Optical Properties, Suspended Sediments, and Chemistry Associated with the Turbidity Maxima of the Delaware Estuary

Biggs, Robert B.; Sharp, Jonathan H.; Church, Thomas M.; Tramontano, J. M.

doi:10.1139/f83-279

Cited by 96 publications

(45 citation statements)

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“…8). The low PN:PP average in the upper estuary has been shown to result from PO, adsorption to inorganic particulates and phosphorus-rich mineral phases (Biggs et al 1983, Lebo & Sharp 1992. In light of this low PN:PP ratio, the elevated PN:PP ratios observed during spring support the interpretation of P-limitation.…”

Section: Temporal Variations In Phytoplankton Growth Limitationmentioning

confidence: 87%

Temporal alternation between light- and nutrient-limitation of phytoplankton production in a coastal plain estuary

Pennock¹,

Sharp²

1994

Mar. Ecol. Prog. Ser.

103

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The potential for Light-and nutrient-limitation of phytoplankton production was examined in the Delaware Estuary, USA, by combining a hierarchy of expenmental approaches including smallscale bioassay experiments, ecosystem-level analysis of nutrient concentration and stoichiometric ratios, and light-limitation modeling. Light was found to be the predominate regulator of phytoplankton growth throughout the estuary during the winter period as a result of high turbidity and a wellmixed water column. However, during late spring, phosphorus (P) was found to limit growth. This observation was confirmed at each of the experimental levels, and was related to several factors, including elevated input ratios (230:l) of dissolved inorganic nitrogen (DIN) to PO, in river waters, accumulation of P into phytoplankton, and low rates of P regeneration. During summer, P no longer limited production. At this time DIN:POI ratios and bioassay experiments revealed the potential for nitrogen (N) limitation -particularly in the lower estuary -while particulate composition ratios and ecosystem nutrient flux estimates gave contradictory evidence. From these data it appears that N was potentially limiting to phytoplankton biomass but that the constant flux of N from upstream and rapid N regeneration maintained non-nutrient-limited steady-state growth. These data document a pattern of recurring system-wide variations in the factors that limit phytoplankton production over several annual sequences. These temporal and spatial variations are related to both light availability -as regulated by incldent light, suspended sediment concentration, and depth of the surface mixed-layerand nutrient availability -as determined by riverine inputs and in situ biogeochemical processes.

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Section: Temporal Variations In Phytoplankton Growth Limitationmentioning

confidence: 87%

Temporal alternation between light- and nutrient-limitation of phytoplankton production in a coastal plain estuary

Pennock¹,

Sharp²

1994

Mar. Ecol. Prog. Ser.

103

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“…However, the qPCR data also indicated higher abundance of AAP bacteria in waters with higher light attenuation. Light attenuation is due to a combination of factors, including the presence of colored dissolved organic matter (9,11) and suspended particles (6,7). In the Baltic, bChl a and colored dissolved organic matter concentrations were positively correlated (26), suggesting an inverse relationship of AAP bacterial abundance with light.…”

Section: Discussionmentioning

confidence: 99%

Aerobic Anoxygenic Phototrophic Bacteria Attached to Particles in Turbid Waters of the Delaware and Chesapeake Estuaries

Waidner

Kirchman

2007

Appl Environ Microbiol

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Aerobic anoxygenic phototrophic (AAP) bacteria are photoheterotrophs that, if abundant, may be biogeochemically important in the oceans. We used epifluorescence microscopy and quantitative PCR (qPCR) to examine the abundance of these bacteria by enumerating cells with bacteriochlorophyll a (bChl a) and the light-reaction center gene pufM, respectively. In the surface waters of the Delaware estuary, AAP bacteria were abundant, comprising up to 34% of prokaryotes, although the percentage varied greatly with location and season. On average, AAP bacteria made up 12% of the community as measured by microscopy and 17% by qPCR. In the surface waters of the Chesapeake, AAP bacteria were less abundant, averaging 6% of prokaryotes. AAP bacterial abundance was significantly correlated with light attenuation (r ‫؍‬ 0.50) and ammonium (r ‫؍‬ 0.42) and nitrate (r ‫؍‬ 0.71) concentrations. Often, bChl a-containing bacteria were mostly attached to particles (31 to 94% of total AAP bacteria), while usually 20% or less of total prokaryotes were associated with particles. Of the cells containing pufM, up to 87% were associated with particles, but the overall average of particleattached cells was 15%. These data suggest that AAP bacteria are particularly competitive in these two estuaries, in part due to attachment to particles.Recent studies indicate that photoheterotrophic bacteria, which are capable of both phototrophy and heterotrophy, may be abundant and important in biogeochemical cycles of the oceans (3,23,28). One type of photoheterotroph, aerobic anoxygenic phototrophic (AAP) bacteria, can harvest light by use of bacteriochlorophyll a (bChl a) for the production of ATP (45). Phototrophy explains the higher growth rates (46) and viability (40) of these bacteria grown in the light compared with the results seen with dark-grown cultures. Some AAP bacteria reduce the production of photosynthetic pigments in response to higher organic carbon concentrations (27,40). These data suggest that AAP bacteria would have competitive advantages over typical heterotrophs when organic carbon concentrations are low (23).This hypothesis was supported by the discovery of AAP bacteria in the open ocean (28), where AAP bacteria can make up from Ͻ1% to 10% of the prokaryotic community (13, 18, 37). However, emerging evidence indicates that these bacteria may be as abundant in eutrophic as in oligotrophic environments (13,37,39). A global survey of bacteria containing bChl a and the reaction center pufM gene found that AAP bacteria were more abundant in the Long Island Sound and Chesapeake Bay than in the open ocean (37). Additionally, these bacteria were more abundant in the North Atlantic Ocean, where chlorophyll concentrations were higher, than in the North Pacific, where AAP bacteria comprised less than 5% of prokaryotes (13). These wide ranges suggest that more data on the abundance of AAP bacteria are needed to determine the ecological controls of these bacteria.To explore what environmental factors control AAP bacteria, we enumerated cells...

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“…"Mean C/N ratio . Biggs et al, 1983). C/N ratio of planktonic or ganisms increase with decomposition, e.g., the C/ N ratio of deep sea (>1000 m) sediments reaches values greater than 10-15 (Miiller, 1977) due to preferential loss of nitrogen relative to carbon (Miiller, 1977;Rosenfield, 1981;Haugen and Lichtentaler, 1991).…”

Section: Discussion Toc Ts and Tn Profilesmentioning

confidence: 99%

Sulfur and organic carbon relationship in sediments from coastal brackish lakes in the Shimane peninsula district, southwest Japan.

et al. 1997

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This paper presents the characteristics of sulfur and organic carbon concentrations, and the general factors controlling them in the brackish coastal lake sediments. Three sediment cores taken from the Lakes Nakaumi and Shinji, southwest Japan, were analyzed for total sulfur (TS), total organic carbon (TOC) and total nitrogen (TN) concentrations in dry weight. The cores' lengths were 12-30 m and the ages of the bottom layers in each core were 7000-10000 yr.B.P. The TS, TOC and TN profiles in the cores were similar, i.e., they were low in the lower portion of the cores, increased upward in the middle portion and decreased upward in the upper portion. Although there were variations in the TS, TOC and TN, the relationship between TS and TOC, and that between TN and TOC showed good correlations . The slopes of TS-TOC and TN-TOC regression lines depended on the depositional environments. The slope of the TS-TOC regression line generally correlated with the mean C/N ratio. The high value of the slope corresponded to the low C/N ratio. This suggests that the effective sulfate reduction depends on the organic matter type. Primarily the degree of preservation of freshly deposited planktonic organic matter is important.The TS-TOC regression line was: TS = 1.13TOC + 0.084 (r = 0.777, n = 278), which slope was ap parently different from the slope of normal marine sediments (0.36). This is indirectly due to the primary productivity, the sedimentation rate and the water depth. In addition, the "initial minimum" amount of consumed organic carbon in the process of sulfate reduction was estimated on the basis of mass balance between consumed TOC and fixed TS.

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Optical Properties, Suspended Sediments, and Chemistry Associated with the Turbidity Maxima of the Delaware Estuary

Cited by 96 publications

References 0 publications

Temporal alternation between light- and nutrient-limitation of phytoplankton production in a coastal plain estuary

Temporal alternation between light- and nutrient-limitation of phytoplankton production in a coastal plain estuary

Aerobic Anoxygenic Phototrophic Bacteria Attached to Particles in Turbid Waters of the Delaware and Chesapeake Estuaries

Sulfur and organic carbon relationship in sediments from coastal brackish lakes in the Shimane peninsula district, southwest Japan.

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