Planktonic carbon cycling and transport in surface waters of the highly urbanized Hudson River estuary

Taylor, Gordon; Way, Juliette; Scranton, Mary I.

doi:10.4319/lo.2003.48.5.1779

Cited by 32 publications

(34 citation statements)

References 50 publications

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“…This interpretation agrees with the systematic decline in DOC concentration that occurs along the same transect (Fig. 1), and with the notion that much (> 75%) of the organic carbon loading to the river occurs in the upper reaches, and that this carbon is progressively decomposed and utilized during transit, fueling ecosystem metabolism along the flow path (Howarth et al 1996, Taylor et al 2003. Our results are consistent with these prior studies, but further suggest that the underlying patterns in carbon consumption and processing are considerably more complex and dynamic than previously thought.…”

Section: Links Between Bp Br and Bgesupporting

confidence: 87%

Relationship of bacterial growth efficiency to spatial variation in bacterial activity in the Hudson River

Giorgio

Pace²,

Fischer³

2006

Aquat. Microb. Ecol.

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Variation in bacterial production (BP) is used as an indicator of bacterial metabolism and carbon processing in the analysis of aquatic ecosystems. The allocation of carbon by bacteria to either BP or respiration (BR), however, is variable and may potentially influence the assessment of carbon cycling by bacteria in ecosystems. We studied 10 transects in the Hudson River estuary where there is a gradient in BP and BR along the flow path of the estuary. We measured BP and BR in filtered samples to derive an estimate of bacterial growth efficiency (BGE) that we could compare with independent measurements of total BP (BP T ) from unfiltered samples to evaluate the relationship of BGE to BP. We further tested the assumption that BGE derived from filtered samples is a good estimator of the ambient BGE on a subset of transects in the upriver section where bacteria dominate respiration. There was good agreement (near 1:1) between respiration measured in unfiltered samples and total BR estimated from BP T and BGE in the filtered fraction (total BR = [BP T /BGE] -BP T ). BGE averaged 0.29 but varied from 0.07 to 0.61, and did not explain the general decline in BP T along the river. Rather, BGE was strongly correlated to the residuals of the BP T and specific BP T (i.e. growth) vs. flow path (= river kilometer) relationship, indicating that shifts in bacterial carbon allocation explained local variations in bacterial metabolic activity, and these shifts were superimposed on the larger scale decline in carbon consumption and BP. The pattern in BP along the Hudson River is clearly a combination of changes in consumption as well as in BGE, to the point that the pattern in BP T or growth would be impossible to recreate from any one of these 2 components. We conclude that BGE indicates changes in carbon allocation of bacteria that reflect shifts in relative BR and BP at shorter time and space scales that are distinct from larger overall patterns in consumption and BP.

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Section: Links Between Bp Br and Bgesupporting

confidence: 87%

Relationship of bacterial growth efficiency to spatial variation in bacterial activity in the Hudson River

Giorgio

Pace²,

Fischer³

2006

Aquat. Microb. Ecol.

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“…) similar to values reported previously for the upper and lower estuary (Taylor et al 2003, Findlay 2006. For complete bacteria and protist abundance and biomass data by date see Table S1 in the electronic supplement at www.int-res.com/articles/ suppl/a061p045_supp.pdf.…”

Section: Abundance and Biomass Patternssupporting

confidence: 83%

“…Although all samples were from a single site within the HRE, it is worth noting that the abundances and biomasses within the microbial community at our study site were similar to data from other portions of the HRE, where comparable data are available, as well as to many other estuarine systems. Bacterial concentrations on different sampling dates ranged over approximately 1 order of magnitude (from 1.5 × 10 9 cells l -1 to 1.3 × 10 10 cells l -1 ) with a mean (± SD) bacterial concentration (4.4 × 10 9 ± 3.9 × 10 9 cells l -1) similar to values reported previously for the upper and lower estuary (Taylor et al 2003, Findlay 2006. For complete bacteria and protist abundance and biomass data by date see Table S1 in the electronic supplement at www.int-res.com/articles/ suppl/a061p045_supp.pdf.…”

supporting

confidence: 78%

“…However, the quantitative importance of both omnivory and mixotrophy are somewhat minimized for the HRE. Because of light limitation, high flushing, and high allochthonous C loading, bacterial production exceeds net primary production (gross production minus phytoplankton respiration) by ~2 to 6 times, the system is strongly net heterotrophic (Taylor et al 2003, Howarth et al 2006, and thus, fluxes through the lower food web are dominated by bacteria-based pathways.One test of the approach is whether the estimated rates for the ciliates and flagellates are consistent with direct estimates from other studies (i.e. based on uptake of labeled prey).…”

mentioning

confidence: 99%

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Heterotrophic microplankton in the lower Hudson River Estuary: potential importance of naked, planktonic amebas for bacterivory and carbon flux

Lesen¹,

Juhl²,

Anderson³

2010

Aquat. Microb. Ecol.

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The present study is the first to simultaneously document the contributions of bacteria, heterotrophic flagellates, ciliates, and naked, planktonic amebas to the carbon (C) budget of an estuarine water column, and is also the first study of protistan bacterivory in the lower Hudson River Estuary (HRE). Observations were collected at a single near-shore location between June 2006 and May 2009. Bacterial counts and biomass varied approximately 1 order of magnitude on different dates, but were comparable to previous studies of the HRE and other estuaries. Of the 3 heterotrophic protist groups enumerated, heterotrophic nanoflagellates were the least variable and generally had the highest biomass (on average equaling 38% of the bacterial biomass). Counts and biomasses of ciliates and amebas were highly variable, ranging over at least 3 orders of magnitude between sampling dates. Much of the variability in ameba abundance was consistent with previous observations of seasonality. Ciliate biomass averaged 8%, and ameba biomass averaged 15% of the bacterial biomass. Thus, at this location, the importance of amebas as micropredators may be comparable to that of the ciliates, a group generally receiving greater research attention. Ameba ingestion rates could not be measured directly but 3 indirect approaches for calculating ingestion rates produced mean values ranging from 1.2 to 2.5 ng C d -1 ng -1 ameba biomass. Each approach demonstrated that ameba C consumption at the study location was highly variable, but was at times high relative to the bacterial standing stock. Taken together, these data suggest that amebas may be more common and of greater importance in estuarine C-fluxes than generally appreciated.KEY WORDS: Amoeboid protists · Bacterivory · Bactivory · Grazing · Microzooplankton · Microbial ecology · Ameba · Amoeba Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 61: [45][46][47][48][49][50][51][52][53][54][55][56] 2010 structural and molecular genetic evidence, place them in 2 major groups: (1) the Amoebozoa, all amebas without a flagellated stage in their life cycle, and (2) Heterolobosea (within the eclectic supergroup 'Excavata'), including the amoebo-flagellates that possess a flagellated stage at some point in their life cycle (Adl et al. 2005). The term 'ameba' will be used here specifically to mean naked (non-testate), amoeboid protists, and we will be specifically focusing on free-living amebas, more typically found in aquatic environments, exclusive of the 'slime molds' and their relatives.Naked amebas are considered the most important bacterial grazers in soils (e.g. Clarholm 1981, Bonkowski 2004, and thus, their role in terrestrial environments (especially agricultural soils) has received more attention than in aquatic habitats. The paucity of research on the role of amebas in aquatic systems may be partially attributed to a prevailing opinion that ameba abundance is very low compared to other protists, particularly in the water column (e...

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“…According to Fig. 9, most respiration quotients ( 0excess CO 2 : AOU) at Site M fell in the range of 0.62Á0.90, which was stoichiometric ratio of aerobic biological respiration in the environment with abundance of HCO 3 ( (Chen et al, 1996;Taylor et al, 2003;Zhai et al, 2005). We can make it sure based on estimated uncertainty of C w and lack of duplicate C w measurements.…”

Section: Gas Transfer Velocites Of Ch 4 and Comentioning

confidence: 97%

Gas transfer velocities of methane and carbon dioxide in a subtropical shallow pond

Xiao

Yang

Liu

et al. 2014

Tellus B: Chemical and Physical Meteorology

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Planktonic carbon cycling and transport in surface waters of the highly urbanized Hudson River estuary

Cited by 32 publications

References 50 publications

Relationship of bacterial growth efficiency to spatial variation in bacterial activity in the Hudson River

Relationship of bacterial growth efficiency to spatial variation in bacterial activity in the Hudson River

Heterotrophic microplankton in the lower Hudson River Estuary: potential importance of naked, planktonic amebas for bacterivory and carbon flux

Gas transfer velocities of methane and carbon dioxide in a subtropical shallow pond

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