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  • 1
    Online Resource
    Online Resource
    Frontiers Media SA ; 2021
    In:  Frontiers in Marine Science Vol. 8 ( 2021-6-24)
    In: Frontiers in Marine Science, Frontiers Media SA, Vol. 8 ( 2021-6-24)
    Abstract: Causes and consequences of jellyfish bloom formation are subject to controversial discussions worldwide. While medusae have been studied to a broader extent, the knowledge on polyp stages of scyphozoans is limited thus hampering reliable prediction of jellyfish bloom formation. This study describes the occurrence, abundance, habitat characteristics and interactions of scyphozoan Aurelia sp. polyp colonies with other fouling organisms in intertidal and subtidal sectors of Trondheimsfjorden (Norway). In total, 982 polyps were found on 70 substrata of varying material types during a field survey in spring-summer 2018 along a longitudinal gradient within and outside Trondheimsfjorden. The polyps were identified as Aurelia sp. based on molecular species identification. Most polyps were found in bays with macroalgae canopy on the down facing side of artificial and natural substrata (rocks, concrete, iron) and inside rock cracks. Polyp microhabitats included the surface of Ascidia mentula (solitary ascidian), increments of Pomatoceros triqueter (polychete) tubes and dead Balanus balanoides (barnacle) shells. Based on the deployment of settling plates, abundance of Aurelia sp. polyps ranged from 1.2 (± 0.7) to 0.12 (± 0.07) polyps cm –2 . Settlement occurred either directly on the PVC settling plates or as epibionts on the ascidian Ascidia mentula and on barnacle shells of Balanus balanoides . This study provides insights into the potential of local Aurelia sp. polyps contributing to the seasonal occurrence and abundance of Aurelia sp. in fjord systems, where intensive blooms occur annually.
    Type of Medium: Online Resource
    ISSN: 2296-7745
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2021
    detail.hit.zdb_id: 2757748-X
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  • 2
    In: Frontiers in Marine Science, Frontiers Media SA, Vol. 7 ( 2021-1-25)
    Abstract: The oceans’ uptake of anthropogenic carbon dioxide (CO 2 ) decreases seawater pH and alters the inorganic carbon speciation – summarized in the term ocean acidification (OA). Already today, coastal regions experience episodic pH events during which surface layer pH drops below values projected for the surface ocean at the end of the century. Future OA is expected to further enhance the intensity of these coastal extreme pH events. To evaluate the influence of such episodic OA events in coastal regions, we deployed eight pelagic mesocosms for 53 days in Raunefjord, Norway, and enclosed 56–61 m 3 of local seawater containing a natural plankton community under nutrient limited post-bloom conditions. Four mesocosms were enriched with CO 2 to simulate extreme p CO 2 levels of 1978 – 2069 μatm while the other four served as untreated controls. Here, we present results from multivariate analyses on OA-induced changes in the phyto-, micro-, and mesozooplankton community structure. Pronounced differences in the plankton community emerged early in the experiment, and were amplified by enhanced top-down control throughout the study period. The plankton groups responding most profoundly to high CO 2 conditions were cyanobacteria (negative), chlorophyceae (negative), auto- and heterotrophic microzooplankton (negative), and a variety of mesozooplanktonic taxa, including copepoda (mixed), appendicularia (positive), hydrozoa (positive), fish larvae (positive), and gastropoda (negative). The restructuring of the community coincided with significant changes in the concentration and elemental stoichiometry of particulate organic matter. Results imply that extreme CO 2 events can lead to a substantial reorganization of the planktonic food web, affecting multiple trophic levels from phytoplankton to primary and secondary consumers.
    Type of Medium: Online Resource
    ISSN: 2296-7745
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2021
    detail.hit.zdb_id: 2757748-X
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  • 3
    Online Resource
    Online Resource
    Frontiers Media SA ; 2021
    In:  Frontiers in Marine Science Vol. 8 ( 2021-11-19)
    In: Frontiers in Marine Science, Frontiers Media SA, Vol. 8 ( 2021-11-19)
    Abstract: During the era of biodiversity loss, a complete species census and understanding where the different species occur is of high priority. Even though this knowledge has increased tremendously, mainly with expanded use of integrated taxonomic identification, there are groups where our knowledge is very limited, both in terms of diversity and distribution. Ctenophores are such a group. Due to a lack of identification literature, damage to specimens during net sampling and sample processing, difficulties with preservation and a considerably undescribed diversity within the phylum, this group is often hard to work with. A citizen science approach was applied during a mapping campaign on ctenophore diversity along the Norwegian coast in order to have a broad geographical coverage. This was achieved by a collaboration with five diving clubs along a south-north geographical gradient that were briefly introduced to ctenophore taxonomy and ecology and sampling techniques using Whatman ® FTA ® Cards. The data collected by the participating divers gave a broad spatial coverage and provided information on ctenophore diversity in these regions. The use of FTA ® Cards in the sampling allowed successful species and genus level identification using DNA barcodes. However, small obstacles such as accurate morphological species identification and labor-intensive issues were identified that can impede the use of large-scale citizen science approaches to map ctenophore diversity and thus recommendations for future implications that address these issues are proposed here.
    Type of Medium: Online Resource
    ISSN: 2296-7745
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2021
    detail.hit.zdb_id: 2757748-X
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  • 4
    Online Resource
    Online Resource
    Sultan Qaboos University ; 2015
    In:  Journal of Agricultural and Marine Sciences [JAMS] Vol. 20 ( 2015-01-01), p. 40-
    In: Journal of Agricultural and Marine Sciences [JAMS], Sultan Qaboos University, Vol. 20 ( 2015-01-01), p. 40-
    Abstract: Live feed are still necessary for the rearing of larval stages of several fish species, especially marine ones. Compared to Artemia, copepods are of superior quality. This is based on a suite of traits like size, movement, and nutritional value. Copepods are for example usually high in protein and fatty acids. Essential fatty acid profiles reflect to a large degree the fatty acid supply, which provides the opportunity to manipulate fatty acid profiles of, amongst others, copepods. By manipulating nutrient supply of the algae Rhodomonas salina we were able to double essential fatty acid concentrations in naupliar and copepodit life stages of the copepod Acartia tonsa. However, this lead to growth depression rather than to increased growth rates in a series of consumer species, including larval fish. The reason for the growth depression is likely to be mineral deficiencies occurring along with the nutrient manipulation of the algae. 
    Type of Medium: Online Resource
    ISSN: 2410-1079 , 2410-1060
    Language: Unknown
    Publisher: Sultan Qaboos University
    Publication Date: 2015
    detail.hit.zdb_id: 2160952-4
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  • 5
    In: The Nansen Legacy Report Series, UiT The Arctic University of Norway, , No. 4 ( 2020-11-25)
    Abstract: Joint Cruise 1-2 with R/V Kronprins Haakon addressed objectives of RF1, RF2 and RF3 on the Nansen Legacy main transect in open water and within the sea ice. The focus was on comparing the state of the physical, chemical and biological conditions in the southern and northern parts of the study area. Given this was the first research cruise on the vessel, the cruise also focused on testing gear and equipment, and establishing routines for gear deployments, collaboration, data management and storing.
    Type of Medium: Online Resource
    ISSN: 2703-7525
    URL: Issue
    Language: Unknown
    Publisher: UiT The Arctic University of Norway
    Publication Date: 2020
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  • 6
    In: Oceanography, The Oceanography Society, Vol. 33, No. 3 ( 2020-09-01), p. 50-59
    Type of Medium: Online Resource
    ISSN: 1042-8275
    Language: Unknown
    Publisher: The Oceanography Society
    Publication Date: 2020
    detail.hit.zdb_id: 1167549-4
    detail.hit.zdb_id: 2268693-9
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  • 7
    Online Resource
    Online Resource
    Frontiers Media SA ; 2022
    In:  Frontiers in Marine Science Vol. 9 ( 2022-4-20)
    In: Frontiers in Marine Science, Frontiers Media SA, Vol. 9 ( 2022-4-20)
    Abstract: Biological invasions of jellyfish may critically affect ecosystems and ecosystem services, yet their complex life cycle makes tracking their origins and dispersal vectors a challenging task. Here we combine citizen science observations, oceanographic modeling, and population genetics to track swarms of the invasive nomad jellyfish, Rhopilema nomadica , across the Eastern Mediterranean Sea. Jellyfish observations were recorded by citizens from two Israeli beaches in two consecutive years. A Lagrangian model coupled with a high-resolution 3D hydrodynamic model (SINMOD) was then used to simulate drift of ephyrae from probable polyp bed locations. Finally, mitochondrial DNA (mtDNA) sequence was constructed to examine swarm connectivity. Temporal (both seasonal and interannual) variation in observed swarms generally exceeded spatial differences between the two surveyed beaches. Early detection of swarms by citizens in offshore waters and the higher offshore particle distribution shown by the drift model, point to considerable offshore transport of the swarms. However, a higher probability was found for a nearshore location of the polyp beds, as nearshore origins were more closely correlated to hits on target beaches. R. nomadica released as ephyrae in early spring were likely to reach target beaches 200-300 km down current within two to three months as swarms of young adults in the early summer bathing season. R. nomadica populations exhibited little temporal or spatial genetic differentiation, a typical feature of a species that has recently undergone rapid population expansion. The offshore transport, the lack of genetic structure, and the interannual differences in both hydrodynamics and citizen scientist observations, all indicate decentralized swarm origins. This type of interdisciplinary approach can thus provide viable tools to track bloom formations. Understanding the complexity of jellyfish swarm dynamics supports future management strategies such as forecasting, preparedness and public education.
    Type of Medium: Online Resource
    ISSN: 2296-7745
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2022
    detail.hit.zdb_id: 2757748-X
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  • 8
    In: Frontiers in Marine Science, Frontiers Media SA, Vol. 6 ( 2019-2-25)
    Type of Medium: Online Resource
    ISSN: 2296-7745
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2019
    detail.hit.zdb_id: 2757748-X
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  • 9
    In: Endocrine-Related Cancer, Bioscientifica, Vol. 25, No. 9 ( 2018-09), p. 783-793
    Abstract: Pancreatic neuroendocrine tumors (PanNETs) are rare in von Hippel–Lindau disease (VHL) but cause serious morbidity and mortality. Management guidelines for VHL-PanNETs continue to be based on limited evidence, and survival data to guide surgical management are lacking. We established the European-American-Asian-VHL-PanNET-Registry to assess data for risks for metastases, survival and long-term outcomes to provide best management recommendations. Of 2330 VHL patients, 273 had a total of 484 PanNETs. Median age at diagnosis of PanNET was 35 years (range 10–75). Fifty-five (20%) patients had metastatic PanNETs. Metastatic PanNETs were significantly larger (median size 5 vs 2 cm; P   〈  0.001) and tumor volume doubling time (TVDT) was faster (22 vs 126 months; P  = 0.001). All metastatic tumors were ≥2.8 cm. Codons 161 and 167 were hotspots for VHL germline mutations with enhanced risk for metastatic PanNETs. Multivariate prediction modeling disclosed maximum tumor diameter and TVDT as significant predictors for metastatic disease (positive and negative predictive values of 51% and 100% for diameter cut-off ≥2.8 cm, 44% and 91% for TVDT cut-off of ≤24 months). In 117 of 273 patients, PanNETs 〉 1.5 cm in diameter were operated. Ten-year survival was significantly longer in operated vs non-operated patients, in particular for PanNETs 〈 2.8 cm vs ≥2.8 cm (94% vs 85% by 10 years; P  = 0.020; 80% vs 50% at 10 years; P  = 0.030). This study demonstrates that patients with PanNET approaching the cut-off diameter of 2.8 cm should be operated. Mutations in exon 3, especially of codons 161/167 are at enhanced risk for metastatic PanNETs. Survival is significantly longer in operated non-metastatic VHL-PanNETs.
    Type of Medium: Online Resource
    ISSN: 1351-0088 , 1479-6821
    Language: Unknown
    Publisher: Bioscientifica
    Publication Date: 2018
    detail.hit.zdb_id: 2010895-3
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