Recognizing Salt Wave Events in Coastal Systems

TL;DR

This paper introduces the concept of 'coastal salt waves' to characterize episodic extreme salinity events, highlighting their variability, ecological impacts, and importance for coastal management strategies.

Contribution

It proposes a novel framework for identifying and analyzing salt wave events, emphasizing their significance beyond long-term salinity trends.

Findings

Salt waves show significant spatial and temporal variability.

Salt wave characteristics can differ from long-term saltwater intrusion trends.

Systems without rising average salinity can still experience frequent or intense salt waves.

Abstract

Saltwater intrusion is a critical challenge to coastal ecosystems, impacting freshwater resources, biogeochemical cycles, and habitat stability. While relevant studies often focus on the long-term trends of salinity, its episodic variability and resulting ecological disturbance remains underexplored. Here, we introduce the concept of "coastal salt waves" - periods of elevated salinity anomalies, akin to heat waves - to better characterize extreme salinity events and emphasize their significance. Using cases studies, we show that coastal salt waves exhibit significant spatial and temporal variability based on their duration, intensity, frequency, cumulation, and timing, with drivers and impacts that may differ from gradual saltwater intrusion. In years with similar average salinity, salt waves may still vary greatly in characteristics like intensity, resulting in varying environmental impacts. Furthermore, systems without rising average salinity may still face more frequent or intense salt waves. This framework supports monitoring and management strategies to mitigate coastal salinization risks.