Spatial Distribution of Diffuse Attenuation of Photosynthetic Active Radiation and Its Main Regulating Factors in Inland Waters of Northeast China

Abstract

Light availability in lakes or reservoirs is affected by optically active components (OACs) in the water. Light plays a key role in the distribution of phytoplankton and hydrophytes, thus, is a good indicator of the trophic state of an aquatic system. Diffuse attenuation of photosynthetic active radiation (PAR) (K d (PAR)) is commonly used to quantitatively assess the light availability. The PAR and the concentration of OACs were measured at 206 sites, which covered 26 lakes and reservoirs in Northeast China. The spatial distribution of K d (PAR) was depicted and its association with the OACs was assessed by grey incidences(GIs) and linear regression analysis. Most importantly, we have demonstrated that the TSM concentration is a reliable measurement for the estimation of the K d (PAR) as 74% of the data produced a relative error (RE) of less than 0.4 in a leave-one-out cross validation (LOO-CV) analysis. Spatial transferability assessment of the model also revealed that TSM performed well as a determining factor of the K d (PAR) for the majority of the lakes. However, a few exceptions were identified where the optically regulating dominant factors were chlorophyll-a (Chl-a) and/or the chromophroic dissolved organic matter (CDOM). These extreme cases represent lakes with exceptionally clear waters.

Atenuación de luz en embalses del sur-este de la Península Ibérica

“…Otros estudios recientes muestran a la turbidez como el principal factor que afecta a ambas propiedades ópticas. Así, en 26 lagos y embalses del noreste de China el principal factor que explica las variaciones en K d (que osciló entre 0.45 y 15.04 m -1 ) fue la turbidez y solamente en lagos excepcionalmente claros se encuentra que K d dependa de la Clorofila o de la materia orgánica disuelta de naturaleza cromofórica (Ma et al, 2016). Igualmente en el trabajo de Borowiak y Borowiak (2016), citado previamente, también la turbidez fue la variable que mejor explicó la variación en K d .…”

Spatial pattern of K<sub>d</sub>(PAR) and its relationship with light absorption of optically active components in inland waters across China

“…Light is one of the most important factors governing primary production and photosynthesis in the aquatic ecosystems (Kirk, 1994;Ma & Song & Wen & Zhao & Shang & Fang & Du, 2016;Song & Ma & Wen & Fang & Shang & Zhao & Wang & Du, 2017). Light availability plays a crucial role in the distribution of phytoplankton and hydrophytes, and it is also a good indicator of the trophic state of an aquatic system.…”

“…However, Environmental change and anthropogenic activity have made it challenging to accurately assess Kd patterns in the extremely turbid inland waters (Zheng & Ren & Li & Huang & Liu & Du & Lyu, 2016). The comprehensive analysis of the relationships between Kd(PAR) and aOACs is an imperative requirement to retrieve Kd(PAR) from remote sensing data for turbid inland waters (Ma et al, 2016).…”

“…Although Kd(PAR) characterization has been carried out in various aquatic environments, including freshwater, estuaries, coastal water, and open ocean water (Belzile et al, 2002;Cunningham, Ramage, and McKee, 2013;Frankovich, Rudnick, and Fourqurean, 2017;Lund-Hansen, 2004;Zhang et al, 2007a), few studies have been performed in the extremely turbid waters and plateau water with strong ultraviolet radiation (Ma et al, 2016;Shi et al, 2014;Song et al, 2017). In transparent marine and freshwater systems, phytoplankton was suggested to be an important component in light attenuation (Brandao et al, 2017;Yang et al, 2005).…”

Water Optics and Water Colour Remote Sensing

“…Ma et al [5] reported the spatial distribution of the diffuse attenuation coefficient of photosynthetic active radiation (PAR) (K d (PAR)) and its main regulating factors in 26 lakes and reservoirs in Northeast China. The results showed that total suspended matter was the dominant factor in determining K d (PAR) values and best correlated with K d (PAR).…”