Microbial Autotrophy: A Primary Source of Organic Carbon in Marine Sediments

Kepkay, Paul E.; Cooke, Robert C.; Novitsky, James A.

doi:10.1126/science.204.4388.68

Cited by 42 publications

(21 citation statements)

References 7 publications

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“…High rates of dark CO, assimilation have also been measured in the Black Sea (Sorokin 1964), the Saelenvann estuary (Indreba, et al IWgb), and the Cariaco Trench (Tuttle and Jannasch 1979). Kepkay et al (1979) found that chemoautotrophy may provide an appreciable source of organic matter in marine sediments, and bacterial chemoautotrophy may be the major source of primary productivity for deep-sea thermal vent communities (Jannasch and Wirsen 1979).…”

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confidence: 99%

Autotrophic processes in meromictic Big Soda Lake, Nevada

Cloern

Cole

Oremland

1983

Limnology & Oceanography

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Daily rates of oxygenic photosynthesis (OP) by phytoplankton, anoxygenic photosynthesis (AP) by purple sulfur bacteria, and chemoautotrophic productivity (CP = dark CO, assimilation) were measured once each season in saline, meromictic Big Soda Lake. Total daily productivity and the relative importance of each autotrophic process varied with seasonal changes in vertical mixing, light availability, and the biomass of phototrophs. Daily productivity was highest (2,830 mg C.rnmz) and was dominated by OP in winter when the mixolimnion was isothermal, the biomass of phytoplankton was high, and the biomass of purple sulfur bacteria was low. During the summer-fall period of thermal stratification, phytoplankton biomass decreased, a plate of purple sulfur bacteria formed below the oxycline, and daily rates of dark CO, assimilation (CP = 390-680 mg C.rnmz) exceeded phototrophic productivity (OP + AP = ZOO-370 mg C.rnmz). Total annual productivity was about 500 g C.me2, of which 60% was produced by phytoplankton (mostly in winter), 30% by chemoautotrophs (nitrifying and sulfuroxidizing bacteria), and only 10% by photosynthetic bacteria.

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Autotrophic processes in meromictic Big Soda Lake, Nevada

Cloern

Cole

Oremland

1983

Limnology & Oceanography

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“…This coupling may also help explain the post-depositional persistence of organic matter in coastal sediments (e.g. Kepkay et al 1979, Rowe & Howarth 1985.…”

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confidence: 99%

Community electron transport of procaryotes in euryoxic estuarine sediment

Matson¹,

Buck²

1987

Mar. Ecol. Prog. Ser.

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Rates of both tetrazolium and oxygen reduction were obtained seasonally from the top 8 cm of euryoxic estuarine sediment in southeastern New England, USA, over an in situ temperature range of 0 to 20 'C. Anoxic tetrazolium reduction was highest i n the 3 to 5 cm layers at 15 O C (up to 860 n m o l 2 e c m 3 h l ) . Changes in the chemistry of deeper pore-waters (20 to 60 cm) occurring over 90 d indicated that metabolic rates (ca 42 nmol 2 e c m 3 h ' ) were about an order of magnitude lower than those in the surface sediments. Parallel simultaneous estimates of 0; reduction (reduced sediment preincubated in Os-saturated ambient waters Â 10 mM NaN3) averaged 4 times greater than tetrazolium reduction. The postulated occurrence of a mixed metabolic community consisting of facultatively anaerobic heterotrophs and chemolithotrophs agrees with the field data. The community is spread out vertically through watery sediment of a quiescent, highly depositional cove. Soft-bodied infauna may help maintain the Eh potential at ca -200 mV from 1 to 60 cm; the sediment is not sufficiently cohesive to be strongly poised,

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“…The sampling site used in this study was the area of Halifax Harbor known as Eastern Passage, which was also the site of previous studies (8,9,13,14,16 …”

Section: Methodsmentioning

confidence: 99%

Microbial activity at the sediment-water interface in Halifax Harbor, Canada

1983

Deep Sea Research Part B. Oceanographic Literature Review

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The sediment-water interface in Halifax Harbor supports a microbial population of 6.95 x 109 cells per g (dry weight). As determined by the standard technique of suspending subsamples in filtered seawater, the uptake of added glutamic acid by this population is 113.5 ng g (dry weight)-1 h-1. An alternate technique was developed to measure the heterotrophic activity of the interface over longer periods of time, using undisturbed cores with the sediment-water interface intact. Under these conditions, the microbes in the water column and the interface increased exponentially in number, with mean doubling times of 9.6 and 4.5 days, respectively. The uptake of glutamic acid by the microbial population of the interface was determined to be 12.7 ng g (dry weight)-' h-1, almost an order of magnitude less than the uptake determined by the previous method. This indicates that substrate diffusion and competition for substrate by the microbes in the water column are important factors when considering the heterotrophic activity of the sediment microbial population. After 48 h of incubation, uptake and respiration ceased, probably due to the exhaustion of labeled substrate. Additional substrate added after 48 h of incubation was taken up at a rate similar to that measured after the first addition. It appears that the microbial population of the interface is able to respond quickly and repeatedly to relatively large nutrient additions. After 10 days of incubation, the number of "viable" cells as determined by autoradiography was much smaller than the increase in numbers as determined by direct counts. Apparently a large part of the viable population is unaffected by nutrient addition.A previous study (13) has identified the sediment-water interface of a coastal marine bay as an area of intense microbial activity. Because of this activity, the interface must be considered as an important part of the sediment-water ecosystem. Unfortunately, few studies have investigated the microbiology of the marine sedimentwater interface (1, 2, 13), and, to my knowledge, only one such study has addressed the problem directly (13). Likewise, the freshwater sedimentwater interface has also not been studied. OlMh (17) examined the sediment-water interface of shallow lakes and found generally higher viable counts at the sediment surface than in the water column or deeper in the sediment but presented no data on microbial activity.To understand the microbial processes at the sediment-water interface and to determine what factors influence these processes, the present study was initiated. Specifically, it was the purpose of this study to characterize the microbiology of the interface and to examine a method to measure the heterotrophic activity of the microbial population of the interface. Since the interface is, by definition, composed of both sediment and water components, I decided to study the interface by keeping all components of the sediment-water system intact. By using techniques that use entire core samples, I attempted to collect data th...

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Microbial Autotrophy: A Primary Source of Organic Carbon in Marine Sediments

Cited by 42 publications

References 7 publications

Autotrophic processes in meromictic Big Soda Lake, Nevada

Autotrophic processes in meromictic Big Soda Lake, Nevada

Community electron transport of procaryotes in euryoxic estuarine sediment

Microbial activity at the sediment-water interface in Halifax Harbor, Canada

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