Temporal shift in biomass and production of macrozoobenthos in the macroalgal belt at Hansneset, Kongsfjorden, after 15 years

• Published in: Polar Biology
• Main Authors: Paar, Martin, Voronkov, Andrey, Hop, Haakon, Brey, Thomas, Bartsch, Inka, Schwanitz, Max, Wiencke, Christian, Lebreton, Benoit, Asmus, Ragnhild, Asmus, Harald
• Other Authors: Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Tromsø department (IMR), Institute of Marine Research Bergen (IMR), University of Bergen (UiB)-University of Bergen (UiB), Norwegian Polar Institute, LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2016
• Subjects: Arctic; Macrozoobenthic; Kelp-associated fauna; Benthic biomass; Somatic production; P/B ratio; Kongsfjorden; [SDE]Environmental Sciences; Svalbard; Kongsfjord*; Polar Biology
• Online Access: https://hal.science/hal-01243387; https://doi.org/10.1007/s00300-015-1760-6

International audience In Arctic macroalgal belt ecosystems, macrozoobenthicproduction is thought to be an important linkbetween primary production and higher trophic levels.Macrozoobenthic biomass and secondary production werestudied along transects (2.5–15 m depth) in the macroalgalbelt at Hansneset in Kongsfjorden, Svalbard, from 2012 to2013. At 2.5 m, the standing stock reached its maxima of174.8 ± 54.4 g ash-free dry weight per 1 m2, while density(4341 ind. m-2 ± 1127 95 % CI) and production(7.0 g C m-2 y-1 ± 2.8 95 % CI) were highest at 5 mwater depth in 2012/13. Compared to a study from1996/98, this re-sampling indicated a drastic change in thedepth distribution of macrozoobenthic biomass and secondaryproduction at Hansneset. While both biomass andsecondary production increased with water depth in1996/98, this pattern was inversed in 2012/13 owing to atenfold increase in biomass and secondary production inthe upper most sublittoral (2.5–5 m). Variability ofmacrozoobenthic biomass and secondary production correspondedto differences in the physical environment andmacroalgal vegetation along the depth gradient. In the lastdecade, the number of ice-free days per year increasedprobably due to Arctic warming. As a result, shallow rockyhabitats (2.5–5 m) are less affected by ice scouring,thereby opening new space for colonisation by benthicfauna. However, faunal secondary production was lowcompared to macroalgal primary production, indicating aconsiderable export of most of the algal production fromthe shallow habitats to the adjacent areas.