Breakdown and Invertebrate Colonization of Leaf Litter in Two Contrasting Streams, Significance of Oligochaetes in a Large River

1993 ◽  
Vol 50 (3) ◽  
pp. 488-495 ◽  
Author(s):  
E. Chauvet ◽  
N. Giani ◽  
M. O. Gessner
Keyword(s):  
Organic Matter ◽  
River Sediments ◽  
Large River ◽  
Mountain Stream ◽  
Total Biomass ◽  
Salix Alba ◽  
Breakdown Rate ◽  
Breakdown Rates ◽  
Fagus Silvatica ◽  
Seventh Order

The breakdown of willow (Salix alba) and beech (Fagus silvatica) leaves and their colonization by invertebrates were studied in a third-order mountain stream (breakdown rate k = 0.0147 and 0.0052∙d−1, respectively) and a seventh-order lowland river (k = 0.0094 and 0.0027∙d−1). Willow leaves broke down three times faster than beech leaves; this difference was twice that between streams. Total invertebrate densities and biomass and the proportion of shredders were higher in the large river; therefore, differences in breakdown capacities between streams cannot be attributed to differences in invertebrate community structure. Instead, microbial processing and abiotic fragmentation are suggested as factors controlling breakdown rates. Owing to the abundance of naidids, up to 2000 invertebrates per leaf bag were recorded in the large river. These oligochaetes appeared to use litter accumulations as a microhabitat that provided shelter and a rich supply of food in the form of fine particulate organic matter. Tubificid oligochaetes accounted for 55% of total biomass on partly degraded leaves at this site. Their abundance and regular occurrence inside willow leaves suggest that tubificids enhance leaf fragmentation and possibly mediate the incorporation of organic matter in river sediments once the plant tissue is sufficiently macerated.

Changes in discharge affect more surface than subsurface breakdown of organic matter in a mountain stream

2016 ◽  
Vol 67 (12) ◽  
pp. 1826 ◽  
Author(s):  
Libe Solagaistua ◽  
Maite Arroita ◽  
Ibon Aristi ◽  
Aitor Larrañaga ◽  
Arturo Elosegi
Keyword(s):  
Organic Matter ◽  
Water Depth ◽  
Alnus Glutinosa ◽  
Mountain Stream ◽  
Litter Breakdown ◽  
Lotic Ecosystems ◽  
Leaf Litter Breakdown ◽  
Discharge Fluctuations ◽  
Breakdown Rates ◽  
Dry Out

Discharge fluctuations modify water depth and velocity in streams and this can affect leaf litter breakdown, which is an important ecosystem function. Both during droughts, when parts of the surface dry out, and during floods, which scour the benthic surface, macroinvertebrates can seek refuge in the subsurface. Therefore, as an important part of them depend on organic matter, the effects of discharge fluctuations on leaf breakdown might be greater on the surface than in the subsurface of lotic ecosystems. To test this hypothesis, we measured microbial and total breakdown rates of alder (Alnus glutinosa (L.) Gaertner) both on the surface and in the subsurface in two areas of a stream, namely, the permanently wet channel and the parafluvial areas. Reduced discharge dried out only the surface of the parafluvial areas, and thus, breakdown rates were reduced only in this habitat. In contrast, breakdown rates were similar in both habitats of the permanently wet channel, but also in the subsurface of the parafluvial area. The subsurface can mitigate the effects of discharge alterations on the breakdown of organic matter in streams, which might be critical for the productivity of these ecosystems under increased drought frequencies.

scholarly journals Nutrient addition does not enhance leaf decomposition in a Southeastern Brazilian stream (Espinhaço mountain range)

2010 ◽  
Vol 70 (3 suppl) ◽  
pp. 747-754 ◽  
Author(s):  
M. Abelho ◽  
M. Moretti ◽  
J. França ◽  
M. Callisto
Keyword(s):  
Nutrient Dynamics ◽  
Nutrient Content ◽  
High Water ◽  
Nutrient Addition ◽  
Mountain Stream ◽  
Mountain Range ◽  
Breakdown Rate ◽  
Eucalyptus Leaves ◽  
Breakdown Rates ◽  
Leaf Bags

A decomposition experiment using eucalyptus leaves was carried out in a Southeastern Brazilian mountain stream located at the transition between the Cerrado and the Atlantic Forest to test whether nutrient addition increases microbial and invertebrate colonisation and accelerates breakdown rates. The results show that none of the tested variables was significantly affected by nutrient addition, despite the average increase in ATP concentrations and invertebrate colonisation observed in the fertilised leaf bags. This could mean that breakdown in the stream was already at its maximum due to the relatively high water temperature and nutrient content, or that the breakdown rate of eucalyptus leaves was too fast to allow the detection of any effects of nutrient addition. Breakdown rates of eucalyptus leaves were much faster than the values reported in literature for most species in Brazilian Cerrado streams, suggesting that the replacement of the natural vegetation by eucalyptus may affect nutrient dynamics in the region.

Distribution of Mercury in Lake St. Clair and the St. Clair River Sediments

1989 ◽  
Vol 24 (1) ◽  
pp. 1-22 ◽  
Author(s):  
Alena Mudroch ◽  
K. Hill
Keyword(s):  
Organic Matter ◽  
Sediment Cores ◽  
River Sediments ◽  
Size Fraction ◽  
Mineralogical Composition ◽  
Recent Sediment ◽  
Geochemical Composition ◽  
Visual Appearance ◽  
Decaying Wood ◽  
Relationship Of

Abstract Sediment cores were collected in Lake St. Clair in 1985 and in the St. Clair River in 1986 to investigate the horizontal and vertical distribution and association of Hg in the sediments. A layer of recent sediment up to about 35 cm thick was differentiated by the geochemical composition and visual appearance from the underlying glacial-lacustrine deposits. The concentration of Hg in the surficial sediments in Lake St. Clair was lower in 1985 (<0.025 to 1.200 µg/g) than that found in 1974 (<0.20 to 3.00 µg/g). Up to 8.30 µg/g of Hg were found in the sediments collected from the nearshore area at Sarnia, Ontario, in the St. Clair River in 1986. The concentrations of Hg ranged from 5.05 to 16.00 µg/g in different sand-sized fractions (0.063 to 0.350 mm) of the sediment. The concentration of Hg was 17.80 µg/g in the silt-clay size fraction (<0.063 mm). No relationship was found between the concentration of organic matter and Hg, and the concentration of silica and Hg in the St. Clair River sediments. The results indicated a relationship of Hg with particles of different mineralogical composition. Up to 3.72 µg/g Hg was found in the surface sediment in Chenal Ecarte. The greatest concentration of Hg (13.15 µg/g) existed in the 0.350 mm particle size fraction, which consisted mainly of small pieces of decaying wood. A good relationship was found between the concentration of Hg and organic matter in the sediment at this area.

scholarly journals Large increases in adipose triacylglycerol flux in Cushingoid CRH-Tg mice are explained by futile cycling

2013 ◽  
Vol 304 (3) ◽  
pp. E282-E293 ◽  
Author(s):  
Charles Harris ◽  
Donald J. Roohk ◽  
Mark Fitch ◽  
Benjamin M. Boudignon ◽  
Bernard P. Halloran ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Collagen Synthesis ◽  
Muscle Protein ◽  
Subcutaneous Fat ◽  
Skin Thickness ◽  
Breakdown Rate ◽  
Triglyceride Synthesis ◽  
Fat Depots ◽  
Breakdown Rates ◽  
Skin Collagen

Glucocorticoids are extremely effective anti-inflammatory therapies, but their clinical use is limited due to severe side effects, including osteoporosis, muscle wasting, fat redistribution, and skin thinning. Here we use heavy water labeling and mass spectrometry to measure fluxes through metabolic pathways impacted by glucocorticoids. We combine these methods with measurements of body composition in corticotropin-releasing hormone (CRH)-transgenic (Tg)+ mice that have chronically elevated, endogenously produced corticosterone and a phenotype that closely mimics Cushing's disease in humans. CRH-Tg+ mice had increased adipose mass, adipose triglyceride synthesis, and greatly increased triglyceride/fatty acid cycling in subcutaneous and abdominal fat depots and increased de novo lipogenesis in the abdominal depot. In bone, CRH-Tg+ mice had decreased bone mass, absolute collagen synthesis rates, and collagen breakdown rate. In skin, CRH-Tg+ mice had decreased skin thickness and absolute collagen synthesis rates but no decrease in the collagen breakdown rate. In muscle, CRH-Tg+ mice had decreased muscle mass and absolute protein synthesis but no decrease in the protein breakdown rate. We conclude that chronic exposure to endogenous glucocorticoid excess in mice is associated with ongoing decreases in bone collagen, skin collagen, and muscle protein synthesis without compensatory reduction (coupling) of breakdown rates in skin and muscle. Both of these actions contribute to reduced protein pool sizes. We also conclude that increased cycling between triglycerides and free fatty acids occurs in both abdominal and subcutaneous fat depots in CRH-Tg+ mice. CRH-Tg mice have both increased lipolysis and increased triglyceride synthesis in adipose tissue.

scholarly journals Performance of Ornamental Plants in Alternative Organic Growing Media Amended with Increasing Rates of Expanded Shale

2010 ◽  
Vol 20 (3) ◽  
pp. 594-602 ◽  
Author(s):  
John J. Sloan ◽  
Raul I. Cabrera ◽  
Peter A.Y. Ampim ◽  
Steve A. George ◽  
Wayne A. Mackay
Keyword(s):  
Organic Matter ◽  
Plant Growth ◽  
Plant Tissue ◽  
Biomass Yield ◽  
Organic Materials ◽  
Total Biomass ◽  
Light Weight ◽  
Growing Media ◽  
Micronutrient Uptake ◽  
Expanded Shale

Organic and inorganic amendments are often used to improve chemical and physical properties of soils. The objective of this study was to determine how the inclusion of light-weight expanded shale in various organic matter blends would affect plant performance. Four basic blends of organic growing media were prepared using traditional or alternative organic materials: 1) 75% pine bark (PB) + 25% sphagnum peatmoss (PM), 2) 50% PB + 50% wastewater biosolids (BS), 3) 100% municipal yard waste compost (compost), and 4) 65% PB + 35% cottonseed hulls (CH). Light-weight expanded shale was then blended with each of these mixtures at rates of 0%, 15%, 30%, and 60% (v/v). Vinca (Catharanthus roseus), verbena (Verbena hybrida), and shantung maple (Acer truncatum) were planted into the growing media after they were transferred into greenhouse pots. Vinca growth was monitored for 3 months before harvesting aboveground plant tissue to determine total biomass yield and elemental composition. Verbena growth was monitored for 6 months, during which time aboveground plant tissue was harvested twice to determine total biomass yield. Additionally, aboveground vinca plant tissue was analyzed for nutrients and heavy metal concentrations. In the absence of expanded shale, verbena and shantung maple trees produced more aboveground biomass in the 50-PB/50-BS blends, whereas vinca grew more biomass in the pure compost blends. Inclusion of expanded shale in the various organic matter blends generally had a negative effect on plant growth, with the exception of shantung maple growth in the 65-PB/35-CH blend. Reduced plant growth was probably due to a lower concentration of nutrients in the growing media. Macro- and micronutrient uptake was generally reduced by addition of expanded shale to the organic growing media. Results suggest that organic materials that have been stabilized through prior decomposition, such as compost or PM, are safe and reliable growing media, but expanded shale offers few benefits to a container growing medium except in cases where additional porosity is needed.

scholarly journals The kinetics curve of nitrogen mineralization from perennial leaves litter decomposed by earthworm (Phretima californica)

2020 ◽  
Vol 17 (2) ◽  
pp. 152
Author(s):  
Kartika Utami ◽  
Eko Hanudin ◽  
Makruf Nurudin
Keyword(s):  
Organic Matter ◽  
N Mineralization ◽  
Second Order ◽  
Total Biomass ◽  
Organic Matter Quality ◽  
Lack Of Information ◽  
Pioneer Plants ◽  
Decomposition Of Organic Matter ◽  
N Release ◽  
Kinetics Of

The kinetics of N release during the process of decomposition of organic matter is influenced by organic matter quality, temperature, humidity, and decomposer. Acacia, coffee, salacca, and bamboo leaf litter are native plants and be the pioneer plants on the slopes of Mount Merapi after the eruption in 2010. However, there is a lack of information on the N mineralization process from the leaves litter of acacia, coffee, salacca, and bamboo. The study aimed to determine the kinetics of N release from the litter leaves of acacia (<em>Acacia decurrens</em>), coffee, salacca, and bamboo, which were tested with three approaches, namely zero order, first order, and second order. The experiment was carried out using 10 <em>Phretima californica </em>earthworms that were incubated with 35g of annual plant leaves at 25°C. The levels of NH<sub>4</sub><sup>+</sup> and NO<sub>3</sub><sup>-</sup> were measured at 0, 7, 15, 30, 45, 75, and 105 days after incubation by using the indophenol blue and derivative spectrophotometric method, respectively. Throughout the decomposition 105 days, the release of NO<sub>3</sub><sup>-</sup> was higher than that of NH<sub>4</sub><sup>+</sup> due to the nature of NH<sub>4</sub><sup>+</sup> that was more easily immobilized than NO<sub>3</sub><sup>-</sup>. The highest NO<sub>3</sub><sup>- </sup>release in acacia litter (1.56 mg kg<sup>-1</sup>) occurred 30 days after incubation, while in coffee, salacca, and bamboo occurred 105 days after incubation, reaching 1.92 mg kg<sup>-1</sup>, 2.47 mg kg<sup>-1</sup>, and 1.88 mg kg<sup>-1</sup>, respectively. High N compound on the leaves litter unaffected to increasing total biomass earthworms in the end of incubation however promotes N mineralization rapidly. The kinetics of the second-order equation showed higher compatibility than the other equations to the N release with coefficient determination was higher. The kinetics of mineralization can be a strategy to use the leaves litter of perennial plants as sources of N nutrient input into soil.

scholarly journals Regulation of the breakdown rates of biotin-containing proteins in Swiss 3T3-L1 cells

1988 ◽  
Vol 251 (3) ◽  
pp. 749-755 ◽  
Author(s):  
C S Chandler ◽  
F J Ballard
Keyword(s):  
Rate Constants ◽  
Degradation Rate ◽  
Mitochondrial Protein ◽  
Acetyl Coa Carboxylase ◽  
Inhibitory Effects ◽  
Breakdown Rate ◽  
Breakdown Rates ◽  
Lysosomal Proteolysis ◽  
Swiss 3T3 ◽  
Inhibitory Agents

1. Degradation rate constants for individual biotin-labelled proteins were measured in Swiss 3T3-L1 adipocytes that had been incubated with inhibitors of autophagy or of lysosomal proteolysis. 2. Inhibitory effects produced by 10 mM-3-methyladenine and a combination of 5 mM-NH4Cl and leupeptin (50 micrograms/ml) were approximately equal. The inclusion of NH4Cl did not significantly enhance the responses to 3-methyladenine, suggesting that autophagy was already maximally inhibited. 3. The extent of inhibition by 3-methyladenine or by the NH4Cl/leupeptin mixture was similar for the cytosolic enzyme acetyl-CoA carboxylase and for the three mitochondrial carboxylases. This inhibition averaged 50%. The breakdown rate of a more-stable 38 kDa biotin-containing mitochondrial protein was more responsive to the inhibitory agents. These results are best explained by mitochondrial proteolysis occurring via a combination of the degradation of whole mitochondria within autophagic vacuoles, supplemented by the selective intramitochondrial breakdown of more labile proteins. 4. A number of intermediate products in the degradation of biotin-containing proteins were detected. Differences in the patterns of radioactivity between these peptides after incubation of cells in the presence of inhibitors of the breakdown process provided evidence that some peptides were produced before autophagy, others as a result of intralysosomal inhibition, while at least one was associated with intramitochondrial proteolysis.

scholarly journals Wetter is Better: Rewetting of Minerotrophic Peatlands Increases Plant Production and Moves Them Towards Carbon Sinks in a Dry Year

Ecosystems ◽  
2020 ◽  
Author(s):  
Sarah Schwieger ◽  
Juergen Kreyling ◽  
John Couwenberg ◽  
Marko Smiljanić ◽  
Robert Weigel ◽  
...  
Keyword(s):  
Organic Matter ◽  
Biomass Production ◽  
Plant Material ◽  
Carbon Sink ◽  
Belowground Biomass ◽  
Plant Production ◽  
Total Biomass ◽  
Carbon Sinks ◽  
Alder Forest ◽  
Organic Matter Accumulation

Abstract Peatlands are effective carbon sinks as more biomass is produced than decomposed under the prevalent anoxic conditions. Draining peatlands coupled with warming releases stored carbon, and subsequent rewetting may or may not restore the original carbon sink. Yet, patterns of plant production and decomposition in rewetted peatlands and how they compare to drained conditions remain largely unexplored. Here, we measured annual above- and belowground biomass production and decomposition in three different drained and rewetted peatland types: alder forest, percolation fen and coastal fen during an exceptionally dry year. We also used standard plant material to compare decomposition between the sites, regardless of the decomposability of the local plant material. Rewetted sites showed higher root and shoot production in the percolation fen and higher root production in the coastal fen, but similar root and leaf production in the alder forest. Decomposition rates were generally similar in drained and rewetted sites, only in the percolation fen and alder forest did aboveground litter decompose faster in the drained sites. The rewetted percolation fen and the two coastal sites had the highest projected potential for organic matter accumulation. Roots accounted for 23–66% of total biomass production, and belowground biomass, rather than aboveground biomass, was particularly important for organic matter accumulation in the coastal fens. This highlights the significance of roots as main peat-forming element in these graminoid-dominated fen peatlands and their crucial role in carbon cycling, and shows that high biomass production supported the peatlands’ function as carbon sink even during a dry year.

Multivariate analyses on heavy metal binding fractions of river sediments in Southern Taiwan

2000 ◽  
Vol 42 (7-8) ◽  
pp. 193-199 ◽  
Author(s):  
K. C. Yu ◽  
C. Y. Chang ◽  
L. J. Tsai ◽  
S. T. Ho
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Organic Matter ◽  
Metal Binding ◽  
River Sediments ◽  
Principal Component ◽  
Fe Oxides ◽  
Data Points ◽  
Southern Taiwan ◽  
Highly Correlated

This study depicts the amounts of heavy metals (Cu, Zn, Pb, Cr, Co, and Ni) bound to four geochemical compositions of sediments (carbonates, Mn oxides, Fe oxides, and organic matters), and the correlations between various geochemical compositions and their heavy-metal complexes. Hundreds of data, obtained from sediments of five main rivers (located in southern Taiwan), were analyzed by using multivariate analysis method. Among the four different geochemical compositions, the total amount of the six heavy metals bound to organic matter is the highest. Zn is easily bound to various geochemical compositions, especially carbonates in sediments of the Yenshui river and the Potzu river (i.e., the heavily heavy-metal polluted sediments); Cr, Pb, and Ni are mainly bound to both Fe oxides and organic matter; Cu has high affinity to organic matter. By performing principal component analyses, the data points of organic matter and both Pb and Cu associated with organic matter cluster together in sediments ofthe Peikang, the Potzu, and the Yenshui rivers, which indicates both Pb and Cu might be discharged from the same pollution sources in these rivers. Moreover, correlations between any two binding fractions of heavy metal associated with Fe oxides in different rivers are not consistent, which indicates some factors including the binding sites of Fe oxides, the extent of heavy metal pollution, binding competitions between heavy metals may affect the amounts of heavy metals bound to Fe oxides. Furthermore, it should be noted that the amount of Pb bound to Fe oxides is highly correlated with the amount of Fe oxides in sediments of the Peikang, the Potzu, and the Yenshui rivers.

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