Andreas Lorke, Daniel F. McGinnis, Piet Spaak, Alfred Wuest (2004):
Acoustic observations of zooplankton in lakes using a Doppler current
profiler. Freshwater Biology; Volume 49, Issue 10, Page 1280-1292
Abstract: 1. In this paper we test the usefulness of acoustic
backscatter measurements from a 614 kHz Acoustic Doppler Current
Profiler (ADCP) for the qualitative and quantitative characterisation of
zooplankton distributions in lakes. ADCP-based backscatter estimates
were compared with frequent net hauls obtained during a calibration
experiment in which the acoustic backscatter was strongly dominated by
vertical migrating Chaoborus flavicans larvae.
2. The correlation between backscatter estimates and the C. flavicans
concentration was very good. Vertical swimming speed of larvae, measured
directly by the ADCP, was up to a maximum of 5 mm s1 and agreed very
well with the observed vertical movement of the backscatter contour
lines. Although the strong backscatter from C. flavicans overwhelmed the
signal from the remaining zooplankton, a good correlation between
backscatter strength and the total remaining zooplankton concentration,
dominated by Cyclops spp., was found for the depth and time intervals
where no C. flavicans were present.
3. In addition to the calibration experiment, longer-term ADCP
measurements from different lakes revealed a strong temporal correlation
between the onset of the up- and downward migration of zooplankton and
the local sunset and sunrise.
4. We conclude that ADCPs can be used to monitor plankton distributions
both temporally and spatially. It also seems possible to estimate
plankton densities after appropriate calibration.
Link:
<a
href="http://www.blackwell-synergy.com/links/doi/10.1111/j.1365-2427.2004.0126";
rel="nofollow">http://www.blackwell-synergy.com/links/doi/10.1111/j.1365-2427.2004.0126</a>
7.x
Sonja Amoser, PhD Student
Institut of Zoology, University of Vienna
Althanstrasse 14, 1090 Vienna, Austria
Tel: +43-1-4277-54515
Mail: [EMAIL PROTECTED]
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