Adina Paytan
University of California, Santa Cruz, IMS, Faculty Member
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The geochemistry of the youngest Mediterranean sapropel layer suggests changes in productivity and water column oxygen conditions during sapropel deposition. The Ba-enriched interval is broader than the organic-carbon-rich interval of... more
The geochemistry of the youngest Mediterranean sapropel layer suggests changes in productivity and water column oxygen conditions during sapropel deposition. The Ba-enriched interval is broader than the organic-carbon-rich interval of this sapropel. We suggest that the Ba-enriched horizon records the original thickness of the sapropel prior to subsequent partial oxidation. The main carrier of Ba is barite, as microcrystals (0.5-5 µm ) having a morphology characteristic of marine barite, particularly abundant beneath high productivity regions. Ba concentrations do not change at the sapropel layer oxidation front and diagenetic barite crystals are absent, thus the Ba-enriched layer reflects original oceanic conditions of increased biological productivity during sapropel deposition and not diagenetic Ba remobilization. Paleoredox indicators point to restricted oxygenated bottom water but not to fully anoxic conditions. Detrital elements within this layer indicate a lower eolian terrigenous input, enhanced humidity, and increased precipitation/runoff, thus likely higher nutrient supply.
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Abstract The atmosphere is an important pathway by which many nutrients and metals reach the surface ocean. The impact of dust deposition on an oceanic ecosystem is dependent on the amount of bioavailable nutrients exported along with the... more
Abstract The atmosphere is an important pathway by which many nutrients and metals reach the surface ocean. The impact of dust deposition on an oceanic ecosystem is dependent on the amount of bioavailable nutrients exported along with the dust. To estimate the atmospheric fluxes of bioavailable nutrients to the Gulf of Aqaba, a suit of investigations have been made on the concentrations of nutrient species in aerosols, the solubility of aerosol nutrients in seawater and the deposition rates of aerosol particles over the Gulf. ...
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Abstract Coral reef ecosystems are currently threatened by anthropogenic loading of CO2 to the atmosphere and global surface oceans. Model predictions and laboratory experiments indicate that as the pH of the oceans drops, the ability of... more
Abstract Coral reef ecosystems are currently threatened by anthropogenic loading of CO2 to the atmosphere and global surface oceans. Model predictions and laboratory experiments indicate that as the pH of the oceans drops, the ability of calcifying corals to build their carbonate skeletons will be significantly reduced. Here, we investigate coral calcification under extreme conditions of natural ocean acidification in a reef lagoon at Puerto Morelos, Mexico. The lagoon experiences highly localized drops in pH (6.8 to 7.6) and its close ...
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This dataset reports trace metal concentrations in seawater from an incubation experiment carried out in China in April 2011.
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The Paleocene-Eocene Thermal Maximum (PETM), ca. 55 Ma, was a period of extreme global warming caused by rapid emission of greenhouse gases. It is unknown what ended this episode of greenhouse warming, but high oceanic export productivity... more
The Paleocene-Eocene Thermal Maximum (PETM), ca. 55 Ma, was a period of extreme global warming caused by rapid emission of greenhouse gases. It is unknown what ended this episode of greenhouse warming, but high oceanic export productivity over thousands of years (as indicated by high accumulation rates of barium, Ba) may have been a factor in ending this warm period by carbon sequestration. However, Ba has a short oceanic residence time (~10 k.y.), so a prolonged global increase in Ba accumulation rates requires an increase in input of Ba to the ocean, increasing barite saturation. We use a novel proxy for barite saturation (Sr/Ba in marine barite) to demonstrate that the seawater saturation state with respect to barite did not change across the PETM. The observations of increased barite burial, no change in saturation, and the short residence time can be reconciled if Ba burial decreased at continental margin and shelf sites due to widespread occurrence of suboxic conditions, leading to Ba release into the water column, combined with increased biological export production at some pelagic sites, resulting in Ba sink reorganization.
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Abstract The Gulf of Aqaba, Red Sea, is a deep, narrow, semi-enclosed oligotrophic basin surrounded by desert. Precipitation and runoff are close to zero and benthic sources of iron are minimized by the steep shelf and intense summertime... more
Abstract The Gulf of Aqaba, Red Sea, is a deep, narrow, semi-enclosed oligotrophic basin surrounded by desert. Precipitation and runoff are close to zero and benthic sources of iron are minimized by the steep shelf and intense summertime stratification. Exchange of seawater between the Gulf and the Red Sea proper occurs only across a 250 m sill at the southern end. This system represents an end-member with respect to aeolian dry deposition of iron to the ocean. We have measured dissolved and total iron concentrations in the Gulf ...
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Coral calcification is expected to decline as atmospheric carbon dioxide concentration increases. We assessed the potential of <i>Porites astreoides</i>, <i>Siderastrea siderea</i> and <i>Porites... more
Coral calcification is expected to decline as atmospheric carbon dioxide concentration increases. We assessed the potential of <i>Porites astreoides</i>, <i>Siderastrea siderea</i> and <i>Porites porites</i> to survive and calcify under acidified conditions in a 2-year field transplant experiment around low pH, low aragonite saturation (Ω<sub>arag</sub>) submarine springs. Slow-growing <i>S. siderea</i> had the highest post-transplantation survival and showed increases in tissue concentrations of Symbiodiniaceae, chlorophyll <i>a</i> and protein at the low Ω<sub>arag</sub> site. Nubbins of <i>P. astreoides</i> had 20% lower survival and higher chlorophyll <i>a</i> concentration at the low Ω<sub>arag</sub> site. Only 33% of <i>P. porites</i> nubbins survived at low Ω<sub>arag</sub> and their linear extension and calcification rates were reduced. The density of skeletons deposited after transplantation at the low Ω<sub>arag</sub> spring was 15–30% lower for all species. These results suggest that corals with slow calcification rates and high Symbiodiniaceae, chlorophyll <i>a</i> and protein concentrations may be less susceptible to ocean acidification, albeit with reduced skeletal density. We postulate that corals in the springs are responding to greater energy demands for overcoming larger differences in carbonate chemistry between the calcifying medium and the external environment. The differential mortality, growth rates and physiological changes may impact future coral species assemblages and the reef framework robustness.
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En Glossary Adsorption The physical adherence or bonding of organic and inorganic phosphate ions onto the surfaces of soil or mineral particles. Assimilation (transitory immobilization) The process of incorporating nutrients into cellular... more
En Glossary Adsorption The physical adherence or bonding of organic and inorganic phosphate ions onto the surfaces of soil or mineral particles. Assimilation (transitory immobilization) The process of incorporating nutrients into cellular biomass. Authigenic Formed in situ rather than by having been transported or deposited in a location through secondary processes. Chelation The reversible binding (complexation) of a ligand to a metal ion. Decomposition The conversion of organic matter into simple inorganic compounds. Diagenesis The process by which sediment undergoes chemical and physical changes during its lithification. Eolian transport Advection of material via the atmosphere or wind. Eutrophication Excessive nutrients in a body of water that causes a dense algal growth, followed by algal decomposition, anoxia, and impairment of the aquatic community. Flux (phosphorus) Rate of flow of phosphorus per unit area, which has the dimensions [quantify] [time] 1 [area] 1 (used for describing phosphorus turnover within a reservoir of flow from one reservoir to another. Immobilization The process by which labile phosphorus is sequestered and removed from the environmental reservoir of bioavailable phosphorus for a period of time. Inorganic phosphorus A class of chemical compounds that comprises those not existing in or derived immediately from living organisms (e.g., phosphate). Mineral formation Processes in which anions react with cations in the environment to form insoluble precipitates.
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Recent increases in atmospheric carbon dioxide of 40% above pre-industrial levels has resulted in rising aqueous CO2 concentrations that lower the pH of the oceans. Currently, the surface ocean has an average pH between 8.1 and 8.2: it is... more
Recent increases in atmospheric carbon dioxide of 40% above pre-industrial levels has resulted in rising aqueous CO2 concentrations that lower the pH of the oceans. Currently, the surface ocean has an average pH between 8.1 and 8.2: it is estimated that over the next 100 years this value will decrease by ~0.4 pH units. Previous studies have highlighted the negative
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ABSTRACTThe marine macroalgae Ulva sp. is considered an ecosystem engineer in rocky shores of temperate waters worldwide. Ulva sp. harbors a rich diversity of associated microbial epibionts, which are known to affect the algae's... more
ABSTRACTThe marine macroalgae Ulva sp. is considered an ecosystem engineer in rocky shores of temperate waters worldwide. Ulva sp. harbors a rich diversity of associated microbial epibionts, which are known to affect the algae's typical morphological development and ‘health’. We examined the interaction between airborne microbes derived from atmospheric aerosols and Ulva ohnoi growth and physiological state. Specifically, we measured U. ohnoi growth rates and photosynthetic efficiency (Fv/Fm), alongside its microbial epibionts abundance, activity and diversity following dust (containing nutrients and airborne microorganisms) or UV-treated dust (only nutrients) amendments to filtered seawater. Parallel incubations with epibionts-free U. ohnoi (treated with antibiotics that removed the algae epibionts) were also tested to specifically examine if dust-borne microbes can replenish the epibiont community of U. ohnoi. We show that viable airborne microbes can restore U. ohnoi natural ...
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Prokaryotic microbes can become aerosolized and deposited into new environments located thousands of kilometers away from their place of origin. The Mediterranean Sea is an oligotrophic to ultra-oligotrophic marginal sea, which neighbors... more
Prokaryotic microbes can become aerosolized and deposited into new environments located thousands of kilometers away from their place of origin. The Mediterranean Sea is an oligotrophic to ultra-oligotrophic marginal sea, which neighbors northern Africa (a major source of natural aerosols) and Europe (a source of mostly anthropogenic aerosols). Previous studies demonstrated that airborne bacteria deposited during dust events over the Mediterranean Sea may significantly alter the ecology and function of the surface seawater layer, yet little is known about their abundance and diversity during ‘background’ non-storm conditions. Here, we describe the abundance and genetic diversity of airborne bacteria in 16 air samples collected over an East-West transect of the entire Mediterranean Sea during non-storm conditions in April 2011. The results show that airborne bacteria represent diverse groups with the most abundant bacteria from the Firmicutes (Bacilli and Clostridia) and Proteobacter...
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Aerosol deposition may supply a high diversity of airborne microbes, which can affect surface microbial composition and biological production. This study reports a diverse microbial community associated with dust and other aerosol... more
Aerosol deposition may supply a high diversity of airborne microbes, which can affect surface microbial composition and biological production. This study reports a diverse microbial community associated with dust and other aerosol particles, which differed significantly according to their geographical air mass origin. Microcosm bioassay experiments, in which aerosols were added to sterile (0.2 µm filtered and autoclaved) SE Mediterranean Sea (SEMS) water, were performed to assess the potential impact of airborne bacteria on bacterial abundance, production, and N2 fixation. Significant increase was observed in all parameters within a few hours, and calculations suggest that airborne microbes can account for one third in bacterial abundance and 50–100% in bacterial production and N2‐fixation rates following dust/aerosol amendments in the surface SEMS. We show that dust/aerosol deposition can be a potential source of a wide array of microorganisms, which may impact microbial compositio...
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The atmosphere plays a fundamental role in transporting airborne prokaryotes across the oceans and land. Despite the harsh atmospheric conditions, a considerable fraction of the airborne prokaryotic microorganisms survive the journey and... more
The atmosphere plays a fundamental role in transporting airborne prokaryotes across the oceans and land. Despite the harsh atmospheric conditions, a considerable fraction of the airborne prokaryotic microorganisms survive the journey and remain viable upon deposition, and can affect the receiving environment. Here, we provide the first estimate of potential viability proxy for airborne prokaryotic cells at the Southeastern Mediterranean coast in 22 events during 2015, representing marine and terrestrial air-mass trajectories and a significant dust storm event. This was assessed using sequence amplicons of the small subunit ribosomal RNA gene (SSU rRNA) jointly with other complementary measurements. To estimate the relative viability in our dataset we used the ratio between the abundance of the bacterial SSU rRNA transcripts in a given sampling date and the lowest measured value (23.7.2015) as a measure of a relative viability proxy. The abundance of prokaryotes SSU rRNA transcripts ...
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ABSTRACT Northern Monterey Bay, California is subject to recurrent algal blooms of dinoflagellates and diatoms, which can persist for over a month. The area of Monterey Bay where the algae persist has been termed &quot;the... more
ABSTRACT Northern Monterey Bay, California is subject to recurrent algal blooms of dinoflagellates and diatoms, which can persist for over a month. The area of Monterey Bay where the algae persist has been termed &quot;the incubator&quot;. While physical conditions contribute to the formation and retention of blooms in the incubator, the source of constituents needed to sustain the bloom in the incubator is poorly understood. This study investigated submarine groundwater discharge (SGD) as a source of nutrients, carbon and metals to the incubator. SGD flux was determined using naturally occurring radiogenic tracers, and was found to be 87± 12 cubic meters per day per meter of shoreline. Bay water from the incubator was then used to conduct time series incubation experiments to investigate the role of groundwater and groundwater constituents in sustaining the incubator. Algae in incubator water showed the greatest response to SGD and nitrogen additions, as measured by chlorophyll increase. SGD around the bay is enriched in nitrogen compared to bay waters, suggesting nitrogen in SGD is an important constituent to maintaining the incubator in Monterey Bay.
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Research Interests: Environmental Science, Oceanography, Productivity, Chemical and Biological Engineering, Global change, and 14 moreAtmospheric deposition, Nitrogen, Iron, Upwelling, Nutrient, Primary Production, Coastal upwelling, Climate Warming, Primary productivity, El Nino, New Products, Chlorophyll a, Cell Growth, and nutrient cycle
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Abstract Several studies have attempted to reconstruct Quaternary climate variability in Meso-America and the Caribbean region (eg, Hodell et al. 1995; Hughen et al. 2004). Interest in this region has been driven in part by evidence that... more
Abstract Several studies have attempted to reconstruct Quaternary climate variability in Meso-America and the Caribbean region (eg, Hodell et al. 1995; Hughen et al. 2004). Interest in this region has been driven in part by evidence that changes in tropical ocean conditions may drive climate on a global scale and by the realization that the region is well-placed to track past shifts in the average position of the Intertropical Convergence Zone, a major control on precipitation and drought cycles in tropical and sub-tropical areas of the ...
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Phosphorus components and barite in untreated and in carbonate-free sediments of ODP Hole 199-1221C, supplement to: Faul, Kristina L; Paytan, Adina (2005): Phosphorus and barite concentrations and geochemistry in Site 1221 Paleocene/Eocene boundary sediments. In: Wilson, PA; Lyle, M; Firth, JV (e...more
We determined changes in equatorial Pacific phosphorus (µmol P/g) and barite (BaSO4; wt%) concentrations at high resolution (2 cm) across the Paleocene/Eocene (P/E) boundary in sediments from Ocean Drilling Program (ODP) Leg 199 Site 1221... more
We determined changes in equatorial Pacific phosphorus (µmol P/g) and barite (BaSO4; wt%) concentrations at high resolution (2 cm) across the Paleocene/Eocene (P/E) boundary in sediments from Ocean Drilling Program (ODP) Leg 199 Site 1221 (153.40 to 154.80 meters below seafloor [mbsf]). Oxide-associated, authigenic, and organic P sequentially extracted from bulk sediment were used to distinguish reactive P from detrital P. We separated barite from bulk sediment and compared its morphology with that of modern unaltered biogenic barite to check for diagenesis. On a CaCO3-free basis, reactive P concentrations are relatively constant and high (323 µmol P/g or ~1 wt%). Barite concentrations range from 0.05 to 5.6 wt%, calculated on a CaCO3-free basis, and show significant variability over this time interval. Shipboard measurements of P and Ba in bulk sediments are systematically lower (by ~25%) than shore-based concentrations and likely indicate problems with shipboard standard calibrati...
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Since Dymond et al. (1992, doi:10.1029/92PA00181) proposed the paleoproductivity algorithm based on "Bio-Ba", which relies on a strong correlation between Ba and organic carbon fluxes in sediment traps, this proxy has been... more
Since Dymond et al. (1992, doi:10.1029/92PA00181) proposed the paleoproductivity algorithm based on "Bio-Ba", which relies on a strong correlation between Ba and organic carbon fluxes in sediment traps, this proxy has been applied in many paleoproductivity studies. Barite, the main carrier of particulate barium in the water column and the phase associated with carbon export, has also been suggested as a reliable paleoproductivity proxy in some locations. We demonstrate that Ba(excess) (total barium minus the fraction associated with terrigenous material) frequently overestimates Ba(barite) (barium associated with the mineral barite), most likely due to the inclusion of barium from phases other than barite and terrigenous silicates (e.g., carbonate, organic matter, opal, Fe-Mn oxides, and hydroxides). A comparison between overlying oceanic carbon export and carbon export derived from Ba(excess) shows that the Dymond et al. (1992) algorithm frequently underestimates carbon export but is still a useful carbon export indicator if all caveats are considered before the algorithm is applied. Ba(barite) accumulation rates from a wide range of core top sediments from different oceanic settings are highly correlated to surface ocean 14C and Chlorophyll a measurements of primary production. This relationship varies by ocean basin, but with the application of the appropriate f ratio to 14C and Chlorophyll a primary production estimates, the plot of Ba(barite) accumulation and carbon export for the equatorial Pacific, Atlantic, and Southern Ocean converges to a global relationship that can be used to reconstruct paleo carbon export.
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Coarse mode aerosols influence Earth's climate and biogeochemistry by interacting with long-wave radiation, promoting ice nucleation, and contributing important elements to biogeochemical cycles during deposition. Yet coarse mode... more
Coarse mode aerosols influence Earth's climate and biogeochemistry by interacting with long-wave radiation, promoting ice nucleation, and contributing important elements to biogeochemical cycles during deposition. Yet coarse mode aerosols have received less emphasis in the scientific literature. Here we present first efforts to globally synthesize available mass concentration, compositionand optical depth data and modeling for the coarse mode aerosols (<10 \u3bcm) in a new project called "COARSEMAP" (http://www.geo.cornell.edu/eas/PeoplePlaces/Faculty/mahowald/COARSEMAP/). We seek more collaborators who have observational data, especially including elemental or composition data, and/or who are interested in detailed modeling of the coarse mode. The goal will be publications synthesizing data with models, as well as providing synthesized results to the wider communit
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Methanesulfonate (MSA) in the marine boundary layer is commonly considered to be solely contributed by the oxidation of ocean‐derived dimethyl sulfide (DMS) and often used as an indicator of marine biogenic sources. But whether this... more
Methanesulfonate (MSA) in the marine boundary layer is commonly considered to be solely contributed by the oxidation of ocean‐derived dimethyl sulfide (DMS) and often used as an indicator of marine biogenic sources. But whether this judgment is valid in coastal seas and how the validity is affected by air mass transport history have been less discussed. Based on multi‐year observations of aerosol MSA in the coastal East China Sea (ECS) and the Gulf of Aqaba (GA), as well as the analysis of air mass transport pattern and exposure to ocean surface phytoplankton biomass, we found that terrestrial sources made a non‐negligible contribution to MSA over the ECS but not over the GA. The abundant MSA in winter over the coastal ECS was likely associated with substantial emissions of volatile organic sulfur compounds from both anthropogenic and natural sources in eastern China and significant terrestrial transport influenced by the East Asian Monsoon. Good correlations between aerosol MSA and...
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Groundwater-derived solute fluxes to the ocean have long been assumed static and subordinate to riverine fluxes, if not neglected entirely, in marine isotope budgets. Here we present concentration and isotope data for Li, Mg, Ca, Sr, and... more
Groundwater-derived solute fluxes to the ocean have long been assumed static and subordinate to riverine fluxes, if not neglected entirely, in marine isotope budgets. Here we present concentration and isotope data for Li, Mg, Ca, Sr, and Ba in coastal groundwaters to constrain the importance of groundwater discharge in mediating the magnitude and isotopic composition of terrestrially derived solute fluxes to the ocean. Data were extrapolated globally using three independent volumetric estimates of groundwater discharge to coastal waters, from which we estimate that groundwater-derived solute fluxes represent, at a minimum, 5% of riverine fluxes for Li, Mg, Ca, Sr, and Ba. The isotopic compositions of the groundwater-derived Mg, Ca, and Sr fluxes are distinct from global riverine averages, while Li and Ba fluxes are isotopically indistinguishable from rivers. These differences reflect a strong dependence on coastal lithology that should be considered a priority for parameterization i...
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Degradation of peatlands via drainage is increasing globally and destabilizing peat carbon (C) stores. The effects of drainage on the timing and magnitude of lateral C losses from degraded peatlands remains understudied. We measured... more
Degradation of peatlands via drainage is increasing globally and destabilizing peat carbon (C) stores. The effects of drainage on the timing and magnitude of lateral C losses from degraded peatlands remains understudied. We measured spatial and temporal variability in lateral C exports from three drained peat islands in the Sacramento‐San Joaquin Delta in California across the 2017 and 2018 water years using measurements of dissolved inorganic C (DIC), dissolved organic C (DOC), and suspended particulate organic C (POC) concentration combined with discharge. These measurements were supplemented with stable isotope data (δ13C‐DIC, δ13C‐POC, δ15N‐PON, and δ2H‐H2O values) to provide insight into hydrological and biogeochemical controls on lateral C exports from drained peatlands. Drainage DOC and DIC concentrations were seasonally variable with the highest values in the winter rainy season, when discharge was also elevated. Seasonal differences in the mobilization of dissolved C appear...
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The northern Red Sea (NRS) is a low-nutrient, low-chlorophyll (LNLC) ecosystem with high rates of atmospheric deposition due to its proximity to arid regions. Impacts of atmospheric deposition on LNLC ecosystems have been attributed to... more
The northern Red Sea (NRS) is a low-nutrient, low-chlorophyll (LNLC) ecosystem with high rates of atmospheric deposition due to its proximity to arid regions. Impacts of atmospheric deposition on LNLC ecosystems have been attributed to the chemical constituents of dust, while overlooking bioaerosols. Understanding how these vast areas of the ocean will respond to future climate and anthropogenic change hinges on the response of microbial communities to these changes. We tested the impacts of bioaerosols on the surface water microbial diversity and the primary and bacterial production rates in the NRS, a system representative of other LNLC oceanic regions, using a mesocosm bioassay experiment. By treating NRS surface seawater with dust, which contained nutrients, metals, and viable organisms, and “UV-treated dust” (which contained only nutrients and metals), we were able to assess the impacts of bioaerosols on local natural microbial populations. Following amendments (20 and 44 h) th...
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Desert dust storms are frequent in the Northern Red Sea region, providing nutrients (i.e., PO4) and trace‐metals (i.e., Fe) that may stimulate dinitrogen (N2) fixation. Dust also carries a high diversity of airborne microbes (bacteria and... more
Desert dust storms are frequent in the Northern Red Sea region, providing nutrients (i.e., PO4) and trace‐metals (i.e., Fe) that may stimulate dinitrogen (N2) fixation. Dust also carries a high diversity of airborne microbes (bacteria and archaea), including diazotrophs, that may remain viable during transport and upon deposition. Here we evaluate the impact of atmospheric deposition and its associated airborne diazotrophs on N2 fixation in the surface water of the low‐nutrient Northern Red Sea, using mesocosm bioassay experiments. We compared the chemical (nutritional) and sole airborne microbial impact of aerosol additions on N2 fixation using “live‐dust” (release nutrients/trace metals and viable airborne microorganisms) and “UV‐killed dust” (release only chemicals). Airborne diazotrophy accounted for about one third of the measured N2 fixation (0.35 ± 0.06 nmol N · L−1 · day−1 and 0.29 ± 0.06 nmol N · L−1 · day−1, for “February 2017” and “May 2017,” “live‐dust” additions, respec...