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Long‐term changes in a zooplankton community revealed by the sediment archive
Author(s) -
Vehmaa Anu,
Katajisto Tarja,
Candolin Ulrika
Publication year - 2018
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.1002/lno.10928
Subject(s) - zooplankton , eutrophication , ecology , copepod , bosmina , biology , abundance (ecology) , dominance (genetics) , sediment , environmental science , cladocera , oceanography , crustacean , geology , biochemistry , nutrient , gene , paleontology
Abstract To reconstruct changes in zooplankton communities in response to past anthropogenic perturbations, one possibility is to use the sedimentary records. We analyzed the sediments at a coastal site in the Northern Baltic Sea to relate changes in the zooplankton community to anthropogenic eutrophication and the invasion of a predatory cladoceran, Cercopagis pengoi . We sampled 30‐cm laminated sediment cores and dated the sediment layers back to the 1950s. From each 1‐cm layer, we measured eutrophication indicators (δ 13 C, δ 15 N, TC, TN, TP) and identified and counted zooplankton resting eggs (cladoceran, calanoid copepod, rotifer). In addition, we estimated the abundance of the cladoceran Bosmina ( Eubosmina ) maritima by counting subfossils (carapaces, headshields, and ephippia) and estimated the experienced stress as the relationship between sexual and asexual reproduction. Using redundancy and variance partitioning analyses, we found ∼ 16% of the variation in the zooplankton community to be explained by eutrophication, and 24% of the variation in B . ( E .) maritima abundance and reproduction mode to be explained by eutrophication and the introduction of the alien predator. Our results show a long‐term shift from calanoid copepods and predatory cladocerans toward small‐sized zooplankton species, like rotifers. Furthermore, the results indicate that the invasion of C. pengoi induced a short‐term increase in sexual reproduction in B . ( E .) maritima . The results indicate that anthropogenic eutrophication since the 1950s has altered the zooplankton community toward smaller species, while the invasion of the predatory cladoceran had only a transitory influence on the community during its expansion phase.