Passive Sampling and High Resolution Mass Spectrometry for Chemical Profiling of French Coastal Areas with a Focus on Marine Biotoxins

Passive samplers (solid phase adsorption toxin tracking: SPATT) are able to accumulate biotoxins produced by microalgae directly from seawater, thus providing useful information for monitoring of the marine environment. SPATTs containing 0.3, 3, and 10 g of resin were deployed at four different coastal areas in France and analyzed using liquid chromatography coupled to high resolution mass spectrometry. Quantitative targeted screening provided insights into toxin profiles and showed that toxin concentrations and profiles in SPATTs were dependent on the amount of resin used. Between the three amounts of resin tested, SPATTs containing 3 g of resin appeared to be the best compromise, which is consistent with the use of 3 g of resin in SPATTs by previous studies. MassHunter and Mass Profiler Professional softwares were used for data reprocessing and statistical analyses. A differential profiling approach was developed to investigate and compare the overall chemical diversity of dissolved substances in different coastal water bodies. Principal component analysis (PCA) allowed for spatial differentiation between areas. Similarly, SPATTs retrieved from the same location at early, medium, and late deployment periods were also differentiated by PCA, reflecting seasonal variations in chemical profiles and in the microalgal community. This study used an untargeted metabolomic approach for spatial and temporal differentiation of marine environmental chemical profiles using SPATTs, and we propose this approach as a step forward in the discovery of chemical markers of short- or long-term changes in the microbial community structure

Reported allelopathic effects of <i>Ulva</i> spp. and <i>Zostera</i> spp. on harmful algal blooms dinoflagellate species in various marine ecosystems.

<p>Reported allelopathic effects of <i>Ulva</i> spp. and <i>Zostera</i> spp. on harmful algal blooms dinoflagellate species in various marine ecosystems.</p

Phytochemicals associated with <i>Ulva rigida</i>, <i>Zostera noltei</i> and <i>Cymodocea nodosa</i> species with their reported biological activity.

<p>Phytochemicals associated with <i>Ulva rigida</i>, <i>Zostera noltei</i> and <i>Cymodocea nodosa</i> species with their reported biological activity.</p

Macrophyte collection sites (North of Tunisia, Southern Mediterranean Sea).

<p>Circle: Menzel Jemil station; Triangle: Menzel Bourguiba station.</p

Cellular toxin contents (pg.cell^-1) at the end of the experiments (after 10 days) of <i>Ostreopsis</i> cf. <i>ovata</i> (<i>O</i>. cf. <i>ovata</i>) and <i>Prorocentrum lima</i> (<i>P</i>. <i>lima</i>) in presence of the leaves/thalli of <i>Cymodocea nodosa</i> (<i>C</i>. <i>nodosa</i>), <i>Zostera noltei</i> (<i>Z</i>. <i>noltei</i>) and <i>Ulva rigida</i> (<i>U</i>. <i>rigida</i>), and of <i>Alexandrium pacificum</i> (<i>A</i>. <i>pacificum</i>) in presence of <i>C</i>. <i>nodosa</i> leaves.

<p>OVTX-a: Ovatoxin-a; OVTX-b: Ovatoxin-b; OA: Okadaic Acid; DTX-1: Dinophysistoxin-1; Neo-STX, GTX1, GTX3 and GTX4: Carbamoyl toxins; C1 and C2: N-sulfocarbamoyl toxins. ‘< LoD’ and ‘< LoQ’ indicate ‘< Limit of Detection’ and ‘< Limit of Quantification’, respectively. Error bars correspond to the standard deviation (N = 3 replicates, except for control (<i>O</i>. cf. <i>ovata</i> and <i>P</i>. <i>lima</i>) for which the controls of the three experiments have been pooled, N varying between 3 and 9 depending on the considered toxin). When only one among the three triplicates of each treatment was above LoD or LoQ, standard deviation was not calculable, and there is thus no error bar in such cases.</p

Light microscope observations of morphological damages of vegetative cells of the targeted dinoflagellate species.

<p>Photographs of <i>Alexandrium pacificum</i> cells cultured with <i>Cymodocea nodosa</i> (a-e) and <i>Ulva rigida</i> (f-j); and of <i>Ostreopsis</i> cf. <i>ovata</i> cultured with <i>Ulva rigida</i> (k-o). a,f,k = control cells; b-e, g-j, l-o = cells under increasing macrophyte weights. Scale bars, 10 μm.</p

Light (a₁,a₁’,b₁,b₁’), epifluorescence (a₂,a₂’,b₂,b₂’) and superposed light-epifluorescence (a₃,a₃’,b₃,b₃’) microscope photographs of dinoflagellate vegetative cells cultured with <i>Ulva rigida</i> thalli.

<p><b>A</b>: <i>Alexandrium pacificum</i> cells (a₁-a₂-a_{3 =} control, a₁’-a₂’-a₃’ ₌ cell exposed to 0.16g (FW) of <i>Ulva rigida</i> after 3 days of co-culture). <b>B</b>: <i>Ostreopsis</i> cf. <i>ovata</i> cells (b₁-b₂-b_{3 =} control; b₁’-b₂’-b₃’ ₌ cell exposed to 1g FW of <i>Ulva rigida</i> after 10 days of co-culture). Scale bars, 10 μm.</p