Liu Xiao-Han, Feng Long-Qing, Zhang Yun-Lin, Zhao Lin-Lin, Zhu Meng-Yuan, Shi Zhi-Qiang, Yin Yan, Ding Yan-Qing
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
Huan Jing Ke Xue. 2012 Feb;33(2):412-20.
An in situ field high-frequency bio-optical measurement was carried out in the littoral region in Meiliang Bay of Lake Taihu, a large shallow lake of China from 24 July to 1 August in 2010. The underwater irradiance, beam attenuation coefficient and absorption coefficient, the related physical-chemical and meteorological parameters were measured and analyzed, in order to determine the relationship between water bio-optical properties and wind waves process. The absorption coefficients of particles a(p) (440), non-phytoplankton a(d) (440), phytoplankton a(ph) (440) and chromophoric dissolved organic matter (CDOM) a(CDOM) (440) were 3.97, 3.97, 6.58 m(-1); 1.69, 2.17, 4.20 m(-1); 2.28, 1.80, 1.33 m(-1); 1.05, 1.04, 1.08 m(-1) with the corresponding 30-minute average wind speed of <3, 3-5 and >5 m x s(-1) under small, middle and large wind and waves, respectively. Phytoplankton particles contributed the most to total absorption coefficient integrated over a range of photosynthetically active radiation (PAR) (400-700 nm) with a value of 42.5% during small wind waves. With the increase of wind speed, the relative contributions of phytoplankton, CDOM and pure water deceased but the relative contribution of non-phytoplankton significantly increased with the values of 33.0%, 41.7% and 52.0% during small, middle and large wind waves, respectively. A significantly positive linear relationship was found between PAR diffuse attenuation coefficients and the mean wind speed within 10 minutes. Sediment resuspension caused by wind waves had a significant effect on PAR diffuse attenuation coefficient. From small wind waves to large wind waves, PAR diffuse attenuation increased 80.0% but the euphotic depth decreased 42.2%. Significant linear relationships were found between PAR diffuse attenuation coefficient, the beam attenuation coefficients at 750 nm, total suspended solid concentration and wind speed, wave height, wave shear stress, in which the correlation between PAR attenuation coefficients and meteorological hydrology factors was most significant. High-frequency bio-optical measurement showed that hydrodynamic process significantly affected the short-term variation of bio-optical properties in algal-dominated lake region of shallow lake through sediment resuspension, mixing and migration of phytoplankton.
2010年7月24日至8月1日，在中国大型浅水湖泊太湖梅梁湾的沿岸区域进行了一次原位现场高频生物光学测量。测量并分析了水下辐照度、光束衰减系数和吸收系数以及相关的物理化学和气象参数，以确定水的生物光学特性与风浪过程之间的关系。在小、中、大三种风浪条件下，对应30分钟平均风速分别<3、3 - 5和>5 m·s⁻¹时，颗粒a(p)(440)、非浮游植物a(d)(440)、浮游植物a(ph)(440)和发色溶解有机物(CDOM) a(CDOM)(440)的吸收系数分别为3.97、3.97、6.58 m⁻¹；1.69、2.17、4.20 m⁻¹；2.28、1.80、1.33 m⁻¹；1.05、1.04、1.08 m⁻¹。在小风浪期间，浮游植物颗粒对光合有效辐射(PAR)(400 - 700 nm)范围内的总吸收系数贡献最大，值为42.5%。随着风速增加，浮游植物、CDOM和纯水的相对贡献降低，但非浮游植物的相对贡献显著增加，在小、中、大三种风浪期间分别为33.0%、41.7%和52.0%。发现PAR漫衰减系数与10分钟内的平均风速之间存在显著的正线性关系。风浪引起的沉积物再悬浮对PAR漫衰减系数有显著影响。从小风浪到大风浪，PAR漫衰减增加80.0%，但真光层深度减少42.2%。在PAR漫衰减系数、750 nm处的光束衰减系数、总悬浮固体浓度与风速、波高、波切应力之间发现了显著的线性关系，其中PAR衰减系数与气象水文因素之间的相关性最为显著。高频生物光学测量表明，水动力过程通过沉积物再悬浮、浮游植物的混合和迁移，显著影响了浅水湖泊藻类主导湖区生物光学特性的短期变化。
