation were those transplanted from the Baltic Proper (southern Baltic Sea). The native bacteria from the Bothnian Sea degraded both allochthonous and autochthonous DOM, while, bacteria from the Baltic Proper consumed mainly the autochthonous part of the DOM. Both autochthonous and allochthonous components of the DOM were found to shape the bacterioplankton community, Cyanobacteria and γ-proteobacteria were favored by all three DOM components, while α-proteobacteria and Bacteroidetes were favored by autochthonous DOM and β-proteobacteria by terrestrial DOM. However, no clear connection between different DOM components, specific bacterial groups and metabolic processes could be identified. Our study thus indicates that climate change can cause unforeseen adjustments of the bacterial community composition and function, governed by complex interactions between bacteria and their chemical environment.
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| 11. |
- Hagström, Åke, et al.
(author)
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Composition and Seasonality of Membrane Transporters in Marine Picoplankton
- 2021
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In: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 12
-
Journal article (peer-reviewed)abstract
- In this study, we examined transporter genes in metagenomic and metatranscriptomic data from a time-series survey in the temperate marine environment of the Baltic Sea. We analyzed the abundance and taxonomic distribution of transporters in the 3 mu m-0.2 mu m size fraction comprising prokaryotes and some picoeukaryotes. The presence of specific transporter traits was shown to be guiding the succession of these microorganisms. A limited number of taxa were associated with the dominant transporter proteins that were identified for the nine key substrate categories for microbial growth. Throughout the year, the microbial taxa at the level of order showed highly similar patterns in terms of transporter traits. The distribution of transporters stayed the same, irrespective of the abundance of each taxon. This would suggest that the distribution pattern of transporters depends on the bacterial groups being dominant at a given time of the year. Also, we find notable numbers of secretion proteins that may allow marine bacteria to infect and kill prey organisms thus releasing nutrients. Finally, we demonstrate that transporter proteins may provide clues to the relative importance of biogeochemical processes, and we suggest that virtual transporter functionalities may become important components in future population dynamics models.
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| 12. |
- Jones, Kevin, et al.
(author)
-
Seasonal variation and importance of catchment area composition for transport of bioavailable carbon to the Baltic Sea
- 2023
-
In: Biogeochemistry. - 0168-2563 .- 1573-515X. ; 165:3, s. 265-276
-
Journal article (peer-reviewed)abstract
- Transport of terrestrial carbon through riverine systems to coastal water has a negative impact on oxygen concentration in coastal areas. However, information on seasonal variation and the impact of catchment composition on the bioavailability of allochthonous carbon is lacking. In this project we address this knowledge gap by investigating the reactivity of dissolved organic carbon (DOC) at river mouths which originate from agricultural or forested dominated catchments over a year. Using a high-capacity oxygen sensing system biological oxygen demand (BOD) was measured and converted to carbon utilization rate. This allowed a spatial and temporal resolution necessary to understand how concentrations of total nitrogen, total phosphorus, DOC, as well as carbon composition influence carbon bioavailability. Seasonality and the differing catchment compositions yielded variable results about which factors were significantly contributing to reactivity. In addition, we found that carbon utilization rate was highest during April, June, and October for most rivers. The bioavailable fraction (BFc) was significantly higher in rivers with agricultural compared to forest dominated catchments during January, April, June, and October. However, rivers with agricultural dominated catchment had a significantly higher carbon utilization rate in August. This indicate that rivers dominated by forest transport larger and more refractory pools of carbon, while rivers with agricultural dominated catchments have a higher percentage of BFc. Based on these results we suggest that management efforts, to reduce the transport of bioavailable carbon, would be most efficient during spring and autumn with equal importance on rivers with catchment areas dominated by agriculture and forest.
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| 13. |
- Lauri, Johanna, 1976-
(author)
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Feministiska fantasier : mellan marknad och feminism
- 2021
-
Doctoral thesis (other academic/artistic)abstract
- Feminism is highly visible in contemporary Sweden. The government labels itself feminist, artists and influencers take a stand for feminism, businesses are branded with feminist advertising and feminist tropes and symbols are visible on clothes, art and jewellery. What this kind of feminism means is not always easy to discern. However, what is evident is that this visible and popular kind of feminism is highly compatible with business and market values. From this starting point, the aim of this dissertation is to explore the different meanings of feminism in four different but concurrent arenas. By using psychoanalytical discourse theory, I analyse: (i) a particular governmental arena through a policy analysis of the governmental articulation of social innovation, (ii) a commercial arena through a study of an advertising campaign, (iii) a business arena through interviews with feminist business owners and (iv) an activist arena through interviews with house-squatters. I use these analyses to explore how feminism is used, articulated and understood at the nexus of the market and feminism. What feminist discourses are articulated in the studied arenas? How are feminist values utilised? What expressions of social change are made intelligible and desirable? How are feminist subjects and the preconditions for feminist mobilisation shaped?Analysing the results of the four studies together shows that a fantasy of the benevolent business is created and sustained. Such a fantasy enhances a logic of good-hearted and ethical capitalism within which business and entrepreneurship become understood as activism, articulated as the ultimate solution to social problems. Such a logic inevitably shapes the preconditions for feminist organisation and activism, and encourages individual solutions at the expense of collective efforts. The fantasy of the benevolent business is immersed in and reinforced by fantasy echoes of feminist and social democratic history. These fantasy echoes both conceal inherent conflicts and intensify the force of the fantasy. In order to sustain this fantasy, the desire to make a difference is directed towards ethical practices. These are articulated as individual practices, thus saturating feminism and social change with individualism. Hence, feminist subjects are shaped into individual and entrepreneurial subjects who desire ethical choices. Furthermore, the thesis shows how “the public” is structured as the guarantor of the fantasy of the good business, which entails that certain expectations are attached to the idea of the public. Such expectations shape how feminism and the work towards social change are organised and practised.
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| 14. |
- Liess, Antonia, 1975-, et al.
(author)
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Ecosystem consequences of boreal lake browning and eutrophication – using mesocoms as tools for food web studies
- 2022
-
In: Abstract Book. ; , s. 111-111
-
Conference paper (other academic/artistic)abstract
- With increasing temperatures and precipitation, as well as land use changes in boreal regions, waterbodies are receiving larger inputs of coloured terrestrial humic substances. At the same time, nutrient inputs are increasing. This brownificationin combination with increasing nutrient levels has consequences for the aquatic food web in terms of species composition and energy transfer efficiency. In Lake Bolmen, Sweden’s 7ths largest lake, brownification additionally creates problems for drinkingwater production, since this lake is an important drinking water reservoir of southern Sweden. Lake monitoring data show a clear pattern of increasing brownification in Lake Bolmen over the preceding decades. To understand the consequences ofincreased browning and of increased nutrient inputs for Lake Bolmen’s food web on bacterial production, and phytoplankton and zooplankton species community composition and abundance, we conducted a 6-week mesocosm experiment during summer 2021. Brownification and nutrient ratios were manipulated. Measures of algal pigment concentrations show that browning has strong effects on algal pigment composition and thus probably on algal taxonomic composition. Our results suggest that brownification affects basic producer community composition in lakes, thus possibly changing community composition and biomass of higher trophic levels of the aquatic food web in boreal regions.
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| 15. |
- Lindh, Markus V., et al.
(author)
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Disentangling seasonal bacterioplankton population dynamics by high-frequency sampling
- 2015
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In: Environmental Microbiology. - : Society for Applied Microbiology and John Wiley & Sons Ltd. - 1462-2912 .- 1462-2920. ; 17:7, s. 2459-2476
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Journal article (peer-reviewed)abstract
- Multiyear comparisons of bacterioplankton succession reveal that environmental conditions drive community shifts with repeatable patterns between years. However, corresponding insight into bacterioplankton dynamics at a temporal resolution relevant for detailed examination of variation and characteristics of specific populations within years is essentially lacking. During 1 year, we collected 46 samples in the Baltic Sea for assessing bacterial community composition by 16S rRNA gene pyrosequencing (nearly twice weekly during productive season). Beta-diversity analysis showed distinct clustering of samples, attributable to seemingly synchronous temporal transitions among populations (populations defined by 97% 16S rRNA gene sequence identity). A wide spectrum of bacterioplankton dynamics was evident, where divergent temporal patterns resulted both from pronounced differences in relative abundance and presence/absence of populations. Rates of change in relative abundance calculated for individual populations ranged from 0.23 to 1.79 day(-1). Populations that were persistently dominant, transiently abundant or generally rare were found in several major bacterial groups, implying evolution has favoured a similar variety of life strategies within these groups. These findings suggest that high temporal resolution sampling allows constraining the timescales and frequencies at which distinct populations transition between being abundant or rare, thus potentially providing clues about physical, chemical or biological forcing on bacterioplankton community structure.
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| 16. |
- Lindh, Markus V., et al.
(author)
-
Local Environmental Conditions Shape Generalist But Not Specialist Components of Microbial Metacommunities in the Baltic Sea
- 2016
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In: Frontiers in Microbiology. - : Frontiers Media. - 1664-302X. ; 7, s. 1-10
-
Journal article (peer-reviewed)abstract
- Marine microbes exhibit biogeographical patterns linked with fluxes of matter and energy. Yet, knowledge of the mechanisms shaping bacterioplankton community assembly across temporal scales remains poor. We examined bacterioplankton 16S rRNA gene fragments obtained from Baltic Sea transects to determine phylogenetic relatedness and assembly processes coupled with niche breadth. Communities were phylogenetically more related over time than expected by chance, albeit with considerable temporal variation. Hence, habitat filtering, i.e., local environmental conditions, rather than competition structured bacterioplankton communities in summer but not in spring or autumn. Species sorting (SS) was the dominant assembly process, but temporal and taxonomical variation in mechanisms was observed. For May communities, Cyanobacteria, Actinobacteria, Alpha- and Betaproteobacteria exhibited SS while Bacteroidetes and Verrucomicrobia were assembled by SS and mass effect. Concomitantly, Gammaproteobacteria were assembled by the neutral model and patch dynamics. Temporal variation in habitat filtering and dispersal highlights the impact of seasonally driven reorganization of microbial communities. Typically abundant Baltic Sea populations such as the NS3a marine group (Bacteroidetes) and the SAR86 and SAR11 clade had the highest niche breadth. The verrucomicrobial Spartobacteria population also exhibited high niche breadth. Surprisingly, variation in bacterioplankton community composition was regulated by environmental factors for generalist taxa but not specialists. Our results suggest that generalists such as NS3a, SAR86, and SAR11 are reorganized to a greater extent by changes in the environment compared to specialists and contribute more strongly to determining overall biogeographical patterns of marine bacterial communities.
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| 17. |
- Lindh, Markus V., et al.
(author)
-
Metapopulation theory identifies biogeographical patterns among core and satellite marine bacteria scaling from tens to thousands of kilometers
- 2017
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In: Environmental Microbiology. - : Wiley-Blackwell. - 1462-2912 .- 1462-2920. ; 19:3, s. 1222-1236
-
Journal article (peer-reviewed)abstract
- Metapopulation theory developed in terrestrial ecology provides applicable frameworks for interpreting the role of local and regional processes in shaping species distribution patterns. Yet, empirical testing of metapopulation models on microbial communities is essentially lacking. We determined regional bacterioplankton dynamics from monthly transect sampling in the Baltic Sea Proper using 16S rRNA gene sequencing. A strong positive trend was found between local relative abundance and occupancy of populations. Notably, the occupancy-frequency distributions were significantly bimodal with a satellite mode of rare endemic populations and a core mode of abundant cosmopolitan populations (e.g. Synechococcus, SAR11 and SAR86 clade members). Temporal changes in population distributions supported several theoretical frameworks. Still, bimodality was found among bacterioplankton communities across the entire Baltic Sea, and was also frequent in globally distributed datasets. Datasets spanning waters with widely different physicochemical characteristics or environmental gradients typically lacked significant bimodal patterns. When such datasets were divided into subsets with coherent environmental conditions, bimodal patterns emerged, highlighting the importance of positive feedbacks between local abundance and occupancy within specific biomes. Thus, metapopulation theory applied to microbial biogeography can provide novel insights into the mechanisms governing shifts in biodiversity resulting from natural or anthropogenically induced changes in the environment.
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| 18. |
- Lindh, Markus V., et al.
(author)
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Transplant experiments uncover Baltic Sea basin-specific responses in bacterioplankton community composition and metabolic activities
- 2015
-
In: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 6
-
Journal article (peer-reviewed)abstract
- Anthropogenically induced changes in precipitation are projected to generate increased river runoff to semi enclosed seas, increasing loads of terrestrial dissolved organic matter and decreasing salinity. To determine how bacterial community structure and functioning adjust to such changes, we designed microcosm transplant experiments with Baltic Proper (salinity 7.2) and Bothnian Sea (salinity 3.6) water. Baltic Proper bacteria generally reached higher abundances than Bothnian Sea bacteria in both Baltic Proper and Bothnian Sea water, indicating higher adaptability. Moreover, Baltic Proper bacteria growing in Bothnian Sea water consistently showed highest bacterial production and beta-glucosidase activity. These metabolic responses were accompanied by basin specific changes in bacterial community structure. For example, Baltic Proper Pseudomonas and Limnobacter populations increased markedly in relative abundance in Bothnian Sea water, indicating a replacement effect. In contrast, Roseobacter and Rheinheknera populations were stable or increased in abundance when challenged by either of the waters, indicating an adjustment effect. Transplants to Bothnian Sea water triggered the initial emergence of particular Burkholderiaceae populations, and transplants to Baltic Proper water triggered Alteromonadaceae populations. Notably, in the subsequent re transplant experiment, a priming effect resulted in further increases to dominance of these populations. Correlated changes in community composition and metabolic activity were observed only in the transplant experiment and only at relatively high phylogenetic resolution. This suggested an importance of successional progression for interpreting relationships between bacterial community composition and functioning. We infer that priming effects on bacterial community structure by natural episodic events or climate change induced forcing could translate into long-term changes in bacterial ecosystem process rates.
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| 19. |
- Mathisen, Peter
(author)
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Environmental factors selecting for predation resistant and potentially pathogenic bacteria in aquatic environments
- 2017
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Doctoral thesis (other academic/artistic)abstract
- The long history of co-existence of bacteria and their protozoan predators in aquatic environments has led to evolution of protozoa resistant bacteria (PRB). Many of these bacteria are also pathogenic to humans. However, the ecological drivers determining the occurrence of different types of PRB in aquatic environments, and the eco-evolutionary link between bacterial adaptation and the resulting implications for mammalian hosts are poorly known. This thesis examines the impact of nutrients and predation on PRB, as well as the ecological and evolutionary connection between their life in aquatic environments and mammalian hosts. In the first study seven bacterial isolates from the Baltic Sea were investigated for their plasticity of adaptation to predation. The response to predation showed large variation where some bacteria rapidly developed a degree of grazing resistance when exposed to predators. The rapid adaptation observed may result in bacterial communities being resilient or resistant to predation, and thus rapid adaptation may be a structuring force in the food web. With the aim to elucidate the link between occurrence of PRB and environmental conditions, a field study and a laboratory experiment were performed. In both studies three PRB genera were found: Mycobacterium, Pseudomonas and Rickettsia. PRB were found both in oligotrophic and eutrophic waters, indicating that waters of all nutrient states can harbor pathogenic bacteria. However, the ecological strategy of the PRB varied depending on environmental nutrient level and disturbance. Using an advanced bioinformatic analysis, it was shown that ecotypes within the same PRB genus can be linked to specific environmental conditions or the presence of specific protozoa, cyanobacteria or phytoplankton taxa. These environmental conditions or specific plankton taxa could potentially act as indicators for occurrence of PRB. Finally, using four mutants (with specific protein deletions) of the pathogenic and predation resistant Francisella tularensis ssp. holarctica, I found evidence of an eco-evolutionary connection between the bacterium´s life in aquatic and mammalian hosts (aquatic amoeba Acanthamoeba castellanii and a murine macrophage). To a large extent F. t. holarctica use similar mechanisms to persist predation by protozoa and to resist degradation by mammal macrophages. To summarize I found a link between predation resistant bacteria in aquatic environments and bacteria that are pathogenic to mammals. Further, I showed that different environmental conditions rapidly selects for PRB with either intracellular or extracellular lifestyles. This thesis provides insights regarding environmental conditions and biomarkers that can be used for assessment of aquatic environments at risk for spreading pathogenic bacteria.
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| 20. |
- Mathisen, Peter, et al.
(author)
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Francisella tularensis subspecies holarctica´s adaptation to protozoan and mammal hosts
-
Other publication (other academic/artistic)abstract
- The long co-existence of bacteria and protozoa in natural ecosystems has led to the evolution of different bacterial predation-resistance mechanisms1, which in turn may have triggered development of mammal pathogens2, such as the tularemia bacterium Francisella tularensis3. We studied links between environmental persistence and pathogenicity of Francisella tularensis subsp. holarctica (F. t. holarctica), by comparing its growth in association with an aquatic amoeba and a murine macrophage. A virulent wild-type strain and four isogenic mutations with different functional protein deletions were compared; DsbA4, 5 a membrane lipoprotein with disulfide oxidoreductase activity important for proper folding in Francisella tularensis; Hfq6 a pleiotropic regulatory RNA binding protein; PilA7, 8 a type IV pilus subunit and PglA9 a protein involved in O-linked protein glycosylation. DsbA was found to be essential for bacterial growth in association with both amoeba and macrophage, while PglA did not affect bacterial persistence in any of the hosts. Absence of PilA and Hfq had marked negative effect on the bacterial cell counts in amoeba, while growth was only slightly impaired in the macrophage. Functional similarities for bacterial persistence in both hosts highlight eco-evolutionary links between persistence of intracellular pathogenic bacteria in aquatic systems and mammal hosts.
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| 21. |
- Myreböe, Synne, 1972-, et al.
(author)
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Configuring Feminist Philosophy in the Context of the Nordic Summer University
- 2023
-
In: Feminist Philosophy. - Huddinge : Södertörns högskola. - 9789189504363 - 9789189504370 ; , s. 359-377
-
Book chapter (peer-reviewed)abstract
- What is the relationship between feminism and philosophy today? Although feminist philosophy is now a recognized field in the institution of philosophy, a tension between the terms feminism and philosophy persists. From the perspective of philosophy, feminist philosophy may seem too committed to political change. From the perspective of feminism, the practice of philosophy may seem too far removed from the pressing concerns of injustice in ordinary life.This volume is an interdisciplinary initiative at the intersection of philosophy, the history of ideas, and feminist theory, where philosophy is scrutinized from a feminist perspective and asks questions about what philosophy has to offer feminism.
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| 22. |
- Pedregal-Montes, Angela, et al.
(author)
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Disinfection by-product formation potential in response to variability in dissolved organic matter and nutrient inputs : Insights from a mesocosm study
- 2024
-
In: Water Research. - Oxford : Elsevier. - 0043-1354 .- 1879-2448. ; 258
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Journal article (peer-reviewed)abstract
- Changes in rainfall patterns driven by climate change affect the transport of dissolved organic matter (DOM) and nutrients through runoff to freshwater systems. This presents challenges for drinking water providers. DOM, which is a heterogeneous mix of organic molecules, serves as a critical precursor for disinfection by-products (DBPs) which are associated with adverse health effects. Predicting DBP formation is complex due to changes in DOM concentration and composition in source waters, intensified by altered rainfall frequency and intensity. We employed a novel mesocosm approach to investigate the response of DBP precursors to variability in DOM composition and inorganic nutrients, such as nitrogen and phosphorus, export to lakes. Three distinct pulse event scenarios, mimicking extreme, intermittent, and continuous runoff were studied. Simultaneous experiments were conducted at two boreal lakes with distinct DOM composition, as reflected in their color (brown and clear lakes), and bromide content, using standardized methods. Results showed primarily site-specific changes in DBP precursors, some heavily influenced by runoff variability. Intermittent and daily pulse events in the clear-water mesocosms exhibited higher haloacetonitriles (HANs) formation potential linked to freshly produced protein-like DOM enhanced by light availability. In contrast, trihalomethanes (THMs), associated with humic-like DOM, showed no significant differences between pulse events in the brown-water mesocosms. Elevated bromide concentration in the clear mesocosms critically influenced THMs speciation and concentrations. These findings contribute to understanding how changing precipitation patterns impact the dynamics of DBP formation, thereby offering insights for monitoring the mobilization and alterations of DBP precursors within catchment areas and lake ecosystems. © 2024 The Author(s)
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| 23. |
- Pontarp, Mikael, et al.
(author)
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Experimentally induced habitat filtering in marine bacterial communities
- 2013
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In: Marine Ecology Progress Series. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 477, s. 77-U406
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Journal article (peer-reviewed)abstract
- We tested the habitat filtering hypothesis by measuring the phylogenetic structure in marine bacterial communities before and after experimentally induced stress. The habitat filtering hypothesis predicts that phylogenetic clustering (mean relatedness) should increase as the environment becomes suitable for only a subset of the original community. We show that community composition and phylogenetic structure were considerably changed with changes in salinity and dissolved organic carbon. Community composition showed no consistent patterns, while the phylogenetic relatedness between species consistently increased with treatment. We have no information about species interactions in our system, but the phylogenetic signal is strong enough to suggest that habitat filtering is the dominant assembly process. Our results support the hypothesis that habitat characteristics and environmental stress can 'filter' a community so that only closely related species can persist. This non-random phylogenetic signal also implies a relationship between ecologically relevant characteristics and species relatedness.
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| 24. |
- Renes, Sophia Elise, et al.
(author)
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Disturbance history can increase functional stability in the face of both repeated disturbances of the same type and novel disturbances - dataset
- 2020
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1
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Other publicationabstract
- Climate change is expected to increase the incidences of extremes in environmental conditions. To investigate how repeated disturbances affect microbial ecosystem resistance, natural lake bacterioplankton communities were subjected to repeated temperature disturbances of two intensities (25 °C and 35 °C), and subsequently to an acidification event. We measured functional parameters (bacterial production, abundance, extracellular enzyme activities) and community composition parameters (richness, evenness, niche width) and found that, compared to undisturbed control communities, the 35 °C treatment was strongly affected in all parameters, while the 25 °C treatment did not significantly differ from the control. Interestingly, exposure to multiple temperature disturbances caused gradually increasing stability in the 35 °C treatment in some parameters, while others parameters showed the opposite, indicating that the choice of parameters can strongly affect the outcome of a study. The acidification event did not lead to stronger changes in community structure, but functional resistance of bacterial production towards acidification in the 35 °C treatments increased. This indicates that functional resistance in response to a novel disturbance can be increased by previous exposure to another disturbance, suggesting similarity in stress tolerance mechanisms for both disturbances. These results highlight the need for understanding function- and disturbance-specific responses, since general responses are likely to be unpredictable.
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| 25. |
- Sjöstedt, Johanna, et al.
(author)
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Abundance of Broad Bacterial Taxa in the Sargasso Sea Explained by Environmental Conditions but Not Water Mass
- 2014
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In: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 80:9, s. 2786-2795
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Journal article (peer-reviewed)abstract
- To explore the potential linkage between distribution of marine bacterioplankton groups, environmental conditions, and water mass, we investigated the factors determining the abundance of bacterial taxa across the hydrographically complex Subtropical Convergence Zone in the Sargasso Sea. Based on information from 16S rRNA gene clone libraries from various locations and two depths, abundances of the predominant taxa (eubacteria, Archaea, Alphaproteobacteria, Gammaproteobacteria, Bacteroidetes, and the Roseobacter, SAR11, and SAR86 clades) were quantified by real-time PCR. In addition, the abundances of Synechococcus, Prochlorococcus, and picoalgae were determined by flow cytometry. Linear multiple-regression models determining the relative effects of eight environmental variables and of water mass explained 35 to 86% of the variation in abundance of the quantified taxa, even though only one to three variables were significantly related to any particular taxon's abundance. Most of the variation in abundance was explained by depth and chlorophyll a. The predominant phototrophs, Prochlorococcus and picoalgae, were negatively correlated with phosphate, whereas eubacteria, heterotrophic bacteria, and SAR86 were negatively correlated with nitrite. Water mass showed limited importance for explaining the abundance of the taxonomical groups (significant only for Roseobacter, explaining 14% of the variation). The results suggest the potential for predicting the abundance of broad bacterioplankton groups throughout the Sargasso Sea using only a few environmental parameters.
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| 26. |
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| 27. |
- Sjöstedt, Johanna, 1982-
(author)
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Effect of environmental factors on bacterioplankton community composition, diversity and functionality
- 2013
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Doctoral thesis (other academic/artistic)abstract
- The ocean covers more than 70 % of the Earth surface and represents the largest ecosystem on Earth. Bacteria are an important part of the marine food web not only in remineralisation but also since they utilize dissolved organic matter (DOM) and make the energy available to higher trophic levels. Despite their small size, the total bacterial biomass exceeds the combined mass of zooplankton and fishes.Bacterial communities are often sensitive to disturbance and the composition changes in response to variations in environmental factors. The diversity of microorganisms is high and the biodiversity is composed of a few abundant and a long tail of rare taxa. The rare taxa contribute most to the diversity, but form a seed bank that is not growing or growing extremely slow. Experimental manipulations showed that the change in community composition in response to disturbance was, at least to some respect, accomplished by rare species becoming abundant. Changes in community composition and diversity did not have an affect on broad scale functions, e.g. utilization of dissolved organic carbon (DOC), indicating that bacterial communities are functionally redundant.Microorganisms are generally believed to be easily dispersed globally because of their small size, high abundance and short generation time. However, changes in community composition have been shown both on temporal and spatial scales but there is limited information about which factors are most important for distribution of bacterial taxa. A study of in situ samples from the Sargasso Sea showed that a large extent of the variation in the abundance of broad bacterial taxa could be explained by environmental factors, whereas abundances generally did not differ between water masses. In addition, an investigation of the phylogenetic structure of bacterial communities from the Baltic Sea and Skagerrak showed that bacterial communities in specific environments usually are more phylogenetic related to each other than expected by chance. Together these results indicate that the environment is an important factor forming the community and that phylogenetically related bacteria are functionally related, sharing similar traits.
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| 28. |
- Sjöstedt, Johanna, et al.
(author)
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Recruitment of members from the rare biosphere of marine bacterioplankton communities after an environmental disturbance.
- 2012
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In: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 78:5, s. 1361-1369
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Journal article (peer-reviewed)abstract
- A bacterial community may be resistant to environmental disturbances if some of its species show metabolic flexibility and physiological tolerance to the changing conditions. Alternatively, disturbances can change the composition of the community and thereby potentially affect ecosystem processes. The impact of disturbance on the composition of bacterioplankton communities was examined in continuous seawater cultures. Bacterial assemblages from geographically closely connected areas, the Baltic Sea (salinity 7 and high dissolved organic carbon [DOC]) and Skagerrak (salinity 28 and low DOC), were exposed to gradual opposing changes in salinity and DOC over a 3-week period such that the Baltic community was exposed to Skagerrak salinity and DOC and vice versa. Denaturing gradient gel electrophoresis and clone libraries of PCR-amplified 16S rRNA genes showed that the composition of the transplanted communities differed significantly from those held at constant salinity. Despite this, the growth yields (number of cells ml(-1)) were similar, which suggests similar levels of substrate utilization. Deep 454 pyrosequencing of 16S rRNA genes showed that the composition of the disturbed communities had changed due to the recruitment of phylotypes present in the rare biosphere of the original community. The study shows that members of the rare biosphere can become abundant in a bacterioplankton community after disturbance and that those bacteria can have important roles in maintaining ecosystem processes.
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| 29. |
- Sjöstedt, Johanna, et al.
(author)
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Reduced diversity and changed bacterioplankton community composition do not affect utilization of dissolved organic matter in the Adriatic Sea
- 2013
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In: Aquatic Microbial Ecology. - : Inter-Research Science Center. - 0948-3055 .- 1616-1564. ; 71:1, s. 15-U132
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Journal article (peer-reviewed)abstract
- To obtain insights into the coupling between community composition, diversity and community function, bacterioplankton assemblages from the Gulf of Trieste (Northern Adriatic Sea) were exposed to increasing environmental stress throughout 2 wk in continuous seawater cultures to construct communities differing in composition and diversity. The assemblages were exposed to (1) decreased temperature, (2) decreased temperature and phosphate addition or (3) decreased temperature, phosphate addition and lowered oxygen level. Bacterial and viral abundances as well as bacterial community composition stabilized during the second week of the experiment. Denaturing gradient gel electrophoresis and pyrosequencing of 16S rRNA genes showed dramatic reductions in bacterial diversity in all treatments and major compositional differences relative to the inoculum. Nevertheless, no differences in the ability to exploit dissolved organic carbon (DOC) were found for the acquired communities relative to the inoculum, indicating that the bacterial communities were functionally redundant. We speculate that oscillations in exploitation of the DOC pool in situ are mainly governed by factors limiting the overall bacterial growth, rather than perturbations affecting only subsets of the microbial biota.
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| 30. |
- Sjöstedt, Johanna, et al.
(author)
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Repeated disturbances affect functional but not compositional resistance and resilience in an aquatic bacterioplankton community
- 2018
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In: Environmental microbiology reports. - : Wiley. - 1758-2229. ; 10:4, s. 493-500
-
Journal article (peer-reviewed)abstract
- Disturbances are believed to be one of the main factors influencing variations in community diversity and functioning. Here we investigated if exposure to a pH press disturbance affected the composition and functional performance of a bacterial community and its resistance, recovery and resilience to a second press disturbance (salt addition). Lake bacterial assemblages were initially exposed to reduced pH in six mesocosms whereas another six mesocosms were kept as reference. Seven days after the pH disturbance, three tanks from each treatment were exposed to a salt disturbance. Both bacterial production and enzyme activity were negatively affected by the salt treatment, regardless if the communities had been subject to a previous disturbance or not. However, cell-specific enzyme activity had a higher resistance in communities pre-exposed to the pH disturbance compared to the reference treatment. In contrast, for cell-specific bacterial production resistance was not affected, but recovery was faster in the communities that had previously been exposed to the pH disturbance. Over time, bacterial community composition diverged among treatments, in response to both pH and salinity. The difference in functional recovery, resilience and resistance may depend on differences in community composition caused by the pH disturbance, niche breadth or acquired stress resistance.
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| 31. |
- Sjöstedt, Johanna, et al.
(author)
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Substrate diversity affects carbon utilization rate and threshold concentration for uptake by natural bacterioplankton communities
- 2022
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In: Aquatic Microbial Ecology. - 0948-3055. ; 88, s. 95-108
-
Journal article (peer-reviewed)abstract
- Persistence of dissolved organic matter (DOM) in aquatic environments may in part be explained by high diversity and low concentrations of carbon substrates. However, changes in dissolved substrate quality can modify aquatic bacterial community composition and rate of carbon uptake. The aim of this study was to test if the presence of multiple simple substrates affects the turnover of organic carbon. Natural bacterial communities were grown in continuous cultures supplied with either individual carbon substrates-salicylic acid (SA), tryptophan (Trp) or tyrosine (Tyr)-or a combination of the 3 substrates. Concentrations were tracked using fluorescence spectroscopy, and steady-state concentrations of a few nanomolar were reached. Bacterial growth efficiency was dependent on which carbon sources were present and reached an intermediate level in the combined treatment. The bacterial community maintained steady-state concentrations of Trp that were lower in the combined treatment than in the individual substrate treatment. In addition, steady-state concentrations were reached faster during growth on combined carbon substrates, although the maximum utilization rate of each individual compound was lower. However, the steady-state concentration of total carbon (sum of carbon content of SA, Trp and Tyr) was higher in the combined culture than in the individual substrate treatments, and seemed to be determined by the carbon substate for which the bacteria had the lowest affinity. The results from this study indicate that persistence of dissolved organic carbon can in part be explained by vast substrate diversity, which raises the threshold concentration for utilization by natural bacterial communities.
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| 32. |
- Sjöstedt, Johanna, 1982-, et al.
(author)
-
Substrate diversity affects carbon utilization rate and threshold concentration for uptake by natural bacterioplankton communities
- 2022
-
In: Aquatic Microbial Ecology. - : Inter-Research Science Center. - 0948-3055 .- 1616-1564. ; 88
-
Journal article (peer-reviewed)abstract
- Persistence of dissolved organic matter (DOM) in aquatic environments may in part be explained by high diversity and low concentrations of carbon substrates. However, changes in dissolved substrate quality can modify aquatic bacterial community composition and rate of carbon uptake. The aim of this study was to test if the presence of multiple simple substrates affects the turnover of organic carbon. Natural bacterial communities were grown in continuous cultures supplied with either individual carbon substrates—salicylic acid (SA), tryptophan (Trp) or tyrosine (Tyr)—or a combination of the 3 substrates. Concentrations were tracked using fluorescence spectroscopy, and steady-state concentrations of a few nanomolar were reached. Bacterial growth efficiency was dependent on which carbon sources were present and reached an intermediate level in the combined treatment. The bacterial community maintained steady-state concentrations of Trp that were lower in the combined treatment than in the individual substrate treatment. In addition, steady-state concentrations were reached faster during growth on combined carbon substrates, although the maximum utilization rate of each individual compound was lower. However, the steady-state concentration of total carbon (sum of carbon content of SA, Trp and Tyr) was higher in the combined culture than in the individual substrate treatments, and seemed to be determined by the carbon substate for which the bacteria had the lowest affinity. The results from this study indicate that persistence of dissolved organic carbon can in part be explained by vast substrate diversity, which raises the threshold concentration for utilization by natural bacterial communities.
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| 33. |
- Sjöstedt, Johanna, 1982-, et al.
(author)
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Variation in cell volume and community composition of bacteria in response to temperature
- 2012
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In: Aquatic Microbial Ecology. - : Inter-Research Science Center. - 0948-3055 .- 1616-1564. ; 66:3, s. 237-246
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Journal article (peer-reviewed)abstract
- Although temperature is a key parameter controlling the activity and growth of all microorganisms, information about how water temperature may structure the bacterioplankton community is not consistent. We examined the relationship between temperature and the community composition, cell volume, and morphology of marine bacterioplankton in 4 continuous cultures harbouring multispecies communities. All 4 cultures were maintained at a turnover time of 0.04 h(-1) but at different temperatures of 10, 15, 20, and 25 degrees C. Denaturing gradient gel electrophoresis analyses showed that the community composition shifted in response to temperature. Cell volumes were determined from digital photomicrographs using an image analysis program, which also allowed the identification of 3 morphological types of bacteria: cocci-, rod-, and vibrio-shaped bacteria. Mean bacterial cell volume decreased with increasing temperature, e.g., by 39% when the temperature was increased from 10 degrees C to 20 degrees C. When the temperature increased, the bacterial morphology also shifted from dominance by rod- and vibrio-shaped bacteria to dominance by coccoid bacteria. The results clearly indicate the potential role of temperature in driving the community succession of bacterioplankton and in selecting for smaller cells at higher temperatures.
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| 34. |
- Uhlén, Mathias, et al.
(author)
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A pathology atlas of the human cancer transcriptome
- 2017
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In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 357:6352, s. 660-
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Journal article (peer-reviewed)abstract
- Cancer is one of the leading causes of death, and there is great interest in understanding the underlying molecular mechanisms involved in the pathogenesis and progression of individual tumors. We used systems-level approaches to analyze the genome-wide transcriptome of the protein-coding genes of 17 major cancer types with respect to clinical outcome. A general pattern emerged: Shorter patient survival was associated with up-regulation of genes involved in cell growth and with down-regulation of genes involved in cellular differentiation. Using genome-scale metabolic models, we show that cancer patients have widespread metabolic heterogeneity, highlighting the need for precise and personalized medicine for cancer treatment. All data are presented in an interactive open-access database (www.proteinatlas.org/pathology) to allow genome-wide exploration of the impact of individual proteins on clinical outcomes.
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| 35. |
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