87 research outputs found
BIOMARKERS RELEVANT TO OIL AND GAS INDUSTRIAL ACTIVITIES IN LOW TEMPERATURE MARINE ECOSYSTEMS
Because of its geographical location, the Arctic environment is considered as pristine.
However, expanding industrial activities in the Arctic require assessment of the toxicity
of chemicals at low temperature. Biomarkers defined as "biological responses to a
chemical or chemicals that give a measure of exposure or toxic effect" were shown to
be relevant to measure in situ impact of oil discharges. Most biomarker studies have
been performed with temperate organisms. The Arctic is characterised by low stable
temperature, strong seasonality in light, resulting in a short primary production in
Spring. Therefore, indigenous organisms have developed specific adaptations to live
with a hmited food supply in water near freezing point. Conversely, physical properties
of petroleum hydrocarbons are affected by low temperature (i.e. reduced solubility).
Consequently, the biological adaptation of cold-water organisms together with the
altered oil behaviour, may affect typical biomarker responses. Because oil compounds
are strongly prooxidant, the research strategy of this work was based on oxidative stress.
The antioxidant defences were investigated by measuring the total oxyradical
scavenging capacity (TOSC). The impact of reactive oxygen species was investigated
by measuring the stability of the cell membranes. Finally, the physiology of the
organisms was considered by looking at heart and respiration rates. Invertebrates were
selected for study owing to their abundance in the polar ecosystem. They were sampled
using dredges and Scuba diving from the research vessel Jan Mayen (University of
Tromso) in May and August 1999, and during May and September 2000 in the l^ords of
Svalbard and in Antarctica as well in January 2000. In the Arctic, two bivalves, Mya
tnincata and Chlamys islandicus, and two crustaceans, Hyas araneus and
Sclerocrangon boreas were selected. In this work, the ecophysiology of Arctic and
Antarctic marine invertebrates was investigated and compared to temperate organisms. Polar marine invertebrates are characterised by low respiration and heart rates and a
high TOSC. The elevated level of antioxidant defences is thought to reflect the
oxidative pressure of the polar marine ecosystem; however, it suggested that a high
TOSC may help to protect biomolecules from oxidative damage as repair mechanisms
are limited due to the lack of food for 9 months. Organisms were exposed to poly
aromatic hydrocarbons either dissolved, dispersed injected or via sediment. TOSC, cell
membrane stabiHty and heart rate were valid biomarkers to monitor the impact of poly
aromatic hydrocarbons in Arctic marine organisms. The biomarker responses obtained
in this study provide essential background information for monitoring the potential
impact of oil and gas activities in the Arctic.Faculty of Science; Akvamilj
In the darkness of the polar night, scallops keep on a steady rhythm
Published version. Source at http://doi.org/10.1038/srep32435.
License CC BY 4.0.Although the prevailing paradigm has held that the polar night is a period of biological quiescence, recent studies have detected noticeable activity levels in marine organisms. In this study, we investigated the circadian rhythm of the scallop Chlamys islandica by continuously recording the animalâs behaviour over 3 years in the Arctic (Svalbard). Our results showed that a circadian rhythm persists throughout the polar night and lasts for at least 4 months. Based on observations across three polar nights, we showed that the robustness and synchronicity of the rhythm depends on the angle of the sun below the horizon. The weakest rhythm occurred at the onset of the polar night during the nautical twilight. Surprisingly, the circadian behaviour began to recover during the darkest part of the polar night. Because active rhythms optimize the fitness of an organism, our study brings out that the scallops C. islandica remain active even during the polar night
Effects of acute exposure to dispersed oil and burned oil residue on long-term survival, growth, and reproductive development in polar cod (Boreogadus saida)
Accepted manuscript version, licensed CC BY-NC-ND 4.0. Published version available at https://doi.org/10.1016/j.marenvres.2018.09.005.The present study investigates the potential long-term physiological effects on maturing polar cod (Boreogadus saida), an Arctic key species, after an acute exposure (48âŻh) to environmentally realistic concentrations of either mechanically dispersed oil (MDO), chemically dispersed oil (CDO) or burned oil residues (BO) (NâŻ=âŻ58â60 per treatment). Following exposure, fish were monitored in a common tank supplied with clean water for a seven-month period coinciding with the period of reproductive development. Females exposed to BO residues were more frequently found in an earlier phase of gonadal maturation compared to unexposed females while no effects of different oil spill response (OSR) actions were seen in the reproductive development of males. Mechanically and chemically dispersed oil induced a transient short-term reduction in growth in the first week post-exposure. Overall, no significant long-term effects of exposure were seen in growth or mortality. Ultimately, this study provides information for the assessment of population consequences of different OSR actions as part of a net environmental benefit analysis
Evidence of separate influence of moon and sun on light synchronization of mussel's daily rhythm during the polar night
Marine organisms living at high latitudes are faced with a light climate that undergoes drastic annual changes, especially during the polar night (PN) when the sun remains below the horizon for months. This raises the question of a possible synchronization and entrainment of biological rhythms under the governance of light at very low intensities. We analyzed the rhythms of the mussel Mytilus sp. during PN. We show that (1) mussels expressed a rhythmic behavior during PN; (2) a monthly moonlight rhythm was expressed; (3) a daily rhythm was expressed and influenced by both sunlight and moonlight; and (4) depending on the different times of PN and moon cycle characteristics, we were able to discriminate whether the moon or the sun synchronize the daily rhythm. Our findings fuel the idea that the capability of moonlight to synchronize daily rhythms when sunlight is not sufficient would be a crucial advantage during PN.publishedVersio
Environmental harm assessment of a wastewater discharge from Hammerfest LNG: A study with biomarkers in mussels (Mytilus sp.) and Atlantic cod (Gadus morhua)
Biologically treated wastewater (WW) from the Hammerfest LNG (liquefied natural gas) plant is discharged to the sea. A study using biomarkers in mussels and Atlantic cod was performed to examine whether this discharge meets a zero harmful emission requirement. Caging of mussels close to the outfall and exposure of mussels and fish to WW in the laboratory were conducted, and a suite of contaminant responsive markers was assessed in exposed animals. In mussels the markers included chemical contaminant levels, haemocyte lysosomal instability and nucleus integrity, cellular energy allocation, digestive gland and gonad histopathology and shell-opening behaviour. In fish, biliary PAH metabolites and gill histopathology biomarkers were measured. A consistent cause-effect relationship between WW treatments and markers measured in test animals was not found. The results therefore indicate that the WW emission is unlikely to represent a significant stress factor for the local marine environment under the conditions studied.acceptedVersio
Model-informed classification of broadband acoustic backscatter from zooplankton in an in situ mesocosm
Funding: The fieldwork was registered in the Research in Svalbard database (RiS ID 11578). Fieldwork and research were financed by Arctic Field Grant Project AZKABAN-light (Norwegian Research Council project no. 322 332), Deep Impact (Norwegian Research Council project no. 300 333), Deeper Impact (Norwegian Research Council project no. 329 305), Marine Alliance for Science and Technology in Scotland (MASTS), the Ocean Frontier Institute (SCORE grant no. HR09011), and Glider Phase II financed by ConocoPhillips Skandinavia AS. Geir Pedersenâs participation was co-funded by CRIMAC (Norwegian Research Council project no. 309 512). Maxime Geoffroy was financially supported by the Ocean Frontier Institute of the Canada First Research Excellence Fund, the Natural Sciences and Engineering Research Council Discovery Grant Programme, the ArcticNet Network of Centres of Excellence Canada, the Research Council of Norway Grant Deep Impact, and the Fisheries and Oceans Canada through the Atlantic Fisheries Fund.Classification of zooplankton to species with broadband echosounder data could increase the taxonomic resolution of acoustic surveys and reduce the dependence on net and trawl samples for âground truthingâ. Supervised classification with broadband echosounder data is limited by the acquisition of validated data required to train machine learning algorithms (âclassifiersâ). We tested the hypothesis that acoustic scattering models could be used to train classifiers for remote classification of zooplankton. Three classifiers were trained with data from scattering models of four Arctic zooplankton groups (copepods, euphausiids, chaetognaths, and hydrozoans). We evaluated classifier predictions against observations of a mixed zooplankton community in a submerged purpose-built mesocosm (12 m3) insonified with broadband transmissions (185â255 kHz). The mesocosm was deployed from a wharf in Ny-Ă
lesund, Svalbard, during the Arctic polar night in January 2022. We detected 7722 tracked single targets, which were used to evaluate the classifier predictions of measured zooplankton targets. The classifiers could differentiate copepods from the other groups reasonably well, but they could not differentiate euphausiids, chaetognaths, and hydrozoans reliably due to the similarities in their modelled target spectra. We recommend that model-informed classification of zooplankton from broadband acoustic signals be used with caution until a better understanding of in situ target spectra variability is gained.Publisher PDFPeer reviewe
The Action Constraints of an Object Increase Distance Estimation in Extrapersonal Space
This study investigated the role of action constraints related to an object as regards allocentric distance estimation in extrapersonal space. In two experiments conducted in both real and virtual environments, participants intending to push a trolley had to estimate its distance from a target situated in front of them. The trolley was either empty (i.e., light) or loaded with books (i.e., heavy). The results showed that the estimated distances were larger for the heavy trolley than for the light one, and that the actual distance between the participants and the trolley moderated this effect. This data suggests that the potential mobility of an object used as a reference affects distance estimation in extrapersonal space. According to embodied perception theories, our results show that people perceive space in terms of constraints related to their potential actions
Hvordan forebygge og hÄndtere episoder med skadelige alger og maneter i oppdrettsnÊringen
Prosjektleder: Trine DaleDette er hovedrapport for prosjektet «Hvordan forebygge og hÄndtere episoder med skadelige alger og maneter i oppdrettsnÊringen» finansiert av Fiskeri og havbruksnÊringens forskningsfinansiering. HovedmÄlet i prosjektet har vÊrt Ä sammenstille eksisterende kunnskap, erfaringer og teknologiske lÞsninger som er i bruk for Ä forebygge og hÄndtere episoder med skadelige alger og maneter og basert pÄ dette utforme og formidle anbefalinger og om mulig beste praksis i ulike situasjoner. Det er utviklet en prototype av et verktÞy som pÄ en enkel og lettfattelig mÄte fremstiller anbefalinger og beste praksis samt kunnskapen som danner bakgrunn for disse.Fiskeri og havbruksnÊringens forskningsfinansiering.publishedVersio
Autonomous Surface and Underwater Vehicles as Effective Ecosystem Monitoring and Research Platforms in the ArcticâThe Glider Project
Effective ocean management requires integrated and sustainable ocean observing systems enabling us to map and understand ecosystem properties and the effects of human activities. Autonomous subsurface and surface vehicles, here collectively referred to as âglidersâ, are part of such ocean observing systems providing high spatiotemporal resolution. In this paper, we present some of the results achieved through the project âUnmanned ocean vehicles, a flexible and cost-efficient offshore monitoring and data management approachâGLIDERâ. In this project, three autonomous surface and underwater vehicles were deployed along the LofotenâVesterĂ„len (LoVe) shelf-slope-oceanic system, in Arctic Norway. The aim of this effort was to test whether gliders equipped with novel sensors could effectively perform ecosystem surveys by recording physical, biogeochemical, and biological data simultaneously. From March to September 2018, a period of high biological activity in the area, the gliders were able to record a set of environmental parameters, including temperature, salinity, and oxygen, map the spatiotemporal distribution of zooplankton, and record cetacean vocalizations and anthropogenic noise. A subset of these parameters was effectively employed in near-real-time data assimilative ocean circulation models, improving their local predictive skills. The results presented here demonstrate that autonomous gliders can be effective long-term, remote, noninvasive ecosystem monitoring and research platforms capable of operating in high-latitude marine ecosystems. Accordingly, these platforms can record high-quality baseline environmental data in areas where extractive activities are planned and provide much-needed information for operational and management purposes
The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase
The Athena X-ray Integral Unit (X-IFU) is the high resolution X-ray
spectrometer, studied since 2015 for flying in the mid-30s on the Athena space
X-ray Observatory, a versatile observatory designed to address the Hot and
Energetic Universe science theme, selected in November 2013 by the Survey
Science Committee. Based on a large format array of Transition Edge Sensors
(TES), it aims to provide spatially resolved X-ray spectroscopy, with a
spectral resolution of 2.5 eV (up to 7 keV) over an hexagonal field of view of
5 arc minutes (equivalent diameter). The X-IFU entered its System Requirement
Review (SRR) in June 2022, at about the same time when ESA called for an
overall X-IFU redesign (including the X-IFU cryostat and the cooling chain),
due to an unanticipated cost overrun of Athena. In this paper, after
illustrating the breakthrough capabilities of the X-IFU, we describe the
instrument as presented at its SRR, browsing through all the subsystems and
associated requirements. We then show the instrument budgets, with a particular
emphasis on the anticipated budgets of some of its key performance parameters.
Finally we briefly discuss on the ongoing key technology demonstration
activities, the calibration and the activities foreseen in the X-IFU Instrument
Science Center, and touch on communication and outreach activities, the
consortium organisation, and finally on the life cycle assessment of X-IFU
aiming at minimising the environmental footprint, associated with the
development of the instrument. Thanks to the studies conducted so far on X-IFU,
it is expected that along the design-to-cost exercise requested by ESA, the
X-IFU will maintain flagship capabilities in spatially resolved high resolution
X-ray spectroscopy, enabling most of the original X-IFU related scientific
objectives of the Athena mission to be retained. (abridged).Comment: 48 pages, 29 figures, Accepted for publication in Experimental
Astronomy with minor editin
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