Effects of salmon carcass decomposition on biofilm growth and wood decomposition

Salmon carcasses from spawning migrations can be retained in stream ecosystems behind woody debris, boulders, and other substrata where they contribute nutrients and organic matter to the stream biota. We hypothesized that carcasses would enhance algal and microbial growth and wood decomposition. To test this, we placed wood and clay pot substrata directly downstream of decomposing salmon in the Little Knife River, Minn., U.S.A., and compared total biofilm biomass on substrata in the vicinity of decomposing salmon and upstream of salmon carcasses. After 335 days in the stream, there was a significant mass loss of wood but no apparent effect of carcass decomposition on wood mass loss. Significantly, more chlorophyll a was found on both wood and pots when carcasses were present (p < 0.05) compared with controls. Stable isotope analyses suggest that the fish-derived nitrogen was taken up by the periphyton and total biofilm. Biofilm on the pots and wood near fish showed a significant increase in ash-free dry mass (p < 0.05). We conclude that fish-derived nutrients enhanced algal and total biofilm growth but did not significantly influence wood decomposition.

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Dating of ice cores from temperate glaciers - Significant mass loss in the accumulation area of the Adamello glacier indicated by the chronology of a 46 m ice core

10.5194/egusphere-egu21-7473 ◽

2021 ◽

Author(s):

Theo Jenk ◽

Daniela Festi ◽

Margit Schwikowski ◽

Valter Maggi ◽

Klaus Oeggl

Keyword(s):

Mass Loss ◽

Ice Core ◽

Ice Cores ◽

Italian Alps ◽

Accumulation Zone ◽

The Core ◽

Annual Layer ◽

Significant Mass Loss ◽

Carbon Concentrations ◽

Significant Mass

Dating glaciers is an arduous yet essential task in ice core studies, which becomes even more challenging for the dating of glaciers suffering from mass loss in the accumulation zone as result of climate warming. In this context, we present the dating of a 46 m deep ice core from the Central Italian Alps retrieved in 2016 from the Adamello glacier (Pian di Neve, 3100 m a.s.l.). We will show how the timescale for the core could be obtained by integrating results from the analyses of the radionuclides 210Pb and 137Cs with annual layer counting derived from pollen and refractory black carbon concentrations. Our results clearly indicate that the surface of the glacier is older than the drilling date of 2016 by about 20 years and that the 46 m ice core reaches back to around 1944. Despite the severe mass loss affecting this glacier even in the accumulation zone, we show that it is possible to obtain a reliable timescale for such a temperate glacier. These results are very encouraging and open new perspectives on the potential of such glaciers as informative palaeoarchives. We thus consider it important to present our dating approach to a broader audience.

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Formation of a planetary nebula by continuous mass loss

International Astronomical Union Colloquium ◽

10.1017/s0252921100094999 ◽

1981 ◽

Vol 59 ◽

pp. 345-346

Author(s):

A. Harpaz ◽

A. Kovetz

Keyword(s):

Mass Loss ◽

Loss Rate ◽

Mass Loss Rate ◽

Central Star ◽

Red Giants ◽

Giant Star ◽

Continuous Mass ◽

Red Giant ◽

Significant Mass Loss ◽

Significant Mass

The evolution of a 1.2Mʘ star along the asymptotic branch with continuous mass loss is presented, showing that this mass loss leads to the formation of a PN with a typical central star in its center.A former investigation (Harpaz and Kovetz, 1980) has shown that mechanisms for PN creation based on sudden violent processes are not likely to work in the envelope of a red giant star. On the other hand, significant mass loss from red giants was observed as a general phenomenon.We have followed the evolution of a 1.2Mʘ star along the asymptotic branch, including in the evolutionary calculations a mass loss according to Reimers’ empirical formula. It was found that towards the end of this stage, the mass loss rate was about 2.7xl0-6Mʘ/y, which is consistent with the formation of a typical PN within 30,000 years. When the mass content of the hydrogen rich envelope dropped to 1.5x10-3Mʘ, the star began to contract rapidly, forming a typical central star of 0.6Mʘ

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Fungal diversity, woody debris, and wood decomposition in managed and unmanaged Patagonian Nothofagus pumilio forests

10.21203/rs.3.rs-366022/v1 ◽

2021 ◽

Author(s):

Ana Laura Gallo ◽

Patricia Valeria Silva ◽

Pablo López Bernal ◽

Alicia Susana Moretto ◽

Alina G. Greslebin

Keyword(s):

Forest Management ◽

Mass Loss ◽

Fungal Diversity ◽

Woody Debris ◽

Canopy Cover ◽

Nothofagus Pumilio ◽

Wood Decomposition ◽

Key Species ◽

Field Incubation ◽

Generalized Linear Mixed Effects

Abstract Fungal diversity, woody debris, and wood decomposition were assessed in Nothofagus pumilio forests with and without forest management. A plot in a managed forest (MF) and a plot in an unmanaged control forest (C) were established in three sites in Chubut, Argentina. On each plot, forest structure, volume of woody debris, temperature, and humidity were recorded. Basidiomata of aphyllophoroid fungi were recorded in the fall and spring for 2 years. A decomposition assay with branches and twigs in two decay classes (DC) was established, and mass loss was measured after 3 and 2 years of field incubation respectively. To evaluate fungal diversity and mass loss within MF and C, generalized linear mixed-effects models (GLMM) were performed. Neither richness nor abundance differed between treatments, and community composition was similar. Only branches in DC2 showed greater mass loss in MF than in C. The volume of CWD was greater in MF and had a positive effect on fungal richness. A few aphyllophoroid species showed significant differences in abundance between treatments. Forest management in the conditions evaluated did not generate evident changes in fungal diversity, nor in wood decomposition. However, the differences observed in mass loss of DC2 could indicate that there were some factors operating in the past, that are no longer seen in the present, which may have accelerated decomposition. This highlights the need for studies evaluating changes in canopy cover, microclimate and fungal community, including potential key species, over a period starting just after the forest management.

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Concerning the Deposition and Diagenesis of Strata in Polar Firn

Journal of Glaciology ◽

10.3189/s0022143000007024 ◽

1988 ◽

Vol 34 (118) ◽

pp. 283-290 ◽

Cited By ~ 9

Author(s):

Richard B. Alley

Keyword(s):

Mass Loss ◽

Temperature Gradients ◽

Large Temperature ◽

Free Atmosphere ◽

High Accumulation ◽

Typically Develop ◽

Gradient Effects ◽

Annual Signal ◽

Significant Mass Loss ◽

Significant Mass

AbstractDepth hoar in polar firn forms when large temperature gradients act on low-density firn, but high-density firn does not develop into depth hoar. Low densities in firn may be depositional (burial of surface hoar or still-air snowfall) or diagenetic (mass loss to the free atmosphere, typically in autumn); however, diagenesis is sufficiently strong to cause significant mass loss only in the top 50–100 mm of firn. Between about 50–100 mm and 2 m depth, grain growth and densification are accelerated strongly by temperature-gradient effects; from 2 to 5 m, temperature gradients have a small but measurable effect on rates of processes in firn, and below 5 m rates essentially have isothermal values.Diagenetic depth-hoar layers typically develop in the autumn, are relatively thick, and have smooth bases. Depositional depth-hoar layers may develop at any season, are relatively thin, and have irregular bases. In low-accumulation regions, visual stratification may preserve only an annual signal, but in high-accumulation regions individual storms or other features may be recognizable.

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Re-examining mechanisms of radiation damage in organic specimens

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100177192 ◽

1990 ◽

Vol 48 (4) ◽

pp. 812-813

Author(s):

David A. Armstrong ◽

Suichu Luo ◽

David C. Joy

Keyword(s):

Mass Loss ◽

Radiation Damage ◽

Low Dose ◽

High Resolution Electron Microscopy ◽

Limiting Factor ◽

High Dose ◽

X Ray ◽

Resolution Electron ◽

Significant Mass Loss ◽

Significant Mass

Radiation damage to organic specimens is the major limiting factor in high resolution electron microscopy studies of biological systems. Electron beam irradiation compromises resolution by altering chemical microstructure, resulting in local mass loss and volume shrinkage in a specimen. All significant mass loss is thought to occur prior to a total incident dose of 50 electrons/ square angstrom If this is the case it is hard to reconcile the observation that images must be recorded at doses of less than 100 el/Å in order to avoid excessive mass loss and shrinkage while microanalytical (EDS and EELS) studies of the same tissue are routinely carried out at doses of 104 - 105el/Å2. Also, since most workers typically use either low dose (for imaging) or high dose (for microapalysis) there are apparently no studies in the literature which attempt to follow the process of radiation damage between these two extremes.We have chosen to investigate mass loss in polymer embedding resins such as are routinely used for TEM imaging as well as for X ray microanalytical applications.

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Infrared spectra of C-type variables with ISO

Symposium - International Astronomical Union ◽

10.1017/s0074180900203057 ◽

1999 ◽

Vol 191 ◽

pp. 181-186 ◽

Cited By ~ 4

Author(s):

J. Hron ◽

R. Loidl ◽

S. Höfner ◽

U.G. Jørgensen ◽

B. Aringer ◽

...

Keyword(s):

Mass Loss ◽

Infrared Spectra ◽

Dust Emission ◽

Dynamical Model ◽

Model Parameters ◽

Carbon Stars ◽

Synthetic Spectra ◽

Corrected Data ◽

Significant Mass Loss ◽

Significant Mass

We present ISO-SWS spectra for several representative AGB carbon stars obtained at several phases of the pulsational cycle. For stars with significant mass loss we correct the spectra for the dust emission by using DUSTY models. We then compare these corrected data to synthetic spectra based on hydrostatic and dynamical model atmospheres. We also discuss the influence of the fundamental model parameters on the resulting synthetic spectra.

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Salmon carcasses alter leaf litter species diversity effects on in-stream decomposition

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f2011-082 ◽

2011 ◽

Vol 68 (8) ◽

pp. 1495-1506 ◽

Cited By ~ 6

Author(s):

Welles D. Bretherton ◽

John S. Kominoski ◽

Dylan G. Fischer ◽

Carri J. LeRoy

Keyword(s):

Mass Loss ◽

Leaf Litter ◽

Ecosystem Functioning ◽

Litter Mixtures ◽

Salmon Carcass ◽

Stream Biodiversity ◽

Full Factorial ◽

Late Stages ◽

Diversity Effects ◽

Salmon Carcasses

Marine-derived nutrients from salmon carcasses and leaf litter inputs from riparian vegetation may interactively support stream biodiversity and ecosystem functioning through enhanced resource heterogeneity. Using a full-factorial design of single- and mixed-species litters, we tested for influences of salmon carcasses on in-stream litter decomposition. Overall, nonadditive (synergistic and antagonistic) effects on decomposition were detected for litter species mixtures, and these effects were explained by litter species composition, but not species richness. In middle to late stages of decay, mixtures of labile (high-quality) litters showed faster than expected mass loss, and recalcitrant (low-quality) litter mixtures showed slower than expected mass loss. The presence or absence of each litter species differentially affected decomposition, but these patterns were stronger when salmon carcasses were available. Across all treatments, the influence of salmon carcasses on decomposition was most pronounced in mid-stages of litter decay, where deceleration of decomposition was likely caused by macroinvertebrates feeding on salmon carcasses and less on litter. Combined, these data demonstrate that salmon carcass inputs to streams can enhance detrital heterogeneity, alter interactions among species in litter mixtures, and influence ecosystem functioning (i.e., decomposition).

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Mechanobiology: A New Frontier in Biology

Biology ◽

10.3390/biology10070570 ◽

2021 ◽

Vol 10 (7) ◽

pp. 570

Author(s):

Tae-Jin Kim

Keyword(s):

Mass Loss ◽

Muscle Mass ◽

Musculoskeletal Tissues ◽

New Frontier ◽

Significant Mass Loss ◽

Significant Mass

As we observe an increase in muscle mass by lifting weights or a significant mass loss in musculoskeletal tissues of astronauts returning after a stay in space, we note the manifestation of the mechanism of mechanotransduction that is central to mechanobiology [...]

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