Remote sensing of size structure of phytoplankton communities using optical properties of the Chukchi and Bering Sea shelf region
Remote sensing of size structure of phytoplankton communities using optical properties of the Chukchi and Bering Sea shelf region
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DOI：
10.5194/bg-8-3567-2011
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发表时间：
2011-12
期刊：
影响因子：
4.9
通讯作者：
A. Fujiwara;T. Hirawake;Koji Suzuki;S. Saitoh
中科院分区：
文献类型：
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作者：
A. Fujiwara;T. Hirawake;Koji Suzuki;S. Saitoh
抽象的。气候变化导致的最近海洋变暖和随后的海冰减少可能会影响楚科奇海和白令海大陆架区域生态系统结构的北移（Grebmeier等人，2006年b）。浮游植物群落的大小结构提供了一个营养级指数，这对于理解这种生态系统变化的机制及其对未来的影响至关重要。本研究提出了一种新的海洋颜色算法推导出这一特点，通过使用该地区的光学特性。尺寸推导模型（SDM）根据浮游植物的光吸收系数aph（λ）和包括藻类在内的悬浮颗粒的后向散射系数bbp（λ），以叶绿素a（chl-a）的尺寸分级为基础，估算浮游植物尺寸指数FL。FL定义为大于5 μm的细胞所占藻类生物量的比例。利用随浮游植物色素组成而变化的aph（λ）比值aph（488）/aph（555）和作为悬浮颗粒平均粒径指标的bbp（λ）光谱斜率γ，建立了一个多元回归模型。一项验证研究表明，69%的未知数据在± 20%的FL范围内正确推导。比较了2006年冷8月和2007年暖8月的FL空间分布，以检验SDM在卫星遥感中的应用。结果表明，浮游植物的大小响应于海表温度的变化。进一步分析卫星获得的FL值和其他环境因素，可以促进我们对楚科奇海和白令海陆架区生态系统结构变化的理解。
Abstract. Recent ocean warming and subsequent sea ice decline resulting from climate change could affect the northward shift of the ecosystem structure in the Chukchi Sea and Bering Sea shelf region (Grebmeier et al., 2006b). The size structure of phytoplankton communities provides an index of trophic levels that is crucial to understanding the mechanisms underlying such ecosystem changes and their implications for the future. This study proposes a new ocean color algorithm for deriving this characteristic by using the region's optical properties. The size derivation model (SDM) estimates the phytoplankton size index FL on the basis of size-fractionated chlorophyll-a (chl-a) using the light absorption coefficient of phytoplankton, aph(λ), and the backscattering coefficient of suspended particles including algae, bbp(λ). FL was defined as the ratio of algal biomass attributed to cells larger than 5 μm to the total. It was expressed by a multiple regression model using the aph(λ) ratio, aph(488)/aph(555), which varies with phytoplankton pigment composition, and the spectral slope of bbp(λ), γ, which is an index of the mean suspended particle size. A validation study demonstrated that 69% of unknown data are correctly derived within FL range of ±20%. The spatial distributions of FL for the cold August of 2006 and the warm August of 2007 were compared to examine application of the SDM to satellite remote sensing. The results suggested that phytoplankton size was responsive to changes in sea surface temperature. Further analysis of satellite-derived FL values and other environmental factors can advance our understanding of ecosystem structure changes in the shelf region of the Chukchi and Bering Seas.