Abstract
Oceanic flows do not necessarily mix planktonic species. Differences in individual organisms’ physical and hydrodynamic properties can cause
changes in drift normal to the mean flow, leading to segregation between
species. This physically-driven heterogeneity may have important consequences
at the scale of population dynamics. Here, we describe how one form
of physical forcing, circulating flows with different inertia effects between
phytoplankton and zooplankton, can dramatically alter excitable plankton
bloom dynamics. This may impact our understanding of the initiation and
development of harmful algal blooms (HABs), which have significant negative
ecological and socio-economic consequences. We study this system in detail,
providing spatio-temporal dynamics for particular scenarios, and summarising
large-scale behaviour via spatially averaged bifurcation diagrams. The key
message is that, across a large range of parameter values, fluid flow can
induce plankton blooms and mean-field population dynamics that are distinct
from those predicted for well-mixed systems. The implications for oceanic
population dynamic studies are manifest: we argue that the formation of HABs
will depend strongly on the physical and biological state of the ecosystem,
and that local increases in zooplankton heterogeneity are likely to precede
phytoplankton blooms
changes in drift normal to the mean flow, leading to segregation between
species. This physically-driven heterogeneity may have important consequences
at the scale of population dynamics. Here, we describe how one form
of physical forcing, circulating flows with different inertia effects between
phytoplankton and zooplankton, can dramatically alter excitable plankton
bloom dynamics. This may impact our understanding of the initiation and
development of harmful algal blooms (HABs), which have significant negative
ecological and socio-economic consequences. We study this system in detail,
providing spatio-temporal dynamics for particular scenarios, and summarising
large-scale behaviour via spatially averaged bifurcation diagrams. The key
message is that, across a large range of parameter values, fluid flow can
induce plankton blooms and mean-field population dynamics that are distinct
from those predicted for well-mixed systems. The implications for oceanic
population dynamic studies are manifest: we argue that the formation of HABs
will depend strongly on the physical and biological state of the ecosystem,
and that local increases in zooplankton heterogeneity are likely to precede
phytoplankton blooms
| Original language | English |
|---|---|
| Article number | 20190247 |
| Number of pages | 10 |
| Journal | Journal of the Royal Society Interface |
| Volume | 16 |
| Issue number | 157 |
| Publication status | Published - 7 Aug 2019 |