Biology subjects

Lacroix, G.

Publications and source records attributed to Lacroix, G..

5 recordsLinked to original sources

bioRxiv2026

PlanktonLake-CEREEP- A Freshwater Plankton Image Dataset with Semi-Automated Label Cleaning

Plankton plays a fundamental role in aquatic ecosystems, influencing biogeochemical cycles and serving as a key food source for many organisms. Recent high-throughput imaging technologies enable the rapid acquisition of large volumes of microscopic images, creating new opportunities for monitoring planktonic ecosystems. However, the manual processing and annotation of the vast amounts of data generated by these devices remain time-consuming tasks. In this context, machine learning-based classification models offer a promising solution. In this data paper, we introduce a new labeled freshwater plankton dataset comprising approximately 88,000 images distributed across 43 taxa. We also present the labeling assistance method we used to facilitate dataset annotation. Finally, we present a baseline based on a convolutional neural network (CNN), which achieves a classification accuracy of 93% on our dataset.

ecology↗

bioRxiv2026

Invasive alien predators overturn the spatial-scaling laws of biocomplexity

The theory of island biogeography and its trophic extensions predict that both species richness and food-web complexity should increase with increasing ecosystem surface area. Accordingly, Species-Area Relationships (SARs) and Network-Area Relationships (NARs) are often observed to be positively-sloped, an observation that came to be considered as a law, and on which rest many area-based conservation plans for biodiversity. However, our mechanistic understanding of the driving mechanisms of SARs and NARs slopes remains limited, undermining our ability to predict how biodiversity will respond to habitat gain or loss. We show in 180 rural ponds sampled across five years that invasive alien predators reversed the SAR and NARs from positive in invader-free ponds, to negative in invaded ponds. Relationship reversal resulted from a higher prevalence of invasive alien predators driving magnified prey extinctions and simplified food webs in larger ponds. The ability of invasive alien predators to reverse SAR and NARs presumably reflected disproportionately high predation rates combined with a low sensitivity to prey extinction conferred by a wide trophic generalism. In a world where virtually all ecosystems face biological invasions, omnipresent invasive alien predators stress the pivotal role played by predation in shaping biocomplexity-area relationships, and highlight a growing need to preserve small ecosystems where invasive alien predators are less prevalent.

ecology↗

bioRxiv2024

KCNG4 genetic variant linked to migraine prevents expression of KCNB1

AO_SCPLOWBSTRACTC_SCPLOWMigraines are a common type of headaches affecting around 15% of the population. The signalling pathways leading to migraines have not been fully understood, but neuronal voltage-gated ion channels have been linked to this pathology, among them KCNG4. KCNG4 (Kv6.4) is a silent member of the superfamily of voltage-gated potassium (Kv) channels, which expresses in heterotetramers with members of the KCNB (Kv2) family. The genetic variant Kv6.4-L360P has previously been linked to migraine, but their mode of action remains unknown. Here, we characterized the molecular characteristics of Kv6.4-L360P when co-expressed with Kv2.1. We found that Kv6.4-L360P almost completely abolishes Kv2 currents, and we propose that this mechanism in the trigeminal system, linked to the initiation of migraine, leads to the pathology.

biophysics↗

bioRxiv2023

Quality matters: stoichiometry of resources modulates spatial feedbacks in aquatic-terrestrial meta-ecosystems

Species dispersal and resource spatial flows greatly affect the dynamics of connected ecosystems. So far, research on meta-ecosystems has mainly focused on the quantitative effect of subsidy flows. Yet, resource exchanges at heterotrophic-autotrophic (e.g., aquatic-terrestrial) ecotones display a stoichiometric asymmetry that likely matters for functioning. Here, we joined ecological stoichiometry and the meta-ecosystem framework to understand how subsidy stoichiometry mediates the response of the meta-ecosystem to subsidy flows. Our model results demonstrate that resource flows between ecosystems can induce a positive spatial feedback loop, leading to higher production at the meta-ecosystem scale by relaxing local ecosystem limitations ("spatial complementarity"). Furthermore, we show that spatial flows can also have an unexpected negative impact on production when accentuating the stoichiometric mismatch between local resources and basal species needs. This study paves the way for studies on the interdependancy of ecosystems at the landscape extent. Data: The code and the data, as well as a small tutorial to run the model are available on Github via Zenodo: https://doi.org/10.5281/zenodo.7733880

ecology↗

bioRxiv2022

From behaviour to complex communities: Resilience to anthropogenic noise in a fish-induced trophic cascade

Sound emissions from human activities represent a pervasive environmental stressor. Individual responses in terms of behaviour, physiology or anatomy are well documented but whether they propagate through nested ecological interactions to alter complex communities needs to be better understood. This is even more relevant for freshwater ecosystems that harbour a disproportionate fraction of biodiversity but receive less attention than marine and terrestrial systems. We conducted a mesocosm investigation to study the effect of chronic exposure to motorboat noise on the dynamics of a freshwater community including phytoplankton, zooplankton, and roach as a planktivorous fish. As expected under the trophic cascade hypothesis, roach predation induced structural changes in the planktonic communities. Surprisingly, although roach changed their feeding behaviour in response to noise, the dynamics of the roach-dominated planktonic communities did not differ between noisy and noiseless mesocosms. This suggests that the top-down structuring influence of roach on planktonic communities might be resilient to noise and reveals the difficulties on extrapolating impacts form individual responses to complex communities.

ecology↗