Important contribution of macroalgae to oceanic carbon sequestration

Jovhana Ortega, Nathan Geraldi, Intikhab Alam, Allan Kamau, Silvia G. Acinas, Ramiro Logares, Josep M. Gasol, Ramon Massana, Dorte Krause-Jensen, Carlos M. Duarte

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The role of macroalgae in Blue Carbon assessments has been controversial, partially due to uncertainties about the fate of exported macroalgae. Available evidence suggests that macroalgae are exported to reach the open ocean and the deep sea. Nevertheless, this evidence lacks systematic assessment. Here, we provide robust evidence of macroalgal export beyond coastal habitats. We used metagenomes and metabarcodes from the global expeditions Tara Oceans and Malaspina 2010 Circumnavigation. We discovered macroalgae worldwide at up to 5,000 km from coastal areas. We found 24 orders, most of which belong to the phylum Rhodophyta. The diversity of macroalgae was similar across oceanic regions, although the assemblage composition differed. The South Atlantic Ocean presented the highest macroalgal diversity, whereas the Red Sea was the least diverse region. The abundance of macroalgae sequences attenuated exponentially with depth at a rate of 37.3% km−1, and only 24% of macroalgae available at the surface were expected to reach the seafloor at a depth of 4,000 m. Our findings indicate that macroalgae are exported across the open and the deep ocean, suggesting that macroalgae may be an important source of allochthonous carbon, and their contribution should be considered in Blue Carbon assessments.
Original languageEnglish (US)
Pages (from-to)748-754
Number of pages7
JournalNature Geoscience
Volume12
Issue number9
DOIs
StatePublished - Aug 5 2019

Fingerprint Dive into the research topics of 'Important contribution of macroalgae to oceanic carbon sequestration'. Together they form a unique fingerprint.

Cite this