Visible Fidelity Collector of a Zooplankton Sample from the Near-Bottom of the Deep Sea

The multi-net visible fidelity zooplankton collector is designed to obtain near-bottom fidelity zooplankton. The collector is sent to the designated sampling location based on the information provided by the camera and altimeter. The host computer sends instructions to control the opening of the net port for sample collection and closing of the sampling cylinder cover after sampling. The collector contains three trawls so that three samples can be collected for each test, and environmental parameters can be collected simultaneously. After sampling, The sample maintains its fidelity, that is, maintaining the temperature and pressure of the seabed sample after sampling. Two experiments were carried out in the Western Pacific, and six bottles of zooplankton samples were successfully obtained. The development of a multi-net visible zooplankton collector is of great significance for the collection of near-bottom zooplankton.

Zooplankton Sample Variation on the Scotian Shelf

Zooplankton sampling experiments on the Scotian Shelf during September 1973 and August 1974 using vertical tows demonstrated that numbers of many zooplankton species had a periodic fluctuation over 26 h. The fluctuations appeared related to the tide during 1974 but not in 1973. The periodic fluctuations accounted for a major portion of the sample variation in many species during both years. The mean numbers of small forms of zooplankton (copepods) obtained from the 26-h time series on a single station were very similar to means obtained during the same cruise over a wide area of the shelf. This suggested that a single station sampled over a period of two tidal cycles may be representative of the sample variation encountered over a wide geographic area of many hundreds of kilometres. Only Calanus and Pseudocalanus were correlated during all the experiments and from year to year. The abundance and distribution of the other species of zooplankton compared from one year to the next were not significantly correlated. This suggested the species populations were independent of one another. Key words: zooplankton, sample variation, time series, Scotian Shelf, fish larvae, Copepoda, tide

Tidal and Diurnal Effects on Zooplankton Sample Variability in a Nearshore Marine Environment

Two 26-h series of duplicate and replicate vertical zooplankton samples taken at two stations at two different times of the year showed that a periodic fluctuation correlated to the tide was present in the biomass of zooplankton and in the numbers of animals of several copepod species. Diurnally migrating species of zooplankton did not show a tidal correlation. The hour to hour fluctuations in zooplankton were generally more important than the difference between stations 1.6 km apart. Similar relations were found between the zooplankton and the tide in May and August even though there were significant differences in the composition of the zooplankton community during the two periods.Correlation coeficients between all species in all samples showed the presence of a diurnally migrating predator community and a nonmigrating prey community consisting of copepods.An experiment using sample data suggested that to obtain a reasonably accurate estimate of the mean numbers of a given species, one should make at least two vertical tows on a station at a 6-h interval.