Seaweed biogeochemistry: Global assessment of C:N and C:P ratios and implications for ocean afforestation.

Autor: Sheppard EJ; Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia., Hurd CL; Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia., Britton DD; Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia., Reed DC; Marine Science Institute, University of California Santa Barbara, Santa Barbara, California, USA., Bach LT; Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia.
Jazyk: angličtina
Zdroj: Journal of phycology [J Phycol] 2023 Oct; Vol. 59 (5), pp. 879-892. Date of Electronic Publication: 2023 Aug 19.
DOI: 10.1111/jpy.13381
Abstrakt: Algal carbon-to-nitrogen (C:N) and carbon-to-phosphorus (C:P) ratios are fundamental for understanding many oceanic biogeochemical processes, such as nutrient flux and climate regulation. We synthesized literature data (444 species, >400 locations) and collected original samples from Tasmania, Australia (51 species, 10 locations) to update the global ratios of seaweed carbon-to-nitrogen (C:N) and carbon-to-phosphorus (C:P). The updated global mean molar ratio for seaweed C:N is 20 (ranging from 6 to 123) and for C:P is 801 (ranging from 76 to 4102). The C:N and C:P ratios were significantly influenced by seawater inorganic nutrient concentrations and seasonality. Additionally, C:N ratios varied by phyla. Brown seaweeds (Ochrophyta, Phaeophyceae) had the highest mean C:N of 27.5 (range: 7.6-122.5), followed by green seaweeds (Chlorophyta) of 17.8 (6.2-54.3) and red seaweeds (Rhodophyta) of 14.8 (5.6-77.6). We used the updated C:N and C:P values to compare seaweed tissue stoichiometry with the most recently reported values for plankton community stoichiometry. Our results show that seaweeds have on average 2.8 and 4.0 times higher C:N and C:P than phytoplankton, indicating seaweeds can assimilate more carbon in their biomass for a given amount of nutrient resource. The stoichiometric comparison presented herein is central to the discourse on ocean afforestation (the deliberate replacement of phytoplankton with seaweeds to enhance the ocean biological carbon sink) by contributing to the understanding of the impact of nutrient reallocation from phytoplankton to seaweeds under large-scale seaweed cultivation.
(© 2023 The Authors. Journal of Phycology published by Wiley Periodicals LLC on behalf of Phycological Society of America.)
Databáze: MEDLINE
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