Environmental Contamination with Micro- and Nanoplastics Changes the Phototaxis of Euryhaline Zooplankton to Paired Photostimulation

Abstract

Our earlier studies showed that paired photostimulation allows the detection of pollutants in an aqueous medium according to the behavioral responses of freshwater Crustacea. The first stimulus initiated and stabilized the behavioral response. The increase in response to the second stimulus made it possible to assess the responsiveness of the zooplankton community. This paper studies the validity of this method for the detection of micro- and nanoplastic contamination of saltwater reservoirs according to the behavioral response of Artemia salina and Moina salina crustaceans. The studies were conducted in laboratory conditions using a submersible holographic camera developed by us, which ensures the in situ detection of the concentration and speed of crustaceans in a volume of up to 1 dm3, as well as makes it possible to change the intensity and duration of the attracting light. It was established that the phototropic response of crustaceans decreases in seawater at the cumulative dose of exposure to microplastics—0.15 mg∙dm−3∙h and nanoplastics—0.3 mg∙dm−3∙h. The paired photostimulation reveals the altering effect of micro- and nanoplastics in the saltwater medium no later than 3 h after their appearance, which indicates the promising potential of this method for the alarm response in monitoring the environmental well-being of water bodies.

Phototropic Behavioral Responses of Zooplankton in Lake Baikal In Situ and during the Anthropogenic Impact Modeling

“…Previously, in laboratory conditions, we showed that the inhibition of phototaxis to the paired photostimulation is a fairly sensitive and stable indicator of such pollutants as micro-and nanoplastics, oil, and standard potassium dichromate toxicant [28,29]. This study additionally registered the characteristics of plankton communities, such as the age variability according to the Shannon index and the presence of cyclic variability in behavioral phototropic response based on the spectral analysis of the pPhR time series.…”

“…Under laboratory conditions, we found [28] that the greatest response rate was observed with the use of the paired photostimulation according to the scheme of "the first stage of photostimulation 5 min, 25% of maximum illuminance + second stage 5 min, 75%" (illuminance as a percentage of maximum illuminance provided by the laser, 1150 lx, and 3450 lx, respectively).…”

“…The paired photostimulation described in detail in Morgalev et al [28] and Dyomin et al [29] was used to reduce the impact of behavioral response variability in the background (interindividual variation) and in case of insufficient photostimulation intensity that does not activate the systems that ensure the behavioral response. The first, smaller light impact activates the functional system [30] responsible for the behavioral response, which reduces inter-individual dispersion and entropy in the system [31].…”

Underwater digital holography of plankton with advanced monitoring capabilities for bioindication in situ

“…In a number of publications, we used the phototropic response of plankton with its photostimulation with attractor radiation to solve the biondication tasks. This requires placing a second source of laser radiation into the DHC, and in the latest modificationsa third source is added to excite the laser induced fluorescence to study phytoplankton [17][18][19].…”

Phototactic Behavioral Responses of Mesozooplankton in the Barents Sea as an Indicator of Anthropogenic Impact

“…The response of zooplankton to photostimulation changes against the background of the changed physiological state of hydrobionts when pollutants act [42,43]. Although, to date, the mechanism of this impact on zooplankton remains poorly understood, laboratory and field studies showed that photostimulation provides early detection of pollutants in the water medium according to behavioral responses [44].…”