Spatial Interaction Among Nontoxic Phytoplankton, Toxic Phytoplankton, and Zooplankton: Emergence in Space and Time

Abstract

In homogeneous environments, by overturning the possibility of competitive exclusion among phytoplankton species, and by regulating the dynamics of overall plankton population, toxin-producing phytoplankton (TPP) potentially help in maintaining plankton diversity-a result shown recently. Here, I explore the competitive effects of TPP on phytoplankton and zooplankton species undergoing spatial movements in the subsurface water. The spatial interactions among the species are represented in the form of reactiondiffusion equations. Suitable parametric conditions under which Turing patterns may or may not evolve are investigated. Spatiotemporal distributions of species biomass are simulated using the diffusivity assumptions realistic for natural planktonic systems. The study demonstrates that spatial movements of planktonic systems in the presence of TPP generate and maintain inhomogeneous biomass distribution of competing phytoplankton, as well as grazer zooplankton, thereby ensuring the persistence of multiple species in space and time. The overall results may potentially explain the sustainability of biodiversity and the spatiotemporal emergence of phytoplankton and zooplankton species under the influence of TPP combined with their physical movement in the subsurface water.

Relationships among cyanobacteria, zooplankton and fish in sub-bloom conditions in the Sulejow Reservoir

“…In contrast, cladocerans are generalist and non-selective grazers; thus, they are more vulnerable to intracellular toxins. Therefore, daphniids have developed various adaptations against the harmful effects of cyanobacteria (Ger et al, 2014), including behavioral responses that consist of avoiding areas with cyanobacterial blooms (Fulton and Paerl, 1987;Roy, 2008;Reichwaldt et al, 2013) and the physiological detoxification of ingested compounds (Pflugmacher et al, 1998). Our results indicate that large filter feeders were negatively correlated with the abundance of cyanobacteria genus Microcystis (number of 16sRNA gene copies), but results in respect to the relationship between zooplankton and biological activity of cyanobacteria were inconclusive (zooplankton correlation with PC2 axis, Tab.…”

“…In dynamic ecosystems subjected to frequent toxic blooms, aquatic animals do not have to follow a predictable relationship proportional to cyanobacteria abundance, as has been demonstrated by Teegarden et al (2008) for copepods. This is especially the case when aquatic animal organisms are regularly exposed to MCs, triggering development of toxinresistant physiological mechanisms that weaken known behavioral (Ernst, 2008;Roy, 2008) or life-trait (Fulton and Paerl, 1987) responses. Nevertheless, further studies of the interactions between cyanobacteria, zooplankton and fish in sub-bloom conditions seems to be important in the face of observed climate change, where higher temperatures promote the growth rate of toxic cyanobacteria to a greater degree than that of nontoxic strains (Davis et al, 2009).…”

“…Consequently, cyanobacteria can cause a decrease in the population growth, fecundity and survival of herbivorous zooplankton (Fulton and Paerl, 1987), as well as change their behavior and phenotypic adaptations (Berthon and Brousse, 1995;Ghadouani and Pinel-Alloul, 2002). A few studies have indicated asynchrony in the spatial distribution of zooplankton and cyanobacteria within lakes and the formation of 'refuge sites' that allow large grazers to persist during blooms (Roy, 2008;Reichwaldt et al, 2013). However, there is an evident gap in our knowledge regarding the possibility that such mechanisms also develop during sub-bloom periods, if low concentrations of cyanobacteria are present.…”

Travelling Waves in Plankton Dynamics

“…Some species of phytoplankton can release poisons that affect zooplankton as well as possibly, directly or indirectly, also fish. Recent investigations have shown that movement can sustain inhomogeneous distribution levels of plankton communities composed of nontoxic phytoplankton, toxic phytoplankton and zooplankton, [3,10]. An idea that has been proposed for explaining the insurgence of red tides is that they are side effects caused by these toxin producing phytoplanktons, [4,5,8,9].…”

Toxic phytoplankton-induced spatiotemporal patterns

“…Recently, spatial movements of planktonic systems in the presence of toxin-producing phytoplankton have been found to generate and maintain inhomogeneous biomass distribution of competing phytoplankton as well as grazer zooplankton [13].…”