Food Web Models Incorporating Plankton Diversity and ENA-Derived Indices in the Golf of Gabès (SE Mediterranean)
Abstract
A thorough understanding of the planktonic food-web functioning is crucial for determining the origin of organic matter that sustains the broader ecosystem, particularly in environments exposed to intense anthropogenic and environmental pressures. This study builds on highly resolved data, enabling an exceptionally detailed representation of the planktonic food web by integrating both the taxonomic and functional diversity of plankton. Using Linear Inverse Modeling coupled with a Markov Chain Monte Carlo approach (LIM–MCMC), we reconstructed the food-web structure during spring and fall in three stations in the Gulf of Gabès, each subjected to varying levels of anthropogenic pressure. Ecological network analysis (ENA) indices were used to describe the emerging properties of each food web, and were compared between stations. Based on the phytoplankton size and diversity, three planktonic food webs (PFW) with different functional ENA indices were determined, hence indicating differently functioning systems. In spring, multivorous and herbivorous pathways were dominant and mainly relied on primary production of large phytoplankton (mainly >10 μm micro-sized diatoms). In fall, the microbial food-web dominated at one station characterized by an intense proliferation of picoprokaryotes (i.e. < 2 μm Synechococcus), providing very high primary production, while herbivorous pathways, supported by large phytoplankton production, prevailed in the others stations. The trophic models, revealed that dinoflagellates were very active with high herbivory and microbivory in the different food webs, suggesting their important role in supplying carbon to higher consumers. Trophic transfer was high in all food webs (22–46% of primary production), particularly via the herbivorous pathway that was characterized by high production of large phytoplankton, intense proliferation of dinoflagellates and high herbivory of mesozooplankton, indicating the efficiency of large phytoplankton-dinoflagellates-mesozooplankton interaction in terms of biogenic carbon transfer. ENA indices revealed that the microbial food web, which had the highest total system throughput and the highest capacity of carbon cycling and retention, was the most active and stable system and relied partly on detrital energy. In opposite, the herbivorous food webs, present at the stations that were exposed to higher chemical pollution, showed the lowest total system flux and cycling, low relative ascendancy and average mutual information features that collectively point to limited activity, weak organization, and low stability. This study showed that trait-based models are suitable to describe detailed processes within carbon transfer pathways. These models combined with ecological indices are effective tools for management and assessment of disturbed marine ecosystems.
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BibTeX
@article{kousri2026food,
title = {{Food Web Models Incorporating Plankton Diversity and ENA-Derived Indices in the Golf of Gabès (SE Mediterranean)}},
author = {Kaouther Mejri Kousri and Ben Sondes Melliti and Marouan Meddeb and Oumayma Chkili and Matilda Haraldsson and Quentin Nogues and Bel Hassen Malika and Nathalie Niquil and Asma Sakka Hlaili},
journal = {Journal of Marine Systems},
year = {2026},
month = aug,
doi = {10.1016/j.jmarsys.2026.104277},
url = {https://hal.science/hal-05775787v1},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Food Web Models Incorporating Plankton Diversity and ENA-Derived Indices in the Golf of Gabès (SE Mediterranean)
AU - Kaouther Mejri Kousri
AU - Ben Sondes Melliti
AU - Marouan Meddeb
AU - Oumayma Chkili
AU - Matilda Haraldsson
AU - Quentin Nogues
AU - Bel Hassen Malika
AU - Nathalie Niquil
AU - Asma Sakka Hlaili
PY - 2026
DA - 2026/08/08
JO - Journal of Marine Systems
DO - 10.1016/j.jmarsys.2026.104277
UR - https://hal.science/hal-05775787v1
AB - A thorough understanding of the planktonic food-web functioning is crucial for determining the origin of organic matter that sustains the broader ecosystem, particularly in environments exposed to intense anthropogenic and environmental pressures. This study builds on highly resolved data, enabling an exceptionally detailed representation of the planktonic food web by integrating both the taxonomic and functional diversity of plankton. Using Linear Inverse Modeling coupled with a Markov Chain Monte Carlo approach (LIM–MCMC), we reconstructed the food-web structure during spring and fall in three stations in the Gulf of Gabès, each subjected to varying levels of anthropogenic pressure. Ecological network analysis (ENA) indices were used to describe the emerging properties of each food web, and were compared between stations. Based on the phytoplankton size and diversity, three planktonic food webs (PFW) with different functional ENA indices were determined, hence indicating differently functioning systems. In spring, multivorous and herbivorous pathways were dominant and mainly relied on primary production of large phytoplankton (mainly >10 μm micro-sized diatoms). In fall, the microbial food-web dominated at one station characterized by an intense proliferation of picoprokaryotes (i.e. < 2 μm Synechococcus), providing very high primary production, while herbivorous pathways, supported by large phytoplankton production, prevailed in the others stations. The trophic models, revealed that dinoflagellates were very active with high herbivory and microbivory in the different food webs, suggesting their important role in supplying carbon to higher consumers. Trophic transfer was high in all food webs (22–46% of primary production), particularly via the herbivorous pathway that was characterized by high production of large phytoplankton, intense proliferation of dinoflagellates and high herbivory of mesozooplankton, indicating the efficiency of large phytoplankton-dinoflagellates-mesozooplankton interaction in terms of biogenic carbon transfer. ENA indices revealed that the microbial food web, which had the highest total system throughput and the highest capacity of carbon cycling and retention, was the most active and stable system and relied partly on detrital energy. In opposite, the herbivorous food webs, present at the stations that were exposed to higher chemical pollution, showed the lowest total system flux and cycling, low relative ascendancy and average mutual information features that collectively point to limited activity, weak organization, and low stability. This study showed that trait-based models are suitable to describe detailed processes within carbon transfer pathways. These models combined with ecological indices are effective tools for management and assessment of disturbed marine ecosystems.
SN - 0924-7963
SN - 1879-1573
ER -