Publication Date:
2022-05-25
Description:
© The Author(s), 2015. This is the author's version of the work and is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Deep Sea Research Part I: Oceanographic Research Papers 106 (2015): 9-16, doi:10.1016/j.dsr.2015.09.006.
Description:
The potential bioaccumulation of 137Cs in marine food webs off Japan became a concern
following the release of radioactive contaminants from the damaged Fukushima nuclear power
plant into the coastal ocean. Previous studies suggest that 137Cs activities increase with trophic
level in pelagic food webs, however, the bioaccumulation of 137Cs from seawater to primary
producers, to zooplankton has not been evaluated in the field. Since phytoplankton are
frequently the largest component of SPM (suspended particulate matter) we used SPM
concentrations and particle-associated 137Cs to understand bioaccumulation of 137Cs in through
trophic pathways in the field. We determined particle-associated 137Cs for samples collected at
20 m depth from six stations off Japan three months after the initial release from the Fukushima
nuclear power plant. At 20 m SPM ranged from 0.65 to 1.60 mg L-1 and rapidly declined with
depth. The ratios of particulate organic carbon to chlorophyll a suggested that phytoplankton
comprised much of the SPM in these samples. 137Cs activities on particles accounted for on
average 0.04% of the total 137Cs in seawater samples, and measured concentration factors of
137Cs on small suspended particles were comparatively low (~102). However, when 137Cs in
crustacean zooplankton was derived based only on modeling dietary 137Cs uptake, we found
predicted and measured 137Cs concentrations in good agreement. We therefore postulate the
possibility that the dietary route of 137Cs bioaccumulation (i.e., phytoplankton ingestion) could
be largely responsible for the measured levels in the copepod-dominated (%) zooplankton
assemblages in Japanese coastal waters. Finally, our data did not support the notion that
zooplankton grazing on phytoplankton results in a biomagnification of 137Cs.
Description:
This project was funded by the Gordon and Betty Moore Foundation through Grants GBMF3007
and GBMF 3423, and JSPS KAKENHI Grant-in-Aid for Scientific Research on Innovative
Areas Grant Number 24110005.
Description:
2016-09-25
Keywords:
Fukushima
;
Cesium
;
Trophic transfer
;
Phytoplankton
;
Zooplankton
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
Format:
application/pdf
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