Degradation of the Peritrophic Membrane of Fresh-Water Zooplankton Fecal Pellets

Bathelt, Ralph W.; Schelske, Claire L.

doi:10.2307/3225836

Cited by 5 publications

(3 citation statements)

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“…Gammarus and Simulium faecal pellets are bound by exopolymers and these maintain the structure of pellets for at least 35 days (the duration of our experiments; the total ‘survival time’ of pellets is unknown but, from our observations, is probably to be months). Gammarus faecal pellets are bound initially by a peritrophic membrane, but this is not essential for maintaining the structure of pellets, as the membrane fractures soon after egestion and is mostly lost within 48 h. This contrasts with the faecal pellets of planktonic copepods, where the peritrophic membrane may remain in place for a week or more (Honjo & Roman, 1978; Bathelt & Schelske, 1983) and where rupture of the membrane causes rapid dispersal of the contents (Poulsen & Kiørboe, 2005).…”

Section: Discussionmentioning

confidence: 99%

“…The faecal pellets of many invertebrates, such as copepods, are bound by peritrophic membrane surrounding the pellet (Bathelt & Schelske, 1983) but most pellets found in aquatic ecosystems are bound by exopolymers (Wotton & Malmqvist, 2001; Wotton, 2005). Pellets contain many microorganisms that survive gut passage and these, together with microorganisms that colonize the pellet after egestion, break the pellet down over time.…”

Section: Introductionmentioning

confidence: 99%

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Faecal pellets in streams: their binding, breakdown and utilization

2007

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1. Faecal pellets of Gammarus (shredders) and Simulium larvae (suspension feeders) are bound by exopolymers. Immediately after egestion, Gammarus pellets are covered by a peritrophic membrane that breaks up within hours, although pellets remain intact because of internal binding materials. 2. Although they expand soon after egestion, the faecal pellets of Gammarus and Simulium remain intact for more than 30 days. Their internal structure is altered and the main agents of this change are bacteria that have survived passage through the gut (and become bound within pellets). 3. When disrupted physically, freshly egested (1-to 2-day old) Simulium faecal pellets break up into relatively large pieces whereas freshly egested Gammarus faecal pellets break apart into much smaller pieces. Disruption of 30-day old Simulium faecal pellets results in similar sized pieces to those from freshly egested pellets, but disruption of 30-day old Gammarus pellets produces pieces that are two orders of magnitude larger than those resulting from disruption of freshly egested pellets. 4. Faecal pellets of Gammarus and Simulium are eaten by stream invertebrates and are sites of microbial breakdown. Faecal pellets are a source of organic matter for benthic invertebrates, bacteria and, indirectly, for plants.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Faecal pellets in streams: their binding, breakdown and utilization

2007

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“…The most likely explanation for the lack of rapid release of DOC from the fecal pellets is that the chitinous peritrophic membrane encapsulating the pellets was relatively impermeable and hindered the diffusion of solute from the particles. We did not examine the degradation of the peritrophic membranes, however several studies have shown that they degrade over periods of several hours to several weeks, depending on temperature (Small & Fowler 1973, Honjo & Roman 1977, Turner 1979, Bathelet & Schelske 1983. It is also possible that diffusion of solute from the fecal pellets occurred before collection or during rinsing, in which case the observed leaching represents solubilization of the remaining material after unassimilated digestive solute was lost.…”

Section: Carbon Releasementioning

confidence: 99%

Decomposition and release of elements from zooplankton debris

Fisher¹

1992

Mar. Ecol. Prog. Ser.

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In experiments examining the retention of trace elements in decomposing zooplankton debris, the rates of C degradation and metal release from radiolabeled copepod fecal pellets and carcasses were measured for up to 1 mo using radlotracers. Fecal pellets incubated at 18 and 2 "C retained 35 to 40 % and 80 % of their I4C, respectively, after 30 d. Carcasses retained only 13 to 18 % and 28 to 38 % of their 14C after 18 d at 18 and 2 "C, respectively. Leaching of 14C from fecal pellets and carcasses as D0I4C accounted for about half of the 14C loss, even in the absence of microbial activity. Proportionately more of the 14C from carcasses was mlcrobially oxidized to I4CO2 than "C from fecal pellets Release of the particle-reactlve transuranic element 2 4 1~n 1 from fecal pellets was unaffected by microbial activity while release of 75Se and 6 5~n from both fecal pellets and carcasses increased with microbial activity and closely followed I4C loss. Release rates of all elements decreased exponentially over time, wlth the most pronounced decreases occurnng wlthin the first 6 d Retention half-times (t,,,,'~) of 2 4 1~m were 248 d in fecal pellets. By contrast, the t,,12's for "Zn ranged from 2.1 to 13.5 d in fecal pellets and both and had t,,,?'s of only about 1 d in carcasses. The results help explain oceanographic observations that C. Se and Zn are recycled in surface waters while scavenged elements like Am are enriched in fecal pellets and have short residence times in surface waters.

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Bacterial Colonization on Fecal Pellets of Harpacticoid Copepods and on Their Diatom Food

et al. 2010

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Fecal pellets make up a significant fraction of the global flux of organic matter in oceans, and the associated bacterial communities in particular are a potential food source for marine organisms. However, these communities remain largely unknown. In the present study, the bacterial communities on fecal pellets of the benthic copepod Paramphiascella fulvofasciata feeding on the diatoms Navicula phyllepta and Seminavis robusta were analyzed. The aim of this study was to characterize the bacterial communities associated with the diatoms and the fecal pellets by means of DGGE profiling. Furthermore, isolated bacteria were characterized by means of partial 16S rRNA gene sequencing. The composition of the bacterial microflora on fecal pellets was studied in terms of the effect of the original food source, the age of the fecal pellets and the copepod's identity. Alphaproteobacteria, Flavobacteria, and Bacilli were found on the fecal pellets; whereas on diatoms, exclusively Gammaproteobacteria were identified. Especially after eating N. phyllepta, there was an important increase in bacterial diversity, although the diatom N. phyllepta harbored a less diverse bacterial community than S. robusta. Our data suggest that the additional bacteria originate from the copepod's digestive tract and largely depends on the initial food source.

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Degradation of the Peritrophic Membrane of Fresh-Water Zooplankton Fecal Pellets

Cited by 5 publications

References 0 publications

Faecal pellets in streams: their binding, breakdown and utilization

Faecal pellets in streams: their binding, breakdown and utilization

Decomposition and release of elements from zooplankton debris

Bacterial Colonization on Fecal Pellets of Harpacticoid Copepods and on Their Diatom Food

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