Effect of rising atmospheric carbon dioxide on the marine nitrogen fixer <i>Trichodesmium</i>

Ramos, Joana Barcelos e; Biswas, Haimanti; Schulz, Kai G.; LaRoche, Julie; Riebesell, Ulf

doi:10.1029/2006gb002898

Cited by 161 publications

(169 citation statements)

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“…The increase in N 2 fixation or PON production under elevated pCO 2 (Barcelos é Ramos et al 2007;Hutchins et al 2007;Kranz et al 2009;Levitan et al 2007) was found to be caused by a prolongation of the N 2 fixation period (Kranz et al 2010a). As these enhanced N 2 fixation rates were not accompanied by larger protein pools of nitrogenase (Levitan et al 2010b), they may have been achieved by post-translational modification and/or higher energy availability for nitrogenase activity.…”

Section: N 2 Fixationmentioning

confidence: 97%

“…In contrast to other marine b-cyanobacteria (e.g., Anabaena, Crocosphaera, Lyngbya, Nodularia, Synechococcus PCC7002), Trichodesmium lacks CO 2 -responsive genes (CcmR/CmpR) as well as genes associated with high-affinity C i acquisition systems (NDH-1 3 , BCT1, SbtA; Price et al 2008). In view of the strong CO 2 dependence in growth and biomass production (Barcelos é Ramos et al 2007;Hutchins et al 2007;Kranz et al 2009Kranz et al , 2010aLevitan et al 2007), one could assume that the CCM of Trichodesmium functions only insufficiently to saturate the carboxylation reaction of RubisCO . Physiological studies have, however, revealed C i affinities high enough to saturate rates of photosynthesis under CO 2 concentrations typical for the present-day ocean (Kranz et al 2009).…”

Section: Inorganic Carbon Acquisitionmentioning

confidence: 99%

“…Four recent studies tested the effect of different CO 2 concentrations on growth, biomass production, and elemental composition of Trichodesmium (Barcelos é Ramos et al 2007;Hutchins et al 2007;Kranz et al 2009;Levitan et al 2007). They concordantly demonstrated higher growth and/or production rates under elevated pCO 2 , with a magnitude exceeding those CO 2 effects previously seen in other marine phytoplankton.…”

Section: Introductionmentioning

confidence: 99%

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Interactions between CCM and N2 fixation in Trichodesmium

2010

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In view of the current increase in atmospheric pCO 2 and concomitant changes in the marine environment, it is crucial to assess, understand, and predict future responses of ecologically relevant phytoplankton species. The diazotrophic cyanobacterium Trichodesmium erythraeum was found to respond strongly to elevated pCO 2 by increasing growth, production rates, and N 2 fixation. The magnitude of these CO 2 effects exceeds those previously seen in other phytoplankton, raising the question about the underlying mechanisms. Here, we review recent publications on metabolic pathways of Trichodesmium from a gene transcription level to the protein activities and energy fluxes. Diurnal patterns of nitrogenase activity change markedly with CO 2 availability, causing higher diel N 2 fixation rates under elevated pCO 2 . The observed responses to elevated pCO 2 could not be attributed to enhanced energy generation via gross photosynthesis, although there are indications for CO 2 -dependent changes in ATP/ NADPH ? H ? production. The CO 2 concentrating mechanism (CCM) in Trichodesmium is primarily based on HCO 3 -uptake. Although only little CO 2 uptake was detected, the NDH complex seems to play a crucial role in internal cycling of inorganic carbon, especially under elevated pCO 2 . Affinities for inorganic carbon change over the day, closely following the pattern in N 2 fixation, and generally decrease with increasing pCO 2 . This down-regulation of CCM activity and the simultaneously enhanced N 2 fixation point to a shift in energy allocation from carbon acquisition to N 2 fixation under elevated pCO 2 levels. A strong light modulation of CO 2 effects further corroborates the role of energy fluxes as a key to understand the responses of Trichodesmium.

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Section: N 2 Fixationmentioning

confidence: 97%

Section: Inorganic Carbon Acquisitionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Interactions between CCM and N2 fixation in Trichodesmium

2010

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“…A recent study has shown that cell division rate doubled and the Redfield ratios (106C/16N/1P) C/P and N/P (not C/N) of the planktonic cyanobacteria Trichodesmium changed markedly, as a response to increasing levels of CO 2 leading to an enhancement of nitrification and potential enhanced CO 2 drawdown (Barcelos e Ramos et al, 2007). It is believed unlikely, but if this proved to be a selective response in phytoplankton, in general it would establish a strong negative feedback to climate, provided the produced POC sank below the mixed layer.…”

Section: Nutrients In Generalmentioning

confidence: 99%

Chapter 1 Impacts of the Oceans on Climate Change

Lewis-Brown¹,

Reid²,

Andersson³

et al. 2009

Advances in Marine Biology

134

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“…In particular, three studies initiated this interest by documenting increased N 2 -fixation rates by Trichodesmium erythraeum in response to elevated P CO 2 (Barcelos e Ramos et al 2007;Hutchins et al 2007; Levitan et al 2007). It is, however, particularly important to answer questions about how multiple environmental factors might change and interact with rising P CO 2 to affect ocean biogeochemical cycles.…”

mentioning

confidence: 99%

Colimitation of the unicellular photosynthetic diazotroph Crocosphaera watsonii by phosphorus, light, and carbon dioxide

Garcia

Hutchins

2013

Limnology & Oceanography

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We describe interactive effects of total phosphorus (total P 5 0.1-4.0 mmol L 21 ; added as H 2 NaPO 4 ), irradiance (40 and 150 mmol quanta m 22 s 21 ), and the partial pressure of carbon dioxide (P CO2 ; 19 and 81 Pa, i.e., 190 and 800 ppm) on growth and CO 2 -and dinitrogen (N 2 )-fixation rates of the unicellular N 2 -fixing cyanobacterium Crocosphaera watsonii (WH0003) isolated from the Pacific Ocean near Hawaii. In semicontinuous cultures of C. watsonii, elevated P CO2 positively affected growth and CO 2 -and N 2 -fixation rates under high light. Under low light, elevated P CO2 positively affected growth rates at all concentrations of P, but CO 2 -and N 2 -fixation rates were affected by elevated P CO2 only when P was low. In both high-light and low-light cultures, the total P requirements for growth and CO 2 -and N 2 -fixation declined as P CO2 increased. The minimum concentration (C min ) of total P and half-saturation constant (K K ) for growth and CO 2 -and N 2 -fixation rates with respect to total P were reduced by 0.05 mmol L 21 as a function of elevated P CO2 . We speculate that low P requirements under high P CO2 resulted from a lower energy demand associated with carbon-concentrating mechanisms in comparison with low-P CO2 cultures. There was also a 0.10 mmol L 21 increase in C min and K K for growth and N 2 fixation with respect to total P as a function of increasing light regardless of P CO2 concentration. We speculate that cellular P concentrations are responsible for this shift through biodilution of cellular P and possibly cellular P uptake systems as a function of increasing light. Changing concentrations of P, CO 2 , and light have both positive and negative interactive effects on growth and CO 2 -, and N 2 -fixation rates of unicellular oxygenic diazotrophs like C. watsonii.Within the past 5 yr, new attention has focused on the effects of elevated partial pressures of carbon dioxide (P CO 2 ) on marine dinitrogen (N 2 ) fixation. In particular, three studies initiated this interest by documenting increased N 2 -fixation rates by Trichodesmium erythraeum in response to elevated P CO 2 (Barcelos e Ramos et al. 2007;Hutchins et al. 2007;Levitan et al. 2007). It is, however, particularly important to answer questions about how multiple environmental factors might change and interact with rising P CO 2 to affect ocean biogeochemical cycles. Hutchins et al. (2007) examined the combined effects of P CO 2 , temperature, and P concentration on N 2 -fixation rates by two strains of T. erythraeum. That study concluded that P CO 2 limitation of N 2 -fixation rates by T. erythraeum was independent of P concentration because the relative magnitude of elevated P CO 2 effects on growth and N 2 -fixation rates was nearly identical in P-limited and Preplete cultures. This finding suggests that decreases in P concentrations, which are likely to accompany future changes in surface ocean warming and stratification (Hutchins et al. 2009), would not influence the effect of elevated P CO 2 on oceanic N 2 ...

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Effect of rising atmospheric carbon dioxide on the marine nitrogen fixer Trichodesmium

Cited by 161 publications

References 42 publications

Interactions between CCM and N2 fixation in Trichodesmium

Interactions between CCM and N2 fixation in Trichodesmium

Chapter 1 Impacts of the Oceans on Climate Change

Colimitation of the unicellular photosynthetic diazotroph Crocosphaera watsonii by phosphorus, light, and carbon dioxide

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