2:15 PM - 2:30 PM
[HQR05-15] River Environmental Monitoring at Yanshui (Salt Water) River, Tainan, using Diatom Assemblages and its Application to the Anthropocene Environmental Reconstruction
Keywords:Diatom, River Environment, Coastal Plain, Anthropocene
(1) Introduction
The Yanshui (Salt Water) River Area is located north of Tainan City, south-western coast of Taiwan. It was a tidal flat until 17C, and was reclaimed according to the expansion of Taiwan City. Recently, the rapid industrial development surrounding the river caused the serious water pollution. In this paper, we monitored the water pollution based by diatom assemblages which were taken from river stones and water glasses. After then, we calculated the relationships between diatom assemblages and river water contents using the multivariate analysis for the statistically river environmental monitoring.
(2) DAIpo for the Quantitative Mesurement of Water Quality
Diatoms are useful environmental indicators for the monitoring of the river water quality. DAIpo (Diatom Pollution Index) is the method for the quantitative measurement for river pollution caused by the Late Prof. Toshiharu Watanabe (Watanabe et al. 2005). They divided all freshwater diatoms into Clean Water species, Polluted Water Species and Wide Distributed species. DAIpo is calculated by the percentages of above three diatom groups, and is ranged 0-100. DAIpo 50 is average, and it decreases by the water pollution, and increases by the cleaning of water quality.
(3) Samplings for the surveys
The diatom samplings were taken four times from April until September in 2024 at 12 points along the Yanshui (Salt Water) River. Several huge typhoons were attacked to the survey area during the summer in 2024, and water volumes of the river shifted more than 20 times at the four sampling times. Beside the diatom sampling, water temperature, ph, DO, Salinity and the water chemistry (Si,Fe,P) were measured.
(4) Results
DAIpo at Yanshui (Salt Water) River lowered from the upstream to the middle stream every monitoring time. After then, it increased to the lower stream again. It showed the heavy river pollution occurred at the middle of the river. Although the volumes of river water changed much between the four samplings, DAIpo trends seem to be stable. DAIpo based on attached algal diatom communities might shows the average water quality.
The multivariate analysis for the statistically river environmental monitoring showed the four dimensions. The first one is defied by the Salty Diatoms which related to Water Conductivity and Salinity. The second one is defined by the Polluted Water Species which negative related to DO. The third one is defined Clean Water Species which related water temperature and Ph. The froth one is Wide Distributed Species which has no strong relationship to the water quality.
(5)Application DAIpo to the Anthropocene Environmental Reconstructions
Diatom valves were preserved sediments easily. Therefore, we can apply the statistically relationships between diatom assemblages and the water pollutions to the diatom fossil assemblages in the sediments. The drilling projects in Tainan Area will be done in 2025, but we applied it to the sediment cores which were taken on July 2024 at the Matsue Castle Moat, Matsue City, Japan. Matsue City Office tried to clean the water quality of the Matsue Castle Moat since 1970’s by supplying of lake water of Lake Shinji into the moat. And the water quality of the moat recovered until 2000, and has kept until now. DAIpo at the sedimentary cores of the moat increased from DAIpo 10 (very polluted) at the lower part of the core to DAIpo 40-50 (a little polluted) at the middle of the core. After then DAIpo has kept surrounding 50 until the upper part of the core. This DAIpo curve showed the possibility of DAIpo index might apply to the historic monitoring during the Anthropocene.
The Yanshui (Salt Water) River Area is located north of Tainan City, south-western coast of Taiwan. It was a tidal flat until 17C, and was reclaimed according to the expansion of Taiwan City. Recently, the rapid industrial development surrounding the river caused the serious water pollution. In this paper, we monitored the water pollution based by diatom assemblages which were taken from river stones and water glasses. After then, we calculated the relationships between diatom assemblages and river water contents using the multivariate analysis for the statistically river environmental monitoring.
(2) DAIpo for the Quantitative Mesurement of Water Quality
Diatoms are useful environmental indicators for the monitoring of the river water quality. DAIpo (Diatom Pollution Index) is the method for the quantitative measurement for river pollution caused by the Late Prof. Toshiharu Watanabe (Watanabe et al. 2005). They divided all freshwater diatoms into Clean Water species, Polluted Water Species and Wide Distributed species. DAIpo is calculated by the percentages of above three diatom groups, and is ranged 0-100. DAIpo 50 is average, and it decreases by the water pollution, and increases by the cleaning of water quality.
(3) Samplings for the surveys
The diatom samplings were taken four times from April until September in 2024 at 12 points along the Yanshui (Salt Water) River. Several huge typhoons were attacked to the survey area during the summer in 2024, and water volumes of the river shifted more than 20 times at the four sampling times. Beside the diatom sampling, water temperature, ph, DO, Salinity and the water chemistry (Si,Fe,P) were measured.
(4) Results
DAIpo at Yanshui (Salt Water) River lowered from the upstream to the middle stream every monitoring time. After then, it increased to the lower stream again. It showed the heavy river pollution occurred at the middle of the river. Although the volumes of river water changed much between the four samplings, DAIpo trends seem to be stable. DAIpo based on attached algal diatom communities might shows the average water quality.
The multivariate analysis for the statistically river environmental monitoring showed the four dimensions. The first one is defied by the Salty Diatoms which related to Water Conductivity and Salinity. The second one is defined by the Polluted Water Species which negative related to DO. The third one is defined Clean Water Species which related water temperature and Ph. The froth one is Wide Distributed Species which has no strong relationship to the water quality.
(5)Application DAIpo to the Anthropocene Environmental Reconstructions
Diatom valves were preserved sediments easily. Therefore, we can apply the statistically relationships between diatom assemblages and the water pollutions to the diatom fossil assemblages in the sediments. The drilling projects in Tainan Area will be done in 2025, but we applied it to the sediment cores which were taken on July 2024 at the Matsue Castle Moat, Matsue City, Japan. Matsue City Office tried to clean the water quality of the Matsue Castle Moat since 1970’s by supplying of lake water of Lake Shinji into the moat. And the water quality of the moat recovered until 2000, and has kept until now. DAIpo at the sedimentary cores of the moat increased from DAIpo 10 (very polluted) at the lower part of the core to DAIpo 40-50 (a little polluted) at the middle of the core. After then DAIpo has kept surrounding 50 until the upper part of the core. This DAIpo curve showed the possibility of DAIpo index might apply to the historic monitoring during the Anthropocene.