Recovery of nitrogen stable isotope signatures in the food web of an intermittently open estuary following removal of wastewater loads

• δ15N values in an ICOLL food web reduced over 8 years without wastewater N input.
• Some δ15N values remained enriched versus a pristine ICOLL, 8 years post-impact.
• Slow recovery of δ15N, compared to open systems, reflects low flushing of ICOLLs.