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High CO2 under nutrient fertilization increases primary production and biomass in subtropical phytoplankton communities: a mesocosm approach

Citation

Hernandez-Hernandez, N and Bach, LT and Montero, MF and Taucher, J and Banos, I and Guan, W and Esposito, M and Ludwig, A and Achterberg, EP and Riebesell, U and Aristegui, J, High CO2 under nutrient fertilization increases primary production and biomass in subtropical phytoplankton communities: a mesocosm approach, Frontiers in Marine Science, 5 Article 213. ISSN 2296-7745 (2018) [Refereed Article]


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Copyright Statement

Copyright 2018 Hernandez-Hernandez, Bach, Montero, Taucher, Banos, Guan, Esposito, Ludwig, Achterberg, Riebesell and Aristegui. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/

DOI: doi:10.3389/fmars.2018.00213

Abstract

The subtropical oceans are home to one of the largest ecosystems on Earth, contributing to nearly one third of global oceanic primary production. Ocean warming leads to enhanced stratification in the oligotrophic ocean but also intensification in cross-shore wind gradients and thus in eddy kinetic energy across eastern boundary regions of the subtropical gyres. Phytoplankton thriving in a future warmer oligotrophic subtropical ocean with enhanced CO2 levels could therefore be patchily fertilized by increased mesoscale and submesoscale variability inducing nutrient pumping into the surface ocean. Under this premise, we have tested the response of three size classes (0.22, 220, and >20 μm) of subtropical phytoplankton communities in terms of primary production, chlorophyll and cell biomass, to increasing CO2 concentrations and nutrient fertilization during an in situ mesocosm experiment in oligotrophic waters off of the island of Gran Canaria. We found no significant CO2-related effect on primary production and biomass under oligotrophic conditions (phase I). In contrast, primary production, chlorophyll and biomass displayed a significant and pronounced increase under elevated CO2 conditions in all groups after nutrient fertilization, both during the bloom (phase II) and post-bloom (phase III) conditions. Although the relative increase of primary production in picophytoplankton (250%) was 2.5 higher than in microphytoplankton (100%) after nutrient fertilization, comparing the high and low CO2 treatments, microphytoplankton dominated in terms of biomass, contributing >57% to the total. These results contrast with similar studies conducted in temperate and cold waters, where consistently small phytoplankton benefitted after nutrient additions at high CO2, pointing to different CO2-sensitivities across plankton communities and ecosystem types in the ocean.

Item Details

Item Type:Refereed Article
Keywords:ocean acidification, primary production, phytoplankton
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Biological Oceanography
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
UTAS Author:Bach, LT (Dr Lennart Bach)
ID Code:133675
Year Published:2018
Web of Science® Times Cited:5
Deposited By:Ecology and Biodiversity
Deposited On:2019-07-05
Last Modified:2019-08-05
Downloads:4 View Download Statistics

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