Publications
Following publications have been announced by our department Biological Carbon Pump. For further information please contact the marked authors of the publications:
Kordubel, K., Martínez-Rincón, R.O., Baschek, B., Boersma, M., Hieronymi, M., Johns, D.G., Kirstein, I.V., Voynova,, Y.G., & Möller, K.O. (2024): Long-term changes in spatiotemporal distribution of Noctiluca scintillans in the southern North Sea. Harmful Algae, Volume 138, 102699, doi:10.1016/j.hal.2024.102699
Abstract:
To assess the spatiotemporal evolution of the heterotrophic dinoflagellate Noctiluca scintillans in the North Sea, the Helgoland Roads time series and Continuous Plankton Recorder survey were analysed using generalized additive models. Over the last decades, blooms of N. scintillans have occurred more frequently and intensively in many regions. This harmful algal bloom forming species can alter food webs, reduce ecosystem productivity, and lead to economic losses while causing lower aquacultural yields. After the 1990s, N. scintillans abundances have significantly increased by 1.65-fold and a significant prolongation of the bloom window was found (from 27.5 to 98 days in recent decades) off the island of Helgoland, Germany. Significant correlations were found between bloom initiation and nutrients, as well as light availability since these factors lead to increased prey availability. Highest abundances of N. scintillans were associated with water temperatures around 17 °C and wind speed below 6 ms−1 causing dense surface accumulations. Solar radiation of more than 200 Wm−2 was identified as a main driver for post-bloom conditions as it can deteriorate the cells and lead to the decline of N. scintillans abundances. In the southern North Sea, N. scintillans occurrences have intensified and spread since the 1980s with hotspots identified as the coastal waters adjacent to the estuaries of the Elbe and Rhine rivers.
Svensen, C., Iversen, M., Norrbin, F., Möller, K.O., Wiedmann, I., Skarðhamar, J., Barth-Jensen, C., Kwasniewski, S., Ormanczyk, M., Dąbrowska, A.M., & Koski, M. (2024): Impact of aggregate-colonizing copepods on the biological carbon pump in a high-latitude fjord. Limnol Oceanogr., doi:10.1002/lno.12641
Abstract:
Zooplankton consumption of sinking aggregates affects the quality and quantity of organic carbon exported to the deep ocean. Increasing laboratory evidence shows that small particle-associated copepods impact the flux attenuation by feeding on sinking particles, but this has not been quantified in situ. We investigated the impact of an abundant particle-colonizing copepod, Microsetella norvegica, on the attenuation of the vertical carbon flux in a sub-Arctic fjord. This study combines field measurements of vertical carbon flux, abundance, and size-distribution of marine snow and degradation rates of fecal pellets and algal aggregates. Female M. norvegica altered their feeding behavior when exposed to aggregates, and ingestion rates were 0.20 μg C ind.−1 d−1 on marine snow and 0.11 μg C ind.−1 d−1 on intact krill fecal pellets, corresponding to 48% and 26% of the females‘ body carbon mass. Due to high sea surface abundance of up to ~ 50 ind. L−1, the population of M. norvegica had the potential to account for almost all the carbon removal in the upper 50 m of the water column, depending on the type of the aggregate. Our observations highlight the potential importance of abundant small-sized copepods for biogeochemical cycles through their impact on export flux and its attenuation in the twilight zone.
