Suspended particle and bacterial maxima in Peruvian coastal waters during a cold water anomaly

Spinrad, Richard W.; Glover, Hilary E.; Ward, Bess B.; Codispoti, Louis A; Kullenberg, Gunnar

doi:10.1016/0198-0149(89)90147-7

Cited by 55 publications

(33 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Bulk seawater counts declined from~6 × 10 5 per ml in the primary chlorophyll maximum and upper oxycline to 1.3 × 10 5 at the oxic-nitrite interface (90 m), before increasing to a maximum of 1.4 × 10 6 at the OMZ core. This pattern agrees with trends from other OMZ sites, where particulate backscattering and bacterial load show local maxima in the photic zone and again in the OMZ (Spinrad et al, 1989;Naqvi et al, 1993;Whitmire et al, 2009). At all depths, gene numbers were substantially higher in the 0.2-1.6 μm (FL) fraction compared with the 1.6-30 μm (PA) fraction, with FL/PA ratios from 8 to 15 (Figure 1f).…”

Section: Oxygen and Nitrogensupporting

confidence: 78%

Size-fraction partitioning of community gene transcription and nitrogen metabolism in a marine oxygen minimum zone

et al. 2015

View full text Add to dashboard Cite

The genetic composition of marine microbial communities varies at the microscale between particleassociated (PA; 41.6 μm) and free-living (FL; 0.2-1.6 μm) niches. It remains unclear, however, how metabolic activities differ between PA and FL fractions. We combined rate measurements with metatranscriptomics to quantify PA and FL microbial activity in the oxygen minimum zone (OMZ) of the Eastern Tropical North Pacific, focusing on dissimilatory processes of the nitrogen (N) cycle. Bacterial gene counts were 8-to 15-fold higher in the FL compared with the PA fraction. However, rates of all measured N cycle processes, excluding ammonia oxidation, declined significantly following particle (41.6 μm) removal. Without particles, rates of nitrate reduction to nitrite (1.5-9.4 nM N d − 1 ) fell to zero and N 2 production by denitrification (0.5-1.7 nM N d − 1 ) and anammox (0.3-1.9 nM N d − 1 ) declined by 53-85%. The proportional representation of major microbial taxa and N cycle gene transcripts in metatranscriptomes followed fraction-specific trends. Transcripts encoding nitrate reductase were uniform among PA and FL fractions, whereas anammox-associated transcripts were proportionately enriched up to 15-fold in the FL fraction. In contrast, transcripts encoding enzymes for N 2 O and N 2 production by denitrification were enriched up to 28-fold in PA samples. These patterns suggest that the majority of N cycle activity, excluding N 2 O and N 2 production by denitrification, is confined to a FL majority that is critically dependent on access to particles, likely as a source of organic carbon and inorganic N. Variable particle distributions may drive heterogeneity in N cycle activity and gene expression in OMZs.

show abstract

Section: Oxygen and Nitrogensupporting

confidence: 78%

Size-fraction partitioning of community gene transcription and nitrogen metabolism in a marine oxygen minimum zone

et al. 2015

View full text Add to dashboard Cite

show abstract

“…There is only limited direct evidence bearing on this question. Recently, Spinrad et al (1989) found in mesocosm studies that changes in bacterial abundance could contribute significantly to the variability in the diffuse attenuation coefficient of seawater. Also, we note a striking similarity (Fig.…”

Section: Discussionmentioning

confidence: 99%

Biogeochemical significance of bacterial biomass in the ocean's euphotic zone

Cho¹,

Azam²

1990

Mar. Ecol. Prog. Ser.

405

254

View full text Add to dashboard Cite

Bacterial abundance and biomass were extensively measured in the euphotic zone at several oligotrophic and mesotrophlc sites of coastal and open Pacific ocean during different seasons. Cornpansons with phytoplankton biomass and l a t h particulate organic carbon (POC) were made in order to determine the quantitative significance of bacteria as a carbon and nitrogen pool in the euphotic zone. Analysis of our data and that from the literature showed that bacterial abundance in the euphotic zone has a lower threshold of ca 3 X 105 1111-' or 6 pg C 1-' Consequently, with increasingly oligotrophic condit~ons photoautotrophic bion~ass may decrease well below the bacterial b~omass. In oligotrophic waters bacterial biomass was comn~only 2 to 3 times greater than phytoplankton biomass. In contrast, In mesotrophic to eutrophic waters bactenal biomass was generally much less than phytoplankton biomass. Cornpanson w~t h total POC (which included bacterial carbon) showed that in o l~g o t r o p h~c waters bacterial b~o m a s s averaged 40 % (range 26 to 62 '6) of POC inexplicably, the sum of bacterial carbon and phytoplankton carbon was always about one-half of POC The dominance of bacterial biomass over phytoplankton biomass in oligotrophlc oceans has sign~ficant impl~cations for the food-web structure, nutr~ent cycling pathways, and for s i n l n g flux of organic matter Future studies should examine the physiological and trophic mechan~sms which lead to the dominance of bacterial biomass in oligotrophlc systems but of photoautotrophic biomass In the e u t r o p h~c systems

show abstract

“…Because of these widespread suboxic and anoxic conditions, very high accumulations of nitrous oxide and hydrogen sulfide occur in this region (Naqvi et al 2000). Denitrifying zones in the subsurface hypoxic layers of the Eastern Tropical Pacific Ocean and the Arabian Sea are recognized by their secondary nitrite maxima (SNM), which also have high bacterial abundances (Spinrad et al 1989, Ward et al 1998. The depth of the SNM is highly correlated with the depth of the particle maxima in oxygen minimum zones of these regions (Naqvi et al 1993).…”

Section: Development Of Denitrification In the Study Areamentioning

confidence: 99%

Diversity of nitrite reductase genes (nirS) in the denitrifying water column of the coastal Arabian Sea

Jayakumar¹,

Francis²,

Naqvi³

et al. 2004

Aquat. Microb. Ecol.

104

105

View full text Add to dashboard Cite

Denitrification often occurs in the water column, underlying zones of intense productivity and decomposition in upwelling regions. In the denitrifying zone off the southwest coast of India, high concentrations of nitrite (>15 µM) and nitrous oxide (> 500 nM) have been reported near the sediment-water interface (< 80 m). We investigated the chemical and molecular indicators of denitrification along the southwest coast of India during the southwest monsoon season of October 2001. Nitrite reduction to nitric oxide is the key step in the denitrification pathway, and is catalyzed by the enzyme nitrite reductase, which is encoded by the genes nirS and nirK. Here we report the diversity and distribution of nirS genes in relation to nitrite and nitrate distribution in the Arabian Sea coastal denitrifying region. nirS gene fragments were PCR-amplified, cloned, and sequenced from DNA extracted from the water column. Clone libraries were also subjected to restriction fragment length polymorphism (RFLP) and rarefaction analyses. These are the first nitrite reductase sequences reported from a water column denitrifying regime. nirS was amplified from DNA extracted from all water samples in which nitrite was present at high concentrations within the low oxygen waters, but was only rarely amplified from waters containing hydrogen sulfide or from well-oxygenated waters. Phylogenetic analysis grouped 132 nirS Arabian Sea sequences into 12 major clusters. Most of the nirS sequences from the coastal water column did not show a high level of identity with other nirS sequences previously reported from marine and estuarine sediments. Identities of the Arabian Sea sequences to those in the public database ranged from 44 to 99% at the amino acid level. The dominant sequence type from 1 surface sample showed 99% identity to the nirS sequence of the cultivated denitrifier Pseudomonas aeruginosa. Rarefaction analysis, based on both sequence and RFLP data, indicated the highest diversity in a sample in which relatively high nitrite concentrations implied the presence of active denitrification, and the lowest diversity in a surface sample where nitrite was undetectable, suggesting a link between functional diversity and ecosystem chemistry. KEY WORDS: Nitrite reductase · nirS · Denitrification · Arabian Sea · Water column Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 34: [69][70][71][72][73][74][75][76][77][78] 2004 the open Arabian Sea, and the other within the seasonal OMZ along the shelf of the southwest coast of India. In the open Arabian Sea, the development of oxygen-deficient conditions leading to denitrification is attributed to excessive oxygen consumption, combined with the low oxygen content of waters responsible for renewal (Swallow 1984, Naqvi 1987. In the coastal OMZ, denitrification occurs seasonally, centered around the southwest monsoon season (May to October), when intensive upwelling takes place along the entire shelf of the southwest coast of India, injecting ...

show abstract

Suspended particle and bacterial maxima in Peruvian coastal waters during a cold water anomaly

Cited by 55 publications

References 18 publications

Size-fraction partitioning of community gene transcription and nitrogen metabolism in a marine oxygen minimum zone

Size-fraction partitioning of community gene transcription and nitrogen metabolism in a marine oxygen minimum zone

Biogeochemical significance of bacterial biomass in the ocean's euphotic zone

Diversity of nitrite reductase genes (nirS) in the denitrifying water column of the coastal Arabian Sea

Contact Info

Product

Resources

About