NIVA Open Access Archive
Not a member yet
8416 research outputs found
Sort by
Nitrous Oxide Dynamics in the Siberian Arctic Ocean and Vulnerability to Climate Change
Get PDFNitrous oxide (N2O) is a strong greenhouse gas and stratospheric ozone-depleting substance. Around 20% of global emissions stem from the ocean, but current estimates and future projections are uncertain due to poor spatial coverage over large areas and limited understanding of drivers of N2O dynamics. Here, we focus on the extensive and particularly data-lean Arctic Ocean shelves north of Siberia that experience rapid warming and increasing input of land-derived nitrogen with permafrost thaw. We combine water column N2O measurements from two expeditions with on-board incubation of intact sediment cores to assess N2O dynamics and the impact of land-derived nitrogen. Elevated nitrogen concentrations in water column and sediments were observed near large river mouths. Concentrations of N2O were only weakly correlated with dissolved nitrogen and turbidity, reflecting particulate matter from rivers and coastal erosion, and correlations varied between river plumes. Surface water N2O concentrations were on average close to equilibrium with the atmosphere, but varied widely (N2O saturation 38%–180%), indicating strong local N2O sources and sinks. Water column N2O profiles and low sediment-water N2O fluxes do not support strong sedimentary sources or sinks. We suggest that N2O dynamics in the region are influenced by water column N2O consumption under aerobic conditions or in anoxic microsites of particles, and possibly also by water column N2O production. Changes in biogeochemical and physical conditions will likely alter N2O dynamics in the Siberian Arctic Ocean over the coming decades, in addition to reduced N2O solubility in a warmer ocean.publishedVersio
Kartlegging av vannkvaliteten i Holsfjorden 2022-2023 [Datarapport]
Get PDFProsjektleder: Jonas PerssonDet bygges en reservevannforsyning til Oslo fra Holsfjorden (en fjordarm av Tyrifjorden) som skal være ferdig i 2028. Vanninntaket til den nye vannforsyningen bygges på Vefsrud, på østsiden av Holsfjorden. Det var i 2022-2023 behov for å utføre en ny, grundig kartlegging av vannkvaliteten i den delen av Holsfjorden. I perioden august 2022 til april 2023 ble det fire ganger innhentet vann fra Holsfjorden ved Vefsrud. Prøver ble tatt fra 5, 25, 50, 100 samt 150 m dybde, samt fra en integrert blandprøve fra epilimnion. Til sammen ble det analysert for mer enn 200 stoffer. Vertikalprofiler 0-150 m av temperatur, ledningsevne, og oksygen ble målt med en multisensor-sonde. Dette er en datarapport som redegjør for metoder og resultater.Oslo kommune v/Vann- og avløpsetatenpublishedVersio
How genomics can help biodiversity conservation
Get PDFThe availability of public genomic resources can greatly assist biodiversity assessment, conservation, and restoration efforts by providing evidence for scientifically informed management decisions. Here we survey the main approaches and applications in biodiversity and conservation genomics, considering practical factors, such as cost, time, prerequisite skills, and current shortcomings of applications. Most approaches perform best in combination with reference genomes from the target species or closely related species. We review case studies to illustrate how reference genomes can facilitate biodiversity research and conservation across the tree of life. We conclude that the time is ripe to view reference genomes as fundamental resources and to integrate their use as a best practice in conservation genomics.publishedVersio
Influence of climate change and pesticide use practices on the ecological risks of pesticides in a protected Mediterranean wetland: A Bayesian network approach
Get PDFPollution by agricultural pesticides is one of the most important pressures affecting Mediterranean coastal wetlands. Pesticide risks are expected to be influenced by climate change, which will result in an increase of temperatures and a decrease in annual precipitation. On the other hand, pesticide dosages are expected to change given the increase in pest resistance and the implementation of environmental policies like the European ´Farm-to-Fork` strategy, which aims for a 50 % reduction in pesticide usage by 2030. The influence of climate change and pesticide use practices on the ecological risks of pesticides needs to be evaluated making use of realistic environmental scenarios. This study investigates how different climate change and pesticide use practices affect the ecological risks of pesticides in the Albufera Natural Park (Valencia, Spain), a protected Mediterranean coastal wetland. We performed a probabilistic risk assessment for nine pesticides applied in rice production using three climatic scenarios (for the years 2008, 2050 and 2100), three pesticide dosage regimes (the recommended dose, and 50 % increase and 50 % decrease), and their combinations. The scenarios were used to simulate pesticide exposure concentrations in the water column of the rice paddies using the RICEWQ model. Pesticide effects were characterized using acute and chronic Species Sensitivity Distributions built with toxicity data for aquatic organisms. Risk quotients were calculated as probability distributions making use of Bayesian networks. Our results show that future climate projections will influence exposure concentrations for some of the studied pesticides, yielding higher dissipation and lower exposure in scenarios dominated by an increase of temperatures, and higher exposure peaks in scenarios where heavy precipitation events occur right after pesticide application. Our case study shows that pesticides such as azoxystrobin, difenoconazole and MCPA are posing unacceptable ecological risks for aquatic organisms, and that the implementation of the ´Farm-to-Fork` strategy is crucial to reduce them.publishedVersio
Organic Alkalinity as an Important Constituent of Total Alkalinity and the Buffering System in River-To-Coast Transition Zones
Get PDFOrganic acid-base species in the dissolved organic carbon pool have been shown to make an important contribution (i.e., organic alkalinity; OrgAlk) to the total alkalinity (TA) in many coastal systems. This study documents an intensive investigation of OrgAlk characteristics in the river-to-coast transition zones of six southeast Chinese rivers. OrgAlk, mainly originating from river input, accounted for an important proportion of TA (0.3%–12%) in six estuaries. Carboxylic acid groups were commonly present in all estuaries. Notable differences in the TA values (1–18 μmol kg−1) determined by several established TA measurement approaches were identified in estuaries where organic acids with pKa 5 in the study estuaries. Across our study sites, OrgAlk might modify H+ concentrations by 3%–69% (i.e., pH by 0.01–0.78) and aragonite saturation states by 1%–72%, indicating that OrgAlk can play a significant role in the coastal carbonate buffering system. It is essential to improve current TA measurement approaches to more accurately represent OrgAlk in the coastal system and assess impacts of OrgAlk on coastal carbonate chemistry.publishedVersio
Predation of Atlantic salmon across ontogenetic stages and impacts on populations
Get PDFManagers and stakeholders increasingly ask whether predation is a driving force behind the poor status of many species, and whether predator control is likely to be a successful management action to intervene. We review existing literature on Atlantic salmon Salmo salar predation and predator control, as well as general ecological theory on the role of predation in the life cycle of this iconic fish. Many bird, mammal, and fish predators target salmon at different life stages. In healthy salmon populations, predation is likely compensated for by reduced intra-specific competition during the freshwater stage. There is little evidence that predation alone has been an underlying mechanism for driving salmon populations below conservation limits. However, depending on the predator’s response to salmon abundance, predation may keep decimated populations from recovering, even when the actual causes of decline have been removed. Under such a scenario, predation control may contribute to recovery, but there are no strong examples that clearly demonstrate the efficacy of managing predators to recover threatened salmon populations, challenging further applications.publishedVersio
Incorporating climate projections in the environmental risk assessment of pesticides in aquatic ecosystems
Get PDFGlobal climate change will significantly impact the biodiversity of freshwater ecosystems, both directly and indirectly via the exacerbation of impacts from other stressors. Pesticides form a prime example of chemical stressors that are expected to synergize with climate change. Aquatic exposures to pesticides might change in magnitude due to increased runoff from agricultural fields, and in composition, as application patterns will change due to changes in pest pressures and crop types. Any prospective chemical risk assessment that aims to capture the influence of climate change should properly and comprehensively account for the variabilities and uncertainties that are inherent to projections of future climate. This is only feasible if they probabilistically propagate extensive ensembles of climate model projections. However, current prospective risk assessments typically make use of process-based models of chemical fate that do not typically allow for such high-throughput applications. Here, we describe a Bayesian network model that does. It incorporates a two-step univariate regression model based on a 30-day antecedent precipitation index, circumventing the need for computationally laborious mechanistic models. We show its feasibility and application potential in a case study with two pesticides in a Norwegian stream: the fungicide trifloxystrobin and herbicide clopyralid. Our analysis showed that variations in pesticide application rates as well as precipitation intensity lead to variations in in-stream exposures. When relating to aquatic risks, the influence of these processes is reduced and distributions of risk are dominated by effect-related parameters. Predicted risks for clopyralid were negligible, but the probability of unacceptable future environmental risks due to exposure to trifloxystrobin (i.e., a risk quotient >1) was 8%–12%. This percentage further increased to 30%–35% when a more conservative precautionary factor of 100 instead of 30 was used.publishedVersio
Estimating Sea Surface Salinity in the East China Sea Using Satellite Remote Sensing and Machine Learning
Get PDFSea surface salinity (SSS) is a master variable in oceanography and important to understand marine biogeochemical and physical processes. In the East China Sea (ECS), a random forest based regression ensemble model (RF) was developed to estimate the SSS with a spatial resolution of ∼1 km based on a large synchronous data set of in situ SSS observations, MODIS-derived remote sensing reflectance (Rrs) and sea surface temperature (SST). The model showed the best performance when the Rrs(412), Rrs(488), Rrs(555), Rrs(667), SST and Julian day (JD) were used as inputs, with a root mean square error (RMSE) of 0.84, mean absolute error (MAE) of 0.31 and coefficient of determination (R2) of 0.81 for model training (N = 4,504), and a RMSE of 0.77, MAE of 0.30 and R2 of 0.86 for the model test (N = 1,153). The accuracy of the SSS model was examined using an independent data set during the period of 2020–2022 with a RMSE of 0.66 and MAE of 0.39 (N = 2,151). The interannual and seasonal signal of modeled SSS of the ECS, showed that important drivers of variability are the Changjiang discharge and the East-Asian monsoon. Applications of the model to other Chinese marginal seas (Yellow and Bohai seas) showed good agreement in distribution patterns when compared with the estimated SSS from NASA Soil Moisture Active Passive. Once more empirical oceanographic data is made available, this robust model can be applied to other regions retraining the model with informed local data sets.publishedVersio
Evaluating the effects of climate change and chemical, physical, and biological stressors on nearshore coral reefs: A case study in the Great Barrier Reef, Australia
Get PDFAn understanding of the combined effects of climate change (CC) and other anthropogenic stressors, such as chemical exposures, is essential for improving ecological risk assessments of vulnerable ecosystems. In the Great Barrier Reef, coral reefs are under increasingly severe duress from increasing ocean temperatures, acidification, and cyclone intensities associated with CC. In addition to these stressors, inshore reef systems, such as the Mackay–Whitsunday coastal zone, are being impacted by other anthropogenic stressors, including chemical, nutrient, and sediment exposures related to more intense rainfall events that increase the catchment runoff of contaminated waters. To illustrate an approach for incorporating CC into ecological risk assessment frameworks, we developed an adverse outcome pathway network to conceptually delineate the effects of climate variables and photosystem II herbicide (diuron) exposures on scleractinian corals. This informed the development of a Bayesian network (BN) to quantitatively compare the effects of historical (1975–2005) and future projected climate on inshore hard coral bleaching, mortality, and cover. This BN demonstrated how risk may be predicted for multiple physical and biological stressors, including temperature, ocean acidification, cyclones, sediments, macroalgae competition, and crown of thorns starfish predation, as well as chemical stressors such as nitrogen and herbicides. Climate scenarios included an ensemble of 16 downscaled models encompassing current and future conditions based on multiple emission scenarios for two 30-year periods. It was found that both climate-related and catchment-related stressors pose a risk to these inshore reef systems, with projected increases in coral bleaching and coral mortality under all future climate scenarios. This modeling exercise can support the identification of risk drivers for the prioritization of management interventions to build future resilient reefs.publishedVersio
Miljøvennlige menstruasjonsprodukter i Osloskolene
Get PDFProsjektleder: Vilde SnekkevikEngangsprodukter som bind og tamponger og deres negative påvirkninger på natur, miljø og helse har hatt lite fokus. Dette til tross for at det finnes mer miljøvennlige alternativer. Oslo kommunes tiltaksordning har som mål å minimere plast- og marinforsøpling i Oslo. Basert på deres plastvedtak har vi i dette prosjektet identifisert hvordan Oslo kommune kan bidra til å redusere bruke av engangs menstruasjonsprodukter, samt utviklet et undervisningsopplegg. Undervisningsopplegget har gjennom kreativ læring og gruppearbeid som mål å informere om miljøproblemene engangs menstruasjonsprodukter representerer og introdusere mer miljøvennlige alternativer som kan gjenbrukes.Oslo KommunepublishedVersio