The contribution of penguin guano to the Southern Ocean iron pool

• Published in: Nature Communications
• Main Authors: Belyaev, Oleg, Sparaventi, Erica, Navarro, Gabriel, Rodríguez-Romero, Araceli, Tovar-Sánchez, Antonio
• Other Authors: Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Ministerio de Ciencia e Innovación (España), European Commission
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Publishing Group 2023
• Subjects: Element cycles; Marine chemistry; Antarctic; Cierva; Guano; Southern Ocean; The Antarctic; Antarc*; Antarctic Krill; antarcticus; baleen whale; Chinstrap penguin; Euphausia superba
• Online Access: http://hdl.handle.net/10261/337529; https://doi.org/10.1038/s41467-023-37132-5; https://doi.org/10.13039/501100011033; https://doi.org/10.13039/501100004837; https://doi.org/10.13039/501100000780; https://api.elsevier.com/content/abstract/scopus_id/85152273547

Iron plays a crucial role in the high-nutrient, low-chlorophyll Southern Ocean regions, promoting phytoplankton growth and enhancing atmospheric carbon sequestration. In this area, iron-rich Antarctic krill (Euphausia superba) and baleen whale species, which are among their main predators, play a large role in the recycling of iron. However, penguins have received limited attention despite their representing the largest seabird biomass in the southern polar region. Here, we use breeding site guano volumes estimated from drone images, deep learning-powered penguin census, and guano chemical composition to assess the iron export to the Antarctic waters from one of the most abundant penguin species, the Chinstrap penguin (Pygoscelis antarcticus). Our results show that these seabirds are a relevant contributor to the iron remobilization pool in the Southern Ocean. With an average guano concentration of 3 mg iron g-1, we estimate that the Chinstrap penguin population is recycling 521 tonnes iron yr-1, representing the current iron contribution half of the amount these penguins were able to recycle four decades ago, as they have declined by more than 50% since then. This research has been funded by the Spanish Government projects PIMETAN (ref. RTI2018-098048-B-I00), DICHOSO (PID2021-125783OB-I00), EQC2018-004275-P and EQC2019-005721-P funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”. E.S. is supported by the Spanish FPI grant (Ref: PRE2019-089679) and A.R.-R. is supported by the Spanish grant Juan de la Cierva Incorporación (Ref: IJC2018-037545-I) funded by MCIN/AEI/ 10.13039/501100011033 and by “ERDF A way of making Europe”. Copernicus Sentinel data (2021) was obtained from Sentinel Hub. Peer reviewed