{"title":"The Coffin Bay Estuary: Influences from coastal upwelling in the eastern Great Australian Bight","authors":"Jochen Kämpf","doi":"10.1016/j.jmarsys.2025.104112","DOIUrl":null,"url":null,"abstract":"<div><div>Using a coupled physical-biological model at different grid resolutions, this work explores the influences from coastal upwelling on the Coffin Bay Estuary in the eastern Great Australian Bight. The Coffin Bay Estuary, which is a negative estuary, consists of a series of interconnected smaller bay. The findings show the main upwelling plume is topographically steered around but does not enter the Coffin Bay Estuary. Instead, the nitrogen load in seawaters near the estuary is derived from secondary circulations and horizontal turbulence. However, due to photosynthetic consumption in the main upwelling zone, dissolved nitrogen levels are reduced to low values (∼0.8 μM) near the estuary and can only support slow phytoplankton growth. While wind-driven currents rapidly flush the outer bay of the estuary, called Coffin Bay, on a timescale of 5 days, this excludes shallower (<20 m) nearshore water that has a turnover time > 40 days. However, it is this shallower water that is connected to the first inner bay of the estuary, Port Douglas Bay, via strong (>1 m/s) tidal flows in the narrow channel. The other inner bays of the estuary have flushing times >100 days and are not influenced by processes on the ambient continental shelf. Hence, the coastal upwelling region in the eastern Great Australian Bight has generally no or only little influence on the nutrient budget in the Coffin Bay Estuary.</div></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"251 ","pages":"Article 104112"},"PeriodicalIF":2.5000,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Marine Systems","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0924796325000752","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Using a coupled physical-biological model at different grid resolutions, this work explores the influences from coastal upwelling on the Coffin Bay Estuary in the eastern Great Australian Bight. The Coffin Bay Estuary, which is a negative estuary, consists of a series of interconnected smaller bay. The findings show the main upwelling plume is topographically steered around but does not enter the Coffin Bay Estuary. Instead, the nitrogen load in seawaters near the estuary is derived from secondary circulations and horizontal turbulence. However, due to photosynthetic consumption in the main upwelling zone, dissolved nitrogen levels are reduced to low values (∼0.8 μM) near the estuary and can only support slow phytoplankton growth. While wind-driven currents rapidly flush the outer bay of the estuary, called Coffin Bay, on a timescale of 5 days, this excludes shallower (<20 m) nearshore water that has a turnover time > 40 days. However, it is this shallower water that is connected to the first inner bay of the estuary, Port Douglas Bay, via strong (>1 m/s) tidal flows in the narrow channel. The other inner bays of the estuary have flushing times >100 days and are not influenced by processes on the ambient continental shelf. Hence, the coastal upwelling region in the eastern Great Australian Bight has generally no or only little influence on the nutrient budget in the Coffin Bay Estuary.
期刊介绍:
The Journal of Marine Systems provides a medium for interdisciplinary exchange between physical, chemical and biological oceanographers and marine geologists. The journal welcomes original research papers and review articles. Preference will be given to interdisciplinary approaches to marine systems.