Cascading effects augment the direct impact of CO2 on phytoplankton growth in a biogeochemical model
Author:
Seifert Miriam1, Nissen Cara1, Rost Björn12, Hauck Judith1
Affiliation:
1. 1Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Am Handelshafen, Bremerhaven, Germany 2. 2Universität Bremen, Bremen, Germany
Abstract
Atmospheric and oceanic CO2 concentrations are rising at an unprecedented rate. Laboratory studies indicate a positive effect of rising CO2 on phytoplankton growth until an optimum is reached, after which the negative impact of accompanying acidification dominates. Here, we implemented carbonate system sensitivities of phytoplankton growth into our global biogeochemical model FESOM-REcoM and accounted explicitly for coccolithophores as the group most sensitive to CO2. In idealized simulations in which solely the atmospheric CO2 mixing ratio was modified, changes in competitive fitness and biomass are not only caused by the direct effects of CO2, but also by indirect effects via nutrient and light limitation as well as grazing. These cascading effects can both amplify or dampen phytoplankton responses to changing ocean pCO2 levels. For example, coccolithophore growth is negatively affected both directly by future pCO2 and indirectly by changes in light limitation, but these effects are compensated by a weakened nutrient limitation resulting from the decrease in small-phytoplankton biomass. In the Southern Ocean, future pCO2 decreases small-phytoplankton biomass and hereby the preferred prey of zooplankton, which reduces the grazing pressure on diatoms and allows them to proliferate more strongly. In simulations that encompass CO2-driven warming and acidification, our model reveals that recent observed changes in North Atlantic coccolithophore biomass are driven primarily by warming and not by CO2. Our results highlight that CO2 can change the effects of other environmental drivers on phytoplankton growth, and that cascading effects may play an important role in projections of future net primary production.
Publisher
University of California Press
Subject
Atmospheric Science,Geology,Geotechnical Engineering and Engineering Geology,Ecology,Environmental Engineering,Oceanography
Reference185 articles.
1. Alvarez-Fernandez, S, Bach, LT, Taucher, J, Riebesell, U, Sommer, U, Aberle, N, Brussaard, CPD, Boersma, M.2018. Plankton responses to ocean acidification: The role of nutrient limitation. Progress in Oceanography165: 11–18. DOI: https//dx.doi.org/10.1016/j.pocean.2018.04.006. 2. Aumont, O, Ethé, C, Tagliabue, A, Bopp, L, Gehlen, M.2015. PISCES-v2: An ocean biogeochemical model for carbon and ecosystem studies. Geoscientific Model Development8(8): 2465–2513. DOI: http://dx.doi.org/10.5194/gmd-8-2465-2015. 3. Aumont, O, Maier-Reimer, E, Blain, S, Monfray, P.2003. An ecosystem model of the global ocean including Fe, Si, P colimitations. Global Biogeochemical Cycles17(2): 1–26. DOI: http://dx.doi.org/10.1029/2001GB001745. 4. Bach, LT.
2015. Reconsidering the role of carbonate ion concentration in calcification by marine organisms. Biogeosciences12(16): 4939–4951. DOI: http://dx.doi.org/10.5194/bg-12-4939-2015. 5. Bach, LT, Hernández-Hernández, N, Taucher, J, Spisla, C, Sforna, C, Riebesell, U, Arístegui, J.2019. Effects of elevated CO2 on a natural diatom community in the subtropical NE Atlantic. Frontiers in Marine Science6: 75. DOI: http://dx.doi.org/10.3389/fmars.2019.00075.
Cited by
2 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|