diff --git a/backend/src/Service/Ingestion/IngestionService.php b/backend/src/Service/Ingestion/IngestionService.php
index a1f6149..a277a74 100644
--- a/backend/src/Service/Ingestion/IngestionService.php
+++ b/backend/src/Service/Ingestion/IngestionService.php
@@ -94,7 +94,7 @@ class IngestionService
 
             // Étape 5 : persistance
             $observation = new SargassumObservation();
-            $observation->setGeometry($geometry);
+            $observation->setGeometry(json_encode($geometry));
             $observation->setDetectedAt($date);
             $observation->setSource($source);
             $observation->setTileId($metadata['tileId']);