Work

How tides significantly alter the flushing of two large neighboring inverse estuaries

Year: 2025

Type: article

Abstract: A three-dimensional hydrodynamic model is applied to study the flushing of two large neighboring inverse estuaries, Spencer Gulf and Gulf St. Vincent, South Australia, with and without tides. A density-driven overturning circulation, peaking in austral late winter and spring controls the flushing of both gulfs. Tidal effects significantly affect the flushing of both estuaries with seawater from the ambient continental shelf. Intensive tidal stirring significantly slows the flushing by ∼9 months in the gulfs’ upper reaches. This tidal stirring weakens lateral density gradients that otherwise would support an exchange circulation enhancing the flushing of the region. To this end, the tidal effect indirectly creates a more hypersaline, dynamically sheltered environment in the Upper Spencer Gulf that ecologically supports the world’s only mass aggregation of the Giant Australian Cuttlefish ( Sepia apama ). On the other hand, strong tidal stirring across a narrow passage, Backstairs Passage, increases the flushing of the southern portion of Gulf St. Vincent by ∼6 months. Findings of this study reveal the significance and opposite roles that tides play in the unique marine environment of South Australian gulfs.

Source: Continental Shelf Research

DOI: 10.1016/j.csr.2025.105605

Author: J. Kämpf

Institution: Flinders University

Language: English

Topic: Oceanographic and Atmospheric Processes

Subfield: Oceanography

Field: Earth and Planetary Sciences

Domain: Physical Sciences

SDG: Life below water

Open Access status: hybrid

Estimated APC paid: $3,260