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Jellyfish radioisotope concentrations
[i]***137Cs activity concentrations were below the detection limit in all measured samples***[/i]
Nov. 2015


Radioactivity in three species of eastern Mediterranean jellyfish
Activity concentrations of 137Cs, 40K, 210Po, 210Pb, 234U and 238U were determined in umbrella and oral arms of three widely distributed jellyfish species; namely [i]Rhopilema nomadica Galil, 1990, Aurelia aurita Linne, 1758 and Aequorea forskalea Péron & Lesueur, 1810 collected from February 2011 to January 2012 in four sampling locations along the Syrian coast (Eastern Mediterranean Sea). The results have shown significant variations in radionuclides activity concentrations amongst the species. The average activity concentrations of 40K, 210Po, 210Pb, 234U and 238U in the umbrella of R. nomadica species were higher than the average activity concentrations in the umbrella of A. aurita species by about 3.2, 1.4, 1.8, 3.2 and 3.2 folds, and A. forskalea species by about 45.5, 15.4, 19, 7.4 and 7.6 folds, respectively. The average activity concentrations of 40K, 210Po, 210Pb, 234U and 238U in oral arms of R. nomadica species were higher than the average activity concentrations in oral arms of A. auritaspecies by about 3.8, 1.7, 1.9, 2.8 and 2.9 folds, respectively. 137Cs activity concentrations were below the detection limit in all measured samples. In addition, activity concentrations of 137Cs, 40K, 210Po, 210Pb, 234U and 238U were also determined in 44 surface seawater samples and the activity concentrations ranged between 10.6 and 11.9 Bq l−1 for 40K, 1.1 and 1.4 mBq l−1 for 210Po, 0.5 and 0.7 mBq l−1 for 210Pb, 40.8 and 44.5 mBq l−1 for 234U, and 36.9 and 38.4 mBq l−1 for 238U, while 137Cs activity concentrations were below the detection limit in all measured samples. Moreover, the umbrella and oral arms readily accumulated 40K, 210Po, 210Pb, 234U and 238U above ambient seawater levels in the sequence of 210Po > 210Pb > 4 K > 234U and 238U. Concentration ratio (CR) values were relatively high for 210Po and 210Pb and reached 103 and 102, respectively for the jellyfish R. nomadica species compared to A. aurita and A. forskalea species. Therefore, R. nomadica can be used as biomonitor for these two radionuclides in the Eastern Mediterranean Sea. However, the obtained data can be considered the first reported baseline values for radioactivity in jellyfish.

WHOI counterparts, Oregon State University recommendation for lack of 137 Cs in jellyfish? A "preferential food"
No mention of accumulation radioisotopes other than 137Cs, as outlined above.
Aug. 2017
Lack of Cesium Bioaccumulation in Gelatinous Marine Life in the Pacific Northwest Pelagic Food-Web

4 Conclusion
Gelatinous organisms seem to show remarkably low retention of radiocesium when compared to their competitors in the food web. Even with 24 h counting periods, several kilograms of sample tissue to concentrate and a relatively high-efficiency HPGe in a low-background environment, only one of all gelatinous samples collected exceeded the detection threshold for Cs-137. CRs were no higher than 4.4 and may very well have been 1.0 for some of the organisms collected. *** Jellyfish may thus serve as a preferential food source during periods of high levels of radiocesium contamination,*** and may experience more population growth due to lack of competition in the event contamination levels are sufficient to produce population level effects in the ecosystem. More work on radiosensitivity of jellyfish and the means by which they maintain such low levels of retention are needed in the future.

Jellyfish Thrive on Climate Change

Messages In This Thread
Jellyfish radioisotope concentrations - HHD - 01-08-2019, 09:41 PM

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