English
norskBlar i forfatter "Chierici, Melissa"
Viser treff 21-34 av 34
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Marine CO2 system variability in a high arctic tidewater-glacier fjord system, Tempelfjorden, Svalbard
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-05-04)The marine CO<sub>2</sub> system in Tempelfjorden (Svalbard) was investigated between August 2015 and December 2017 using total alkalinity, pH, temperature, salinity, oxygen isotopic ratio, and nutrient data. Primary production resulted in the largest changes that were observed in the partial pressure of CO<sub>2</sub> (<i>p</i>CO<sub>2</sub>, 140 μatm) and the saturation state of aragonite ... -
Methane release from open leads and new ice following an Arctic winter storm event
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-03)We examine an Arctic winter storm event, which led to ice break–up, the formation of open leads, and the subsequent freezing of these leads. The methane (CH<sub>4</sub>) concentration in under–ice surface water before and during the storm event was 8–12 nmol L<sup>−1</sup>, which resulted in a potential sea–to–air CH<sub>4</sub> flux ranging from +0.2 to +2.1 mg CH<sub>4</sub> m<sup>−2</sup> ... -
Pelagic Ecosystem Characteristics Across the Atlantic Water Boundary Current from Rijpfjorden, Svalbard, to the Arctic Ocean during Summer (2010-2014)
(Journal article; Peer reviewed, 2019-04-09)The northern coast of Svalbard contains high-arctic fjords, such as Rijpfjorden (80°N 22°30′E). This area has experienced higher sea and air temperatures and less sea ice in recent years, and models predict increasing temperatures in this region. Part of the West Spitsbergen Current (WSC), which transports relatively warm Atlantic water along the continental slope west of Svalbard, bypasses these ... -
Planktic foraminiferal and pteropod contributions to carbon dynamics in the Arctic Ocean (north Svalbard margin)
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-09)Planktic foraminifera and shelled pteropods are some of the major producers of calcium carbonate (CaCO<sub>3</sub>) in the ocean. Their calcitic (foraminifera) and aragonitic (pteropods) shells are particularly sensitive to changes in the carbonate chemistry and play an important role for the inorganic and organic carbon pump of the ocean. Here, we have studied the abundance distribution of planktic ... -
Seasonal dynamics of carbonate chemistry, nutrients and CO2 uptake in a sub-Arctic fjord
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-17)Environmental change can have a significant impact on biogeochemical cycles at high latitudes and be particularly important in ecologically valuable fjord ecosystems. Seasonality in biogeochemical cycling in a sub-Arctic fjord of northern Norway (Kaldfjorden) was investigated from October 2016 to September 2018. Monthly changes in total inorganic carbon (C<sub>T</sub>), alkalinity (A<sub>T</sub>), ... -
Seasonal dynamics of the marine CO2 system in Adventfjorden, a West Spitsbergen fjord
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-11)Time series of the marine CO<sub>2</sub> system and related parameters at the IsA Station, by Adventfjorden, Svalbard, were investigated between March 2015 and November 2017. The physical and biogeochemical processes that govern changes in total alkalinity (TA), total dissolved inorganic carbon (DIC) and the saturation state of the calcium carbonate mineral aragonite (Ω<sub>Ar</sub>) were assessed ... -
Seasonal plankton dynamics in Kongsfjorden during two years of contrasting environmental conditions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-24)Seasonal plankton time-series data are presented from Kongsfjorden from two years with contrasting environmental conditions. Kongsfjorden (west coast of Spitsbergen – 79°N) integrates inputs from Atlantic and Arctic waters, and glacier run-off, and is thus a prime location to study impacts on ecosystem dynamics of key environmental drivers that are relevant across the Arctic. Despite extensive ... -
Seasonality of marine calcifiers in the northern Barents Sea: Spatiotemporal distribution of planktonic foraminifers and shelled pteropods and their contribution to carbon dynamics
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-07)The Barents Sea is presently undergoing rapid warming and the sea-ice edge and the productive zones are retreating northward at accelerating rates. Planktonic foraminifers and shelled pteropods are ubiquitous marine calcifiers that play an important role in the carbon budget and being particularly sensitive to ocean biogeochemical changes and ocean acidification. Their distribution at high latitudes ... -
Seasonality of the Physical and Biogeochemical Hydrography in the Inflow to the Arctic Ocean Through Fram Strait
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-29)Eastern Fram Strait and the shelf slope region north of Svalbard is dominated by the advection of warm, salty and nutrient-rich Atlantic Water (AW). This oceanic heat contributes to keeping the area relatively free of ice. The last years have seen a dramatic decrease in regional sea ice extent, which is expected to drive large increases in pelagic primary production and thereby changes in marine ... -
Shell density of planktonic foraminifera and pteropod species Limacina helicina in the Barents Sea: Relation to ontogeny and water chemistry
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-28)Planktonic calcifiers, the foraminiferal species <i>Neogloboquadrina pachyderma</i> and <i>Turborotalita quinqueloba</i>, and the thecosome pteropod <i>Limacina helicina</i> from plankton tows and surface sediments from the northern Barents Sea were studied to assess how shell density varies with depth habitat and ontogenetic processes. The shells were measured using X-ray microcomputed tomography ... -
Still Arctic? — The changing Barents Sea
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-13)The Barents Sea is one of the Polar regions where current climate and ecosystem change is most pronounced. Here we review the current state of knowledge of the physical, chemical and biological systems in the Barents Sea. Physical conditions in this area are characterized by large seasonal contrasts between partial sea-ice cover in winter and spring versus predominantly open water in summer and ... -
Temporal variability in surface water pCO2 in Adventfjorden (West Spitsbergen) with emphasis on physical and biogeochemical drivers
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-26)Seasonal and interannual variability in surface water partial pressure of CO<sub>2</sub> (<i>p</i>CO2) and air‐sea CO<sub>2</sub> fluxes from a West Spitsbergen fjord (IsA Station, Adventfjorden) are presented, and the associated driving forces are evaluated. Marine CO<sub>2</sub> system data together with temperature, salinity, and nutrients, were collected at the IsA Station between March 2015 and ... -
Thin and transient meltwater layers and false bottoms in the Arctic sea ice pack-Recent insights on these historically overlooked features
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-07)The rapid melt of snow and sea ice during the Arctic summer provides a significant source of low-salinity meltwater to the surface ocean on the local scale. The accumulation of this meltwater on, under, and around sea ice floes can result in relatively thin meltwater layers in the upper ocean. Due to the small-scale nature of these upper-ocean features, typically on the order of 1 m thick or less, ... -
Valuing blue carbon changes in the Arctic ocean
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-25)The ocean capacity to store carbon is crucial, and currently absorbs about 25% CO<sub>2</sub> supply to the atmosphere. The ability to store carbon has an economic value, but such estimates are not common for ocean environments, and not yet estimated for the Arctic Ocean. With the severe climatic changes in the Arctic Ocean, impacting sea ice and potentially the vertical carbon transport mechanisms, ...
