Kinetics of glucose and amino acid uptake by attached and free-living marine bacteria in oligotrophic waters

Ayo, Begoña; Unanue, Marian; Azúa, Iñigo; Gorsky, Gabriel; Turley, CM; Iriberri, Juan

doi:10.1007/s002270000518

Cited by 23 publications

(21 citation statements)

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“…Attached bacteria can exhibit high rates of uptake of e.g., glucose and amino acids (Ayo et al 2001), despite low thymidine incorporation rates (Kirchman 1983). Since they have low-affinity uptake characteristics adapted to high substrate concentrations (Ayo et al 2001), a concentrated organic carbon environment such as copepod fecal pellets, might attune their metabolism to production and release of ectoenzymes rather than to growth. Thus, despite higher production rates, growth rates of attached bacteria could be lower than those of free-living bacteria (Alldredge et al 1986).…”

Section: Discussionmentioning

confidence: 99%

Fate of organic carbon released from decomposing copepod fecal pellets in relation to bacterial production and ectoenzymatic activity

Thor

Dam²,

Rogers³

2003

Aquat. Microb. Ecol.

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Fecal pellets were produced by Acartia tonsa fed 14 C-labeled diatom, cryptophyte, and dinoflagellate diets, and were incubated in 1.2 µm-filtered Long Island Sound seawater. Based on the 14 C label, the decrease in fpOC (fecal pellet organic carbon), the release and fate of dissolved organic carbon (DOC) and particulate organic carbon (POC), as well as bacterial production and enzymatic activity, were followed over a 96 h period. fpOC decreased by 9, 14, and 19% d -1 in diatom, cryptophyte, and dinoflagellate pellets, respectively. There was a fast, possibly passive, leakage of DOC from pellets from all 3 diets within a few hours after egestion, which may not have been utilized by attached bacteria. Bacterial production rates were 17, 12, and 31 pg C pellet -1 h -1, on diatom, cryptophyte, and dinoflagellate pellets, respectively. These were 5 orders of magnitude higher than production rates of free-living bacteria, indicating that copepod fecal pellets are hot spots of pelagic microbial production. The high production was caused primarily by high initial bacterial abundances. Accordingly, production and growth were entirely uncoupled in diatom pellets. There were no increases in abundance of attached bacteria on any of the 3 diets, indicating that the produced bacterial cells were released from the fecal pellets. Attached bacteria had a higher ectoenzymatic activity than free-living bacteria, but their production and ectoenzymatic activity were uncoupled and they only assimilated a minor fraction of the released DOC. DOC was therefore released favoring free-living microbes. The chitinase activity, which increased several-fold, was coupled to the production of attached bacteria; thus, chitin may play an important role in bacterial production on copepod fecal pellets.KEY WORDS: Copepod fecal pellets · Fecal pellet decomposition · Pelagic DOC flux · Pelagic POC flux · Attached bacterial production · Ectoenzymatic activity Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 33: [279][280][281][282][283][284][285][286][287][288] 2003 cycled (Wotton & Malmqvist 2001, Turner 2002 and that most carbon originating from these fecal pellets remains part of the long-lived organic carbon in the epipelagic (Legendre & Michaud 1998). Hence, the role of fecal pellets from small copepods is that of supplying nutrients to the epipelagic planktonic microbial community rather than maintaining the vertical flux of organic matter.Copepod fecal pellets host an extensive flora of attached bacteria (Gowing & Silver 1983, Bianchi et al. 1992, Delille & Razouls 1994, Hansen & Bech 1996. Breakdown of the fecal pellets is in part governed by microbial decomposition driven by the hydrolytic activity of these bacteria. The potential hydrolytic activity is generally high in pelagic aggregates of organic matter (Karner & Herndl 1992, Smith et al. 1992, and if this potential is fully exploited in fecal pellets, then decomposition and hence recycling of organic matter may occur rapidly....

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Section: Discussionmentioning

confidence: 99%

Fate of organic carbon released from decomposing copepod fecal pellets in relation to bacterial production and ectoenzymatic activity

Thor

Dam²,

Rogers³

2003

Aquat. Microb. Ecol.

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“…Biofilms on marine particles are assumed to confer a growth advantage to marine bacteria by affording them stable access to one of the most important sources of DOM in the ocean (40), yet the ecological consequences of this process are unclear. Recently, Yawata and coworkers (41) directly compared the behavioral strategies of two sympatric and genetically very closely related populations of marine bacteria (Vibrio cyclitrophicus) (42,43), and they found that their differential propensities to attach to and form biofilms on particles is the key factor in determining their stable coexistence in the environment (41).…”

Section: Biofilm Formation On Marine Particles: When the Dynamic Natumentioning

confidence: 99%

Microfluidic Studies of Biofilm Formation in Dynamic Environments

et al. 2016

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bThe advent of microscale technologies, such as microfluidics, has revolutionized many areas of biology yet has only recently begun to impact the field of bacterial biofilms. By enabling accurate control and manipulation of physical and chemical conditions, these new microscale approaches afford the ability to combine important features of natural and artificial microbial habitats, such as fluid flow and ephemeral nutrient sources, with an unprecedented level of flexibility and quantification. Here, we review selected case studies to exemplify this potential, discuss limitations, and suggest that this approach opens new vistas into biofilm research over traditional setups, allowing us to expand our understanding of the formation and consequences of biofilms in a broad range of environments and applications.

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“…In the pelagic realm, EP and larger aggregates can serve bacteria as special microhabitats, and have been recognized as sites of increased microbial activity (Smith et al 1992, Sherr et al 1999, Ayo et al 2001, Grossart et al 2003. Junge et al (2002) report that a remarkably high fraction of the total number of respiring sea ice bacteria is associated with particles.…”

Section: Ep Colonizationmentioning

confidence: 99%

Abundance, size distribution and bacterial colonization of exopolymer particles in Antarctic sea ice (Bellingshausen Sea)

Meiners¹,

Brinkmeyer²,

Granskog³

et al. 2004

Aquat. Microb. Ecol.

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The abundance, size spectra and bacterial colonization of exopolymer particles were investigated in Antarctic sea ice and underlying water in the Bellingshausen Sea during April 2001. In addition to exopolymer particles (EP), different abiotic (temperature, salinity, ice texture, oxygen isotopic composition, inorganic nutrient concentrations) and biotic (particulate organic carbon/nitrogen, algal pigments, abundance and biomass of bacteria and diatoms) parameters were measured from the samples. The sea ice showed different communities occurring in physically distinct layers of the ice. Algal and bacterial biomass in the ice showed strong vertical gradients and ranged between 59.4 and 5140.4 µg C l -1 and 8.8 and 119.4 µg C l -1 , respectively. EP concentrations in the sea ice were high, with EP abundance ranging between 10.2 and 260.1 × 10 6 particles l -1 and EP area between 3.4 and 92.1 cm 2 l -1 . Median EP concentrations in the ice exceeded under-ice values by 1 order of magnitude. Crude estimates of integrated sea ice EP carbon were equivalent to 14-32% of the integrated POC, and to 34-78% of the integrated diatom biomass. The estimated integrated EP carbon in sea ice exceeded the bacterial biomass by a factor of 10 to 20. The abundance of EP was inversely correlated with size of the particles. EP size spectra showed relatively flat slopes, indicating a relatively large contribution of larger particles. The bacterial colonization of individual EP in the ice and in the underice water was not significantly different. In contrast, due to the large difference of EP concentrations in the 2 habitats, the median proportion of attached bacteria was much higher in the ice (14.8% of the total bacterial number) than in the under-ice water (1.9% of the total bacterial number). The data suggest that EP are an integral component of Antarctic sea ice communities and that EP serve as important substrates for ice-associated bacteria. After the ice melts in spring, large amounts of EP are available to be released to the water, where they may significantly contribute to and alter the particle flux of the ice-covered Southern Ocean.

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Kinetics of glucose and amino acid uptake by attached and free-living marine bacteria in oligotrophic waters

Cited by 23 publications

References 0 publications

Fate of organic carbon released from decomposing copepod fecal pellets in relation to bacterial production and ectoenzymatic activity

Fate of organic carbon released from decomposing copepod fecal pellets in relation to bacterial production and ectoenzymatic activity

Microfluidic Studies of Biofilm Formation in Dynamic Environments

Abundance, size distribution and bacterial colonization of exopolymer particles in Antarctic sea ice (Bellingshausen Sea)

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