Dataset on onshore groundwaters and offshore submarine spring of a Mediterranean karst aquifer during flow reversal and saltwater intrusion.

Groundwater from various shallow and deep reservoirs converges in interaction with marine waters into the limestone aquifer of the Balaruc peninsula (Thau lagoon, southern France). This aquifer faces temporary phenomena of marine water intrusion through the Vise submarine spring located at -29.5 m below the lagoon level. Since the 1960s, seven flow reversal phenomena have occurred, the last one occurring between 11/28/2020 and 03/14/2022. During these phenomena, which can last from a few weeks to several months, the salty water is absorbed from the lagoon to the conduit of the submarine spring, which leads to the salinization of the underlying karst aquifer. The monitoring of flow, water specific conductivity and water temperature data from the karst submarine spring is a key element of the research project to understand the hydrogeological functioning of the karst aquifer under normal conditions or during flow reversal periods. This monitoring allows the characterization of the (in- or out-) flows at the submarine spring, the evaluation of the volume or mass balances, the identification of the hydrogeological and physico-chemical responses (water temperature, specific conductivity) observed within the karstic aquifer. Here, we present the means implemented offshore to acquire data at the submarine spring over the 06/25/2019 - 12/31/2022 time period together with lagoon water's physico-chemical parameters and levels and onshore groundwater's physico-chemical parameters and levels acquired at springs and boreholes from the karst aquifer.

A drop does not fall in a straight line: a rationale for the width of stalagmites.

Drops loaded in calcium ions detach from stalactites and impact the underlying stalagmites, thereby allowing these latter to grow through calcite precipitation. Nevertheless, little is known about the influence of the drop free fall and splash dynamics on stalagmite shape and width. Through high-speed imaging of impacting drops on stalagmites from several caves, we observed that the impact point position of the drops is scattered, sometimes over several centimetres. We show that this dispersal has no external cause and must, therefore, be self-induced. Using a Langevin-like equation, we then propose a prediction of the impact point dispersal as a function of the falling height travelled by the drops. We finally show that measured stalagmite widths are correlated to the dispersal in the impact point position of the drop.

Insights about transport mechanisms and fracture flow channeling from multi-scale observations of tracer dispersion in shallow fractured crystalline rock.

In fractured media, solute transport is controlled by advection in open and connected fractures and by matrix diffusion that may be enhanced by chemical weathering of the fracture walls. These phenomena may lead to non-Fickian dispersion characterized by early tracer arrival time, late-time tailing on the breakthrough curves and potential scale effect on transport processes. Here we investigate the scale dependency of these processes by analyzing a series of convergent and push-pull tracer experiments with distance of investigation ranging from 4m to 41m in shallow fractured granite. The small and intermediate distances convergent experiments display a non-Fickian tailing, characterized by a -2 power law slope. However, the largest distance experiment does not display a clear power law behavior and indicates possibly two main pathways. The push-pull experiments show breakthrough curve tailing decreases as the volume of investigation increases, with a power law slope ranging from -3 to -2.3 from the smallest to the largest volume. The multipath model developed by Becker and Shapiro (2003) is used here to evaluate the hypothesis of the independence of flow pathways. The multipath model is found to explain the convergent data, when increasing local dispersivity and reducing the number of pathways with distance which suggest a transition from non-Fickian to Fickian transport at fracture scale. However, this model predicts an increase of tailing with push-pull distance, while the experiments show the opposite trend. This inconsistency may suggest the activation of cross channel mass transfer at larger volume of investigation, which leads to non-reversible heterogeneous advection with scale. This transition from independent channels to connected channels when the volume of investigation increases suggest that both convergent and push-pull breakthrough curves can inform the existence of characteristic length scales.

[Septo-optic dysplasia. Apropos of a new case report]. / La dysplasie septo-optique. A propos d'une nouvelle observation.

Septo-optic dysplasia was detected in a 3 month-old boy. Abnormalities consisted of agenesis of septum lucidum as shown by cerebral CT scan and of hypoplasia of optic nerves resulting in pendular nystagmus and visual impairment. A slight visual improvement was observed at 10 months of age. Growth curve was normal and blood GH determination was not performed. Rubella infection had occurred in the 2nd month of pregnancy with rising antibody titers up to the 7 1/2 month.