Distribution and biomass of gelatinous zooplankton in relation to an oxygen minimum zone and a shallow seamount in the Eastern Tropical North Atlantic Ocean

• Published in: Marine Environmental Research
• Main Authors: Luskow, Florian, Christiansen, Bernd, Chi, Xupeng, Silva, Pericles, Neitzel, Philipp, Brooks, Mollie E., Jaspers, Cornelia
• Format: Report
• Language: English
• Published: ELSEVIER SCI LTD 2022
• Subjects: Cape Verde Ocean Observatory; Ctenophore; Jellyfish; Oxygen minimum zone; Pyrosome; Senghor Seamount; Length-weight regressions; Deoxygenation; Global change; Environmental Sciences & Ecology; Marine & Freshwater Biology; Toxicology; Environmental Sciences; LOW DISSOLVED-OXYGEN; MNEMIOPSIS-LEIDYI; HYPOXIA; RATES; CTENOPHORES; SCYPHOZOA; RESOURCE; PLANKTON; ECOLOGY; WEIGHT; North Atlantic
• Online Access: http://ir.qdio.ac.cn/handle/337002/178800; https://doi.org/10.1016/j.marenvres.2022.105566

Physical and topographic characteristics can structure pelagic habitats and affect the plankton community composition. For example, oxygen minimum zones (OMZs) are expected to lead to a habitat compression for species with a high oxygen demand, while upwelling of nutrient-rich deep water at seamounts can locally in -crease productivity, especially in oligotrophic oceanic waters. Here we investigate the response of the gelatinous zooplankton (GZ) assemblage and biomass to differing oxygen conditions and to a seamount in the Eastern Tropical North Atlantic (ETNA) around the Cape Verde archipelago. A total of 16 GZ taxa (>1100 specimens) were found in the upper 1000 m with distinct species-specific differences, such as the absence of deep-living species Atolla wyvillei and Periphylla periphylla above the shallow seamount summit. Statistical analyses consid-ering the most prominent groups, present at all stations, namely Beroe spp., hydromedusae (including Zygocanna vagans, Halicreas minimum, Colobonema sericeum, Solmissus spp.) and total GZ, showed a strong positive corre-lation of abundance with temperature for all groups, whereas oxygen had a weak negative correlation only with abundances of Beroe spp. and hydromedusae. To account for size differences between species, we established length-weight regressions and investigated total GZ biomass changes in relation to physical (OMZ) and topo-graphic characteristics. The highest GZ biomass was observed at depths of lowest oxygen concentrations and deepest depth strata at the southeastern flank of the seamount and at two stations south of the Cape Verde ar-chipelago. Our data suggest that, irrespective of their patchy distribution, GZ organisms are ubiquitous food web members of the ETNA, and their habitat includes waters of low oxygen content.