Local effects of large food-falls on nematode diversity at an arctic deep-sea site : results from an in situ experiment at the deep-sea observatory HAUSGARTEN

To study the response of the smaller benthic biota to larger food-falls and their possible effects on the biodiversity at the deep seafloor, we deployed the halves of a sagittally bisected porpoise (1.3 m in length: each half approximately 18 kg) at 2500 m and 5400 m water depth at the LTER (Long-Te...

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Bibliographic Details
Published in:Journal of Experimental Marine Biology and Ecology
Main Authors: Soltwedel, Thomas, Guilini, Katja, Sauter, Eberhard, Schewe, Ingo, Hasemann, Christiane
Format: Article in Journal/Newspaper
Language:English
Published: 2018
Subjects:
Biology and Life Sciences
Earth and Environmental Sciences
HAUSGARTEN
Deep sea
In situ experiment
Food-fall
Nematodes
Diversity
OXYGEN MINIMUM ZONE
COMMUNITY STRUCTURE
WHALE FALLS
ADONCHOLAIMUS-THALASSOPHYGAS
CONSUMPTION RATES
SPECIES-DIVERSITY
MARINE NEMATODES
ATLANTIC-OCEAN
MATURITY INDEX
SEDIMENTS
Arctic
Fram Strait
Online Access:https://biblio.ugent.be/publication/8548846
http://hdl.handle.net/1854/LU-8548846
https://doi.org/10.1016/j.jembe.2017.03.002
https://biblio.ugent.be/publication/8548846/file/8548854
Description
Summary:To study the response of the smaller benthic biota to larger food-falls and their possible effects on the biodiversity at the deep seafloor, we deployed the halves of a sagittally bisected porpoise (1.3 m in length: each half approximately 18 kg) at 2500 m and 5400 m water depth at the LTER (Long-Term Ecological Research) observatory HAUSGARTEN in the eastem Fram Strait. Five weeks after the porpoise deployment, sediments beneath the carcasses and at different distances (0, 20, 40 cm) from these artificial food-falls were sampled with push-corers handled by a Remotely Operated Vehicle. The samples provided empirical evidence for a quick response by sediment-inhabiting bacteria and metazoan meiofauna to the carcasses at both water depths. Compared to control sediments, the substantial pulse of organic matter also led to generally increased meiofauna/nematode densities around the artificial food-falls. The comparison of nematode communities in sediments affected by the carcasses with those in control sediments exhibited shifts in the structural composition and the associated trophic and functional diversity of the nematodes. Our results confirmed that the impact of large food-falls on the deep benthic community largely depend on environmental factors (water depth, alternative food sources) as well as the background species composition, i.e., the structure of the prevailing meiofauna/nematode assemblages and the composition of the necrophagous community present in the wider area.

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