A comparison between quasi-horizontal and vertical observations of phytoplankton microstructure

Micro-scale patchiness enhances trophic transfer efficiency and potential plankton biodiversity

“…Recent observations have revealed ubiquitous intermittency in phytoplankton distributions at the micro ( mm ) scale 8–11 , and a few recent modelling studies have suggested that this micro-scale variability impacts plankton ecosystem dynamics and biodiversity 12–14 . Modelling is an essential tool for studying complex food webs, by linking the observed ecological patterns with experimental findings to understand mechanisms and make future predictions.…”

Micro-Scale Variability Impacts the Outcome of Competition Between Different Modeled Size Classes of Phytoplankton

“…Nearly all plankton ecosystem models have been developed based on the mean field approximation, i.e., ignoring intermittency in the distributions of biomass and nutrients by averaging over spatiotemporal scales much greater than those relevant to planktonic organisms (Mandal et al, 2014;Foloni-Neto et al, 2015). Micro-scale intermittency has long been known to affect the dynamics of aquatic microbes, nutrients, and carbon, because aggregates constitute "hotspots" of biological activity (Azam et al, 1994).…”

Stirring, Mixing, Growing: Microscale Processes Change Larger Scale Phytoplankton Dynamics

“…Yet the distinction between the time scales of turbulent stirring and the time scales of irreversible mixing is never considered. In spite of mounting evidence of ubiquitous presence of patchiness in the vertical direction across the mixed layer (Currie and Roff, 2006;Doubell et al, 2009Doubell et al, , 2014Foloni-Neto et al, 2016), theories of the onset of the bloom freely interchange turbulent stirring and irreversible mixing as if they were one and the same thing (see the recent review Fischer et al, 2014 and references therein). On the other hand, most of the literature on mixed layer plankton patchiness (Huisman et al, 2006;Durham and Stocker, 2011;Cullen, 2015;Moeller et al, 2019) focuses on unveiling the underlying mechanisms but does not investigate how patchiness contributes to signal at larger scales and how it should be included in predictive models.…”

“…This variability, in turn, is enhanced by biological processes such as the interplay between light and nutrient gradients, cell buoyancy adjustments, gyrotaxis, convergent swimming, and light-dependent grazing (Huisman et al, 2006;Durham and Stocker, 2011;Cullen, 2015;Moeller et al, 2019). The emerging very-high-resolution sampling techniques suggest that plankton remain patchy at the scales of one meter both in the vertical and in the horizontal (Foloni-Neto et al, 2016), and that homogeneity might not be reached even at the centimeter scales (Currie and Roff, 2006;Doubell et al, 2009;Foloni-Neto et al, 2016). As we shall illustrate in section 3, models assuming that biological scalars are homogeneously distributed at the fine and micro scales may easily incur serious biases.…”