Time Scale Variations of Estuarine Stratification Parameters and Impact on the Food Chains of the Chesapeake Bay

Tyler, Mary A.; Seliger, H. H.

doi:10.1007/978-1-4612-4562-9_10

Cited by 7 publications

(6 citation statements)

References 27 publications

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“…The extremely large riverine input of nutrients into the system supports a very large photosynthetic biomass in the pycnocline in the spring period of our study (Tyler & Seliger 1989, Malone 1991. Grazing on this biomass would provide the in situ detritus for the exhaustion of dissolved oxygen by methylotrophic bacteria (Janvier et al 1985, Sieburth et al 1993a along with the simultaneous production and oxidation of methane, and the production of hydrogen sulphide by their consortial sulphate-reducing bacteria, could turn the bottom layer of water into a n 'anoxysphere' that would exclude aerobiosis.…”

Section: Discussionsupporting

confidence: 60%

C1 bacteria in the water column of Chesapeake Bay USA. I. Distribution of sub-populations of O2-tolerant, obligately anaerobic, methylotrophic methanogens that occur in microniches reduced by their bacterial consorts

Sieburth¹

1993

Mar. Ecol. Prog. Ser.

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Sub-populations of 02-tolerant, obligately anaerobic methanogens were enriched with monomethylamine (MMA) under 3 different regimens: Reglmen 1, where oxygenated seawater was reduced by the aerobic bacterial consorts of the methanogens in sealed gas-permeable polycarbonate flasks that apparently prevented the accumulation of hydrogen sulphlde whlle allowing the production of traces of ethane and ethylene; Regimen 2, like 1, but with bacterial reduchon in glass serum bottles that permitted the accun~ulation of hydrogen sulphide formed by sulphate-reduction but not the C2 hydrocarbons; and Regimen 3, an anaerobic mehum chemically reduced by sodium sulphide and cysteine that is used to culture methanogens from anoxic sediment. In Regimens 1 and 2 , methanogenic bacterial consortia (MBC) were initiated by MMA-oxidizing bacteria that formed reduced microzones in which MMA could be cleaved by methylotrophlc methanogens to form methane, which was apparently oxidized by aerobic methanotrophs almost as quickly as it was produced until dissolved oxygen was exhausted. The process was accelerated under Regimen 2, whose enrichments were used for the most probable number estimation of methanogenic particulates which showed that they accumulate in the pycnoche. These methanogenic particulates were quite sensitive to filter concentration. The distribution of the 3 sub-populations of methanogens is then shown at 10 stations along the density gradient of the estuary where water samples were obtained from the surface layer, pycnocline and bottom layer of water. The results were similar for each layer, where Reqmen 2 consistently produced twice the number of methanogenic enrichments as obtained with Regimen 1 or 2. In contrast, there was a marked dfference in the distribution of the methanogen populations down the density gradient of the estuary. Enrichment in Regimen 3, which was very successful up the estuary, decreased in effectiveness with increasing density. Enrichments in Reg~rnen 2 were quite effective throughout the transect of stratified waters, while those in Regimen 1 had a narrower distribution. I conclude that 02-tolerant methanogens that occur throughout the water column and peak in the pycnocline grow in fragile microniches that are reduced by bacteria that either consume oxygen, produce hydrogen sulphide, or both. A 'top-down' working hypothesis is presented that could explain the diversity, nature and distribution of the bacterial components of the methanogenic enrichments of the water column, and how the methanogens in anoxic sedunents lacking aerobic bacterial consorts may be selected from them. I also postulate that the methanogens living in bacterially reduced microniches may be unique both physiologically and taxonomically, and may have redox potential (Eh) requirements less strict than methanogens from anoxic H2S-rich sediments.

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Section: Discussionsupporting

confidence: 60%

C1 bacteria in the water column of Chesapeake Bay USA. I. Distribution of sub-populations of O2-tolerant, obligately anaerobic, methylotrophic methanogens that occur in microniches reduced by their bacterial consorts

Sieburth¹

1993

Mar. Ecol. Prog. Ser.

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“…Immunological fingerprinting of these dominant planktonic methanogens indicated that they all are new species and probably include new taxa that are distinct from benthic methanogens (Sieburth et al 1993b). More detailed studies on the methane cycle in the water column of Chesapeake Bay were not practical due to time scale variations of estuarine stratification parameters (Tyler & Seliger 1989), which preclude the resampling of the same vertical water column.…”

Section: Introductionmentioning

confidence: 99%

Planktonic methane production and oxidation within the algal maximum of the pycnocline: seasonal fine-scale observations in an anoxic estuarine basin

Sieburth¹,

Donaghay²

1993

Mar. Ecol. Prog. Ser.

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High resolution profiles of methane concentration and potential methane-oxidation rates were used to test the importance of in situ production and oxidation in controlling methane structure and dynamics in the southern anoxic basin of the Pettaquamscutt Estuary, Rhode Island, USA. Profiles conducted in both April and August showed low but increasing methane concentrations in the surface oxic layer, a minor maximum about 0.75 m above the Eh = 0 boundary, a methane minimum just above Eh = 0, and a rapid increase to a major maximum about 0.75 m below Eh = 0. Methane concentrations in both maxima increased between April and August while concentrations in the methane minimum decreased. This methane minimum in the suboxic zone was strongly associated with a minor oxygen maximum and a major peak in chlorophyll due to the oxygenic alga Euglena proxima. April incubations in the presence of added oxygen at 2°C supported oxidation rates as high as 9% d-' in and just below the methane minimum at the Eh = 0 boundary, due to psychrophilic methane-oxidation. Similar experiments conducted in August at 22°C showed a similar narrow peak in potential methaneoxidation rates in and just below the methane minimum at the Eh = 0 boundary, suggesting that the boundary was now dynamically controlled by rapid mesophilic methane-oxidation. Analysis of the August incubations at 2°C showed a decline in methane at the depths of the major methane maximum for 4 d, followed by a 4 d increase in methane concentration at the same depths, due presumably to the exhaustion of dissolved oxygen and the cessation of the masking oxidation. These results indicate that the seasonal increase in the major methane maximum is generated Ln situ by psychrophilic methaneproduction, a production that IS largely masked by a concomitant psychrophilic methane-oxidation. The shift from an initial dominance of methane-oxidation to a final dominance of methane-production in the same water sample bottles indicates just how sensitive the structure of the major methane maximum is to the bacterial processes of methanogenesis and methanotrophy, changes in water temperature, and oxygen inputs by in situ primary production and physical intrusions. Such processes have made it bfficult to document a major production of methane in the pycnocllne.

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“…Local winds in the region also drive these low oxygen (occasionally sulfidic), high nutrient deeper waters over the shallow flanks of the Bay and its tributaries (e.g. Malone et al, 1986;Tuttle et al, 1987;Tyler and Seliger, 1989), exposing immobile benthic populations to severe oxygen stress. The frequencies and durations of these low DO exposures are sufficient to reduce oyster growth and productivity in shallow, normally aerated depths from late spring-early fall (Osman and Abbe, 1994).…”

Section: Discussionmentioning

confidence: 97%

Prorocentrum minimum blooms: potential impacts on dissolved oxygen and Chesapeake Bay oyster settlement and growth

Brownlee

Sellner

2005

Harmful Algae

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Time Scale Variations of Estuarine Stratification Parameters and Impact on the Food Chains of the Chesapeake Bay

Cited by 7 publications

References 27 publications

C1 bacteria in the water column of Chesapeake Bay USA. I. Distribution of sub-populations of O2-tolerant, obligately anaerobic, methylotrophic methanogens that occur in microniches reduced by their bacterial consorts

C1 bacteria in the water column of Chesapeake Bay USA. I. Distribution of sub-populations of O2-tolerant, obligately anaerobic, methylotrophic methanogens that occur in microniches reduced by their bacterial consorts

Planktonic methane production and oxidation within the algal maximum of the pycnocline: seasonal fine-scale observations in an anoxic estuarine basin

Prorocentrum minimum blooms: potential impacts on dissolved oxygen and Chesapeake Bay oyster settlement and growth

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