Autumnal bottom-up and top-down impacts of Cyanea capillata: a mesocosm study
Journal article, 2015

Jellyfish are effective predators on mesozooplankton and release large amounts of dissolved organic matter. Nevertheless, jellyfish initiated trophic cascades and bottom-up influences impacting lower trophic levels have received limited attention. We conducted a mesocosm experiment to quantify simultaneous top-down and bottom-up effects of a common jellyfish, Cyanea capillata, in a natural plankton community during autumn. Treatments were 0, 2 or 5 jellyfish per 2.5 m3 mesocosm, four replicates each, with initial additions of inorganic nutrients. Primary and bacterial production, species abundance and composition of several trophic levels and nutrient and carbon dynamics were followed during the 8-day experiment. Multivariate statistics and generalized additive mixed modelling were applied to test whether jellyfish carbon concentration (0–1.26 mg jellyC L−1) in the mesocosms affected the variables monitored. Unexpected negligible predatory impact of jellyfish on mesozooplankton was observed, potentially related to jellyfish senescence. Community compositions of bacteria, phytoplankton and mesozooplankton changed with time, but did not differ between treatments. However, nutrient regeneration by jellyfish was evident, and jellyfish had a positive impact on total and specific bacterial production, total primary production and the >10 µm chlorophyll a fraction. Bottom-up influences from abundant jellyfish could thus stimulate productivity in nutrient depleted autumnal surface waters.

food web

gelatinous zooplankton

trophic interactions

Author

Aino Hosia

University of Bergen

Havforskningsinstituttet

Christina B. Augustin

Institut fur Ostseeforschung Warnemunde

University of Rostock

Julie Dinasquet

University of Copenhagen

Scripps Institution of Oceanography

Lena Granhag

Chalmers, Shipping and Marine Technology, Maritime Environmental Sciences

Maria L. Paulsen

University of Bergen

Lasse Riemann

University of Copenhagen

Janne-Markus Rintala

University of Helsinki

Outi Setala

Finnish Environment Institute

Julia Talvitie

Aalto University

Josefin Titelman

University of Oslo

Journal of Plankton Research

0142-7873 (ISSN) 1464-3774 (eISSN)

Vol. 37 5 1042-1055

Subject Categories

Biological Sciences

DOI

10.1093/plankt/fbv046

More information

Latest update

9/6/2018 1