NIVA Open Access Archive
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Driftskontroll av kalkdoseringsanlegg i Vegårvassdraget. År 2022
Get PDFProsjektleder: Øyvind KasteDriftskontroll av kalkdoseringsanlegg er et system som overvåker effektiviteten ved anlegg som doserer kalk i sure vassdrag. På Hauglandsfoss doseringsanlegg i Storelva, Vegårvassdraget, ble det etablert driftskontroll i 2001. Denne rapporten gir en dokumentasjon på driften i 2022 og inneholder samtidig en fortegnelse over hendelser og avvik som kan danne grunnlag for forbedringstiltak knyttet til driftsrutiner, installasjoner eller kalkingsstrategi.Vegårshei kommunepublishedVersio
Social and genetic connectivity despite ecological variation in a killer whale network
Get PDFPhilopatric kin-based societies encourage a narrow breadth of conservative behaviours owing to individuals primarily learning from close kin, promoting behavioural homogeneity. However, weaker social ties beyond kin, and across a behaviourally diverse social landscape, could be sufficient to induce variation and a greater ecological niche breadth. We investigated a network of 457 photo-identified killer whales from Norway (548 encounters in 2008–2021) with diet data available (46 mixed-diet individuals feeding on both fish and mammals, and 411 exclusive fish-eaters) to quantify patterns of association within and between diet groups, and to identify underlying correlates. We genotyped a subset of 106 whales to assess patterns of genetic differentiation. Our results suggested kinship as main driver of social bonds within and among cohesive social units, while diet was most likely a consequence reflective of cultural diffusion, rather than a driver. Flexible associations within and between ecologically diverse social units led to a highly connected network, reducing social and genetic differentiation between diet groups. Our study points to a role of social connectivity, in combination with individual behavioural variation, in influencing population ecology in killer whales.publishedVersio
Anoxia begets anoxia: A positive feedback to the deoxygenation of temperate lakes
Get PDFDeclining oxygen concentrations in the deep waters of lakes worldwide pose a pressing environmental and societal challenge. Existing theory suggests that low deep-water dissolved oxygen (DO) concentrations could trigger a positive feedback through which anoxia (i.e., very low DO) during a given summer begets increasingly severe occurrences of anoxia in following summers. Specifically, anoxic conditions can promote nutrient release from sediments, thereby stimulating phytoplankton growth, and subsequent phytoplankton decomposition can fuel heterotrophic respiration, resulting in increased spatial extent and duration of anoxia. However, while the individual relationships in this feedback are well established, to our knowledge, there has not been a systematic analysis within or across lakes that simultaneously demonstrates all of the mechanisms necessary to produce a positive feedback that reinforces anoxia. Here, we compiled data from 656 widespread temperate lakes and reservoirs to analyze the proposed anoxia begets anoxia feedback. Lakes in the dataset span a broad range of surface area (1–126,909 ha), maximum depth (6–370 m), and morphometry, with a median time-series duration of 30 years at each lake. Using linear mixed models, we found support for each of the positive feedback relationships between anoxia, phosphorus concentrations, chlorophyll a concentrations, and oxygen demand across the 656-lake dataset. Likewise, we found further support for these relationships by analyzing time-series data from individual lakes. Our results indicate that the strength of these feedback relationships may vary with lake-specific characteristics: For example, we found that surface phosphorus concentrations were more positively associated with chlorophyll a in high-phosphorus lakes, and oxygen demand had a stronger influence on the extent of anoxia in deep lakes. Taken together, these results support the existence of a positive feedback that could magnify the effects of climate change and other anthropogenic pressures driving the development of anoxia in lakes around the world.publishedVersio
Taming the terminological tempest in invasion science
Get PDFStandardised terminology in science is important for clarity of interpretation and communication. In invasion science – a dynamic and rapidly evolving discipline – the proliferation of technical terminology has lacked a standardised framework for its development. The result is a convoluted and inconsistent usage of terminology, with various discrepancies in descriptions of damage and interventions. A standardised framework is therefore needed for a clear, universally applicable, and consistent terminology to promote more effective communication across researchers, stakeholders, and policymakers. Inconsistencies in terminology stem from the exponential increase in scientific publications on the patterns and processes of biological invasions authored by experts from various disciplines and countries since the 1990s, as well as publications by legislators and policymakers focusing on practical applications, regulations, and management of resources. Aligning and standardising terminology across stakeholders remains a challenge in invasion science. Here, we review and evaluate the multiple terms used in invasion science (e.g. ‘non-native’, ‘alien’, ‘invasive’ or ‘invader’, ‘exotic’, ‘non-indigenous’, ‘naturalised’, ‘pest’) to propose a more simplified and standardised terminology. The streamlined framework we propose and translate into 28 other languages is based on the terms (i) ‘non-native’, denoting species transported beyond their natural biogeographic range, (ii) ‘established non-native’, i.e. those non-native species that have established self-sustaining populations in their new location(s) in the wild, and (iii) ‘invasive non-native’ – populations of established non-native species that have recently spread or are spreading rapidly in their invaded range actively or passively with or without human mediation. We also highlight the importance of conceptualising ‘spread’ for classifying invasiveness and ‘impact’ for management. Finally, we propose a protocol for classifying populations based on (i) dispersal mechanism, (ii) species origin, (iii) population status, and (iv) impact. Collectively and without introducing new terminology, the framework that we present aims to facilitate effective communication and collaboration in invasion science and management of non-native species.publishedVersio
Diversification of marine aquaculture in Norway under climate change
Get PDFRecently there has been increased interest in species diversification in aquaculture as a strategy to adapt to climate change. Since species diversification is a long-term strategy, climate change and future farming conditions must be considered. The aim of this study was to evaluate how changing temperatures under different IPCC climate scenarios may affect marine aquaculture species diversification in Norway. Since farm conditions vary between locations, this study focused on four geographic areas (South, West, North and Arctic) and three farms within each area. Using a climate model downscaling of three climate scenarios (Shared Socioeconomic Pathways; SSP1–2.6, SSP2–4.5, and SSP5–8.5), daily temperatures from the years 2020–2099 were evaluated at each farm location to identify challenging conditions for 34 species. A Challenging Conditions Index (CCI) was developed based on species thermal tolerances to compare the 34 potential aquaculture species. The results showed differences in the number of challenging days (hot and cold) between areas, and even within areas, highlighting the need to consider site-specific conditions. For warm-water species more commonly farmed in the Mediterranean (e.g. European seabass, gilthead seabream), the calibrated model projections at the investigated Norwegian farm sites suggest that cold temperatures would still be challenging. Differences in the number of challenging days between the climate scenarios become more apparent towards the mid and end of century, though all scenarios show interannual variation rather than a constant change in conditions over time. Hence, any species selected for diversification purposes will have to be able to tolerate a range of temperature conditions, and species with narrower tolerance ranges could be a risk. These findings underline the importance of considering the interannually varying conditions that species will be exposed to rather than focusing solely on long-term averages. Establishing a new large-scale commercial aquaculture species takes a considerable amount of time and resources. Therefore, to support interpretation of the results and further studies on diversification under climate change, this study also introduces Aquaculture Readiness Level (ARL®) as a consistent evaluation of the research and development status, progress towards commercialisation and climate action orientated production. As species will have to be able to tolerate a range of temperature conditions over different years, the level of knowledge, resources, and innovation will have to be continually enhanced to improve adaptive capacity.publishedVersio
Environmental and societal effects and impacts of hydro floating solar power plants
Get PDFProsjektleder: Ingrid NesheimFloating solar (FPV) energy production represents an innovative technology with the potential to increase renewable power production, meeting both rising consumption and the need to replace fossil-based energy. The HydroSun Competence project, led by the Institute for Energy Technology (IFE) and funded by the Norwegian Research Council, aims to support the rapid, cost-efficient, and sustainable development of renewable energy. This report, a deliverable of the work package led by NIVA, addresses the environmental and societal impacts of FPV on hydropower or multi-purpose reservoirs. Using the Magat reservoir in the Philippines as a case study, it investigates the effects of different FPV scenarios on environmental variables such as evaporation, water temperature, oxygen levels, and greenhouse gas emissions, as well as economic and socio-cultural factors. The study compares baseline, low cover, and high cover FPV scenarios, suggesting measures to enhance benefits and mitigate adverse impacts. The findings emphasize the importance of context-specific assessments and provide recommendations for optimizing FPV design and deployment to optimize benefits.Norwegian Research CouncilpublishedVersio
Getting the errors right: The importance of partitioning sources of uncertainty for ecological indicators
Get PDFEnvironmental policies such as the Water Framework Directive (WFD) requires that the confidence of ecological status assessments should be reported. Such assessments are typically based on aggregating several ecological indicators, but the uncertainty of these is rarely quantified and when exceptionally it is estimated, the indicator variance can be grossly underestimated, resulting in overconfident assessment. We demonstrate with a simple example that incorrect partitioning of different sources of variation, typically characterizing monitoring data, can underestimate the standard error of an indicator by 33 %. This is due to sampling constraints in monitoring programs, implying that observations are not independent replicates across all levels of sampling. We also carried out a comprehensive analysis, quantifying the magnitude of different sources of variation for monitoring variables used to calculate ecological indicators for WFD status classification in Sweden. We demonstrate that these variances can be estimated from regular monitoring data, although it was not possible to estimate all relevant sources of variation. We propose to occasionally include spatial and temporal replicate samples in the existing monitoring programs such that relevant sources of uncertainty can be quantified with sufficient precision. This library of variance parameter estimates allows for calculating the uncertainty of ecological indicators more correctly for any combination of sampling in time and space by different institutions/taxonomists. It also identifies the dominant sources of random variation affecting the indicator uncertainty, providing a basis for optimal sampling design as well as potential improvement of current sampling and analysis procedures, both aiming at reducing uncertainty. Whilst it is commonly understood that sampling occasions should be spread appropriately across time and space, the relatively large variability among institutes/taxonomists implies that spreading samples among these also helps reducing indicator uncertainty, particularly for biological indices. It is important to change the perception that ecological indicators can stand alone as single values, without considering the associated uncertainties which allow for quantifying the confidence in ecological status assessments. This study demonstrates that this is possible based on appropriate partitioning of sources of uncertainty.publishedVersio
Monitoring of microplastics in the Norwegian environment (MIKRONOR) 2023
Get PDFProsjektleder: Vanja AllingThe MIKRONOR monitoring program aims to establish baseline levels of microplastics in the Norwegian environment and to identify potential sources and sinks. This third MIKRONOR report focuses mainly on results from air samples, including data on tyre wear particles (TWP), as well as river and fjord surface water samples, and their correlation to rainfall and river discharge levels. Additionally, it presents data from sand samples taken from an OSPAR beach in the outer Oslofjord. The results for 2023 provide evidence of the omnipresence of microplastics in the environment. However, levels were higher near cities and populated areas, with decreasing levels further from human activities. This trend was observed in both air and surface water samples. Sand samples from the OSPAR beach in the Oslofjord showed levels of microplastics comparable to, or slightly higher than studied beaches at Svalbard. Since no other beach studies have been conducted in the MIKRONOR program, it is difficult to determine typical microplastic levels on a beach in the outer Oslofjord. Determined levels of microplastics in the beach samples were comparable to levels in marine bottom sediment at remote areas along the coast and lower than levels in sediments from the Oslofjord. Main conclusions of this report highlight the need for further research into the processes that control the levels and variations of microplastics and TWPs, such as weather conditions, river discharge, and air mass movement. Sampling of different matrices should, where possible, be conducted using similar strategies and equipment to improve the comparability of results. Additionally, the high spatial and temporal variability between samples must be considered to determine the appropriate number of analyses needed to obtain reliable results.Monitoring of microplastics in the Norwegian environment (MIKRONOR) 2023MiljødirektoratetpublishedVersio
Competition, payment and flexible trust on a Sierra Leonean fishing boat
Get PDFThis article analyses a competitive payment practice common aboard artisanal fishing boats in Sierra Leone. The competition for payment between crew members on board fishing boats complicates common discursive claims about generalized mistrust in post-war Sierra Leone. Through a phenomenological ethnography of working relations at sea, I show how competitive practices generate flexible trust between crew members. Competing in what is known as handfailure produces moments where others’ intentions and moral character become legible, allowing fishermen to forge and revise trust in light of shifting evaluations of trustworthiness. The trust forged through handfailure differs from older patron–client relationships between boat owners and fishermen, and from the interpretations of social breakdown in fishing communities given by government officials. The article contributes to recent anthropological conversations about mis/trust by showing how, in contexts where people question trust or claim that mistrust is widespread, trust can nevertheless be forged anew on more flexible and negotiable terms.publishedVersio
Classification and risk assessment of sediment in the Karosta Canal after dredging
Get PDFProsjektleder: Sissel Brit RanneklevSediment samples were collected from the Karosta Canal, Liepaja, Latvia, in December 2023, shortly after dredging of the Canal. The sediments were analysed for a selection of contaminants and data was provided for the Norwegian Institute for Water Research (NIVA). Measured concentrations of heavy metals, polycyclic aromatic hydrocarbons (PAH), and oil (hydrocarbons) were classified according to classification systems used in Norway, Latvia, and HELCOM. A risk assessment of sediments, following the guidelines developed by the Norwegian Environmental Agency, were executed on the collected sediments in the Karosta Canal. Classification of the sediment samples shows that the sediment still contains high concentrations of some heavy metals, PAH compounds, and oil. The sediment in the mid and inner part of the Karosta Canal had the highest concentrations of heavy metals and oil, while the sediment in the outer part of the canal was less polluted. Sediment samples taken outside the dredged area, close to the slopes of the canal had higher concentrations of oil, PAH-compounds, and heavy metals, compared to the dredged areas. The risk assessment concludes that there is a risk of spreading contaminated sediments, a risk of harm on the ecosystem and a risk for human health if fish or shellfish from the Karosta Canal are consumed.Liepaja Special Economic Zone (LSEZ)publishedVersio