摘要
We examined fossil pigments in a 210Pb-dated sediment core to document the temporal variations in phytoplankton biomass over the past 150 years in a semi-enclosed bay, Beppu Bay, in the western Seto Inland Sea, Japan. The flux of fossil pigments was used as an index of phytoplankton biomass, which we reconstructed after removing the effect of post-burial degradation on the concentrations of fossil pigments. The flux doubled from the 1960s to the early 1970s, decreased or remained stable in the early 1980s, and increased again from the late 1980s to the early 1990s. The first increase in phytoplankton biomass during the 1960s was likely caused by eutrophication due to an increase in terrestrial nutrient fluxes from watersheds. The decreasing phytoplankton biomass in the early 1980s was likely related to the establishment of a sewage treatment system that reduced the terrestrial nutrient fluxes to the sea. However, the terrestrial nutrient fluxes could not explain the second increase from the late 1980s to the early 1990s. Intensification of the influx of nutrients from the shelf slope to the sea was likely the cause of the second increase in phytoplankton biomass. This is supported by the inverse relationship between phytoplankton biomass and sea level at the shelf slope, the latter being an index of the intensity of the influx of oceanic nutrients from the shelf slope to the sea. The supply of oceanic nutrients may be therefore a critical factor in the determination of primary production in the western Seto Inland Sea. KeywordsPrimary production Pigments Eutrophication Kuroshio current Palaeoceanography Seto Inland Sea
摘要译文
我们检查了一个sup 210 / sup Pb日期沉积物核心中的化石颜料，以记录过去150年在半封闭的海湾，别府湾的浮游植物生物量的时间变化，在日本西部濑户内海，化石颜料的通量被用作浮游植物生物量的指标，在去除了埋藏后降解对化石颜料浓度的影响后，我们重新构建了这种通量，从20世纪60年代到70年代初，在20世纪80年代初期下降或保持稳定，从80年代末到90年代初再次增加20世纪60年代浮游植物生物量的首次增加可能是由于富营养化引起的，因为流域的陆地营养通量增加20世纪80年代早期浮游植物生物量的减少可能与建立将陆地营养物质流向海洋的污水处理系统相关联。然而，陆地营养通量无法解释从二十世纪八十年代末到二十世纪九十年代初的第二次增长营养物质从货架斜坡向海洋的强化可能是浮游植物生物量第二次增加的原因浮游植物生物量与货架边坡海平面的反比关系得到支持，后者是海洋养分从搁浅坡向海洋流入的强度的指标因此，海洋养分的供应可能是西部濑户内陆海域初级生产确定的关键因素关键词主要生产颜料富营养化黑潮当前古海洋学濑户内海
Narumi K. Tsugeki [1 [4] ;Michinobu Kuwae [1] ;Yukinori Tani [2] ;Xinyu Guo [1] ;Koji Omori [1] ;Hidetaka Takeoka [3]. Temporal variations in phytoplankton biomass over the past 150 years in the western Seto Inland Sea, Japan[J]. Journal of Oceanography, 2017,73(3): 309-320