| 1. |
- Zimmerman, Jenny K. M., 1972-
(författare)
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Noble Crayfish (Astacus astacus) in a Changing World : Implications for Management
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The noble crayfish (Astacus astacus) is critically endangered in Sweden. This is mainly due to the crayfish plague (Aphanomyces astaci), a lethal disease that, among other things, can be spread through the stocking of fish from contaminated water or contaminated fishing gear. The largest single propagation path is the illegal introduction of infected signal crayfish (Pacifastacus leniusculus). A conservation measure for crayfish is to re-introduce it to where it has a chance to survive, though a sustainable, locally regulated fishing can also serve as an indirect protection for the species. When the local inhabitants are allowed to keep their fishing culture and when fishing is acceptable, the incentive for illegal stocking of signal crayfish is low. However, it is important to avoid overfishing because the recovery, especially in the northern regions, can take several years. Therefore, it is important to know how crayfish respond long-term to fishing and environmental factors.Crayfish populations became extinct in the River Ljungan for unknown reasons in 1999. The water flow of the river has been used for activities such as fishing, timber transport and hydroelectric power since the 1500s, and the noble crayfish has been part of the fauna since the last century. The River Ljungan was known as one of Sweden's best fishing areas for crayfish and fishing became an important part of the local tradition. When the crayfish populations became extinct, a reintroduction program was a natural step, and crayfish are nowadays re-established in the river.From 1963 to 1990 the Swedish Board of Fisheries collected data from crayfish fishing in the River Ljungan to determine the economic damage to fishery owners caused by the construction of a power plant. After each season the fishermen reported the catch. In this thesis, the data was used to investigate which factors influence the long-term size of the crayfish catch and how the crayfish catches were affected by the power plant building. After re-introduction of the crayfish to the River Ljungan, the local fishermen monitored the population development in a simple, standardized way. To examine the validity of their measurements and to investigate the body growth of the individuals, a capture-recapture technique with a permanent marking of the crayfish was used.The crayfish catches were primarily impacted by the previous years' catch size, and a large catch the previous year resulted in a reduced catch the following year. A mild winter climate (NAO-index > -0.7) six years before the catch implied a large catch, whereas a high water flow during the autumn or spring (>95m3s-1) two years before the catch, implied a poor catch. Major habitat changes in the form of greatly reduced water flow (~90%) were negative for crayfish catches. The standardized method of fishing used by the local fishermen to monitor the development of the crayfish population was precise enough to detect population trends and this method can therefore be recommended to monitor future re-introductions of crayfish. Although the River Ljungan is located at the northern edge of the species' range, noble crayfish in the river presently have a body growth rate that is close to the maximum measured for crayfish (8 mm/moult for females and 10 mm/moult for males).Based on the results, the most important advice for sustainable fisheries in Ljungan and other northern rivers is to:Monitor the population trends, NAO-index and water flow in May and October. Use the results from the monitoring to determine the number of allowed fishing days and traps.Collect data about the catch size and efforts from legal fishing and use it to evaluate the sustainability of the fishing.Enhance the buildup of the harvestable cohort by-saving reproductive females-introduce a size limit of 10 cm-provide proper shelters for the non-harvestable cohort.
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| 2. |
- Gylle, A Maria, 1965-
(författare)
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Physiological adaptations in two ecotypes of Fucus vesiculosus and in Fucus radicans with focus on salinity
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The in origin intertidal marine brown alga Fucus vesiculosus L. grow permanently sublittoral in the brackish Bothnian Sea, side by side with the recently discovered F. radicans L. Bergström et L. Kautsky. Environmental conditions like salinity, light and temperature are clearly different between F. vesiculosus growth sites in the Bothnian Sea (4-5 practical salinity units, psu; part of the Baltic Sea) and the tidal Norwegian Sea (34-35 psu; part of the Atlantic Ocean). The general aims of this thesis were to compare physiological aspects between the marine ecotype and the brackish ecotype of F. vesiculosus as well as between the two Bothnian Sea species F. vesiculosus and F. radicans.The result in the study indicates a higher number of water soluble organic compounds in the marine ecotype of F. vesiculosus compared to the brackish ecotype. These compounds are suggested to be compatible solutes and be due to an intertidal and sublittoral adaptation, respectively; where the intertidal ecotype needs the compounds as a protection from oxygen radicals produced during high irradiation at low tide. The sublittoral ecotype might have lost the ability to synthesize these compound/compounds due to its habitat adaptation. The mannitol content is also higher in the marine ecotype compared to the brackish ecotype of F. vesiculosus and this is suggested to be due to both higher level of irradiance and higher salinity at the growth site.77 K fluorescence emission spectra and immunoblotting of D1 and PsaA proteins indicate that both ecotypes of F. vesiculosus as well as F. radicans have an uneven ratio of photosystem II/photosystem I (PSII/PSI) with an overweight of PSI. The fluorescence emission spectrum of the Bothnian Sea ecotype of F. vesiculosus however, indicates a larger light-harvesting antenna of PSII compared to the marine ecotype of F. vesiculosus and F. radicans. Distinct differences in 77 K fluorescence emission spectra between the Bothnian Sea ecotype of F. vesiculosus and F. radicans confirm that this is a reliable method to use to separate these species.The marine ecotype of F. vesiculosus has a higher photosynthetic maximum (Pmax) compared to the brackish ecotype of F. vesiculosus and F. radicans whereas both the brackish species have similar Pmax. A reason for higher Pmax in the marine ecotype of F. vesiculosus compared to F. radicans is the greater relative amount of ribulose-1.5-bisphosphate carboxylase/oxygenase (Rubisco). The reason for higher Pmax in marine ecotype of F. vesiculosus compare to the brackish ecotype however is not due to the relative amount of Rubisco and further studies of the rate of CO2 fixation by Rubisco is recommended. Treatments of the brackish ecotype of F. vesiculosus in higher salinity than the Bothnian Sea natural water indicate that the most favourable salinity for high Pmax is 10 psu, followed by 20 psu. One part of the explanation to a high Pmax in 10 psu is a greater relative amount of PsaA protein in algae treated in 10 psu. The reason for greater amount of PsaA might be that the algae need to produce more ATP, and are able to have a higher flow of cyclic electron transport around PSI to serve a higher rate of CO2 fixation by Rubisco. However, studies of the rate of CO2 fixation by Rubisco in algae treated in similar salinities as in present study are recommended to confirm this theory.
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| 3. |
- Svensson, Filip, 1980-
(författare)
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Effects of warming on the ecology of algal-dominated phytobenthic communities in the Baltic Sea
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Through climate change, the global average air and surface water temperature has risen 0.85°C during the last 100 years. The Baltic Sea experienced one of the most rapid increase in temperature recorded of marine ecosystems. During the last two decades of the 20th century, the surface water temperature of the Baltic Sea has increased seven times faster than the global average.This thesis is an investigation of how community traits, trophic interactions and ecophysiological processes in the filamentous algal belt in the northern Baltic Sea are affected by warming. The majority of the studies were conducted in or in the vicinity of the Forsmark Biotest basin, an artificial heated enclosure of the southern Bothnian Sea (northern Baltic Sea). One study also included sampling along a natural salinity gradient - the Swedish east coast.In the benthic diatom community, we found that cell size decreases with decreasing seasonal temperature, and increased with warming during the cold season. Warming also selected for motile and colonial traits. Along the salinity gradient, cell size decreased with decreasing salinity, apparently mediated by changes in the nitrogen to phosphorus ratio.In the filamentous algal community, warming increased algal cover and photosynthetic capacity, and affected the ratio of carotene to chlorophyll a ratio. Warming also desensitized the photosynthetic response and growth of algal communities exposed to anthropogenic stressors: increased nitrogen and phosphor concentrations as well as copper additions. In connection to one of the field studies, the first finding of the non-native bivalve Mytilopsis leucophaeata in Sweden was also done.Using a fish exclusion experiment in heated and non-heated areas, we found that warming decreases the number of trophic levels in the lower parts of the food web, which in turn lead to increased top-down control and higher algal biomass at heated than unheated sites.In summary, warming has here been shown to have major impacts on the phytobenthic community due to a combination of direct effects on physiological processes, as well as indirect effects mediated by interactions among species and trophic levels.
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| 4. |
- Christensen, Jonas, 1963-, et al.
(författare)
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The Beautiful Risk of Collaborative and Interdisciplinary Research. A Challenging Collaborative and Critical Approachtoward Sustainable Learning Processes in Academic Profession
- 2021
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Ingår i: Sustainability. - Basel : MDPI. - 2071-1050. ; 13, s. 1-20
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Tidskriftsartikel (refereegranskat)abstract
- In this article, we aim to identify and explore possibilities and challenges of academicinterdisciplinary capacities and ethos. The objective is that this knowledge could be used both infuture interdisciplinary research projects and in educational settings. We achieve this through selfreflectivelearning processes among a group of interdisciplinary scholars from four distinctly differentsubjects. The method used is an autoethnographic and empirical self-reflective approach to datacollection, analysis and deconstruction of professional learning processes. This also serves to establishresearch methodological trustworthiness and authenticity. The results show that interdisciplinarityis undervalued by grant-giving institutions and the academic system, in general. It also entailstime-consuming and risky research practices. However, interdisciplinary and collaborative researchcreates a more innovative and stimulating learning environment and enforces new ways of thinkingand doing, in ascertaining each individual’s knowledge and competences. We argue that a long-terminterdisciplinary and collaborative research process could enhance and raise a critical thinking andcreative consciousness among scholars, contributing to a more holistic, sustainable and socially robustlearning in research and higher education. Finally, we conclude that this academic interdisciplinarycapacity and ethos could be framed and enhanced by the notion of Challenge-Based Learning.
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| 5. |
- Christersson, Cecilia E., et al.
(författare)
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Challenge-Based Learning in Higher Education : A Malmö University Position Paper
- 2022
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Ingår i: International Journal of Innovative Teaching and Learning in Higher Education. - : IGI Global. - 2644-1624 .- 2644-1640. ; 3:1, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- Higher education institutions (HEIs) have a pivotal role in fulfilling the social dimension of sustainability and contributing to a complex changing society. To meet these challenges, Malmö University has in interdisciplinary groups researched the role of challenge-based learning (CBL) in relation to staff, students, disciplines, and stakeholders. This position paper is based on that work. Malmö University argues that with a CBL approach, HEIs will actively contribute to the building of a sustainable learning society through collaboration in education, research, and innovation. This paper theoretically explores the CBL approach as a collaborative learning exchange within HEIs and society at large. CBL is defined through eight key elements, clustered as entities of three domains: diversity and inclusion, co-creation and collaboration, and change agents and contextual challenges. These are discussed and empirically exemplified with the purpose to support designing, planning, and accomplishing CBL in teaching and learning in HE for a global learning society.
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| 6. |
- Manik, Sadhana, et al.
(författare)
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Take Stock of Fracking Risks and Count the Costs Towards an Ecosystem Services Assessment in South Africa
- 2023
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Ingår i: Alternation : Interdisciplinary Journal for the Study of the Arts and Humanities in Southern Africa. - : Centre for the Study of Southern African Literature and Languages. - 1023-1757 .- 2519-5476. ; 30:1
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Tidskriftsartikel (refereegranskat)abstract
- Many citizens in countries now accept that there is a need to adapt to climate change and to invest in renewable resources. This paper contributes to the planning of energy development in South Africa. Currently, South Africa is faced with a crisis in energy security with ‘load shedding’ resulting in hours without power. Coal, a fossil fuel, is the main source for energy in South Africa with negative effects for the environment and human health. To provide security over the future supply of domestic energy, the technique of fracking on and offshore is being advanced as an alternative by government which has been granting exploratory fracking licences. A review of the literature at the nexus of fracking, the Sustainable Development Goals (SDGs) and ecosystem services was undertaken from a triple risk lens (Prpich & Coulon 2018). The findings indicate that fracking operations may create a short-lived economic boom but there is substantive scholarly evidence on the immense long- term risks for both the environment and human health. The impact of land use changes through fracking and the risks of fracking operations for ecosystems, climate change and achieving the SDGs of Agenda 2030 are evident and form a ‘self-reinforcing loop’. We conclude that if fracking is predominantly being perceived from a prism of its economic benefits, then economic value needs to be attached to all the services that are provided by ecosystems. Thus, we recommend that an ecosystem services assessment must precede the granting of frackinglicences to evaluate whether fracking is a viable option. It is also suggested Take Stock of Fracking Risks and Count the Costs239that compensatory justice, be included as a policy measure for rehabilitation of the land where fracking has already commenced. In conclusion, we assert that healthy, environmentally sustainable living conditions need to be provided for all citizens and investment is needed to support adequate renewable energy infrastructure, a pre- requisite for government’s Just Energy Transformation (JET).
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| 7. |
- Nygård, Charlotta A
(författare)
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Ecophysiological responses of Baltic and Atlantic Fucus vesiculosus to environmental factors
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The Baltic Sea is a species-poor ecosystem where marine species coexist with freshwater species. The Baltic Sea offers low salinity, low content of inorganic carbon, long cold winters and no tides.One of the few marine species that can be found in the Baltic, is the brown alga Fucus vesiculosus, which is regarded as ecologically the most important alga in this area. The aim of the present thesis was to examine physiological (photosynthesis and growth) differences between F. vesiculosus in the Bothnian Sea (northern Baltic) and the Atlantic. Measurements were performed with plants in their natural seawaters and under changed conditions of salinity, temperature, nutrients and inorganic carbon concentrations.
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| 8. |
- Sandström, Jennie
(författare)
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Phytoplankton response to a changing climate in lakes in northern Sweden
- 2013
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In a climate change perspective, increased air temperatures are already a reality and are expected to increase even more in the future, especially in areas at high latitudes. The present thesis therefore addresses the influence of climate change on the physical properties and the phytoplankton communities of typical small and oligotrophic lakes in northern Sweden (62-64˚N). In the first part of the study, we found a significant trend (10 lakes from 1916 to 2010) of ice break-ups occurring increasingly earlier. The timing of ice break-up was strongly influenced by the April air temperature indicating that expected increases in air temperature in the future will also result in an earlier ice break-up. We also used concentrations of chlorophyll a (chl a) as estimations of phytoplankton biomass and discovered a positive relationship between surface water temperature and concentrations of chl a in Lake Remmaren (from 1991 to 2008). The second part of the thesis focuses on climatic conditions and cyanobacteria abundance in three small, oligotrophic lakes in northern Sweden; Lake Remmaren, Lake S. Bergsjön and Lake Gransjön. The concentration and relative abundance of cyanobacteria differ between 2011 and 2012, with different climatic conditions. The "warm" year of 2011 had higher concentrations and relative abundance of cyanobacteria than the "cold" year of 2012. Trends in increasing surface water temperatures as well as increasing abundance of cyanobacteria in August were found in Lake Remmaren (from 1988 to 2011). The direct or indirect effects of warming had a positive effect on the cyanobacteria abundance, since nutrients (Tot N and Tot P) did not display an increasing trend in Lake Remmaren. An analysis on the composition of phytoplankton species in Lake Remmaren, Lake S. Bergsjön and Lake Gransjön revealed that the cyanobacteria Merismopedia sp. was more common in 2011 than 2012. If different cyanobacteria become more common in oligotrophic lakes in the future, the functioning of lake ecosystems may be impacted. Small zooplankton eats small phytoplankton and if smaller phytoplankton species, e.g. cyanobacteria, increase at the expense of other phytoplankton groups, an extra step in the food chain might be added. Less energy might be transferred to the upper levels because many cyanobacteria contain toxic compounds and are less edible than other phytoplankton groups. An increase of toxic containing cyanobacteria in lakes can also make lakes less attractive for recreational purposes in the future.
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