Hypoxia in the Persian Gulf and the Strait of Hormuz

• Published in: Marine pollution bulletin 2021-06, Vol.167, p.112354-112354, Article 112354
• Main Authors: Saleh, Abolfazl, Abtahi, Behrooz, Mirzaei, Nikoo, Chen, Chen-Tung Arthur, Ershadifar, Hamid, Ghaemi, Maryam, Hamzehpour, Ali, Abedi, Ehsan
• Format: Article
• Language: English
• Subjects: Acidification; Autumn; Cruises; Dissolved oxygen; Hypoxia; Ocean acidification; Persian Gulf; Persian Gulf Explorer; Straits; Summer
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2021.112354

In this article dissolved oxygen results of research cruises through the Persian Gulf during 2018–2019 are discussed. The results showed that summer to autumn hypoxia occurred mainly at depths ≥ 50 m to the bottom. This seasonal hypoxia started in late summer reaching its greatest severity in mid-autumn with an area of 50,000 km2 in the Persian Gulf. The minimum oxygen measured at the near-bottom layer of the western basin in autumn (25.8 μmol/kg) was lower than any previous measurement in the open waters of the Persian Gulf. In the Strait of Hormuz, the seasonal hypoxia appeared in summer in the near bottom of the most eastern part at the Iranian side. pHT values recorded in hypoxic waters were as low as what is predicted for surface ocean under ocean acidification in 2100. Considering the results, we suggest evaluating the effects of hypoxia and acidification on the Persian Gulf ecosystems. [Display omitted] •Hypoxia in the Persian Gulf evaluated during 2018–2019•Seasonal summer to autumn hypoxia occurred at depths ≥ 50 m to the bottom.•The estimated near-bottom hypoxia in the Persian Gulf was about 50,000 km2 in autumn.•The measured oxygen values were the lowest reported values in the open waters of the Persian Gulf, so far.