A study of absorption characteristics of chromophoric dissolved organic matter and particles in Lake Taihu, China

Abstract

Absorptions by non-phytoplankton particles and phytoplankton, and chromophoric dissolved organic matter (CDOM) were measured at 50 sites in large, shallow, Lake Taihu in winter and summer 2006 to study their seasonal and spatial variations, and their relative contributions to total absorption. The CDOM absorption was significantly higher in winter than in summer, due to degradation and release of fixed carbon in phytoplankton and submerged aquatic vegetation (SAV). The hyperbolic model was used to model the spectral absorption of CDOM, and the mean spectral slope of 6.38 nm -1 was obtained. At most sites, the spectral absorption of non-phytoplankton particles was similar to that of the total particles, demonstrating that the absorption of the total particles is dominated by the absorption of non-phytoplankton particles. In summer, phytoplankton absorption increased markedly, due to frequent algal blooms especially in Meiliang Bay. In winter, the significant increase in non-phytoplankton particle absorption resulted from the increase of inorganic particulate matter caused by sediment resuspension. Strong linear relationships were found between a d (440) and total suspended matter (TSM), organic suspended matter (OSM), and inorganic suspended matter (ISM). Strong linear relationships were also found between a ph (440), a ph (675) and chlorophyll a (Chl-a) concentration. The total relative contributions of non-phytoplankton particles over the range of photosynthetically active radiation (PAR) (400-700 nm) were 48.4 and 79.9% in summer and winter respectively. Non-phytoplankton particle absorption dominated the total absorption, especially in winter, in Lake Taihu, due to frequent sediment resuspension in the large shallow lake as a result of strong windy conditions. The results indicate that strong

Variations in Spectral Absorption Properties of Phytoplankton, Non-algal Particles and Chromophoric Dissolved Organic Matter in Lake Qiandaohu

“…There was no great variability in the properties of OACs in Lake Qiandaohu compared to Lake Taihu [47,48], both within and between seasons. Table 2 presents the Chl-a concentration and observed ranges of some parameters measured in Lake Qiandaohu during the four cruises in 2015 and 2016.…”

A Landsat-based model for retrieving total suspended solids concentration of estuaries and coasts in China

“…Estuaries and coasts are the most important intermediate zones that connect hydrosphere, pedosphere and atmosphere, which then pass on a deep and wide impact on many aspects of our societal and natural environment (Nechad et al, 2010;Pozdnyakov et al, 2005). The topics of TSS concentration monitoring and spatial and temporal variation assessment have been paid great attention, and the associated research work has been conducted frequently by a variety of scholars, government branches and society communities (Caballero et al, 2014;Giardino et al, 2015;Liu et al, 2003;Lu et al, 2012;Montanher et al, 2014;Nechad et al, 2010;Olmanson et al, 2013;Pozdnyakov et al, 2005;Rao et al, 2009;Shen et al, 2008;Tang et al, 2004b;Zhang et al, 2007). Many methods can be used to estimate TSS concentrations of water bodies, including hydrologicalsite monitoring, in situ investigation, physical models, numerical simulation, remote sensing and so on (Chen et al, 2015a).…”

Classification of Several Optically Complex Waters in China Using in Situ Remote Sensing Reflectance

“…These stations are located in several typical Chinese optically complex waters, including the Three Gorges Reservoir, Lake Chaohu, Lake Dianchi, Lake Taihu, and the Yellow River estuary (Figure 2). Data from Lake Taihu were obtained by Zhang et al [4,39,40] in January, July, and October 2006, and January, and April 2007. Data from Lake Chaohu (June 2009), Lake Taihu (March and April 2009), the Three Gorges Reservoir (August, 2009), and Lake Dianchi (September and December 2009) were obtained by Sun et al [41], and data from the Yellow River estuary were obtained by Zhang et al [42] in June 2012.…”

“…The DOC was obtained using a 1020 Total Organic Carbon Analyzer after filtering with Whatman GF/F fiberglass filters. NASA ocean optics protocols [39]. The cpg (λ) and aCDOM (λ) values were obtained from soluble absorption samples using a Shimadzu UV2401PC UV-Vis spectrophotometer.…”