Description
Arcachon Bay is an inland sea that breathes. It meets the Atlantic only through channels some three kilometres wide, between the tip of Cap Ferret and the Dune du Pilat. On every spring tide, some 370 million cubic metres of water flow in and out again, and two thirds of its surface are uncovered at low water. Beneath this coming and going, the sand never stays put: the current sculpts it into ripples, banks and submerged dunes — sedimentologists speak of tidal dunes — that advance with the flood and fall back with the ebb. Sailors know this shifting relief: for nearly thirty years, the buoyage of the northern channel has been laid anew every year before summer, after a fresh survey of the seabed.
The photograph is taken straight above the mouth of the bay, off Pyla-sur-Mer, on an August afternoon in 2021. Sand and water compose a work that no one designed: pale crests, almost parallel, creasing like cloth; below them, the sharp edge of the channel, where the water turns at once from celadon to emerald. Only a small boat, set at the edge of the shadow, reminds us that this landscape is real, and immense. By the next tide, the pattern will have moved.
The first part of the Ondulations series, which looks at the same shifting matter in three states: relief, surface, edge.





