scholarly journals The chemistry of fruits and vegetables, Yakima River Valley, Washington, and the influence of the 1980 Mount St. Helens ash fall episodes

10.3133/b1640 ◽  
1986 ◽  
Keyword(s):  
Fruits And Vegetables ◽  
River Valley ◽  
Ash Fall ◽  
Yakima River ◽  
Mount St Helens

Influence of Mount St. Helens ash on litter decomposition. II. Experimental studies with Douglas-fir needles

1994 ◽  
Vol 24 (4) ◽  
pp. 832-838 ◽  
Author(s):  
Heather E. Erickson ◽  
Robert L. Edmonds
Keyword(s):  
Forest Floor ◽  
Experimental Studies ◽  
Similar Rate ◽  
Douglas Fir ◽  
Decomposition Rates ◽  
Ash Fall ◽  
Needle Decomposition ◽  
Forest Floors ◽  
Mount St Helens ◽  
Floor Temperature

The influence of air-fall tephra (ash) from the 1980 Mount St. Helens eruptions on decomposition of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) needles was studied in a field experiment at the Cedar River watershed near Seattle, Wash. Ash that fell on Yakima, Wash., was transported to the site and placed on 5 × 5 m plots in a 50-year-old Douglas-fir stand at depths of 5 and 20 cm. Objectives of the study were to determine: (i) decomposition rates of Douglas-fir needles on the ash surface, buried under ash, and in an untreated control; (ii) the effect of ash depth on decomposition rates; and (iii) the influence of ash on forest floor temperature and moisture. Yakima ash had considerable influence on forest floor temperature and moisture and Douglas-fir needle decomposition rates. Needles buried under 5 cm of ash had increased rates of decomposition after 2 years (k = 0.595/year) relative to control needles (k = 0.347/year), while those buried under 20 cm of ash had a similar rate of decomposition to control needles (k = 0.349/year), perhaps owing to ash compaction. Those on the ash surface had decreased rates of decomposition relative to buried needles. These results are similar to results found in the ash fall zone near Mount St. Helens, where needles located on top of ash decomposed slower than buried needles. Increased decomposition of tephra-affected forest floors, relative to unaffected areas, may have facilitated plant regrowth by increasing the availability of limiting nutrients. Ash created a more favorable temperature environment for decomposition beneath the ash with the forest floor under ash being cooler in summer and warmer in the cooler months. Forest floor moisture was reduced under the ash but did not appear to be limiting to decomposition.

The Dorothy bentonite: an extraordinary case of secondary thickening in a late Campanian volcanic ash fall in central Alberta

2002 ◽  
Vol 39 (12) ◽  
pp. 1745-1754 ◽  
Author(s):  
J F Lerbekmo
Keyword(s):  
British Columbia ◽  
Refractive Index ◽  
Volcanic Ash ◽  
Red Deer ◽  
Silica Content ◽  
River Valley ◽  
Ash Fall ◽  
Isopach Map ◽  
Thickness Measurements ◽  
Glass Shards

The late Campanian (~73 Ma) Dorothy bentonite outcrops in the marine Bearpaw Shale for 20 km along the Red Deer River valley east of Drumheller, Alberta, and is up to 13.5 m thick. An isopach map based upon 230 sub surface and surface thickness measurements illustrates an elongated southwest–northeast lobe with maximum dimensions of about 300 km by 50 km. The volume is ~57 km3 distributed within an area of ~11 000 km2. This bentonite is the altered product of what is believed to be a short-lived Plincan-type eruption from part of the Howell Creek Instrusives in southeastern British Columbia. Fortuitous preservation of the original ash in an up to 2.5 m thick calcite-cemented tuffaceous zone near the middle of the bentonite shows the original ash to have been >99% glass shards and pumice. The remainder of the ash is a crystal component consisting mostly of plagioclase and biotite. The silica content of the isotropic glass shards of about 77%, and a refractive index of 1.503 ± 0.001, suggest a magma of rhyolitic composition.

Influence of Mount St. Helens ash on litter decomposition. I. Pacific silver fir needle decomposition in the ash-fall zone

1994 ◽  
Vol 24 (4) ◽  
pp. 826-831 ◽  
Author(s):  
Robert L. Edmonds ◽  
Heather E. Erickson
Keyword(s):  
Litter Decomposition ◽  
Forest Floor ◽  
Silver Fir ◽  
Considerable Influence ◽  
Decomposition Rates ◽  
Oxygen Levels ◽  
Ash Fall ◽  
Needle Decomposition ◽  
Substrate Moisture ◽  
Mount St Helens

The influence of air-fall tephra (ash) from the May 18 1980 eruption of Mount St. Helens on decomposition of Pacific silver fir (Abiesamabilis (Dougl.) Forbes) needles was studied at two sites along the ash-fall plume northeast of the mountain, Elk Pass and Chambers Lake (20 and 60 km from the crater, respectively). Ash depths beneath the canopy of the old-growth stands at Elk Pass and Chambers Lake were 18 and 5 cm, respectively. Objectives of the study were to determine: (i) the decomposition rates of needles on the ash surface, buried under ash, and in control plots with ash removed; (ii) the effect of site on decomposition rates; and (iii) the influence of ash on forest floor temperature, moisture, and oxygen levels. Ash had considerable influence on litter decomposition. After 3 years, needles buried under ash had faster decomposition rates at both sites (k = 0.34 and 0.29/year at Elk Pass and Chambers Lake, respectively) than needles on the ash surface or in cleared control plots. There was a trend for needles on the ash surface to have slower decomposition (k = 0.18–0.23/year) than needles on control plots (k = 0.22–0.28/year). Site had little influence on buried needle decomposition; rates at Elk Pass and Chambers Lake were not significantly different, despite differences in ash texture and depth. Ash apparently did not reduce oxygen levels enough to reduce decomposition, but instead increased decomposition by influencing substrate moisture and temperature. Fastest decomposition occurred under the ash where conditions were moist and cool; slowest decomposition occurred on the ash surface where conditions were drier and warmer.

Flavonoids in adipose tissue inflammation and atherosclerosis: one arrow, two targets

2020 ◽  
Vol 134 (12) ◽  
pp. 1403-1432 ◽  
Author(s):  
Manal Muin Fardoun ◽  
Dina Maaliki ◽  
Nabil Halabi ◽  
Rabah Iratni ◽  
Alessandra Bitto ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Fruits And Vegetables ◽  
Metabolic Diseases ◽  
Therapeutic Agents ◽  
Adipose Tissue Inflammation ◽  
Cellular Mechanisms ◽  
Tissue Inflammation ◽  
Cholesterol Levels ◽  
Naturally Occurring ◽  
Pro Inflammatory Cytokines

Abstract Flavonoids are polyphenolic compounds naturally occurring in fruits and vegetables, in addition to beverages such as tea and coffee. Flavonoids are emerging as potent therapeutic agents for cardiovascular as well as metabolic diseases. Several studies corroborated an inverse relationship between flavonoid consumption and cardiovascular disease (CVD) or adipose tissue inflammation (ATI). Flavonoids exert their anti-atherogenic effects by increasing nitric oxide (NO), reducing reactive oxygen species (ROS), and decreasing pro-inflammatory cytokines. In addition, flavonoids alleviate ATI by decreasing triglyceride and cholesterol levels, as well as by attenuating inflammatory mediators. Furthermore, flavonoids inhibit synthesis of fatty acids and promote their oxidation. In this review, we discuss the effect of the main classes of flavonoids, namely flavones, flavonols, flavanols, flavanones, anthocyanins, and isoflavones, on atherosclerosis and ATI. In addition, we dissect the underlying molecular and cellular mechanisms of action for these flavonoids. We conclude by supporting the potential benefit for flavonoids in the management or treatment of CVD; yet, we call for more robust clinical studies for safety and pharmacokinetic values.

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