Dissecting the microbial food web: structure and function in the absence of autotrophs

Sintes, Eva; Martínez-Taberner, A.; Moyà, G.; Ramón, Guillem

doi:10.3354/ame037283

Cited by 13 publications

(5 citation statements)

References 57 publications

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“…The relationship between HNFs and prokaryotes in aquifers might not be correctly represented by the Gasol model (Gasol, 1994). The potential reasons for deviations are: the relatively low numbers of active and viable prokaryotic cells in groundwater (Sintes et al, 2004), the impact of other predators, and HNFs using alternative food sources or grazing at low prey densities (Cho et al, 2000).…”

Section: Proposed Carbon Flux Within An Alpine Groundwater Microbial ...mentioning

confidence: 99%

Bottom-Up Control of the Groundwater Microbial Food-Web in an Alpine Aquifer

Karwautz

Zhou

Kerros³

et al. 2022

Front. Ecol. Evol.

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Groundwater ecosystems are typically poor in organic carbon and productivity sustaining a low standing stock of microbial biomass. In consequence, microbial food webs in oligotrophic groundwater are hypothesized to be bottom-up controlled. To date, quantitative information on groundwater microbial communities, food web interactions, and carbon flow is relatively lacking in comparison to that of surface waters. Studying a shallow, porous alpine aquifer we collected data on the numbers of prokaryotes, virus-like particles and heterotrophic nanoflagellates (HNFs), the concentration of dissolved (DOC) and assimilable organic carbon (AOC), bacterial carbon production (BCP), and physical-chemical conditions for a 1 year hydrological cycle. The potential effects of protozoan grazing and viral lysis onto the prokaryotic biomass was tested. Flow of organic carbon through the microbial food web was estimated based on data from the literature. The abundance of prokaryotes in groundwater was low with 6.1 ± 6.9 × 104 cells mL–1, seasonally influenced by the hydrological dynamics, with higher densities coinciding with a lower groundwater table. Overall, the variability in cell numbers was moderate, and so it was for HNFs (179 ± 103 HNFs mL–1) and virus-like particles (9.6 ± 5.7 × 105 VLPs mL–1). The virus to prokaryotes and prokaryote to HNF ratios ranged between 2–230 and 33–2,084, respectively. We found no evidence for a viral control of prokaryotic biomass, and the biomass of HNFs being bottom-up controlled. First estimations point at carbon use efficiencies of 0.2–4.2% with prokaryotic production, and carbon consumed and recycled by HNFs and phages to be of minor importance. This first groundwater microbial food web analysis strongly hints at a bottom-up control on productivity and standing stock in oligotrophic groundwater ecosystems. However, direct measurement of protozoan grazing and phage mediated lysis rates of prokaryotic cells are urgently needed to deepen our mechanistic understanding. The effect of microbial diversity on the population dynamics still needs to be addressed.

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Section: Proposed Carbon Flux Within An Alpine Groundwater Microbial ...mentioning

confidence: 99%

Bottom-Up Control of the Groundwater Microbial Food-Web in an Alpine Aquifer

Karwautz

Zhou

Kerros³

et al. 2022

Front. Ecol. Evol.

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“…This low value of primary production reflects the low value of the Gironde's TST, which is on the same order of magnitude as that of the Ems estuary (Baird & Ulanowicz 1993) or of Dublin bay (Wilson & Parkes 1998), but 5 times lower than the Seine's TST. This implies no pronounced phytoplanktonic bloom, but constant seasonal high concentrations of allochthonous matter (Sintes et al 2004). As a consequence, the trophic organisation of the Gironde appears to be strongly detritus based; 88% of the total flows in the system come from the Detritus compartment.…”

Section: Topological Patterns In the Gironde Estuarine Trophic Networkmentioning

confidence: 99%

Diversity and stability of an estuarine trophic network

Lobry¹,

David²,

Pasquaud³

et al. 2008

Mar. Ecol. Prog. Ser.

108

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“…Temperature, salinity, total dissolved solids, dissolved oxygen, hardness, ORP, and sulfate generally increase at all locations with increasing depth with a few exceptions. In contrast, two studies of anchialine water bodies in the caves of Mallorca (Carey et al, 2001;Sintes et al, 2004) found dissolved oxygen decreased with depth. Both of these studies also found that temperature and Microbial diversity in caves of Mallorca, Spain microbial community.…”

Section: Resultsmentioning

confidence: 93%