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norskBlar i forfatter "Sen, Arunima"
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Atypical biological features of a new cold seep site on the LofotenVesterålen continental margin (northern Norway)
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-11)A newly discovered cold seep from the Lofoten-Vesterålen margin (Norwegian Sea) is dominated by the chemosymbiotrophic siboglinid <i>Oligobrachia haakonmosbiensis</i> like other high latitude seeps, but additionally displays uncharacteristic features. Sulphidic bottom water likely prevents colonization by cnidarians and sponges, resulting in fewer taxa than deeper seeps in the region, representing ... -
Chemosynthesis influences food web and community structure in high-Arctic benthos
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10-25)Cold seeps are locations where seafloor communities are influenced by the seepage of methane and other reduced compounds from the seabed. We examined macro-infaunal benthos through community analysis and trophic structure using stable isotope analysis at 3 seep locations in the Barents Sea. These seeps were characterized by high densities of the chemosymbiotic polychaetes Siboglinidae, clade Frenulata ... -
Cold Seeps in a Warming Arctic: Insights for Benthic Ecology
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-21)Cold-seep benthic communities in the Arctic exist at the nexus of two extreme environments; one reflecting the harsh physical extremes of the Arctic environment and another reflecting the chemical extremes and strong environmental gradients associated with seafloor seepage of methane and toxic sulfide-enriched sediments. Recent ecological investigations of cold seeps at numerous locations on the ... -
Cryptic frenulates are the dominant chemosymbiotrophic fauna at Arctic and high latitude Atlantic cold seeps
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-12-28)We provide the first detailed identification of Barents Sea cold seep frenulate hosts and their symbionts. Mitochondrial COI sequence analysis, in combination with detailed morphological investigations through both light and electron microscopy was used for identifying frenulate hosts, and comparing them to Oligobrachia haakonmosbiensis and Oligobrachia webbi, two morphologically similar species ... -
Frenulate siboglinids at high Arctic methane seeps and insight into high latitude frenulate distribution
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-09)Frenulate species were identified from a high Arctic methane seep area on Vestnesa Ridge, western Svalbard margin (79°N, Fram Strait) based on mitochondrial cytochrome oxidase subunit I (mtCOI). Two species were found: <i>Oligobrachia haakonmosbiensis</i>, and a new, distinct, and undescribed <i>Oligobrachia</i> species. The new species adds to the cryptic <i>Oligobrachia</i> species complex found ... -
Geophysical and geochemical controls on the megafaunal community of a high Arctic cold seep
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-07-25)Cold-seep megafaunal communities around gas hydrate mounds (pingos) in the western Barents Sea (76°N, 16°E, ∼ 400 m depth) were investigated with high-resolution, geographically referenced images acquired with an ROV and towed camera. Four pingos associated with seabed methane release hosted diverse biological communities of mainly nonseep (background) species including commercially important fish ... -
Image based quantitative comparisons indicate heightened megabenthos diversity and abundance at a site of weak hydrocarbon seepage in the southwestern Barents Sea
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-08)<p><i>Background - </i>High primary productivity in the midst of high toxicity defines hydrocarbon seeps; this feature usually results in significantly higher biomass, but in lower diversity communities at seeps rather than in the surrounding non-seep benthos. Qualitative estimates indicate that this dichotomy does not necessarily hold true in high latitude regions with respect to megafauna. Instead, ... -
Iron cycling in Arctic methane seeps
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-26)Anoxic marine sediments contribute a significant amount of dissolved iron (Fe<sup>2+</sup>) to the ocean which is crucial for the global carbon cycle. Here, we investigate iron cycling in four Arctic cold seeps where sediments are anoxic and sulfidic due to the high rates of methane-fueled sulfate reduction. We estimated Fe<sup>2+</sup> diffusive fluxes towards the oxic sediment layer to be in the ... -
Lack of detectable chemosynthesis at a sponge dominated subarctic methane seep
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-07-20)We used high-resolution imagery within a Geographic Information System (GIS), free gas and porewater analyses and animal bulk stable isotope measurements to characterize the biotic and abiotic aspects of the newly discovered Vestbrona Carbonate Field (VCF) seep site on the Norwegian shelf (63°28′N, 6° 31′E, ∿270 m water depth). Free gas was mainly composed of microbial methane. Sediment porewater ... -
Lack of strong seasonality in macrobenthic communities from the northern Barents Sea shelf and Nansen Basin
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-12)The Barents Sea has been coined ‘the Arctic hotspot’ of climate change due to the rapidity with which environmental changes are taking place. This transitional domain from Atlantic to Arctic waters is home to highly productive benthic communities. This system strongly fluctuates on a seasonal basis in its sympagic-pelagicbenthic coupling interactions, with potential effects on benthic standing ... -
Methane cold seeps as biological oases in the high-Arctic deep sea
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-10-27)Cold seeps can support unique faunal communities via chemosynthetic interactions fueled by seabed emissions of hydrocarbons. Additionally, cold seeps can enhance habitat complexity at the deep seafloor through the accretion of methane derived authigenic carbonates (MDAC). We examined infaunal and megafaunal community structure at high-Arctic cold seeps through analyses of benthic samples and ... -
New cold seep sites on the continental slope southwest to Svalbard
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-04-09)We discovered seafloor features such as bacterial mats and carbonate crusts typical for active methane seeps on the continental slope southwest of Svalbard. These features are associated with two main northwest-southeast trending morphological structures that are oriented parallel to the regional continental slope. Both structures occur at c. 800 m water depth, at the boundary between the Storfjorden ... -
The phylogeography and ecology of Oligobrachia frenulate species suggest a generalist chemosynthesis-based fauna in the arctic
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-02)We used ancient DNA (aDNA) extraction methods to sequence museum voucher samples of Oligobrachia webbi, a frenulate siboglinid polychaete described from a northern Norwegian fjord over fifty years ago. Our sequencing results indicate a genetic match with the cryptic seep species, Oligobrachia haakonmosbiensis (99% pairwise identity for 574 bp mtCOI fragments). Due to its similarity with O. webbi, ... -
Seafloor warm water temperature anomalies impact benthic macrofauna communities of a high-Arctic cold-water fjord
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-06-05)Amid the alarming atmospheric and oceanic warming rates taking place in the Arctic, western fjords around the Svalbard archipelago are experiencing an increased frequency of warm water intrusions in recent decades, causing ecological shifts in their ecosystems. However, hardly anything is known about their potential impacts on the until recently considered stable and colder northern fjords. We ...
