Browsing Bergen Open Research Archive by Author "Langbehn, Tom"
Now showing items 1-12 of 12
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Bergmann patterns in planktivorous fishes: A light-size or zooplankton community-size rule is just as valid explanation as the temperature-size rule
Ljungström, Anna Jeja Gabriella; Langbehn, Tom; Jørgensen, Christian (Journal article; Peer reviewed, 2024)Aim Bergman patterns, the tendency of organisms to be larger at higher latitudes and lower temperatures, are a well-studied biogeographic pattern. Yet, there is no consensus on the driver or underlying mechanisms. We ... -
Blue mussels in western Norway have vanished where in reach of crawling predators
Meister, Nadja; Langbehn, Tom; Varpe, Øystein; Jørgensen, Christian (Journal article; Peer reviewed, 2023)Blue mussels (Mytilus spp.) are declining around the world. In western Norway, they have widely disappeared from rocky shores but still thrive on floating structures. Other refugia are cracks in rocks, exposed sites, and ... -
Catastrophic dynamics limit Atlantic cod recovery
Sguotti, Camilla; Otto, Saskia A; Frelat, Romain; Langbehn, Tom; Plambech Ryberg, M; Lindegren, Martin; Durant, Joel Marcel; Stenseth, Nils Christian; Möllmann, Christian (Peer reviewed; Journal article, 2019-03-13)Collapses and regime changes are pervasive in complex systems (such as marine ecosystems) governed by multiple stressors. The demise of Atlantic cod (Gadus morhua) stocks constitutes a text book example of the consequences ... -
Egg size and density estimates for three gadoids in Icelandic waters and their implications for the vertical distribution of eggs along a stratified water column
Butler, W.E.; Gudmundsdottir, L.; Logemann, K.; Langbehn, Tom; Marteinsdottir, G. (Journal article; Peer reviewed, 2020)The vertical distribution of fish eggs can have important consequences for recruitment through its influence on dispersal trajectories and thus connectivity between spawning and nursery locations. Egg density and size are ... -
Light and visual foraging in the pelagic: Opportunities and constraints along gradients of seasonality
Langbehn, Tom (Doctoral thesis, 2019-04-30)Light has a twofold fundamental impact on marine ecosystems; it allows photosynthesis that is at the source of most marine food chains, but it also governs top-down control through visual foraging. Here, I focus on the ... -
Light comfort zone in a mesopelagic fish emerges from adaptive behaviour along a latitudinal gradient
Langbehn, Tom; Aksnes, Dag Lorents; Kaartvedt, Stein; Fiksen, Øyvind; Jørgensen, Christian (Peer reviewed; Journal article, 2019)Throughout the oceans, small fish and other micronekton migrate between daytime depths of several hundred meters and near-surface waters at night. These diel vertical migrations of mesopelagic organisms structure pelagic ... -
Model of mesopelagic fish predation on eggs and larvae shows benefits of tuna spawning under full moon
Ottmann, Daniel; Langbehn, Tom; Reglero, Patricia; Alvarez-Berastegui, Diego; Fiksen, Øyvind (Journal article; Peer reviewed, 2023)Most mesopelagic fish are small planktivores that migrate up at nightfall to feed in the safety of darkness and descend to depth at dawn to escape visual predators. However, the trophic roles can reverse since mesopelagic ... -
Model-informed classification of broadband acoustic backscatter from zooplankton in an in situ mesocosm
Dunn, Muriel Barbara; McGowan-Yallop, Chelsey; Pedersen, Geir; Falk-Petersen, Stig; Daase, Malin Hildegard Elisabeth; Last, Kim; Langbehn, Tom; Fielding, Sophie; Brierley, Andrew S.; Cottier, Finlo Robert; Basedow, Sünnje Linnéa; Camus, Lionel; Geoffroy, Maxime (Journal article; Peer reviewed, 2023)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 ‘ground truthing’. Supervised ... -
Pelagic organisms avoid white, blue, and red artificial light from scientific instruments
Geoffroy, Maxime; Langbehn, Tom; Priou, Pierre; Varpe, Øystein; Johnsen, Geir; Le Bris, Arnault; Fisher, Jonathan A. D.; Daase, Malin; Mckee, David; Cohen, Jonathan H.; Berge, Jørgen (Journal article; Peer reviewed, 2021)In situ observations of pelagic fish and zooplankton with optical instruments usually rely on external light sources. However, artificial light may attract or repulse marine organisms, which results in biased measurements. ... -
Poleward distribution of mesopelagic fishes is constrained by seasonality in light
Langbehn, Tom; Aksnes, Dag Lorents; Kaartvedt, Stein; Fiksen, Øyvind; Ljungström, Anna Jeja Gabriella; Jørgensen, Christian (Journal article; Peer reviewed, 2022)Aim: Mesopelagic fishes have a near-global distribution in the upper 1,000 m from tropical to sub-Arctic oceans across temperature regimes. Yet, their abundance decreases poleward and viable populations seem excluded from ... -
Sea-ice loss boosts visual search: fish foraging and changing pelagic interactions in polar oceans
Langbehn, Tom; Varpe, Øystein (Peer reviewed; Journal article, 2017)Light is a central driver of biological processes and systems. Receding sea ice changes the lightscape of high-latitude oceans and more light will penetrate into the sea. This affects bottom-up control through primary ... -
Visual predation risk and spatial distributions of large Arctic copepods along gradients of sea ice and bottom depth
Langbehn, Tom; Aarflot, Johanna Myrseth; Freer, Jennifer J.; Varpe, Øystein (Journal article; Peer reviewed, 2023)Changes in the community size structure of Arctic copepods toward smaller and less fat individuals or species have been linked to environmental changes. The underpinning mechanisms are, however, poorly understood. We use ...