The amount of precipitation around the Sagami River estuary in autumn 2020
was 38% of that in autumn 2019 and this was expected to reduce the inflow of river-ater to the estuary. To estimate the effects of the decreased precipitation, the abiotic and biotic envi-ronments were measured in the estuary in January 2021 and were compared with those in De-cember 2019. The reduced precipitation clearly affected the abiotic environment. The coastal water-mass derived from river water, which was observed in December 2019, was not observed in this study. The open sea water-mass covered the estuary and the salinities measured in this study were ca. 0.4‰ higher than those of December 2019. The reduced precipitation also affected the biotic environment. The phytoplankton biomass was significantly lower and the accumulation of phytoplankton on the seafloor was not observed in this study. Corresponding to the lower biomass, the surface densities of the dominant diatom species (Skeletonema costa-tum complex) in this study decreased to ca. 40% of those in December 2019, although decreases in cell density were not observed in the dominant haptophyte species (Gephyrocapsa oceanica). The effects of lower precipitation varied from species to species, resulting in significant chang-es in the species composition of phytoplankton communities. This study showed that decreased precipitation has a marked impact not only on abiotic environments in the estuary but also on biotic ones.
内容記述
原著
2020年度 神奈川大学総合理学研究所共同研究助成論文
雑誌名
Science Journal of Kanagawa University
巻
32
ページ
73 - 79
発行年
2021-06-30
ISSN
1880-0483
書誌レコードID
AA12068302
著者版フラグ
publisher
その他の言語のタイトル
Long-Term Monitoring of Environmental Changes in the Sagami River estuary IIX. Impact of Low Precipitation on Biotic and Abiotic Environments
出版者
神奈川大学総合理学研究所
Research Institute for Integrated Science, Kanagawa University
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12 相模湾河口域における長期環境変動モニタリング8 降雨量が非生物的・生物的環境へ与える影響
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