Histopatholical gill damage of experimental groups over time.

<p>MLH: Mild lamellar hyperplasia; MLF: Mild lamellar fusion; MoLH: Moderate lamellar hyperplasia; MoLF: Moderate lamellar fusion; MCA: Mild cellular anomalies; MoCA: Moderate cellular anomalies; SLH: Severe lamellar hyperplasia; MCO: Mild cellular oedema; FM: Fish mortality; (NA): data not available; (---): Non significant gill damage. Colours indicate the severity of gill damage: cream colour = mild injuries; orange = medium level of injuries; violet and purple = medium-high and high level of gill damage respectively.</p

Average gill scores of treatment groups.

<p>Gill scores of control, low, medium and high <i>Pelagia noctiluca</i> jellyfish density groups before (0 h) and at different times after <i>Sparus aurata</i> exposure to jellyfish. Fish were not sampled from the highest jellyfish density group at 24 h, 3 and 4 weeks sampling points (vertical bars denote standard error).</p

Gill lesions in fish exposed to <i>Pelagia noctiluca</i>.

<p>A. Healthy fish gill from the control (no jellyfish) group (0h) (100x); B-E. pathology in fish gills from the treatment groups after 8-h exposure to jellyfish: B. black arrows indicate lamellar hyperplasia on fish gill from the low jellyfish density group at 9h (400x); C. lamellar hyperplasia (1) and fusion (2) from the medium jellyfish density group after 1 week (100x); D. epitheliocystis (black arrow) and lamellar oedema (1) from the medium jellyfish density group after 3 weeks (400x); E. hyperplasia of the epithelium of the primary lamellae (1), necrosis focal of secondary lamellae (2) and circulatory disturbances (3) from the high jellyfish density group after 48h (100x).</p

External lesions on <i>Sparus aurata</i> due to <i>Pelagia noctiluca</i> jellyfish exposure.

<p>A. Fish gill from control group; B. abrasion, haemorrhage, depigmentation and increased thickness of lamellar filaments of a fish from the high jellyfish density group 24 h after exposure to jellyfish; C. wound with necrotic tissue on the flank of <i>Sparus aurata</i> fish from the medium density group 2 weeks after exposure to jellyfish.</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>Reported allelopathic effects of <i>Ulva</i> spp. and <i>Zostera</i> spp. on harmful algal blooms dinoflagellate species in various marine ecosystems.</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

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

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

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