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Seasonal-Spatial Distribution and Long-Term Variation of Transparency in Xin'anjiang Reservoir: Implications for Reservoir Management.

Wu Z, Zhang Y, Zhou Y, Liu M, Shi K, Yu Z - Int J Environ Res Public Health (2015)

Bottom Line: The seasonal effects were distinct, with lower values in the summer than in the winter, most likely due to river runoff and phytoplankton biomass increases.The transparency decreased significantly with a linear slope of 0.079 m/year, indicating a 2.05 m decrease and a marked decrease in water quality.A marked increase occurred in chlorophyll a (Chla) concentration, and a significant correlation was found between the transparency and Chla concentration, indicating that phytoplankton biomass can partially explain the long-term trend of transparency in Xin'anjiang Reservoir.

View Article: PubMed Central - PubMed

Affiliation: Chun'an Environmental Monitoring Station, Hangzhou 311700, China. caepb@126.com.

ABSTRACT
Water transparency is a useful indicator of water quality or productivity and is widely used to detect long-term changes in the water quality and eutrophication of lake ecosystems. Based on short-term spatial observations in the spring, summer, and winter and on long-term site-specific observation from 1988 to 2013, the spatial, seasonal, long-term variations, and the factors affecting transparency are presented for Xin'anjiang Reservoir (China). Spatially, transparency was high in the open water but low in the bays and the inflowing river mouths, reflecting the effect of river runoff. The seasonal effects were distinct, with lower values in the summer than in the winter, most likely due to river runoff and phytoplankton biomass increases. The transparency decreased significantly with a linear slope of 0.079 m/year, indicating a 2.05 m decrease and a marked decrease in water quality. A marked increase occurred in chlorophyll a (Chla) concentration, and a significant correlation was found between the transparency and Chla concentration, indicating that phytoplankton biomass can partially explain the long-term trend of transparency in Xin'anjiang Reservoir. The river input and phytoplankton biomass increase were associated with soil erosion and nutrient loss in the catchment. Our study will support future management of water quality in Xin'anjiang Reservoir.

No MeSH data available.


Related in: MedlinePlus

Correlations between the chlorophyll a concentration and the transparency from 2001 to 2013 in Xin’anjiang Reservoir. The dotted line shows the linear fitting excluding the maximal chlorophyll a of 17.5 µg/L as labeled in the cycle.
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ijerph-12-09492-f008: Correlations between the chlorophyll a concentration and the transparency from 2001 to 2013 in Xin’anjiang Reservoir. The dotted line shows the linear fitting excluding the maximal chlorophyll a of 17.5 µg/L as labeled in the cycle.

Mentions: To further analyze the effect of the phytoplankton biomass on transparency, we performed a correlation analysis and found negative linear relationships between the Chla concentration and transparency (Figure 8). For Daba in April and July, and when all of the data including those from Daba and Hangtoudao were considered together, the linear relationships were statistically significant (p < 0.05). Considering that the maximal Chla of 17.5 µg/L is significantly higher than the second highest Chla of 10.4 µg/L and that the median value is 2.7 µg/L, we fit Chla and transparency, excluding the maximal Chla of 17.5 µg/L. The linear relationship was still statistically significant (p < 0.05) (Figure 8c). In addition, the low air temperature inhibiting phytoplankton growth can partially explain the anomalous high value in 2000 (Figure 8c). Considering that the transparency investigation was carried out in the first ten-day period of a month, we found the monthly average air temperature for November (a month advance of transparency investigation) in 2000 was the second lowest value during the period of 1988–2013. Therefore, these results further demonstrate that a phytoplankton biomass increase could partially explain the decreased transparency in the past 26 years. Many previous studies have also reported that a transparency decrease was linked to an increase in the phytoplankton biomass in ocean, coastal and inland waters [29,32,37,38]. For example, water transparency in the open Baltic Sea has decreased during the last one hundred years, and 13–17% variability in transparency was caused by phytoplankton [29]. In addition, the increased TN and Chla concentrations and the decreased transparency jointly confirm that Xin’anjiang Reservoir underwent accelerating eutrophication.


Seasonal-Spatial Distribution and Long-Term Variation of Transparency in Xin'anjiang Reservoir: Implications for Reservoir Management.

Wu Z, Zhang Y, Zhou Y, Liu M, Shi K, Yu Z - Int J Environ Res Public Health (2015)

Correlations between the chlorophyll a concentration and the transparency from 2001 to 2013 in Xin’anjiang Reservoir. The dotted line shows the linear fitting excluding the maximal chlorophyll a of 17.5 µg/L as labeled in the cycle.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555293&req=5

ijerph-12-09492-f008: Correlations between the chlorophyll a concentration and the transparency from 2001 to 2013 in Xin’anjiang Reservoir. The dotted line shows the linear fitting excluding the maximal chlorophyll a of 17.5 µg/L as labeled in the cycle.
Mentions: To further analyze the effect of the phytoplankton biomass on transparency, we performed a correlation analysis and found negative linear relationships between the Chla concentration and transparency (Figure 8). For Daba in April and July, and when all of the data including those from Daba and Hangtoudao were considered together, the linear relationships were statistically significant (p < 0.05). Considering that the maximal Chla of 17.5 µg/L is significantly higher than the second highest Chla of 10.4 µg/L and that the median value is 2.7 µg/L, we fit Chla and transparency, excluding the maximal Chla of 17.5 µg/L. The linear relationship was still statistically significant (p < 0.05) (Figure 8c). In addition, the low air temperature inhibiting phytoplankton growth can partially explain the anomalous high value in 2000 (Figure 8c). Considering that the transparency investigation was carried out in the first ten-day period of a month, we found the monthly average air temperature for November (a month advance of transparency investigation) in 2000 was the second lowest value during the period of 1988–2013. Therefore, these results further demonstrate that a phytoplankton biomass increase could partially explain the decreased transparency in the past 26 years. Many previous studies have also reported that a transparency decrease was linked to an increase in the phytoplankton biomass in ocean, coastal and inland waters [29,32,37,38]. For example, water transparency in the open Baltic Sea has decreased during the last one hundred years, and 13–17% variability in transparency was caused by phytoplankton [29]. In addition, the increased TN and Chla concentrations and the decreased transparency jointly confirm that Xin’anjiang Reservoir underwent accelerating eutrophication.

Bottom Line: The seasonal effects were distinct, with lower values in the summer than in the winter, most likely due to river runoff and phytoplankton biomass increases.The transparency decreased significantly with a linear slope of 0.079 m/year, indicating a 2.05 m decrease and a marked decrease in water quality.A marked increase occurred in chlorophyll a (Chla) concentration, and a significant correlation was found between the transparency and Chla concentration, indicating that phytoplankton biomass can partially explain the long-term trend of transparency in Xin'anjiang Reservoir.

View Article: PubMed Central - PubMed

Affiliation: Chun'an Environmental Monitoring Station, Hangzhou 311700, China. caepb@126.com.

ABSTRACT
Water transparency is a useful indicator of water quality or productivity and is widely used to detect long-term changes in the water quality and eutrophication of lake ecosystems. Based on short-term spatial observations in the spring, summer, and winter and on long-term site-specific observation from 1988 to 2013, the spatial, seasonal, long-term variations, and the factors affecting transparency are presented for Xin'anjiang Reservoir (China). Spatially, transparency was high in the open water but low in the bays and the inflowing river mouths, reflecting the effect of river runoff. The seasonal effects were distinct, with lower values in the summer than in the winter, most likely due to river runoff and phytoplankton biomass increases. The transparency decreased significantly with a linear slope of 0.079 m/year, indicating a 2.05 m decrease and a marked decrease in water quality. A marked increase occurred in chlorophyll a (Chla) concentration, and a significant correlation was found between the transparency and Chla concentration, indicating that phytoplankton biomass can partially explain the long-term trend of transparency in Xin'anjiang Reservoir. The river input and phytoplankton biomass increase were associated with soil erosion and nutrient loss in the catchment. Our study will support future management of water quality in Xin'anjiang Reservoir.

No MeSH data available.


Related in: MedlinePlus