Spatiotemporal dynamics of chlorophyll-a in a large reservoir as derived from Landsat 8 OLI data: understanding its driving and restrictive factors

• Published in: Environmental science and pollution research international Vol. 25; no. 2; pp. 1359 - 1374
• Main Authors: Li, Yuan, Zhang, Yunlin, Shi, Kun, Zhou, Yongqiang, Zhang, Yibo, Liu, Xiaohan, Guo, Yulong
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.01.2018; Springer Nature B.V
• Subjects: Algae; Algal growth; Algorithms; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; China; Chlorophyll; Chlorophyll - analysis; Chlorophyll A; Correlation coefficient; Correlation coefficients; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental factors; Environmental Health; Environmental monitoring; Environmental Monitoring - methods; Environmental science; Eutrophication; Fresh Water - chemistry; Hydrology; Inflow; Landsat; Landsat satellites; Nitrogen - analysis; Nutrients; Phosphorus; Phosphorus - analysis; Pollution load; Rainfall; Remote sensing; Research Article; Reservoirs; Waste Water Technology; Water inflow; Water Management; Water pollution; Water Pollution Control; Water Quality; Water quality management; Inflow rate; Chlorophyll; Landsat 8 OLI; Xin’anjiang reservoir; Nutrient restriction; Eutrophication; Chlorophyll-a
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-017-0536-7

Chlorophyll-a (Chl a ) is an important indicator of water quality and eutrophication status. Monitoring Chl a concentration ( C Chl a ) and understanding the interactions between C Chl a and related environmental factors (hydrological and meteorological conditions, nutrients enrichment, etc.) are necessary for assessing and managing water quality and eutrophication. An acceptable Landsat 8 OLI-based empirical algorithm for C Chl a has been developed and validated, with a mean absolute percentage error of 14.05% and a root mean square error of 1.10 μg L −1 . A time series of remotely estimated C Chl a was developed from 2013 to 2015 and examined the relationship of C Chl a to inflow rate, rainfall, temperature, and sunshine duration. Spatially, C Chl a values in the riverine zone were higher than in the transition and lacustrine zones. Temporally, mean C Chl a value were ranked as spring > summer > autumn > winter. A significant positive correlation [Pearson correlation coefficient ( r ) = 0.88, p  < 0.001] was observed between the inflow rate and mean C Chl a in the northwest segment of the Xin’anjiang Reservoir. However, no significant relation was observed between mean C Chl a and meteorological conditions. Mean (± standard deviation) value for the ratio of total nitrogen concentration to total phosphorus concentration in our in situ dataset is 75.75 ± 55.72. This result supports that phosphorus is the restrictive factor to algal growth in Xin’anjiang Reservoir. In addition, the response of nutrients to Chl a has spatial variabilities. Current results show the potential of Landsat 8 OLI data for estimating Chl a in slight turbid reservoir and indicate that external pollution loading is an important driving force for the Chl a spatiotemporal variability.