Role of fungi, bacteria, and invertebrates in leaf litter breakdown in a polluted river

Pascoal, Cláudia; Cássio, Fernanda; Marcotegui, Aránzazu; Sanz, B. Ferreiro; Gomes, Pedro T.

doi:10.1899/05-010.1

Cited by 111 publications

(93 citation statements)

References 41 publications

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“…Detritus is a poor-quality resource under ambient nutrient concentrations even when colonized by microbes, but nutrient enrichment can cause dramatic changes in detrital quality (Robinson and Gessner 2000, Pascoal et al 2005, Chung and Suberkropp 2009). However, this quality response may differ for small-and large-sized detrital particles as a result of fungal vs bacterial dominance or the chemical and structural characteristics of substrates (e.g., differences in initial C:nutrient ratios, lignin content).…”

mentioning

confidence: 99%

Stream nutrient enrichment has a greater effect on coarse than on fine benthic organic matter

2013

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Abstract. Nutrient enrichment affects bacteria and fungi associated with detritus, but little is known about how biota associated with different size fractions of organic matter respond to nutrients. Bacteria dominate on fine (,1 mm) and fungi dominate on coarse (.1 mm) fractions, which are used by different groups of detritivores. We measured the effect of experimental nutrient enrichment on fungal and bacterial biomass, microbial respiration, and detrital nutrient content on benthic fine particulate organic matter (FPOM) and coarse particulate organic matter (CPOM). We collected FPOM and CPOM from 1 reference and 1 enriched stream. CPOM substrates consisted of 2 litter types with differing initial C:nutrient ratios (Acer rubrum L. and Rhododendron maximum L.). Fungal and bacterial biomass, respiration, and detrital nutrient content changed with nutrient enrichment, and effects were greater on CPOM than on FPOM. Fungal biomass dominated on CPOM (,99% total microbial biomass), whereas bacterial biomass dominated on FPOM (,95% total microbial biomass). These contributions were unchanged by nutrient enrichment. Bacterial and fungal biomass increased more on CPOM than FPOM. Respiration increased more on CPOM (up to 300% increase) than FPOM (,50% increase), indicating important C-loss pathways from these resources. Microbial biomass and detrital nutrient content were positively related. Greater changes in nutrient content were observed on CPOM than on FPOM, and changes in detrital C:P were greater than changes in detrital C:N. Threshold elemental ratios analyses indicated that enrichment may reduce P limitation for shredders and exacerbate C limitation for collector-gatherers. Changes in CPOMdominated pathways are critical in predicting shifts in detrital resource quality and C flow that may result from nutrient enrichment of detritus-based systems.

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mentioning

confidence: 99%

Stream nutrient enrichment has a greater effect on coarse than on fine benthic organic matter

2013

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“…There is evidence that increases in nitrate and phosphate concentrations stimulate microbial respiration and fungal and bacterial activity (biomass buildup, sporulation, and/or productivity) on plant litter, leading to faster leaf decomposition in freshwaters (16,17,26,34). However, fungal demands of nitrate and phosphate are reported to be fulfilled at relatively low levels (1,12), and further increases in these nutrients in the stream water do not necessarily result in enhanced fungal activity.…”

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confidence: 99%

Microbial Decomposer Communities Are Mainly Structured by Trophic Status in Circumneutral and Alkaline Streams

Duarte

Pascoal

Garabetian

et al. 2009

Appl Environ Microbiol

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In streams, the release of nitrogen and phosphorus is reported to affect microbial communities and the ecological processes they govern. Moreover, the type of inorganic nitrogen (NO 3 , NO 2 , or NH 4 ) may differently impact microbial communities. We aimed to identify the environmental factors that structure aquatic microbial communities and drive leaf litter decomposition along a gradient of eutrophication. We selected five circumneutral (Portuguese) and five alkaline (French) streams differing in nutrient concentrations to monitor mass loss of alder leaves, bacterial and fungal diversity by PCR-denaturing gradient gel electrophoresis, fungal biomass and reproduction, and bacterial biomass during 11 weeks of leaf immersion. The concentrations of inorganic nutrients in the stream water ranged from 5 to 300 g liter ؊1 soluble reactive phosphorus, 0.30 to 5.50 mg liter ؊1 NO 3 -N, 2 to 103 g liter ؊1 NO 2 -N, and <4 to 7,100 g liter ؊1 NH 4 -N. Species richness was maximum in moderately anthropized (eutrophic) streams but decreased in the most anthropized (hypertrophic) streams. Different species assemblages were found in subsets of streams with different trophic statuses. In both geographic areas, the limiting nutrient, either nitrate or phosphate, stimulated the microbial activity in streams of intermediate trophic status. In the hypertrophic streams, fungal biomass and reproduction were significantly lower, and bacterial biomass dramatically decreased at the site with the highest ammonium concentration. The limiting nutrients that defined the trophic status were the main factor structuring fungal and bacterial communities, whatever the geographic area. A very high ammonium concentration in stream water most probably has negative impacts on microbial decomposer communities.

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“…Processing rates of organic matter typically are higher in urban than in forested watersheds because of excess nutrients and stimulated microbial processing (Pascoal et al 2005, Imberger et al 2008) but can decline because of decreases in macroinvertebrate consumers (Chadwick et al 2006). Physical fragmentation associated with higher storm runoff in urban watersheds can increase losses of organic matter to downstream reaches (Paul et al 2006).…”

Section: Drivermentioning

confidence: 99%

“…These factors include negative effects of genetically modified crop by-products on detritivore growth rates in agricultural streams ), inhibition of biological processing by acid and heavy metals in mining regions (Dangles et al 2004, Roussel et al 2008, and general increases in sediment loading that reduce algal production and invertebrate processing of organic matter (Schofield et al 2004, Pascoal et al 2005.…”

Section: Loss Of Conifer Treesmentioning

confidence: 99%

“…2). Elevated nutrients stimulate microbial production associated with detritus (Suberkropp et al 2010) and increase litter breakdown rates (Pascoal et al 2005, Ferreira et al 2006, Greenwood et al 2007. Increased temperatures will stimulate microbial respiration rates (Bä rlocher et al 2008) but may inhibit metazoan feeding rates (Friberg et al 2009, Ferreira et al 2010, Boyero et al 2011).…”

Section: Reach-scale Effects Of Organic Matter Changes On Freshwater mentioning

confidence: 99%

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Effects of CO₂-altered detritus on growth and chemically mediated decisions in crayfish (Procambarus clarkii)

Adams

Tuchman

Moore

2005

Journal of the North American Benthological Society

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Role of fungi, bacteria, and invertebrates in leaf litter breakdown in a polluted river

Cited by 111 publications

References 41 publications

Stream nutrient enrichment has a greater effect on coarse than on fine benthic organic matter

Stream nutrient enrichment has a greater effect on coarse than on fine benthic organic matter

Microbial Decomposer Communities Are Mainly Structured by Trophic Status in Circumneutral and Alkaline Streams

Effects of CO₂-altered detritus on growth and chemically mediated decisions in crayfish (Procambarus clarkii)

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Role of fungi, bacteria, and invertebrates in leaf litter breakdown in a polluted river

Cited by 111 publications

References 41 publications

Stream nutrient enrichment has a greater effect on coarse than on fine benthic organic matter

Stream nutrient enrichment has a greater effect on coarse than on fine benthic organic matter

Microbial Decomposer Communities Are Mainly Structured by Trophic Status in Circumneutral and Alkaline Streams

Effects of CO2-altered detritus on growth and chemically mediated decisions in crayfish (Procambarus clarkii)

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Effects of CO₂-altered detritus on growth and chemically mediated decisions in crayfish (Procambarus clarkii)