Seasonal variability of picophytoplankton under contrasting environments in northern Tunisian coasts, southwestern Mediterranean Sea

Salhi, N.; Triki, Habiba Zmerli; Molinero, Juan Carlos; Laabir, Mohamed; Sehli, Emna; Zouari, Amel Bellaaj; Yahia, Nejib Daly; Yahia, Ons Kéfi–Daly

doi:10.1016/j.marpolbul.2017.10.029

Cited by 16 publications

(5 citation statements)

References 61 publications

(85 reference statements)

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“…The two Mediterranean ecosystems, lagoon and offshore, were sampled during the four seasons. The metabolic rates (CR: community respiration and PP: primary production) and the phytoplankton biomass measured in the present study were in agreement with previous studies in this region (Meddeb et al, 2018;Sakka Hlaili et al, 2008) and were comparable to reports from similar ecosystems in the Mediterranean basin (Ciavatta et al, 2008;Pérez-Ruzafa et al, 2005;Sfriso et al, 2003), with seasonal variations for both marine and lagoon waters (Salhi et al, 2018).…”

Section: In Situ Biomass and Metabolic Activitiessupporting

confidence: 93%

Impacts of chemical contamination on bacterio-phytoplankton coupling

et al. 2020

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Phytoplankton and bacterioplankton are the key components of the organic matter cycle in aquatic ecosystems, and their interactions can impact the transfer of carbon and ecosystem functioning. The aim of this work was to assess the consequences of chemical contamination on the coupling between phytoplankton and bacterioplankton in two contrasting marine coastal ecosystems: lagoon waters and offshore waters. Bacterial carbon demand was sustained by primary carbon production in the offshore situation, suggesting a tight coupling between both compartments. In contrast, in lagoon waters, due to a higher nutrient and organic matter availability, bacteria could rely on allochthonous carbon sources to sustain their carbon requirements, decreasing so the coupling between both compartments.Exposure to chemical contaminants, pesticides and metal trace elements, resulted in a significant inhibition of the metabolic activities (primary production and bacterial carbon demand) involved in the carbon cycle, especially in offshore waters during spring and fall, inducing a significant decrease of the coupling between primary producers and heterotrophs. This coupling loss was even more evident upon sediment resuspension for both ecosystems due to the important release of nutrients and organic matter. Resulting enrichment alleviated the toxic effects of contaminants as indicated by the stimulation of phytoplankton biomass and carbon production, and modified the composition of the phytoplankton community, impacting so the interactions between phytoplankton and bacterioplankton.

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Section: In Situ Biomass and Metabolic Activitiessupporting

confidence: 93%

Impacts of chemical contamination on bacterio-phytoplankton coupling

et al. 2020

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“…Similar seasonal and spatial patterns were also observed for plankton (bacterioplankton, phytoplankton and zooplankton) (Meddeb et al, 2018;Salhi et al, 2018) as well as in comparable coastal ecosystems (Aubry and Acri, 2004) suggesting close interactions between the planktonic communities and the chemical composition of the marine water Pringault et al, 2016).…”

Section: Discussionsupporting

confidence: 68%

“…One-way analysis of variance (ANOVA) was performed to test the null hypothesis that there was no significant difference between concentrations measured in situ and those measured after mixing with elutriate. When these conditions were not met, differences between concentrations were tested using the non-parametric Kruskall (Pringault et al, 2016;Salhi et al, 2018) and in similar Mediterranean ecosystems (Bec et al, 2005;Solidoro et al, 2004). Pesticide concentrations were, as a general rule, more important in the lagoon rather than in the offshore waters.…”

Section: Discussionmentioning

confidence: 99%

Seasonal changes of chemical contamination in coastal waters during sediment resuspension

et al. 2019

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The potential of remobilization of pollutants is a major problem for anthropogenic ecosystems, because even when the anthropogenic source of pollution is identified and removed, pollutants stored in sediments can be released into the water column and impact pelagic communities during sediment resuspension provoked by dredging, storms or bottom trawling. The objectives of the present study were to assess the changes observed in the chemical composition of the water column following resuspension of a polluted marine sediment and the consequences for the chemical composition of adjacent marine waters according to season. For that purpose, an experimental sediment resuspension protocol was performed on four distinct occasions, spring, summer, fall and winter, and the changes in nutrients, organic contaminants and inorganic contaminants were measured after mixing sediment elutriate with lagoon waters and offshore waters sampled nearby. Significant seasonal variations in the chemical composition of the contaminated sediments were observed, with a strong accumulation of PAHs in fall, whereas minimum PAH concentrations were observed during winter. In all seasons, sediment resuspension provoked a significant enrichment in nutrients, dissolved organic carbon, and trace metal elements like Ni, Cu, and Zn in offshore waters and lagoon waters, with enrichment factors that were season and site dependent. The most pronounced changes were observed for offshore waters, especially in spring and winter, whereas the chemical composition of lagoon waters was weakly impacted by the compounds supplied by sediment resuspension.

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“…At a global scale, their higher abundances were observed in warm waters as demonstrated by Flombaum et al (2013). Nevertheless, several studies reported abundances of 10 3 -10 4 cells mL −1 in the winter (temperature < 15°C) in the Mediterranean Sea (Vaulot and Partensky 1990;Babić et al 2017;Salhi et al 2017). Prochlorococcus has even been detected within temperatures ranging from 6.33 to 26.93°C in the Adriatic Sea (Šantić et al 2011).…”

Section: Syn1 Prochlmentioning

confidence: 99%

Pico- and Nanophytoplankton Dynamics in Two Coupled but Contrasting Coastal Bays in the NW Mediterranean Sea (France)

Delpy

Serranito

Jamet

et al. 2018

Estuaries and Coasts

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Due to its ecological context, the Toulon bay represents a site of scientific interest to study temporal plankton distribution, particularly pico-and nanophytoplankton dynamics. A monthly monitoring was performed during a two-year cycle (October 2013-December 2015) at two coupled sampling sites, referred to as Little and Large bays, which had different morphometric characteristics and human pressures. Flow cytometry analyses highlighted the fact that pico-and nanophytoplankton were more abundant in the eutrophic Little bay. Furthermore, it evidenced two community structures across the Toulon bays: at times, a co-dominance of picoeukaryotes, nanoeukaryotes, Synechococcus 1-like cells and Prochlorococcus-like cells was found, and at other times, a Synechococcus 1like dominated community existed. The alternation of one structure or the other can be explained by a combined action of temperature regime, nutrient conditions and degree of contamination. This study showed that pico-and nanophytoplankton dynamics were mainly driven by temperature in both sites, as in other temperate Mediterranean regions. Thus, the community was mainly composed of picoeukaryotes and Prochlorococcus-like cells in the winter (< 15 °C), while it was dominated by Synechococcus 1-like cells in the summer (> 20 °C). Additionally, the multiple human stressors in the Little bay seemed to affect the increase in abundance of Synechococcus 1-like cells as they were preferentially observed in the Large bay.

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Seasonal variability of picophytoplankton under contrasting environments in northern Tunisian coasts, southwestern Mediterranean Sea

Cited by 16 publications

References 61 publications

Impacts of chemical contamination on bacterio-phytoplankton coupling

Impacts of chemical contamination on bacterio-phytoplankton coupling

Seasonal changes of chemical contamination in coastal waters during sediment resuspension

Pico- and Nanophytoplankton Dynamics in Two Coupled but Contrasting Coastal Bays in the NW Mediterranean Sea (France)

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