Interannual and Subdecadal Variability in the Nutrient Geochemistry of the Cariaco Basin

Scranton, Mary I.; Taylor, Gordon T.; Thunell, Robert C.; Benitez-Nelson, Claudia R.; Muller‐Karger, Frank E.; Fanning, Kent A.; Lorenzoni, Laura; Montes, Enrique; Varela, Ramón; Astor, Yrene

doi:10.5670/oceanog.2014.18

Cited by 35 publications

(74 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Additional work is needed to test this paradigm in other ecosystems, especially under non-steadystate conditions. Nevertheless, many aquatic ecosystems are permanently or almost permanently anoxic (8,40,60), and hence, our approach and conclusions are expected to be particularly applicable to these systems.…”

Section: Consequences For Geobiologymentioning

confidence: 99%

Integrating biogeochemistry with multiomic sequence information in a model oxygen minimum zone

Louca

Hawley

Katsev

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

120

View full text Add to dashboard Cite

Microorganisms are the most abundant lifeform on Earth, mediating global fluxes of matter and energy. Over the past decade, high-throughput molecular techniques generating multiomic sequence information (DNA, mRNA, and protein) have transformed our perception of this microcosmos, conceptually linking microorganisms at the individual, population, and community levels to a wide range of ecosystem functions and services. Here, we develop a biogeochemical model that describes metabolic coupling along the redox gradient in Saanich Inlet-a seasonally anoxic fjord with biogeochemistry analogous to oxygen minimum zones (OMZs). The model reproduces measured biogeochemical process rates as well as DNA, mRNA, and protein concentration profiles across the redox gradient. Simulations make predictions about the role of ubiquitous OMZ microorganisms in mediating carbon, nitrogen, and sulfur cycling. For example, nitrite "leakage" during incomplete sulfide-driven denitrification by SUP05 Gammaproteobacteria is predicted to support inorganic carbon fixation and intense nitrogen loss via anaerobic ammonium oxidation. This coupling creates a metabolic niche for nitrous oxide reduction that completes denitrification by currently unidentified community members. These results quantitatively improve previous conceptual models describing microbial metabolic networks in OMZs. Beyond OMZ-specific predictions, model results indicate that geochemical fluxes are robust indicators of microbial community structure and reciprocally, that gene abundances and geochemical conditions largely determine gene expression patterns. The integration of real observational data, including geochemical profiles and process rate measurements as well as metagenomic, metatranscriptomic and metaproteomic sequence data, into a biogeochemical model, as shown here, enables holistic insight into the microbial metabolic network driving nutrient and energy flow at ecosystem scales.M icrobial communities catalyze Earth's biogeochemical cycles through metabolic pathways that couple fluxes of matter and energy to biological growth (1). These pathways are encoded in evolving genes that, over time, spread across microbial lineages and today shape the conditions for life on Earth. High-throughput sequencing and mass-spectrometry platforms are generating multiomic sequence information (DNA, mRNA, and protein) that is transforming our perception of this microcosmos, but the vast majority of environmental sequencing studies lack a mechanistic link to geochemical processes. At the same time, mathematical models are increasingly used to describe local-and global-scale biogeochemical processes or predict future changes in global elemental cycling and climate (2, 3). Although these models typically incorporate the catalytic properties of cells, they fail to integrate the information flow from DNA to mRNA, proteins, and process rates as described by the central dogma of molecular biology (4). Hence, a mechanistic framework integrating multiomic data with geochemical information has...

show abstract

Section: Consequences For Geobiologymentioning

confidence: 99%

Integrating biogeochemistry with multiomic sequence information in a model oxygen minimum zone

Louca

Hawley

Katsev

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

120

View full text Add to dashboard Cite

show abstract

“…Due to the geomorphology of the basin, advection is confined to the surface layers of the water column, from which biogenic material and detritus rich in opal, organic carbon and lithogenic material are exported to the deeper waters (THUNELL et al, 2000;. The laminated sediments underlying the anoxic water mass serve as an important repository for past variability of inter-and extra-tropical climate (REUER et al, 2003;MULLER-KARGER et al, 2001;SCRANTON et al, 2014). The data presented in this study originate from samples that were collected monthly from January 2006 to September 2007 at the Cariaco sampling station ( Figure 1) at 18 water depths from the surface down to 1310 m (1, 7, 15, 25, 35, 55, 75, 100, 130, 160, 200, 250, 300, 350, 400, 500, 750, 1310 m).…”

Section: Study Areamentioning

confidence: 99%

“…The upper layers of the basin present the most pronounced changes in temperature due to the influence of coastal upwelling and lateral advection of cooler water masses from the Caribbean Sea (ASTOR et al, 1998;MULLER-KARGER et al, 2001;ASTOR et al, 2003). Vertical mixing below 100 m is inhibited by the presence of a strong pycnocline (SCRANTON et al, 1987;SCRANTON et al, 2014). Temperatures were only used down to 200 meters.…”

Section: Study Areamentioning

confidence: 99%

“…Based on equations used by (BROECKER; PENG,1982) on inorganic carbon derived from calcareous test and organic carbon from soft tissue (REDFIELD, 1963), is the slope of the TA vs TCO 2 relationship (RÍOS et al, 1995). m depth and is relatively cool (22 to 23ºC; Figure 3) and enriched in nutrients (ASTOR et al, 1998;MULLER-KARGER et al, 2001;ASTOR et al, 2003;SCRANTON et al, 2014). Despite the high productivity, TCO 2 concentrations were relatively low in the photic zone (< 200 m), with values between 1968 and 2300 µmol kg -1 .…”

Section: Study Areamentioning

confidence: 99%

“…Temperatures were only used down to 200 meters. Below 200 m, the waters are isolated and acquire anoxic characteristics with almost constant temperature and salinity (ASTOR et al, 1998;SCRANTON et al, 2014). Primary productivity (PP) was determined from the inorganic carbon fraction assimilated by phytoplankton using 14 C bicarbonate following the method of STEEMAN-NIELSEN (1952) with modifications by KNAP et al (1997) and UNESCO (1994).…”

Section: Study Areamentioning

confidence: 99%

See 2 more Smart Citations

Carbon regeneration in the Cariaco Basin, Venezuela

et al. 2017

Self Cite

View full text Add to dashboard Cite

The carbon regeneration in the water column of the Cariaco Basin (Venezuela) was investigated using a regression model of total alkalinity (TA) and the concentration of total inorganic carbon (TCO 2 ). Primary productivity (PP) was determined from the inorganic carbon fraction assimilated by phytoplankton and the variation of the 22 and 23°C isotherm was used as an indicator of coastal upwelling. The results indicate that CO 2 levels were lowest (1962 µmol/kg) at the surface and increased to 2451 µmol/kg below the oxic-anoxic redox interface. The vertical regeneration distribution of carbon was dominated (82%) by organic carbon originating from the soft tissue of photosynthetic organisms, whereas 18% originated from the dissolution of biogenic calcite. The regeneration of organic carbon was highest in the surface layer in agreement with the primary productivity values. However, at the oxic-anoxic interface a second more intense maximum was detected (70-80%), generated by chemotrophic respiration of organic material by microorganisms. The percentages in the anoxic layers were lower than in the oxic zone because aerobic decomposition occurs more rapidly than anaerobic respiration of organic material because more labile fractions of organic carbon have already been mineralized in the upper layers. AbstrAct

show abstract

Decadal variability in the oxygen inventory of North Atlantic subtropical underwater captured by sustained, long‐term oceanographic time series observations

Montes

Muller‐Karger

Cianca

et al. 2016

Global Biogeochemical Cycles

Self Cite

View full text Add to dashboard Cite

Historical observations of potential temperature (θ), salinity (S), and dissolved oxygen concentrations (O 2 ) in the tropical and subtropical North Atlantic (0-500 m; 0-40°N, 10-90°W) were examined to understand decadal-scale changes in O 2 in subtropical underwater (STUW). STUW is observed at four of the longest, sustained ocean biogeochemical and ecological time series stations, namely, the CArbon Retention In A show that STUW O 2 has decreased approximately 0.71, 0.28, and 0.37 μmol kg À1 yr À1 , respectively. No apparent change in STUW O 2 was observed at ESTOC over the course of the time series (1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013). Ship observation data for the tropical and subtropical North Atlantic archived at NOAA National Oceanographic Data Center show that between 1980 and 2013, STUW O 2 (upper 300 m) declined 0.58 μmol kg À1 yr À1 in the southeastern Caribbean Sea (10-15°N, 60-70°W) and 0.68 μmol kg À1 yr À1 in the western subtropical North Atlantic (30-35°N, 60-65°W). A declining O 2 trend was not observed in the eastern subtropical North Atlantic (25-30°N, 15-20°W) over the same period. Most of the observed O 2 loss seems to result from shifts in ventilation associated with decreased wind-driven mixing and a slowing down of STUW formation rates, rather than changes in diffusive air-sea O 2 gas exchange or changes in the biological oceanography of the North Atlantic. Variability of STUW O 2 showed a significant relationship with the wintertime (January-March) Atlantic Multidecadal Oscillation index (AMO, R 2 = 0.32). During negative wintertime AMO years trade winds are typically stronger between 10°N and 30°N. These conditions stimulate the formation and ventilation of STUW. The decreasing trend in STUW O 2 in the three decades spanning 1980 through 2013 reflects the shift from a strongly negative wintertime AMO between the mid-1980s and mid-1990s to a positive wintertime AMO observed between the mid-1990s and 2013. These changes in STUW O 2 were captured by the CARIACO, BATS, and Hydrostation S time series stations. Sustained positive AMO conditions could lead to further deoxygenation in tropical and subtropical North Atlantic upper waters.

show abstract

Interannual and Subdecadal Variability in the Nutrient Geochemistry of the Cariaco Basin

Cited by 35 publications

References 41 publications

Integrating biogeochemistry with multiomic sequence information in a model oxygen minimum zone

Integrating biogeochemistry with multiomic sequence information in a model oxygen minimum zone

Carbon regeneration in the Cariaco Basin, Venezuela

Decadal variability in the oxygen inventory of North Atlantic subtropical underwater captured by sustained, long‐term oceanographic time series observations

Contact Info

Product

Resources

About