Tracking changes in the fjord environment over a winter season using ice bulk salinity and δ18O

Ice that forms in the fjords of northern Norway often undergoes temperature fluctuations, rising above and below freezing, throughout winter and experiences variable conditions at the ice-ocean interface due to changes in freshwater runoff from surrounding land. Conditions at the interface can be difficult to track throughout the season without consistent measurement, resultantly limiting understanding of how freshwater runoff from land may impact a fjord throughout winter. Ice samples gathered from fjords, however, offer a unique opportunity to examine the connection between bulk ice properties like salinity and δ18O and environmental conditions including growth rate and the composition of water at the interface. Using relationships from the literature, a method was developed to invert bulk ice salinity and δ18O simultaneously to determine the history of growth rate and interface water composition of ice samples gathered in March 2018 from six fjords located in northern Norway. Quantitative results depend on knowledge of salinity and δ18O of both the seawater and freshwater leading into the fjord. It was found that five of the six investigated sites had ice grown from a brackish layer with 0 to 40% seawater content, while one site had ice grown from water with 50 to 90% seawater content. The brine volume fraction of the ice from four out of the six fjords was partly or entirely below 5% which is too low to allow for efficient brine transport. It is additionally shown that at ice temperatures between − 2 and 0 ◦C, ice grown from water having a composition of up to 30% seawater at the ice ocean interface will fall below the 5% brine volume fraction, depending on growth rate. Through use of this method, an improved understanding was obtained of fluctuations in the composition of water at the ice-ocean interface in a sub-arctic coastal environment and, when ice growth rate is considered, the substantial influence on ice bulk properties

Redusere avrenning fra ferskfisk transport på lastebiler

By law, fresh fish is transported on ice in the EEA. This system is tried and proven and works perfectly except that upward of 1000 L of meltwater drain onto the road from a typical trailer load. This is most noticeable near packing and slaughterhouses, on ferries, and on certain roads (e.g. Laksevegen Fv. 714 in Trøndelag). This is a nuisance, publicity issue, and a matter of road safety.Redusere avrenning fra ferskfisk transport på lastebilersubmittedVersio

Microstructure evolution of young sea ice from a Svalbard fjord using micro-CT analysis

We analysed the three-dimensional microstructure of sea ice by means of X-ray-micro computed tomography. Microscopic (brine- and air- pore sizes, numbers and connectivity) and macroscopic (salinity, density, porosity) properties of young Arctic sea ice were analysed. The analysis is based on ice cores obtained during spring 2016. Centrifuging of brine prior to CT imaging has allowed us to derive confident relationships between the open, vertically connected and total porosity of young sea ice at relatively high temperatures. We analysed the dependence of the microscopic properties on vertical position and total brine porosity. Most bulk properties (salinity,density) and pore space properties (pore sizes and their distribution) show a strong dependence on total brine porosity, but did not change significantly over the course of the field work.However, significant changes were observed for pore numbers decreasing over time) and pore connectivity (increasing over time). CT-based salinity determinations are subject to larger than standard uncertainties (from conductivity), while the CT method yields important information about the salinity contributions from closed and open pores. We also performed a comparison of CT-based air porosity with calculations based on density from hydrostatic weighing. The consistency is encouraging and gives confidence to our CT-based results.publishedVersio

From above and standing atop- two views of Norwegian fjord ice

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From above and standing atop- two views of Norwegian fjord ice

Poster presentation at the online CIRFA Annual Conference, 12.10.2020 - 14.10.2020 (https://cirfa.uit.no/welcome-to-the-cirfa-annual-conference-2020/), arranged by CIRFA: https://cirfa.uit.no/. In O’Sadnick et al. (2020), estimations of ice extent along the coast of Norway since 2001 determined from MODIS imagery are presented. From our findings, it is evident that the amount of ice in one fjord over time often varies and shows little consistency leading to the next question of ‘Why’? The study continues to relate freezing degree days, rainfall plus snowmelt, and snowfall to values of ice area to determine if significant correlations exist when fjords are grouped into regions. Six out of the ten regions were significantly postiviely correlated to freezing degree days (p < 0.05). Ice area in two regions was positively correlated to daily new snowfall, and in one region negatively correlated to rainfall plus snowmelt. Please see the publication for further description of methods and findings

Ice Formation in Norwegian Fjords – Findings from the 2018 - 2019 Field Season

Understanding ice conditions in fjords is imperative to ensure safe operations and to protect the surrounding environment. Seven fjords in northern Norway were visited in March 2019, six with significant ice cover. In each location, measurements of ocean temperature and salinity, and δ18O for ocean water and river water leading into the fjords were gathered. In addition, where ice was present, measurements of ice bulk salinity and δ18O were obtained along with an extra core to examine ice stratigraphy and pore structure. Results show ice of low bulk salinity, < 1.5 psu, and δ18O, < -7.67 ‰, in five fjords holding ice with maximum ice thickness being upwards of 0.46 m. This result combined with examination of stratigraphy cores reveals ice closely resembling freshwater ice in structure despite lying atop an ocean of average salinity 32 – 33.5 (psu). Ice salinity profiles elude to varying environmental conditions impacting ice formation throughout the winter season. Due to the impact of significant freshwater flux, ice properties differed significantly from sea ice forming in the open ocean, an important characteristic when considered in application to coastal operations.publishedVersio

Ice conditions in northern Norwegian fjords: Observations and measurements from three winter seasons, 2017–2020

Freshwater provided by rivers beginning deep within the mountains, feeds into fjords along the coast of Norway, often forming a brackish surface layer that will change in its salinity, thickness, and extent throughout the year. As temperature drops below freezing, ice can form from this layer along the entire coastline from 71° N down to 58° N. The influence of freshwater combined with changing weather and oceanographic conditions, can lead to ice that varies not only in its thickness and extent but its properties including crystal fabric, bulk salinity, and pore structure. Resultantly, how ice interacts with the surrounding environment including communities that use the ice for winter activities, boats transiting through fjords, pollutants like oil, and the biota living within the ice and fjord waters, will be impacted. To enhance understanding of the drivers of ice formation and resultant properties in Norwegian fjords, seven fjords located in northern Norway were monitored over three winter seasons between 2017 and 2020. Measurements of ice thickness, stratigraphy, bulk salinity, and δ18O were gathered along with measurements of ocean salinity, temperature, and δ18O of both snow and river water. Ice thickness ranged from non-existent up to 0.8 m with the proportion of congelation to granular ice changing between seasons and fjords. While ocean salinities directly below the ice on the day of measurement were primarily above 31 psu, ice bulk salinity varied from 0 psu to 5.6 psu with values of δ18O between - 13.3 ‰ and 0.2 ‰, indicating ice frozen from fresh water as well as seawater. Findings support that ice conditions in a single fjord or in a geographic region should not be generalized, with substantial variations measured between years and locations. We examine openly accessible interpolated weather and runoff data obtained through seNorge for possible causes for the variable ice conditions observed. Results reveal freezing degree days are not a dependable predictor of ice thickness when applied to Norwegian fjords, and substantial consideration of the date of onset of ice formation and snow cover are needed. Freshwater runoff and snowfall as well as the timing of weather and oceanic conditions throughout the three winter seasons are also presented to highlight their potential to influence ice formation considerably.Ice conditions in northern Norwegian fjords: Observations and measurements from three winter seasons, 2017–2020publishedVersio

Hvordan håndteres avrenning fra ferskfisktransport i andre fiskenasjoner, en komparativ studie av Irland, Island og Færøyene

Det ble gjennomført en komparativ studie hos villfiskforedlere, lakseslakteri, transportbyrå og tilsynsmyndigheter i Irland, Island og Færøyene der man diskuterte problemstillingen rundt avrenning fra lastebiler som transporterer fersk fisk på is. Disse tre landene ble valgt, siden de har både fangst av villfisk, samt har oppdrett av laks. I tillegg representerer de land innenfor og utenfor EU. Det var til dels store forskjeller mellom hvilket fokus dette fenomenet hadde i de tre landene. I Irland var det tilnærmet ingen oppmerksomhet knyttet til avrenning, der hverken publikum eller myndigheter gav det noen oppmerksomhet. På Island var det forbud mot å la det renne ut på veien, og det var påbudt for lastebiler som transporterte fersk fisk å ha montert oppsamlingstanker på lastebilene. De hadde derimot ikke noe ordnet system på hvor tankene skulle tømmes, og det var heller ikke mye fokus på fra myndighetenes side på at dette ble overholdt. Tilsynelatende førte dette til at mange ikke lukket ventilen på oppsamlingtanken. På Færøyene var det forbud og krav til oppsamling for laksetransport. Dette skyldes frykt for smitte av ILA til villfisk i færøyske vassdrag. Til forskjell fra Island, så har de organisert oppsamling, og vannet desinfiseres før det slippes ut.Hvordan håndteres avrenning fra ferskfisktransport i andre fiskenasjoner, en komparativ studie av Irland, Island og FærøyenepublishedVersio

Reduksjon av smeltevann fra fisketransport

Undersøkelser i prosjektet viser at det er store forskjeller mellom de ulike aktørene i bransjen med tanke på temperaturkontroll av fisk. Hovedutfordringen med avrenning ligger nok hos produsentene, der fisken generelt ikke blir tilfredsstillende nedkjølt. De aller fleste som deltok i studien har et temperaturmål på 1-3 °C for fisk som pakkes med is, noe som vil gi smelting av is og avrenning under lagring og transport. Det finnes flere tilgjengelige metoder for å samle opp smeltevann som produseres. Tette kasser fremstår som et alternativ som raskt kan implementeres hvis fisken er tilstrekkelig nedkjølt. Et annet alternativ er å montere oppsamlingstanker på lastebilene. Det var til dels store forskjeller hvilket fokus avrenning hadde i Irland, Island og Færøyene. Færøyene hadde det beste systemet med organisert oppsamling og mottak av avrenningsvann. Den matematiske modellen som ble utviklet, bekrefter at temperaturen på fisken har størst innvirkning på avrenningen, men at lastebilen også må gjøre sin del av jobben. Det anbefales at fisken er kaldere enn 1 °C, og at lastebilen stilles inn på -1 til 0 °C.Reduksjon av smeltevann fra fisketransportpublishedVersio

Reduksjon av smeltevann fra fisketransport

Undersøkelser i prosjektet viser at det er store forskjeller mellom de ulike aktørene i bransjen med tanke på temperaturkontroll av fisk. Hovedutfordringen med avrenning ligger nok hos produsentene, der fisken generelt ikke blir tilfredsstillende nedkjølt. De aller fleste som deltok i studien har et temperaturmål på 1-3 °C for fisk som pakkes med is, noe som vil gi smelting av is og avrenning under lagring og transport. Det finnes flere tilgjengelige metoder for å samle opp smeltevann som produseres. Tette kasser fremstår som et alternativ som raskt kan implementeres hvis fisken er tilstrekkelig nedkjølt. Et annet alternativ er å montere oppsamlingstanker på lastebilene. Det var til dels store forskjeller hvilket fokus avrenning hadde i Irland, Island og Færøyene. Færøyene hadde det beste systemet med organisert oppsamling og mottak av avrenningsvann. Den matematiske modellen som ble utviklet, bekrefter at temperaturen på fisken har størst innvirkning på avrenningen, men at lastebilen også må gjøre sin del av jobben. Det anbefales at fisken er kaldere enn 1 °C, og at lastebilen stilles inn på -1 til 0 °C.Reduksjon av smeltevann fra fisketransportpublishedVersio