Trichodesmium around Australia: A view from space

Qi, Lin; Wang, Menghua; Hu, Chuanmin; Capone, Douglas G.; Subramaniam, Ajit; Carpenter, Edward J.; Xie, Yuyuan

Responsible for half of the ocean's nitrogen input through nitrogen fixation, the saltwater cyanobacterium Trichodesmium is ubiquitous in global tropical and subtropical oceans but particularly abundant around Australia. However, although the earliest report goes back to the 18th century, the knowledge of where and when large quantities of Trichodesmium can be found around Australia is still incomplete. Based on satellite imagery and deep learning, we quantified relative abundance of Trichodesmium around Australia for the period of 2012–2021. Surface aggregations of Trichodesmium were found almost everywhere except the southern coast, with a cumulative footprint exceeding 4.6 million km2. Strong seasonality was found, with peak months between September and November. The spatial distributions and seasonality were found to correlate well with water temperature, iron-rich dust from Australian desert, and black carbon aerosols from frequent bushfires. With the projected ocean warming in the coming century, Trichodesmium may expand further south, making the cumulative footprint even larger.

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Also Published In

Geophysical Research Letters

More About This Work

Academic Units
Lamont-Doherty Earth Observatory
Biology and Paleo Environment
Published Here
September 7, 2023