Biological early warning system based on the responses of aquatic organisms to disturbances: A review

The “Dreissena-Monitor” is a biological early warning system used in the continuous monitoring of water quality. The system is based on a computer assessment of valve movements in two groups of up to 42 zebra mussels (Dreissena polymorpha). Every 5 minutes, the percentage of open mussels and the average number of valve movements per mussel are calculated to describe the activity behaviour of the mussels. Rapid changes in both parameters normally reflect the onset of stress. More than 5½ years of experience in the continuous monitoring of water quality have revealed (1) that the “Dreissena-Monitor” is suited to large rivers like the Rhine as well as small rivers like the Erft or Ruhr, (2) that a lack of technical interruptions guarantees reliable, unattended operation, (3) that normally less than 3 hours of weekly maintenance are required, (4) that the validity check of the primary measurements was capable of identifying dead mussels and poorly aligned measurement components, (5) that the system can operate under unfavourable conditions (e.g. temperatures below 5° C), (6) that mortality rates were low and correlated positively with temperature, and (7) that the alarm thresholds provided a high degree of statistical security.

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Development and evaluation of new behavioral indexes for a biological early warning system using Daphnia magna

Drinking Water Engineering and Science Discussions ◽

10.5194/dwesd-6-39-2013 ◽

2013 ◽

Vol 6 (1) ◽

pp. 39-58

Author(s):

T. Y. Jeong ◽

J. H. Jeon ◽

S. D. Kim

Keyword(s):

Daphnia Magna ◽

Early Warning ◽

Early Warning System ◽

Warning System ◽

Exposure Test ◽

Copper Solution ◽

Biological Early Warning System ◽

Toxicity Level ◽

Improved Performance ◽

The Individual

Abstract. New behavioral indexes including combined index (CI), distribution index (DI), toxic index (TI), and altitude index (AI) for a biological early warning system (BEWS) were developed and evaluated using Daphnia magna in this study. The sensitivity and stability of each index were compared to evaluate the performance of the indexes through a real-time exposure test with a synthetic copper solution. The applicability of the CI to the field sample was evaluated through an effluent exposure test. The proportional relationship between toxicity level and magnitude of response was much lower in the effluent due to the complexity of water than in the copper solution. The results showed that the CI was most sensitive among the three indexes, while the DI was confirmed as the most useful index among the individual indexes. The combined index (CI) shows not only sensitivity but also stability in normal conditions below the statistically significant threshold (p < 0.01), whereas the individual indexes displayed unstable index values in normal conditions (p > 0.01). The CI improved performance of the BEWS in terms of sensitivity and stability, and it was confirmed as the higher correlation coefficient between the magnitude of the index and the toxicity level of the water sample.

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