Data-based assessment of environmental controls on global marine nitrogen fixation

Luo, Ya‐Wei; Lima, Ivan D.; Karl, David M.; Deutsch, Curtis; Doney, Scott C.

doi:10.5194/bg-11-691-2014

Cited by 97 publications

(125 citation statements)

References 63 publications

Supporting

Mentioning

107

Contrasting

Order By: Relevance

“…Although numerous studies have investigated the biogeography and controlling mechanisms of marine BNF in recent years (e.g., Moore et al, 2009;Monteiro et al, 2011;Luo et al, 2014;Fernández-Castro et al, 2016), the limiting factors of this process are still under debate. Due to the high energetic cost of fixing N 2 in comparison to the assimilation of dissolved inorganic nitrogen (DIN) (mainly ammonia and nitrate), DIN-replete environments have been considered as inhibitory for the growth of diazotrophs and BNF activity (Holl and Montoya, 2005).…”

Section: Introductionmentioning

confidence: 99%

Biological N2 Fixation in the Upwelling Region off NW Iberia: Magnitude, Relevance, and Players

et al. 2017

View full text Add to dashboard Cite

The classical paradigm about marine N 2 fixation establishes that this process is mainly constrained to nitrogen-poor tropical and subtropical regions, and sustained by the colonial cyanobacterium Trichodesmium spp. and diatom-diazotroph symbiosis. However, the application of molecular techniques allowed determining a high phylogenic diversity and wide distribution of marine diazotrophs, which extends the range of ocean environments where biological N 2 fixation may be relevant. Between February 2014 and December 2015, we carried out 10 one-day samplings in the upwelling system off NW Iberia in order to: (1) investigate the seasonal variability in the magnitude of N 2 fixation, (2) determine its biogeochemical role as a mechanism of new nitrogen supply, and (3) quantify the main diazotrophs in the region under contrasting hydrographic regimes. Our results indicate that the magnitude of N 2 fixation in this region was relatively low (0.001 ± 0.002 -0.095 ± 0.024 µmol N m −3 d −1 ), comparable to the lower-end of rates described for the subtropical NE Atlantic. Maximum rates were observed at the surface during both upwelling and relaxation conditions. The comparison with nitrate diffusive fluxes revealed the minor role of N 2 fixation (<2%) as a mechanism of new nitrogen supply into the euphotic layer. Small diazotrophs (<10 µm) were responsible for all N 2 fixation activity detected in the region. Quantitative PCR targeting the nifH gene revealed the highest abundances of two sublineages of Candidatus Atelocyanobacterium thalassa or UCYN-A (UCYN-A1 and UCYN-A2), mainly at surface waters during upwelling and relaxation conditions, and of Gammaproteobacteria γ-24774A11 at deep waters during downwelling. Maximum abundance for the three groups were up to 6.7 × 10 2 , 1.5 × 10 3 , and 2.4 × 10 4 nifH copies L −1 , respectively. Our findings demonstrate measurable N 2 fixation activity and presence of diazotrophs throughout the year in a nitrogen-rich temperate region.

show abstract

Section: Introductionmentioning

confidence: 99%

Biological N2 Fixation in the Upwelling Region off NW Iberia: Magnitude, Relevance, and Players

et al. 2017

View full text Add to dashboard Cite

show abstract

“…IPSL tends to have high DNF on the eastern side of the Indian Ocean and low DNF in the southeast Pacific Ocean. Figure 2 shows comparisons of modelled DNF rates to observations compiled by Luo et al (2012Luo et al ( , 2014. Figure 2a shows the spatial distribution of measurements; almost all of the data are located in the Pacific and Atlantic Oceans and during the 2000-2010 time period (Luo et al, 2012).…”

Section: Resultsmentioning

confidence: 99%

“…Since understanding of ocean DNF is still very limited (Diez et al, 2008;Sohm et al, 2011;Luo et al, 2012Luo et al, , 2014Voss et al, 2013), the models are quite diverse in their approaches to modelling DNF. Most models represent DNF as a function of light, temperature, and nutrient concentrations, or some combination of these.…”

Section: Cmip5 Models and Experimentsmentioning

confidence: 99%

mentioning

confidence: 99%

“…In the case of UVicESCM, only two periods of 20 years (1980-1999 and 2080-2099) were available to us. We refer to the individual models as CanESM, CESM, GFDL, IPSL, MPI and UVic to signify CanESM2, CESM1-BGC, GFDL-ESM2M, IPSL-CM5A-LR, MPI-ESM-LR, and UVicESCM.Since understanding of ocean DNF is still very limited (Diez et al, 2008;Sohm et al, 2011;Luo et al, 2012Luo et al, , 2014Voss et al, 2013), the models are quite diverse in their approaches to modelling DNF. Most models represent DNF as a function of light, temperature, and nutrient concentrations, or some combination of these.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Ocean dinitrogen fixation and its potential effects on ocean primary production in Earth system model simulations of anthropogenic warming

Riche

Christian

2018

Elementa: Science of the Anthropocene

View full text Add to dashboard Cite

Dinitrogen fixation (DNF) provides a large fraction of the 'new' nitrogen supporting upper ocean productivity, and is associated with environmental conditions likely to show substantial change under anthropogenic warming. For example, surface warming induces stronger stratification, weaker nutrient supply and more rapid nutrient depletion. Using six Earth System Models, we have examined spatial patterns and trends of DNF in the CMIP5 historical and RCP 8.5 experiments. Four models (CanESM2, CESM1-BGC, IPSL-CM5R-LR, and UVicESCM) show high DNF rates in warm, stratified waters mostly associated with the western parts of the ocean basins, while GFDL-ESM2M and MPI-ESM-LR show elevated rates near the eastern boundaries because of coupling of DNF and denitrification. Despite a growing body of data, the spatial pattern of DNF is still insufficiently resolved by available observations, and none of the models agrees well with the observations. Modelled and observed rates are mostly in the same general range except for UVicESCM, and frequency distributions are similar, but spatial pattern correlations are weak and in most cases not statistically significant. Only a few models show strong trends in DNF and primary production in a warming climate, and the signs of the trends are inconsistent. Observations of primary production at the benchmark subtropical station ALOHA (22.75°N, 158°W) and proxies for historical DNF from the same region appear to corroborate trends in CanESM2 that are not present in other models. However, the CanESM DNF parameterization does not include any limitation by P or Fe, so modelled future trends may not materialize due to nutrient limitation. Analysis of available models and observations suggests that our understanding of environmental controls on ocean DNF remains limited and future trends are highly uncertain. Long-term global simulations of DNF will only be meaningful if we maintain long-term observations and extend coverage to undersampled regions.Keywords: ocean dinitrogen fixation; Earth system modelling; anthropogenic climate change Riche and Christian: Ocean dinitrogen fixation and its potential effects on ocean primary production in Earth system model simulations of anthropogenic warming Art. 16, page 2 of 18 of phosphorus or iron are available, with opposing effects on primary production (Karl et al., 1995(Karl et al., , 1997Karl, 1999). As diazotrophic phytoplankton thrive in warm, stratified waters (Sohm et al., 2011), investigating the potentially enhanced role of diazotrophs in tropical and subtropical ocean ecosystems in a warming climate is important. Proxy δ 15N measurements of the DNF contribution to the N inventory in the subtropical Pacific suggest that the recent apparent enhancement discussed by Karl (1999) is a long-term trend throughout the 20 th century, possibly associated with anthropogenic warming (Sherwood et al., 2014).We have examined trends in DNF in a variety of Earth System Models associated with the CMIP5 project (Taylor et al., 2012) to determine which if any sh...

show abstract

Contrasted geographical distribution of N₂ fixation rates and nifH phylotypes in the Coral and Solomon Seas (southwestern Pacific) during austral winter conditions

Bonnet

Rodier

Turk‐Kubo

et al. 2015

Global Biogeochemical Cycles

View full text Add to dashboard Cite

Biological dinitrogen (N2) fixation and the distribution of diazotrophic phylotypes were investigated during two cruises in the Coral Sea and the Solomon Sea (southwestern Pacific) during austral winter conditions. N2 fixation rates were measurable at every station, but integrated (0–150 m) rates were an order of magnitude higher in the Solomon Sea (30 to 5449 µmol N m−2 d−1) compared to those measured in the Coral Sea (2 to 109 µmol N m−2 d−1). Rates measured in the Solomon Sea were in the upper range (100–1000 µmol N m−2 d−1) or higher than rates compiled in the global MARine Ecosystem biomass DATa database, indicating that this region has some of the highest N2 fixation rates reported in the global ocean. While unicellular diazotrophic cyanobacteria from group A (UCYN‐A1 and UCYN‐A2) and the proteobacteria γ‐24774A11 dominated in the Coral Sea and were correlated with N2 fixation rates (p < 0.05), Trichodesmium and UCYN‐B dominated in the Solomon Sea and were correlated (p < 0.05) with N2 fixation rates. UCYN‐A were totally absent in the Solomon Sea. The biogeographical distribution of diazotrophs is discussed within the context of patterns in measured environmental parameters.

show abstract

Data-based assessment of environmental controls on global marine nitrogen fixation

Cited by 97 publications

References 63 publications

Biological N2 Fixation in the Upwelling Region off NW Iberia: Magnitude, Relevance, and Players

Biological N2 Fixation in the Upwelling Region off NW Iberia: Magnitude, Relevance, and Players

Ocean dinitrogen fixation and its potential effects on ocean primary production in Earth system model simulations of anthropogenic warming

Contrasted geographical distribution of N₂ fixation rates and nifH phylotypes in the Coral and Solomon Seas (southwestern Pacific) during austral winter conditions

Contact Info

Product

Resources

About

Data-based assessment of environmental controls on global marine nitrogen fixation

Cited by 97 publications

References 63 publications

Biological N2 Fixation in the Upwelling Region off NW Iberia: Magnitude, Relevance, and Players

Biological N2 Fixation in the Upwelling Region off NW Iberia: Magnitude, Relevance, and Players

Ocean dinitrogen fixation and its potential effects on ocean primary production in Earth system model simulations of anthropogenic warming

Contrasted geographical distribution of N2 fixation rates and nifH phylotypes in the Coral and Solomon Seas (southwestern Pacific) during austral winter conditions

Contact Info

Product

Resources

About

Contrasted geographical distribution of N₂ fixation rates and nifH phylotypes in the Coral and Solomon Seas (southwestern Pacific) during austral winter conditions