Direct measurement of dissolved organic carbon release by phytoplankton and incorporation by microheterotrophs

Wiebe, W. J.; Smith, David F.

doi:10.1007/bf00397745

Cited by 134 publications

(72 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Such utilization can be rapid enough to influence apparent excretion rates after several hours of incubation (Nalewajko et al, 1976;Lancelot, 1979;Billen et al, 1980). It has generally been assumed that excreted carbon equilibrates so quickly with added tracer that underestimates due to tracer disequilibrium would not be an important problem in short incubat i o n~, and there is experimental support for this view (Wiebe and Smith, 1977;Wolter, 1982). However, our results show that short incubations can generate serious underestimates, depending on algal growth conditions, due to disequilibrium.…”

Section: Discussionmentioning

confidence: 43%

Carbon exchange and 14C tracer methods in a nitrogen-limited diatom, Thalassiosira pseudonana

Smith¹,

Piatt²

1984

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

A simple carbon-exchange model accounted for the kinetics of I4C uptake and release by the diatom 73alassiosira pseudonana in nitrogen-limited chernostat culture. The model treats the cells as consisting of 2 pools of carbon; an exchanging pool which carries out photosynthesis, respiration and excretion, and a synthetic pool which does not exchange, but accumulates carbon from the exchanging pool. The model fitted well to observed I4C kinetics over a 10-fold range of growth rates and was demonstrably superior to 2 alternate models which have been prevalent in the theory and application of 14C methodology in primary production studies. The exchanging pool was small (4 to 15 % of cell carbon) and rapidly cycled (90 % turnover time of 1 to 12 h) in all steady-state cultures, but was larger (21 %) and more slowly cycled (15 h) in a chemostat deprived of its limiting nitrogen supply for 24 h. In all cultures, the observed kinetics indicated that usual I4C estimates of phytoplankton production should be close to net production rates, but that short-term 14C estimates of excretion should be too low for slow-growing populations.

show abstract

Section: Discussionmentioning

confidence: 43%

Carbon exchange and 14C tracer methods in a nitrogen-limited diatom, Thalassiosira pseudonana

Smith¹,

Piatt²

1984

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

show abstract

“…Water was collected only at slack low tide in the Duplin River, while in the offshore region it was collected regardless of tidal stage. At the time of collection the water was Size fractionation of water samples was similar to the reverse filtration procedure described by Wiebe & Smith (1977) and Williams (1981). Within 1 h of sampling, water, collected in 12 or 20 1 containers, was gently agitated with a magnetic stirrer, and back-filtered with less than 7 cm head through a 20 cm diameter filtering tube with 1 or 10 pm nitex screening attached across one end.…”

Section: Methodsmentioning

confidence: 99%

“…Wiebe & Smith 1977, Hagstrom et al 1979, Williams 1981, Moriarty 1984, Wright 1984, Wright & Coffin 1984. Of these techniques, the measurement of system respiration has several advantages; it provides a rapid and simple assessment of heterotrophic metabolism which can b e directly related to the oxidation of organic matter.…”

Section: Introductionmentioning

confidence: 99%

Size fractionated metabolism of coastal microbial plankton

Hopkinson¹,

Sherr²,

Wiebe³

1989

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

The quantitative significance of microbial heterotrophs in overall plankton metabolism was investigated in estuarine and coastal waters off the Georgia coast (USA). Three size classes were examined: < 208 pm, < 10 pm and < 1 p m Respiration was measured by monitoring the rate of oxygen consumption in water samples incubated at in situ temperatures in the dark. Rates by all size classes of plankton were highest in the upper reaches of the Duplin h v e r estuary during summer (52.4 pg O2 1-l h-') and lowest 10 km offshore during winter (10.1 pg O2 1-l h-'). Respiration by organisms passing a 1 pm screen exceeded rates in 208 pm and 10 pm filtered samples, but this enhancement decreased w~t h increasing distance offshore. This increased bacterial (< 1 pm) respiration could not be attributed to artifacts of the filtration procedure or to bacterial growth. Respiration results were consistent with concurrently conducted studies of bacterioplankton growth and bactivorous microprotozoan grazing. Static models of carbon and nitrogen flow between bacterioplankton and heterotrophic protozoa suggest that the C/N ratio of the bacterial food source could largely dictate organic carbon conversion efficiency of planktonic bacteria, the relative role of bacteria and microprotozoans as recyclers of nitrogen and the rate of organic carbon utilization. The relative importance of bacterial nitrogen remineralization decreases as the C/N ratio of the organic substrate increases. Results of this study are discussed in context of the microbial loop and the trophic flow leading to higher organisms.

show abstract

“…Thus the DOC production is on average about 20% of primary production. This will exclude DOC produced as extracellular release since cell exudation products turn over rapidly (Iturriaga and Hoppe 1977;Wiebe and Smith 1977), the rate of their consumption by bacteria often equalling their rate of production (Fogg 1983). This is further substantiated by the lack of a close correlation between DOC and primary production cycles (Fig.…”

Section: Referencesmentioning

confidence: 99%

Seasonal changes of dissolved organic matter (C, N, P) in permanently well mixed temperate waters

Wafar

Corre

Birrien

1984

Limnology & Oceanography

View full text Add to dashboard Cite

Seasonal changes of dissolved organic carbon (DOC), nitrogen (DON), phosphorus (DOP), chlorophyll a, and primary production were followed for 17 months in the permanently well mixed waters of the English Channel. There was a proportionality between the intensities of Chl a and the subsequent DOC peaks and the increase in DOC from a previous low value, showing that a major part of the DOC is produced through degradation of particulate organic matter. This DOC production was equivalent to 66 g C · m−2 · yr−1. Phytoplankton excretion may add about 16 g C · m−2 · yr−1 to the DOC pool. The DOM production following a phytoplankton bloom was characterized by a sequential appearance of DON, DOC, and DOP.

show abstract

Direct measurement of dissolved organic carbon release by phytoplankton and incorporation by microheterotrophs

Cited by 134 publications

References 27 publications

Carbon exchange and 14C tracer methods in a nitrogen-limited diatom, Thalassiosira pseudonana

Carbon exchange and 14C tracer methods in a nitrogen-limited diatom, Thalassiosira pseudonana

Size fractionated metabolism of coastal microbial plankton

Seasonal changes of dissolved organic matter (C, N, P) in permanently well mixed temperate waters

Contact Info

Product

Resources

About