Diel fluctuations in rates of CO2 evolution from standing dead leaf litter of the emergent macrophyte Juncus effusus

Kuehn, Kevin A.; Suberkropp, Keller

doi:10.3354/ame014171

Cited by 46 publications

(44 citation statements)

References 38 publications

(60 reference statements)

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“…Recently, researchers have shown that it is likely that in general fungi dominate secondary microbial production in marine and freshwater standing decaying grass shoots (26,27,37,46,50,53). Kohlmeyer et al (25) found a diverse community of ascomycetous decomposers that are especially adapted to standing decaying blades of black needlerush (J. roemerianus).…”

Section: Discussionmentioning

confidence: 99%

Autumnal Biomass and Potential Productivity of Salt Marsh Fungi from 29° to 43° North Latitude along the United States Atlantic Coast

Newell

Blum

Crawford

et al. 2000

Appl Environ Microbiol

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It has been established that substantial amounts of fungal mass accumulate in standing decaying smooth cordgrass (Spartina alterniflora) marshes in the southeastern United States (e.g., in standing decaying leaf blades with a total fungal organic mass that accounts for about 20% of the decay system organic mass), but it has been hypothesized that in marshes farther north this is not true. We obtained samples of autumnal standing decaying smooth cordgrass from sites in Florida to Maine over a 3-year period. The variation in latitude could not explain any of the variation in the living fungal standing crop (as determined by ergosterol content) or in the instantaneous rates of fungal growth (as determined by acetate incorporation into ergosterol at a standard temperature, 20°C), which led to the conclusion that the potential levels of fungal production per unit of naturally decaying grass are not different in northern and southern marshes. Twenty-one percent of the variation in the size of the living fungal standing crop could be explained by variation in the C/N ratio (the higher the C/N ratio the smaller the fungal crop), but the C/P ratio was not related to the size of the fungal crop. Instantaneous rates of fungal growth were negatively related to the size of the living fungal crop (r ‫؍‬ ؊0.35), but these rates were not correlated with C/nutrient ratios. The same two predominant species of ascomycetes (one Phaeosphaeria species and one Mycosphaerella species) were found ejecting ascospores from standing decaying smooth cordgrass blades at all of the sites examined from Florida to Maine.

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Section: Discussionmentioning

confidence: 99%

Autumnal Biomass and Potential Productivity of Salt Marsh Fungi from 29° to 43° North Latitude along the United States Atlantic Coast

Newell

Blum

Crawford

et al. 2000

Appl Environ Microbiol

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“…Dew is also an important wetting phenomenon for standing-decaying blades of freshwater macrophytes (Kuehn & Suberkropp 1998b). Since there would not appear to be a difference in dew formation between adjacent freshwater marsh and saltmarsh ecosystems, the limitation of fungi in freshwater leaves may be a consequence of response of particular types of decaying blades to dewset.…”

Section: Discussionmentioning

confidence: 99%

Fungal content and activities in standing-decaying leaf blades of plants of the Georgia Coastal Ecosystems research area

Newell¹

2003

Aquat. Microb. Ecol.

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Change in salinity, including expansion or contraction of salt-and freshwater marshes, due to altered river outflow may influence a variety of ecosystem processes, and the literature to date suggests that fungal activity in standing-decaying blades of macrophytes may be lower in freshwater marshes than in saltmarshes. I measured living-fungal mass (as ergosterol), rate of CO 2 evolution, and rate of fungal membrane synthesis (acetate incorporation into ergosterol) for standing-decaying blades from a series of macrophytes, including saltmarsh cordgrass in both saline and fresher-water sites. Three terrestrial plants with prominent standing-decaying leaf blades were included for comparison. Species involved were: Spartina alterniflora, S. cynosuroides, Zizaniopsis miliacea, Typha angustifolia, Sabal palmetto, Uniola paniculata, and Panicum amarum. Although there was no difference in fungal content of S. alterniflora blades from saltier and fresher sites, there was a significant trend downwards (from > 500 to < 250 µg ergosterol g -1 system organic mass) in mean content of living-fungal mass moving from saltmarsh-adapted toward freshwater-adapted plants, and 2 of 3 terrestrial plants were also low (ca. 100 µg g -1 ). The activity measurements (CO 2 , acetate incorporation) revealed an opposite pattern: blades from fresher-water plants had higher activities per unit livingfungal mass (range of about 4-fold for mean rate of acetate incorporation per unit ergosterol), and lower CO 2 release per unit fungal membrane synthesis, than did more saline-adapted plants. It is proposed that this is perhaps largely a consequence of the microstructure (lignification, cuticular hydrophobicity) of the blades of the fresher-water plants (and 2 of the terrestrial plants) limiting duration of fungal activity. Upon thorough wetting, such as eventually occurs when blades move to the marsh-sediment surface, fungi within the fresher-water blades would be permitted to grow quickly, which would explain reported increases in ergosterol content of fallen blades.KEY WORDS: Fungal biomass · Fungal productivity · CO 2 release · Standing decay · Ergosterol · Saltmarsh · Freshwater marsh · Altamaha River Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 32: [95][96][97][98][99][100][101][102][103] 2003 acetate incorporation into ergosterol (Newell 2001a). This substantial fungal productivity is consistent with findings of high rates of animal outflow associated with Georgia saltmarshes (Turner & Boesch 1988, Kneib 2000, Teal & Howes 2000, Zimmerman et al. 2000, and with accumulating evidence of fungal input into the marsh foodweb (e.g. Graça et al. 2000).The high rates of fungal production per unit decaysystem mass found for smooth cordgrass contrast sharply with rates found using the same techniques during cold and warm seasons for a freshwater sedge (Carex walteriana, Walter's sedge) (1 technique difference: 20°C incubation for cordgrass and 25°C for sedge; Newell et al. 1995). The maxi...

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“…As a result, large amounts of dead plant matter remain standing within wetland habitats (Findlay et al 1990, Lee 1990, Wetzel & Howe 1999, and are colonized and decomposed in an upright aerial position (Newell 1993, Newell et al 1995, Bärlocher & Biddiscombe 1996, Kuehn & Suberkropp 1998a,b Kuehn et al. 1999, Gessner 2000b.…”

Section: Abstract: Litter Decomposition · Phragmites Australis · Wetmentioning

confidence: 99%

Microbial biomass, growth, and respiration associated with submerged litter of Phragmites australis decomposing in a littoral reed stand of a large lake

Komínková¹,

Kuehn²,

Büsing³

et al. 2000

Aquat. Microb. Ecol.

Self Cite

128

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This study examined the microbial dynamics associated with decomposing litter of the widespread emergent macrophyte Phragmites australis in a littoral reed stand of a large lake. Standing dead leaf and stem litter were collected, placed into fine and coarse mesh litter bags, and submerged in the reed stand. Litter bags were retrieved periodically and analyzed for fungal and bacterial biomass, fungal growth rates and production, rates of microbial respiration, litter mass loss, nutrient concentrations (N and P), and rates of dissolved organic carbon (DOC) release. Microbial biomass associated with both leaf and stem litter (12 to 85 mg C g -1 detrital C) was predominantly fungal (always ≥ 90% of the total biomass), even though bacterial biomass (0.13 to 5.6 mg C g -1 detrital C) increased and fungal biomass decreased or remained constant as litter decay proceeded. Although rates of fungal growth (0.02 to 0.08% h -1 ) and production (leaves only; 3 to 51 µg C g -1 detrital C h -1 ), and rates of microbial respiration (11 to 257 µg C g -1 detrital C h -1 ) decreased following litter submergence, fungi continued to be metabolically active in both leaf and stem litter. Significant differences in fungal and bacterial biomass, fungal production rates, and rates of respiration were observed between leaf and stem material, with leaves often having 5 times higher values than corresponding stems. Rates of mass loss differed significantly between leaf litter in fine and coarse mesh bags, with less than 10% of the initial mass remaining in coarse mesh bags after 86 d, versus nearly 60% remaining in fine mesh bags. Nitrogen and P concentrations of leaf litter enclosed in fine mesh bags increased during litter decay, whereas N concentrations of leaf litter in coarse mesh bags remained unchanged and P concentrations decreased. Both N and P concentrations of stem litter were similar among litter bags and varied little throughout the study period. Results obtained in this study indicate that significant changes in microbial colonization and activity associated with P. australis litter can occur following the collapse of standing dead plant matter to the water. Furthermore, these findings suggest that fungi are active on submerged litter and thus play a vital role in the decomposition of P. australis litter in the aquatic environment. KEY WORDS: Litter decomposition · Phragmites australis · Wetland · Microbial productivity · Fungi · Nutrients · Respiration · Growth efficiencyResale or republication not permitted without written consent of the publisher Aquat Microb Ecol 22: 271-282, 2000 In many emergent macrophytes, such as Phragmites australis, abscission and collapse of plant material to the sediment or overlying surface waters typically do not occur immediately following shoot senescence and death. As a result, large amounts of dead plant matter remain standing within wetland habitats (Findlay et al. 1990, Lee 1990, Wetzel & Howe 1999, and are colonized and decomposed in an upright aerial position (Newell 1993, Ne...

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Diel fluctuations in rates of CO2 evolution from standing dead leaf litter of the emergent macrophyte Juncus effusus

Cited by 46 publications

References 38 publications

Autumnal Biomass and Potential Productivity of Salt Marsh Fungi from 29° to 43° North Latitude along the United States Atlantic Coast

Autumnal Biomass and Potential Productivity of Salt Marsh Fungi from 29° to 43° North Latitude along the United States Atlantic Coast

Fungal content and activities in standing-decaying leaf blades of plants of the Georgia Coastal Ecosystems research area

Microbial biomass, growth, and respiration associated with submerged litter of Phragmites australis decomposing in a littoral reed stand of a large lake

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