Pre-treatment of Culture Media with an Extremely Low-Frequency Magnetic Field Alters Daily Response of Dinoflagellate Cultures to Space Weather Variables Similar to Direct Magnetic Exposure

Paulo Vale

The Portuguese Sea and Atmosphere Institute, I.P. (IPMA, IP), Sea and Marine Resources Department (DMRM) R. Alfredo Magalhães Ramalho, 6. 1495-165 Algés. PORTUGAL


ORCID ID: 0000-0002-2524-4453

Keywords: Gymnodinium catenatum; Alexandrium pacificum; extremely low frequency magnetic field; water memory; mycosporine-like amino acids; saxitoxins; hormesis

Submitted: April 6, 2022
Reviewed: October 10, 2022
Accepted: November 1, 2022
Published: January 27, 2023

DOI: 10.14294/WATER.2022.3



The dinoflagellates, Gymnodinium catenatum and Alexandrium pacificum, have been previously studied regarding daily variations in solar-terrestrial interaction, known as space weather (SPW). To perform in vitro simulation of geomagnetic pulsations, an external extremely low-frequency magnetic field was employed previously for the study of their growth and metabolite production. Here, the same field was “informationally” transferred through a prior 24 h exposure of a culture media aliquot, the so-called “water memory” effect. To understand the effect of the magnetically treated culture media (MTCM), results had to be interpreted in light of the hormesis dose-response curve regarding natural fluctuations in SPW. The MTCM reduced growth at the hormesis optimum for selected SPW parameters. In these cells with reduced growth, the ultraviolet -photoprotective pigments mycosporine-like amino acids (MAAs) and the paralytic shellfish poisoning toxins (PSTs) increased in concentration. G. catenatum was more affected by MTCM than A. pacificum, with a generalized reduction trend in growth and MAA concentration. These pigments, besides having a UV-protection role, can also function as osmolites and antioxidants in microalgae. The use of MTCM elicited the same effect as direct exposure to an external extremely low-frequency magnetic field.

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