Publication Date:
2022-05-25
Description:
Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Limnology and Oceanography 62 (2017): 1742–1753, doi:10.1002/lno.10530.
Description:
While considerable effort has been devoted to understanding the factors regulating the
development of phytoplankton blooms, the mechanisms leading to bloom decline and
termination have received less attention. Grazing and sedimentation have been invoked as
the main routes for the loss of phytoplankton biomass, and more recently, viral lysis,
parasitism and programmed cell death (PCD) have been recognized as additional removal
factors. Despite the importance of bloom declines to phytoplankton dynamics, the
incidence and significance of various loss factors in regulating phytoplankton populations
have not been widely characterized in natural blooms. To understand mechanisms
controlling bloom decline, we studied two independent, inshore blooms of Alexandrium
fundyense, paying special attention to cell mortality as a loss pathway. We observed
increases in the number of dead cells with PCD features after the peak of both blooms,
demonstrating a role for cell mortality in their terminations. In both blooms, sexual cyst
formation appears to have been the dominant process leading to bloom termination, as
both blooms were dominated by small-sized gamete cells near their peaks. Cell death and
parasitism became more significant as sources of cell loss several days after the onset of
bloom decline. Our findings show two distinct phases of bloom decline, characterized by
sexual fusion as the initial dominant cell removal processes followed by elimination of
remaining cells by cell death and parasitism.
Description:
This article is a result of research funded by the National Oceanic and
Atmospheric Administration Center for Sponsored Coastal Ocean Research ECOHAB
program under award no. NA09NOS4780166 to the University of Texas Marine Science
Institute (D.L.E) and the Woods Hole Center for Oceans and Human Health by National
Science Foundation (NSF) award no. OCE-1314642 and National Institute of
Environmental Health Sciences (NIEHS) award no. 1-P01-ES021923-014 to D.M.A. and
M.L B.
Keywords:
Phytoplankton bloom dynamics
;
Harmful Algal Blooms (HABs) declines
;
Phytoplankton mortality
;
Programmed cell death (PCD)
;
Life cycle transitions
;
Alexandrium fundyense
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
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