title: Widespread dispersal and bio-accumulation of toxic microcystins in benthic marine ecosystems.
abstract: Freshwater cyanobacteria produce toxic microcystins (MCs), which travel from freshwater areas into the sea. The MCs produced by cyanobacteria in a freshwater reservoir were discharged frequently into the adjacent Isahaya Bay, remained in the surface sediments, and then accumulated in various macrobenthic animals on the seafloor. The MCs were transported further outside of Isahaya Bay (Ariake Bay), and the median values of the MC contents in the sediments were in the same levels in both bays, while their temporal variations were also similar during the study period. Therefore, the fluctuations of the MC contents in the surface sediments were physically controlled by the timing of the discharge from the reservoir. The MC contents in polychaetes and oysters collected in Isahaya Bay increased markedly during winter. The median values of the carbon-based MC contents in the sediments, primary consumers, and secondary consumers in the bay were 87, 160, and 250 ngMC gC-1, respectively. These results demonstrated bio-accumulation at lower trophic levels in benthic marine ecosystems. An understanding of the processes occurring between sediments and macrobenthic animals is important for clarifying MC dynamics in ecosystems.
authors.affiliation: Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, 3-1-100 Tsukide, Kumamoto, 862-8502, Japan. Electronic address: umehara84@gmail.com.
authors.forename: Akira
authors.initials: A
authors.lastname: Umehara
authors.affiliation: Department of Medical Technology, Kumamoto Health Science University, 325 Izumi-machi, Kumamoto, 861-5598, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Takahashi
authors.affiliation: Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, 3-1-100 Tsukide, Kumamoto, 862-8502, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Komorita
authors.affiliation: Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, 3-1-100 Tsukide, Kumamoto, 862-8502, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Orita
authors.affiliation: Korea Institute of Ocean Science and Technology, 41 Jangmok 1-gil, Jangmok-Myon, Geoji, 656-834, Republic of Korea.
authors.forename: Jin-Woo
authors.initials: JW
authors.lastname: Choi
authors.affiliation: Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, 3-1-100 Tsukide, Kumamoto, 862-8502, Japan.
authors.forename: Risa
authors.initials: R
authors.lastname: Takenaka
authors.affiliation: Department of Environmental Science, Faculty of Science, Shinshu University, Matsumoto, 390-8621, Japan.
authors.forename: Rie
authors.initials: R
authors.lastname: Mabuchi
authors.affiliation: Department of Environmental Science, Faculty of Science, Shinshu University, Matsumoto, 390-8621, Japan.
authors.forename: Ho-Dong
authors.initials: HD
authors.lastname: Park
authors.affiliation: Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, 3-1-100 Tsukide, Kumamoto, 862-8502, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Tsutsumi
mesh_terms: D000818:Animals; D059001:Aquatic Organisms / Q000187:drug effects*; D061006:Bays / Q000737:chemistry* / Q000382:microbiology; D000458:Cyanobacteria / Q000254:growth & development*; D017753:Ecosystem; D019015:Geologic Sediments / Q000737:chemistry* / Q000382:microbiology; D007564:Japan; D052998:Microcystins / Q000032:analysis / Q000633:toxicity*; D012623:Seawater / Q000737:chemistry / Q000382:microbiology
chemical_list: D052998:Microcystins
keywords: Accumulation; Cyanotoxin; Discharge; Reservoir; Sedimentation