Regional-scale drivers of marine nematode distribution in Southern Ocean continental shelf sediments

• Published in: Progress in Oceanography
• Main Authors: Hauquier, Freija, Verleyen, Elie, Tytgat, Bjorn, Vanreusel, Ann
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2018
• Subjects: Biology and Life Sciences; Earth and Environmental Sciences; Antarctica; Free-living marine nematoda; Community ecology; Continental shelf; Dispersal; Environmental filtering; Variation partitioning; DEEP-SEA BIODIVERSITY; SPATIAL PROCESSES; BETA DIVERSITY; DISPERSAL LIMITATION; COMMUNITY DYNAMICS; SPECIES-DIVERSITY; NEIGHBOR MATRICES; PATTERNS; METACOMMUNITIES; MEIOFAUNA; Southern Ocean; Antarc*
• Online Access: https://biblio.ugent.be/publication/8558867; http://hdl.handle.net/1854/LU-8558867; https://doi.org/10.1016/j.pocean.2018.04.005; https://biblio.ugent.be/publication/8558867/file/8572975

Many marine meiofauna taxa seem to possess cosmopolitan species distributions, despite their endobenthic lifestyle and restricted long-distance dispersal capacities. In light of this paradox we used a metacommunity framework to study spatial turnover in free-living nematode distribution and assess the importance of local environmental conditions in explaining differences between communities in surface and subsurface sediments of the Southern Ocean continental shelf. We analysed nematode community structure in two sediment layers (0-3 cm and 3-5 cm) of locations maximum 2400 km apart. We first focused on a subset of locations to evaluate whether the genus level is sufficiently taxonomically fine-grained to study large-scale patterns in nematode community structure. We subsequently used redundancy and variation partitioning analyses to quantify the unique and combined effects of local environmental conditions and spatial descriptors on genus-level community composition. Macroecological patterns in community structure were highly congruent at the genus and species level. Nematode community composition was highly divergent between both depth strata, likely as a result of local abiotic conditions. Variation in community structure between the different regions largely stemmed from turnover (i.e. genus/species replacement) rather than nestedness (i.e. genus/species loss). The level of turnover among communities increased with geographic distance and was more pronounced in subsurface layers compared to surface sediments. Variation partitioning analysis revealed that both environmental and spatial predictors significantly explained variation in community structure. Moreover, the shared fraction of both sets of variables was high, which suggested a substantial amount of spatially structured environmental variation. Additionally, the effect of space independent of environment was much higher than the effect of environment independent of space, which shows the importance of including spatial descriptors in meiofauna and ...