title: Dispersion/dilution enhances phytoplankton blooms in low-nutrient waters.
abstract: Spatial characteristics of phytoplankton blooms often reflect the horizontal transport properties of the oceanic turbulent flow in which they are embedded. Classically, bloom response to horizontal stirring is regarded in terms of generation of patchiness following large-scale bloom initiation. Here, using satellite observations from the North Pacific Subtropical Gyre and a simple ecosystem model, we show that the opposite scenario of turbulence dispersing and diluting fine-scale (∼1-100 km) nutrient-enriched water patches has the critical effect of regulating the dynamics of nutrients-phytoplankton-zooplankton ecosystems and enhancing accumulation of photosynthetic biomass in low-nutrient oceanic environments. A key factor in determining ecological and biogeochemical consequences of turbulent stirring is the horizontal dilution rate, which depends on the effective eddy diffusivity and surface area of the enriched patches. Implementation of the notion of horizontal dilution rate explains quantitatively plankton response to turbulence and improves our ability to represent ecological and biogeochemical processes in oligotrophic oceans.
authors.affiliation: Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Yoav
authors.initials: Y
authors.lastname: Lehahn
authors.affiliation: Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Ilan
authors.initials: I
authors.lastname: Koren
authors.affiliation: Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Shlomit
authors.initials: S
authors.lastname: Sharoni
authors.affiliation: Sorbonne Universités (UPMC, Université Paris 06)-CNRS-IRD-MNHN, LOCEAN-IPSL Laboratory, 4 Place Jussieu, 75005 Paris, France.
authors.forename: Francesco
authors.initials: F
authors.lastname: d'Ovidio
authors.affiliation: Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Assaf
authors.initials: A
authors.lastname: Vardi
authors.affiliation: School of Marine Sciences, University of Maine, Orono, Maine 04469-5741, USA.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Boss
mesh_terms: D000818:Animals; D018533:Biomass; D002244:Carbon; D002734:Chlorophyll; D017753:Ecosystem; D005068:Eutrophication / Q000502:physiology*; D008954:Models, Biological; D000078622:Nutrients; D009792:Oceans and Seas; D010839:Phytoplankton / Q000502:physiology*; D010933:Plankton / Q000502:physiology; D063809:Satellite Imagery; D015048:Zooplankton / Q000502:physiology*
chemical_list: D002244:Carbon; D002734:Chlorophyll; D000078622:Nutrients