Micronekton biomass distribution, improved estimates across four north Atlantic basins

Klevjer, Thor A.; Melle, Webjørn; Knutsen, Tor; Strand, Espen; Korneliussen, Rolf J.; Dupont, Nicolas; Salvanes, Anne Gro Vea; Wiebe, Peter H.

doi:10.1016/j.dsr2.2019.104691

Cited by 18 publications

(19 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the North Atlantic, mesopelagic biomass, abundance, taxonomic composition, and the proportion of diel vertical migrators differ on a basin scale (Klevjer, Melle, Knutsen, Strand, et al., 2020). Clear differences exist between the basins of the Irminger and Labrador Seas in the south‐west (below the Arctic Circle) and the Norwegian and Iceland Seas to the north‐east (which in parts extend far above the above the Arctic Circle).…”

Section: Discussionmentioning

confidence: 99%

“…The case studied here is highly relevant for the distribution of DVM mesopelagic fishes at high latitudes. Benthosema glaciale is prominent among the diel vertical migrators and dominates the catches of mesopelagic fishes in the Norwegian Sea and Iceland Sea (Klevjer, Melle, Knutsen, Strand, et al., 2020). The Nordic Seas (the Greenland, Iceland, and Norwegian Seas) are the only deep ocean basins globally above the polar circles that remain largely ice‐free year‐round.…”

Section: Methodsmentioning

confidence: 99%

“…However, the eye sensitivities of mesopelagic fishes and their predators are hard to quantify. We used values that correspond to the upper and lower ambient light intensity observed for the mesopelagic scattering layer, dominated by B. glaciale (Klevjer, Melle, Knutsen, Strand, et al., 2020; Norheim et al., 2016) in the study area, 10 −8 mW/m 2 /nm at 486 nm for the mesopelagic fish and 4 × 10 −4 mW/m 2 /nm at 486 nm for the piscivores (Norheim et al., 2016, see fig. 4b therein).…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Poleward distribution of mesopelagic fishes is constrained by seasonality in light

Langbehn

Aksnes

Kaartvedt

et al. 2021

Global Ecol Biogeogr

View full text Add to dashboard Cite

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 high latitudes. Why? Location North Atlantic between 50–85°N, with implications for high‐latitude oceans globally. Time period Present‐day. Major taxa studied Diel vertically migrating (DVM) mesopelagic fishes. Methods We use a mechanistic, state‐dependent life‐history model to characterize DVM mesopelagic fishes. This model links light‐dependent encounters and temperature‐dependent physiology, allowing optimal DVM strategies to emerge. We run the model along a latitudinal gradient with increasing seasonality in light and track individual fitness‐related measures, that is, survival and surplus energy, through the annual cycle to make predictions about population consequences. Results Mesopelagic fishes thrive in the oceans’ twilight zone, and many are dependent on periods of darkness for safe foraging near the surface, before migrating back to depth during daytime. When daylight lasts for 24 hr during the Arctic summer, these fish are trapped in deep waters void of prey because it is never safe to forage in the shallow waters where zooplankton prey are found. Hence, they are left with two poor options, starvation at depth or depredation while foraging. Our model predicts surplus energy, vital for reproduction and growth, to halve from 50–85°N and annual survival to drop by two‐thirds over a narrow range of 10° of latitude around the Arctic Circle. Thus, low recruitment and high predation mortality during summer make polar waters population sinks for mesopelagic fishes because of the extreme seasonality in light. Main conclusions At high latitudes, foraging mesopelagic fishes are exposed to sunlight in upper waters also at night. This makes them easy prey for visual predators, which limits their poleward distribution. Our findings highlight the importance to think beyond temperature to explain high‐latitude range limits.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Poleward distribution of mesopelagic fishes is constrained by seasonality in light

Langbehn

Aksnes

Kaartvedt

et al. 2021

Global Ecol Biogeogr

View full text Add to dashboard Cite

show abstract

“…The reduced backscatter at high and low frequencies reflects reduced abundances of both micronekton and macrozooplankton across polar fronts. Furthermore, the LADCP data revealed the absence of sound scattering layers below ~400 m in poleward ecosystems, in contrast to equatorial and boreal regions where they are ubiquitous features 2,9,19,20,34 . The coincidence of the mesopelagic boundaries with polar fronts reflects a strong relationship between temperature and pelagic vertical structure.…”

Section: Main Textmentioning

confidence: 96%

“…As a first order approximation, biomass of mesopelagic organisms should scale with energy input to the mesopelagic zone. However, research on mesopelagic macrozooplankton and micronekton has mainly focused on low-or mid-latitude systems 19,20 and knowledge of their vertical structure and effect on carbon fluxes at high latitudes remains scarce [21][22][23][24][25] . Scientific echosounders are frequently used to map mesopelagic deep-scattering layers (DSL).…”

Section: Main Textmentioning

confidence: 99%

The transformation of mesopelagic structure across polar fronts

Chawarski¹,

Klevjer²,

Côté³

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

The oceans sequester 31% of atmospheric carbon annually 1, but the magnitude of biologically enhanced sequestration is not evenly distributed across the globe 2. Measuring surface primary productivity offers a reasonable proxy for estimating carbon flux into the ocean 3 but entirely misses the processes that affect carbon export to sequestration depths. A high proportion of carbon flux is broken up 4 or respired 5 by organisms at mesopelagic depths (200-1000 m). At low and mid-latitudes, daytime biomass peaks of mesopelagic organisms are clearly present and detectable as sound-scattering layers, and up to 40% of oceanic carbon passes through these layers 6,7. Here we demonstrate that acoustic backscatter, a proxy for abundance of mesopelagic fish and zooplankton decreases by up to 97% across polar fronts, revealing a distinct pelagic structure in high latitude systems. As mesopelagic fish and macrozooplankton comprise a large component of active carbon transport in the upper ocean, this latitudinal reduction in mesopelagic biomass across thermal fronts, in both the Arctic and Antarctic, suggests different carbon flux attenuation schemes exists in ocean twilight zones of polar ecosystem compared to low latitude systems. Rapid ocean warming projected at mesopelagic depths8 will likely disrupt vertical connectivity and alter biogeochemical cycles at high latitudes.

show abstract

Spatial patterns and environmental associations of deep scattering layers in the northwestern subtropical Pacific Ocean

et al. 2022

View full text Add to dashboard Cite

Micronekton biomass distribution, improved estimates across four north Atlantic basins

Cited by 18 publications

References 29 publications

Poleward distribution of mesopelagic fishes is constrained by seasonality in light

Poleward distribution of mesopelagic fishes is constrained by seasonality in light

The transformation of mesopelagic structure across polar fronts

Spatial patterns and environmental associations of deep scattering layers in the northwestern subtropical Pacific Ocean

Contact Info

Product

Resources

About