A chemiluminescent technique for the determination of nanomolar concentrations of nitrate and nitrite in seawater

Garside, C.

doi:10.1016/0304-4203(82)90039-1

Cited by 325 publications

(197 citation statements)

References 2 publications

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“…These measurements were done on discrete samples (Niskin casts) from up to 18 depths (O-200 m). On every other station, low-level nitrate concentrations were measured according to the chemoluminescence method of Garside (1982). As part of our efforts to develop models of oceanic Measurements of the minimum and maximum fluoprimary production based on remotely sensed variables, rescence yield, F. and F,, were made with a prototype we have attempted to map photosynthetic characteristics pump-and-probe fluorometer (Kolber et al 1988).…”

Section: Methodsmentioning

confidence: 99%

Synoptic study of variations in the fluorescence based maximum quantum efficiency of photosynthesis across the North Atlantic Ocean

Olaizola¹,

Geider

Harrison

et al. 1996

Limnology & Oceanography

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Using ship-based phytoplankton fluorescence techniques on a 9-d transect of the North Atlantic Ocean, we have produced the first synoptic view of variations in the maximum quantum yield of photosynthetic energy conversion (4,) on an ocean-wide basis. Based on our 4, measurements, the North Atlantic can be divided into two basins. The southeastern basin (from the African coast to the midocean ridge) is characterized by relatively little horizontal variation in 4, over vast stretches of the ocean. In the northwestern basin (from the midocean ridge to the Canadian coast), we measured lower values of 4, than in the eastern basin, particularly in the upper water column. Lowest surface values were found in an area of strong horizontal flow. Our results suggest that nutrient supply limits phytoplankton productivity over vast stretches of the North Atlantic in this period (early summer). However, surface values of 4, across the North Atlantic appear to be independent of nutrient concentration and distance to nitrate supply. We propose that horizontal advection may play an important role in determining the local conditions to which phytoplankton productivity parameters respond. Our results also suggest that an apparent relationship between remotely sensed variables (ocean color, sea surface height) and phytoplankton photosynthetic parameters exists that may provide the basis for the development of new algorithms used to estimate phytoplankton productivity from satellites.To understand the role of oceanic phytoplankton in global biogeochemical cycles, it is necessary to estimate phytoplankton productivity on a global scale. Ocean color remote sensing can now be used to estimate phytoplankton abundance on a global scale. Satellite sensors can also provide data on atmospheric transmittance, thus allowing estimation of incident irradiance on the ocean surface. However, satellite sensors cannot measure the reactivity (photosynthetic rate) of the phytoplankton pool directly. To estimate oceanic productivity, it is necessary to know l Present address:

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Section: Methodsmentioning

confidence: 99%

Synoptic study of variations in the fluorescence based maximum quantum efficiency of photosynthesis across the North Atlantic Ocean

Olaizola¹,

Geider

Harrison

et al. 1996

Limnology & Oceanography

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“…During the SCBS cruises, nitrate was also measured in fresh samples with the chemiluminescent technique of Garside (1982). Concentrations of Chl a (Strickland and Parsons 1972) POC, and PON (Sharp 1974) were determined for each depth at the beginning and end of a 24-h time-course.…”

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confidence: 99%

Particulate thiols in coastal waters: The effect of light and nutrients on their planktonic production

Matrai

Vetter

1988

Limnology & Oceanography

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Reduced sulfur compounds of low molecular weight, mainly particulate glutathione, were present in concentrations up to 600 pM in Saanich Inlet and off southern California. The vertical distributions of particulate glutathione (PGSH) in Saanich Inlet showed a subsurface maximum and decreased with depth in close correspondence with chlorophyll profiles. As with other measures of phytoplankton standing stock, PGSH decreased offshore in the Southern California Bight. In response to exposure to lower than ambient light levels, PGSH decreased in samples after 24‐h, on‐deck incubations except when the ambient nitrate concentration was high. Nitrate enrichment experiments, however, did not lead to enhanced PGSH production in offshore samples that were initially low in nitrate. Diel changes in PGSH were calculated to represent 0.5–4.5% of the corresponding calculated change in total particulate sulfur.

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“…Measurement of the NO released into the gas phase was performed by measurement of the light emitted from the chemiluminescence reaction of NO with ozone in the analyzer. Quantification of nitrite was performed by comparison of NO release from standard solutions of nitrite to that from the assay samples (33). The concentrations of nitrate and nitrite, collectively, were determined using a reaction mixture consisting of 1% VCl 3 in 2 N HCl at 90°C.…”

Section: Methodsmentioning

confidence: 99%

Nitrosyl-Heme Complexes Are Formed in the Ischemic Heart

Tiravanti

Samouilov

Zweíer

2004

Journal of Biological Chemistry

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In addition to the generation from specific nitric-oxide (NO) synthases, NO formation from nitrite occurs in ischemic tissues, such as the heart. Although NO binding to heme-centers is the basis for NO-mediated signaling as occurs through guanylate cyclase, it is not known if this process is triggered with physiologically relevant periods of sublethal ischemia and if nitrite serves as a critical substrate. Therefore electron paramagnetic resonance studies were performed to measure nitrosylheme formation during the time course of myocardial ischemia and reperfusion and the role of nitrite in this process. Rat hearts were either partially nitrite-depleted by nitrite-free buffer perfusion or nitrite-enriched by preinfusion with 50 M nitrite. Ischemic hearts loaded with nitrite showed prominent spectra of six-coordinate nitrosyl-heme complexes, primarily NOmyoglobin, that increased as a function of ischemic duration, whereas in nonischemic-controls these signals were not seen. Total nitrosyl-heme concentrations within the heart were 6.6 ؎ 0.7 M after 30 min of ischemia. Nitrite-depleted hearts also gave rise to NO-heme signals during ischemia, but levels were 8-fold lower. Nitrite-mediated NO-heme complex formation during ischemia was associated with activation of guanylate cyclase. Upon reperfusion, the levels of NO-heme complexes decreased 3-fold by the first 15 min but remained elevated for over 45 min. The decrease in NO-heme complex levels was paralleled by the formation of nitrate, suggesting the oxidation of heme-bound NO upon reperfusion. Thus, nitrite-mediated NO-heme formation occurs progressively during ischemia, with these complexes serving as a store of NO with concordant activation of NO signaling pathways.

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A chemiluminescent technique for the determination of nanomolar concentrations of nitrate and nitrite in seawater

Cited by 325 publications

References 2 publications

Synoptic study of variations in the fluorescence based maximum quantum efficiency of photosynthesis across the North Atlantic Ocean

Synoptic study of variations in the fluorescence based maximum quantum efficiency of photosynthesis across the North Atlantic Ocean

Particulate thiols in coastal waters: The effect of light and nutrients on their planktonic production

Nitrosyl-Heme Complexes Are Formed in the Ischemic Heart

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