TY - JOUR
T1 - Changes to upper‐ocean ecosystems may directly impact abyssal scavenger communities
AU - De jonge, Daniëlle S. W.
AU - Smith, Alycia J.
AU - Sweetman, Andrew K.
N1 - © 2024 Association for the Sciences of Limnology and Oceanography.
Data are available in the PANGAEA repository at doi: 10.1594/PANGAEA.961272, doi: 10.1594/PANGAEA.961319, and doi: 10.1594/PANGAEA.961314 (de Jonge et al., 2023a,b,c). The Rmarkdown PDF file with (statistical) analysis, creation of figures, and all results is available from the Zenodo repository at doi: 10.5281/zenodo.11220569 (de Jonge et al., 2024). Supplementary figures, tables, and analyses are found in Supplementary Material A. A photographic guide of the observed morphospecies is found in Supplementary Material B. Timelapse videos of deployment AKS298 (squid) and AKS299 (fish) are available as Supplementary Material C and D, respectively.
PY - 2024/7/4
Y1 - 2024/7/4
N2 - Human pressures are changing ocean environments, such as a shift from fish- to squid-dominated ecosystems in overfished, poorly oxygenated environments. After death, carcasses of upper ocean fauna sink to the seafloor where they provide food for demersal scavengers. It is unclear how shifts in carcass type impact abyssal scavengers. We performed baited benthic camera lander deployments in the Cabo Verde Abyssal Basin to test how a shift from fish- to squid-dominated carrion could modify abyssal scavenger ecology. At the fish bait, peak scavenger abundance was greater and occurred later for the majority of observed fauna. However, removal rates of squid bait were up to 10-fold greater, and a significantly different community composition developed, favoring faster organisms with lower chemosensory thresholds. At the fish bait, slower organisms were less disadvantaged as the bait persisted for longer periods allowing the development of a more complex community and dense amphipod aggregations. The rapid squid consumption indicates that the accumulation of this type of food fall at the seafloor may not occur, preventing scientific observations necessary to estimate the importance of squid carrion to the biological C pump and deep-sea food webs. As such, the flux of squid carrion to the seafloor is likely greater than currently recognized in this part of the Atlantic. The differences observed between bait types indicate how future changes in upper ocean ecosystems may impact abyssal scavengers and their ecosystem functions, including controlling seafloor biomass, regulating the behavior of benthic fauna, and contributing to nutrient cycling and energy transfer.
AB - Human pressures are changing ocean environments, such as a shift from fish- to squid-dominated ecosystems in overfished, poorly oxygenated environments. After death, carcasses of upper ocean fauna sink to the seafloor where they provide food for demersal scavengers. It is unclear how shifts in carcass type impact abyssal scavengers. We performed baited benthic camera lander deployments in the Cabo Verde Abyssal Basin to test how a shift from fish- to squid-dominated carrion could modify abyssal scavenger ecology. At the fish bait, peak scavenger abundance was greater and occurred later for the majority of observed fauna. However, removal rates of squid bait were up to 10-fold greater, and a significantly different community composition developed, favoring faster organisms with lower chemosensory thresholds. At the fish bait, slower organisms were less disadvantaged as the bait persisted for longer periods allowing the development of a more complex community and dense amphipod aggregations. The rapid squid consumption indicates that the accumulation of this type of food fall at the seafloor may not occur, preventing scientific observations necessary to estimate the importance of squid carrion to the biological C pump and deep-sea food webs. As such, the flux of squid carrion to the seafloor is likely greater than currently recognized in this part of the Atlantic. The differences observed between bait types indicate how future changes in upper ocean ecosystems may impact abyssal scavengers and their ecosystem functions, including controlling seafloor biomass, regulating the behavior of benthic fauna, and contributing to nutrient cycling and energy transfer.
U2 - 10.1002/lno.12603
DO - 10.1002/lno.12603
M3 - Article
SN - 0024-3590
JO - Limnology and Oceanography
JF - Limnology and Oceanography
ER -