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Marie LöfResearcher

About me

I am an environmental scientist and a marine ecotoxicologist with focus on the effects of hazardous substances in the Baltic Sea. I hold a PhD in Applied environmental science from Stockholm University with focus on Baltic Sea ecotoxicology. I also have a deep interest for science communication and knowledge exchange, both from an applied and a research perspective. These are vital elements of my work as a researcher at the Baltic Sea Centre, and I have a keen interest for making environmental science easy to grasp and accessible for decision makers. 

My overarching aim is to make science matter - for a sustainable development for the Baltic Sea.


My research interests include:

  • Knowledge exchange between science and society
  • Knowledge co-production
  • Effects of hazardous substances on marine organisms
  • Cumulative effects of stressors on marine organisms
  • Effects of mixture toxicity on benthic organisms
  • Reproduction effects in amphipods
  • Linking biomarker and bioindicator responses
  • Effects of microplastics in the marine environment
  • Chemicals in consumer products



Research projects


A selection from Stockholm University publication database

  • Principles for knowledge co-production in sustainability research

    2020. Albert Norström (et al.). Nature Sustainability


    Research practice, funding agencies and global science organizations suggest that research aimed at addressing sustainability challenges is most effective when 'co-produced' by academics and non-academics. Co-production promises to address the complex nature of contemporary sustainability challenges better than more traditional scientific approaches. But definitions of knowledge co-production are diverse and often contradictory. We propose a set of four general principles that underlie high-quality knowledge co-production for sustainability research. Using these principles, we offer practical guidance on how to engage in meaningful co-productive practices, and how to evaluate their quality and success. Research addressing sustainability issues is more effective if 'co-produced' by academics and non-academics, but definitions of co-production vary. This Perspective presents four knowledge co-production principles for sustainability research and guides on how to engage in co-productive practices.

    Read more about Principles for knowledge co-production in sustainability research
  • Building university-based boundary organisations that facilitate impacts on environmental policy and practice

    2018. Chris Cvitanovic (et al.). PLoS ONE 13 (9)


    Responding to modern day environmental challenges for societal well-being and prosperity necessitates the integration of science into policy and practice. This has spurred the devel- opment of novel institutional structures among research organisations aimed at enhancing the impact of environmental science on policy and practice. However, such initiatives are seldom evaluated and even in cases where evaluations are undertaken, the results are rarely made publicly available. As such there is very little empirically grounded guidance available to inform other organisations in this regard. To help address this, the aim of this study is to evaluate the Baltic Eye Project at Stockholm University – a unique team consisting of researchers from different fields, science communicators, journalists and policy analysts – working collectively to support evidence-informed decision-making relating to the sustainable management of the Baltic Sea environment. Specifically, through qualitative interviews, we (1) identify the impacts achieved by the Baltic Eye Project; (2) understand the challenges and barriers experienced throughout the Baltic Eye Project; and (3) highlight the key features that are needed within research organisations to enhance the impact of science on policy and practice. Results show that despite only operating for three years, the Baltic Eye Project has achieved demonstrable impacts on a range of levels: impacts on policy and practice, impacts to individuals working within the organisation and impacts to the broader University. We also identify a range of barriers that have limited impacts to date, such as a lack of clear goals at the establishment of the Baltic Eye Project and existing metrics of aca- demic impact (e.g. number of publications). Finally, based on the experiences of employees at the Baltic Eye Project, we identify the key organisational, individual, financial, material, practical, political, and social features of university-based boundary organisations that have impact on policy and practice. In doing so this paper provides empirically-derived guidance to help other research organisations increase their capacity to achieve tangible impacts on environmental policy and practice.

    Read more about Building university-based boundary organisations that facilitate impacts on environmental policy and practice
  • Evaluating the consumption of chemical products and articles as proxies for diffuse emissions to the environment

    2018. Dämien J. Bolinius (et al.). Environmental Science 20 (10), 1427-1440


    In this study we have evaluated the use of consumption of manufactured products (chemical products and articles) in the EU as proxies for diffuse emissions of chemicals to the environment. The content of chemical products is relatively well known. However, the content of articles (products defined by their shape rather than their composition) is less known and currently has to be estimated from chemicals that are known to occur in a small set of materials, such as plastics, that are part of the articles. Using trade and production data from Eurostat in combination with product composition data from a database on chemical content in materials (the Commodity Guide), we were able to calculate trends in the apparent consumption and in-use stocks for 768 chemicals in the EU for the period 2003-2016. The results showed that changes in the apparent consumption of these chemicals over time are smaller than in the consumption of corresponding products in which the chemicals are present. In general, our results suggest that little change in chemical consumption has occurred over the timespan studied, partly due to the financial crisis in 2008 which led to a sudden drop in the consumption, and partly due to the fact that each of the chemicals studied is present in a wide variety of products. Estimated in-use stocks of chemicals show an increasing trend over time, indicating that the mass of chemicals in articles in the EU, that could potentially be released to the environment, is increasing. The quantitative results from this study are associated with large uncertainties due to limitations of the available data. These limitations are highlighted in this study and further underline the current lack of transparency on chemicals in articles. Recommendations on how to address these limitations are also discussed.

    Read more about Evaluating the consumption of chemical products and articles as proxies for diffuse emissions to the environment
  • Biomarker-enhanced assessment of reproductive disorders in Monoporeia affinis exposed to contaminated sediment in the Baltic Sea

    2016. Marie Löf (et al.). Ecological Indicators 63, 187-195


    Introducing biomarkers into monitoring programs requires understanding of their responses in relation to higher-level biological effects as well as modulating effects of confounding environmental factors. We evaluated relationships between the general toxicity biomarkers (acetylcholinesterase [AChE], lysosomal membrane stability [LMS], oxygen radical absorbance capacity [ORAC]) and reproductive performance (fecundity and embryo aberrations) in the amphipod Monoporeia affinis in the Baltic Sea. To further link biomarker response to contaminant (PCBs, PAHs and metals) levels in the surrounding sediments as well as environmental factors (salinity, bottom depth and total organic carbon in sediments [TOC]), correlation and partial least square regression (PLSR) analyses were applied. The observed contaminants levels were frequently elevated for heavy metals and PAHs, but not PCBs. In the amphipod populations, female ORAC values were positively related to the occurrence of females carrying malformed or membrane-damaged embryos and to the percentage of such embryos in their broods, but also to the fecundity. Female AChE activity was negatively related to the frequency of the membrane-damaged embryos, and positively to the frequency of embryos with arrested development in the broods. Moreover, higher AChE activity and ORAC values in the females occurred at elevated concentrations of metals and PAHs, while there was a negative correlation between embryo ORAC and some PCB congeners. The PLSR models explained over 80% of the variation in the female ORAC and AChE values by variation in contaminant concentrations in combination with environmental variables. Specifically, CB180 and PAM4,9 were identified as negative predictors for ORAC, whereas many PAHs and some metals were positive predictors. The AChE activity was positively related to some metals and negatively to PCBs. In the PLSR models, environmental factors had significant modulating effects, with positive effect of salinity on female ORAC and AChE, and negative effect of TOC on the AChE. The LMS data were less informative, with no apparent relation to any of the contaminants. Linking subcellular responses to the reproduction effects facilitates environmental stress assessment and understanding of the response mechanisms, but also calls for more experimental and field data providing a mechanistic understanding to these linkages.

    Read more about Biomarker-enhanced assessment of reproductive disorders in Monoporeia affinis exposed to contaminated sediment in the Baltic Sea
  • Embryo aberrations in the amphipod Monoporeia affinis as indicators of toxic pollutants in sediments

    2016. Marie Löf (et al.). Ecological Indicators 60, 18-30


    Reproduction in the amphipod Monoporeia affinis is sensitive to contaminant exposure, and embryo aberrations are used in the Swedish National Monitoring Program to indicate biological effects of contaminants. However, empirical support for a causal relationship between contaminant load and frequency of aberrations is largely based on experimental studies. A field evaluation of aberration frequency in relation to contaminant exposure is required, if we are to use reproductive disorders as indicators of contaminant effects in risk assessment. In this study, we evaluated occurrence of females carrying malformed embryos and frequency of specific embryo aberrations in broods of M. affinis in relation to concentrationsof various pollutants in sediments. Gravid M. affinis and surface sediment were sampled at ten sites in the Gulf of Bothnia located at varying proximity to historical and current polluting point sources. At each site, concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and trace and heavy metals in surface sediments were determined. Amphipod fecundity and embryo development status were assayed with regard to morphologically recognizable aberrations (malformed embryos, membrane-damaged embryos, embryos with arrested development and females with dead brood). Our key finding is that different types of embryo aberrations were significantly associated with specific contaminant groups in the sediment. In particular, occurrence of females with embryo malformations was strongly related to elevated concentrations of Cd and PCBs, while females with membrane-damaged embryos occurred at high PAH concentrations. Also, frequency of embryos with arrested development was linked to elevated concentrations of PAHs and metals. Finally, frequency of females carrying dead broods, which was earlier considered to be a hypoxia-induced pathology, was significantly positively related to PAH concentrations. Thus, these reproductive aberrations in M. affinis can serve as contaminant-specific indicators of PCB, PAH and heavy metal exposure in biological effect monitoring.

    Read more about Embryo aberrations in the amphipod Monoporeia affinis as indicators of toxic pollutants in sediments
  • Exposure to contaminants exacerbates oxidative stress in amphipod Monoporeia affinis subjected to fluctuating hypoxia

    2013. Elena Gorokhova (et al.). Aquatic Toxicology 127, 46-53


    Fitness and survival of an organism depend on its ability to mount a successful stress response when challenged by exposure to damaging agents. We hypothesized that co-exposure to contaminants may exacerbate oxidative stress in hypoxia-challenged benthic animals compromising their ability to recover upon reoxygenation. This was tested using the amphipod Monoporeia affinis exposed to hypoxia followed by reoxygenation in sediments collected in polluted and pristine areas. In both sediment types, oxygen radical absorbance capacity (ORAC) and antioxidant enzyme activities [superoxide dismutase (SOD) and catalase (CAT)] increased during hypoxia, suggesting that M. affinis has a strategy of preparation for oxidative stress that facilitates recovery after a hypoxic episode. Exposure to contaminants altered this anticipatory response as indicated by higher baselines of ORAC and SOD during hypoxia and no response upon reoxygenation. This coincided with significantly elevated oxidative damage evidenced by a marked reduction in glutathione redox status (ratio of reduced GSH/oxidized GSSG) and an increase in lipid peroxidation (TSARS levels). Moreover, RNA:DNA ratio, a proxy for protein synthetic activity, decreased in concert with increased TBARS, indicating a linkage between oxidative damage and fitness. Finally, inhibited acetylcholinesterase (AChE) activity in animals exposed to contaminated sediments suggested a neurotoxic impact, whereas significant correlations between AChE and oxidative biomarkers may indicate connections with redox state regulation. The oxidative responses in pristine sediments suggested a typical scenario of ROS production and removal, with no apparent oxidative damage. By contrast, co-exposure to contaminants caused greater increase in antioxidants, lipid peroxidation, and slowed recovery from hypoxia as indicated by CAT, GSH/GSSG, TBARS and AChE responses. These results support the hypothesized potential of xenobiotics to hamper ability of animals to cope with fluctuating hypoxia. They also emphasize the importance of understanding interactions between antioxidant responses to different stressors and physiological mechanisms of oxidative damage.

    Read more about Exposure to contaminants exacerbates oxidative stress in amphipod Monoporeia affinis subjected to fluctuating hypoxia
  • Single and combined effects of hypoxia and contaminated sediments on the amphipod Monoporeia affinis in laboratory toxicity bioassays based on multiple biomarkers

    2010. Elena Gorokhova (et al.). Aquatic Toxicology 99 (2), 263-274


    In estuaries, hypoxic conditions and pollution are among the major factors responsible for the declines in habitat quality, yet little is known about their combined effects on estuarine organisms. In this study, to investigate single and combined effects of hypoxia and contaminated sediment, the Baltic amphipod Monoporeia affinis was exposed for 5-9 days to four different combinations of oxygen conditions (moderate hypoxia vs. normoxia) and contamination (polluted vs. unpolluted sediments) at environmentally realistic levels. To detect oxidative stress, a suite of biomarkers was used - antioxidant enzymes [superoxide dismutases (SOD), catalase (CAT), and glutathione S-transferases (GST)], acetylcholinesterase (AChE), lipid peroxidation status (TBARS concentration), protein carbonyl content (PCC), and DNA strand breakage (DNA-SB). To assay effects at the organism level, we used RNA:DNA ratio as a proxy for growth and metabolic rate and mortality. There were significant increases in CAT and SOD activities and TBARS levels in response to both moderate hypoxia and contaminated sediment, while GST increased and AChE decreased in response to the contamination only. Significant positive correlations were observed among the antioxidant enzymes and between the enzyme activities and TBARS concentration, suggesting a complex response to the oxidative stress. No significant changes in PCC were recorded in any of the treatments. Furthermore, the negative effect of hypoxia on DNA integrity was significant; with frequency of DNA-SB increasing in animals exposed to hypoxia in contaminated sediment. Despite clear effect at the cellular and biochemical levels, no responses at the organism level were observed. Multivariate analyses of the dataset have allowed us to link exposure factors to individual biomarker responses. Of the potential biomarkers assessed in this study, CAT activity was found to be associated with hypoxia, while SOD, GST and AChE activities appear to predict best the effects of exposure to sediments containing several contaminants (e.g. heavy metals, PCBs and PAHs), and TBARS concentration is particularly indicative of combined effects of hypoxia and contamination. In addition to providing new knowledge on the combined effects of multiple stressors on estuarine organisms, the findings of the present study are also important to understand data from biomonitoring studies in the Baltic Sea and in other regions where multiple stress factors co-occur.

    Read more about Single and combined effects of hypoxia and contaminated sediments on the amphipod Monoporeia affinis in laboratory toxicity bioassays based on multiple biomarkers

Show all publications by Marie Löf at Stockholm University