Vast amounts of munitions dumped in the marine environment, have been reported to leak chemicals due to munition corrosion. The subsequent increased levels of explosives and related chemicals (E&RC), as well as chemical warfare agents and related chemicals (CWA&RC), raise risks for environmental and human health Yet, ecotoxicity data on primary producers is currently scarce. Therefore, this study investigated the acute effects of three CWA&RC (1,4-oxathiane, 1,4-dithiane, and thiodiglycol) and four E&RC (2,4,6-trinitrotoluene (TNT), tetryl, 1,3-dinitrobenzene (1,3-DNB), and picric acid) on Phaeodactylum tricornutum, a key marine diatom at the basis of the aquatic food web. Results showed that none of the three CWA&RC significantly inhibited the growth rate of Phaeodactylum tricornutum at the tested concentrations. Interestingly, picric acid stimulated growth up under the experimental conditions, suggesting a hormetic effect. TNT, tetryl, and 1,3-DNB strongly inhibited growth, with experimentally derived EC10 and EC50 values approaching environmentally relevant concentrations near dumpsites. Consequently, diatom biomass may be significantly affected by TNT, tetryl, and 1,3-DNB, potentially disturbing primary production and ocean chemistry. Future research should examine potential synergies between munition compounds and other marine pollutants, which may aggravate toxic effects, as well as consider long-term toxicity tests.
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RBINS Staff Publications 2026
A zero-dimensional model for phytoplanktonicproduction in turbid, macro-tidal, well-mixed estuaries is proposed. It is based on the description of light-dependentalgal growth, phytoplankton respiration and mortality. The model is forced by simple time-functions for solar irradiance, water depth and light penetration. The extinction coefficientis directly related to the dynamics of suspended particulate matter. Model results show that the description of phyto-plankton growth must operate at a time resolution sufficientlyhigh to describe the interference between solarly and tidallydriven physical forcing functions. They also demonstrate that in shallow to moderately deep systems, simulations using averaged, instead of time-varying, forcing functions lead to significant errors in the estimation of phytoplankton productivity. The highest errors are observed when the temporalpattern of light penetration, linked to the tidal cycle of solidssettling and resuspension, is neglected. The model has alsobeen applied using realistic forcing functions typical of two locations in the Scheldt estuary. Model results are consistentwith the typical phytoplankton decay observed along the lon-gitudinal, seaward axis in the tidal river and oligohaline part of this estuary.
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