Water depth changes and biomass allocation in two contrasting macrophytes

1994 ◽  
Vol 45 (8) ◽  
pp. 1459 ◽  
Author(s):  
N Rea ◽  
GG Ganf
Keyword(s):  
Total Mass ◽  
Turnover Rate ◽  
Inorganic Carbon ◽  
Morphological Plasticity ◽  
Water Levels ◽  
Root Mass ◽  
Water Level Changes ◽  
Below Ground ◽  
Insight Into ◽  
Slow Turnover

The response of B. arthrophylla and T. procerum in pot experiments to depth and depth changes provided insight into how plants survive fluctuating water levels. At 0 cm depth, most biomass was placed below ground, which can be interpreted as the placement of resource-acquiring tissues (roots, rhizomes) in resource (nutrients, space) -supplying environments. At 50 and 100 cm, the placement of biomass into shoots recognized the need for a higher supply of above-ground resources (light, inorganic carbon, oxygen). However, the responses of the two species to flooding or exposure differed. Rhizome storage supported an increase in the number and height of B. arthrophylla stems when flooded by 50 cm but this species was unable to counteract submergence to 100 cm without the critical loss of root mass. The slow turnover rate of the cuticularized B. arthrophylla stems indicates that biomass needs to be allocated above water as well as above ground. Other responses indicated that this species may be better suited to seasonally fluctuating rather than permanent water levels. T. procerum dealt with water level changes via morphological plasticity. Along with the rapid growth and turnover of the spongy leaves, its shoot and total mass were maintained primarily from resources in the tubers.

Biomass partitioning in a miniature-scale loblolly pine spacing trial

2009 ◽  
Vol 39 (2) ◽  
pp. 320-329 ◽  
Author(s):  
Matthew B. Russell ◽  
Harold E. Burkhart ◽  
Ralph L. Amateis
Keyword(s):  
Loblolly Pine ◽  
Total Mass ◽  
Spatial Scales ◽  
Biomass Partitioning ◽  
Below Ground ◽  
Initial Spacing ◽  
Using Data ◽  
Pinus Taeda L ◽  
Stand Conditions ◽  
Insight Into

Stand conditions influence the partitioning of biomass to stem, needle, branch, and root components. Using data from 4- to 6-year-old loblolly pine ( Pinus taeda L.) trees grown in a miniature-scale spacing trial, this study determined the effect of initial spacing on the biomass partitioning of loblolly pine. Multivariate analysis of variance procedures concluded that row and column spacing did not have a significant effect on the relative amount of biomass among tree components. Root/shoot and height/diameter ratios, however, differed across densities, indicating that allometric-based partitioning tradeoffs occurred. Results from the miniature-scale trees showed trends similar to those observed with mature-sized trees at operational spatial scales. Stem and woody roots were 70% and 14% of total mass, respectively. Since these trees were physiologically young at the time of harvest, the allocation of mass to needle continued to be a priority, accounting for 10% of the total mass. Initial planting spacing did not directly affect partitioning patterns; however, allometric ratios offered some evidence that partitioning may have changed between above- and below-ground tree components. This analysis offers insight into using principles from similarity analysis to analytically relate biomass partitioning from miniature to operational spatial scales.

scholarly journals Development of Fragility Curves for Piping and Slope Stability of River Levees

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 738
Author(s):  
Nicola Rossi ◽  
Mario Bačić ◽  
Meho Saša Kovačević ◽  
Lovorka Librić
Keyword(s):  
Slope Stability ◽  
Fragility Curves ◽  
Safety Margin ◽  
Water Levels ◽  
Flood Event ◽  
Soil Parameters ◽  
Design Code ◽  
A Site ◽  
Insight Into

The design code Eurocode 7 relies on semi-probabilistic calculation procedures, through utilization of the soil parameters obtained by in situ and laboratory tests, or by the means of transformation models. To reach a prescribed safety margin, the inherent soil parameter variability is accounted for through the application of partial factors to either soil parameters directly or to the resistance. However, considering several sources of geotechnical uncertainty, including the inherent soil variability, measurement error and transformation uncertainty, full probabilistic analyses should be implemented to directly consider the site-specific variability. This paper presents the procedure of developing fragility curves for levee slope stability and piping as failure mechanisms that lead to larger breaches, where a direct influence of the flood event intensity on the probability of failure is calculated. A range of fragility curve sets is presented, considering the variability of levee material properties and varying durations of the flood event, thus providing crucial insight into the vulnerability of the levee exposed to rising water levels. The procedure is applied to the River Drava levee, a site which has shown a continuous trend of increased water levels in recent years.

Aboveground growth habits of two Vaccinium species in relation to habitat

1995 ◽  
Vol 73 (3) ◽  
pp. 465-473 ◽  
Author(s):  
Anne Tolvanen
Keyword(s):  
Morphological Plasticity ◽  
Vaccinium Myrtillus ◽  
Open Habitat ◽  
Branching Angle ◽  
Below Ground ◽  
Growth Habits ◽  
Intercepted Radiation ◽  
Shoot Mass ◽  
Aboveground Growth ◽  
Vaccinium Myrtillus L

Ramet morphology in the deciduous Vaccinium myrtillus L. and the evergreen Vaccinium vitis-idaea L. was compared between the forest and open, clear-felled habitats. Growth habits were measured in terms of branching, shoot mass, bud type, branching angle, and vertical elevation of ramets. New ramets of both species were produced from buds on the below-ground stem. Branching occurred from buds on 1-year-old shoots in young ramets. Aging and flowering induced rejuvenation, i.e., production of new shoots from buds on older shoot generations within the ramets. Sympodial V. myrtillus ramets were more branched than the predominantly monopodial V. vitis-idaea ramets. In ramets of both species, vegetative shoots grew primarily from distal buds in the forest, whereas a greater number of lower buds were activated in the ramets in the open habitat. Vaccinium myrtillus ramets grew more horizontally and had wider branching angles to increase the intercepted radiation in the forest, whereas compact, vertically growing ramets prevailed in the open habitat, where light was not limited. No difference in branch orientation was observed between habitats in V. vitis-idaea. Production of flowers was greater in the open habitat than in the forest in both species. The observed differences in growth habits between forest and open habitat were assumed to indicate high morphological plasticity in both species, allowing the plants to respond rapidly to changed environmental conditions. Key words: architecture, branching, growth habit, shrub, Vaccinium.

Nature of Soils and Soil Development

2007 ◽  
Author(s):  
Earl B. Alexander ◽  
Roger G. Coleman ◽  
Todd Keeler-Wolfe ◽  
Susan P. Harrison
Keyword(s):  
Lower Limit ◽  
Total Mass ◽  
Ground Surface ◽  
Root Penetration ◽  
Unconsolidated Material ◽  
Below Ground ◽  
Porous Soil ◽  
Living Organisms ◽  
Bacteria And Fungi ◽  
The Many

We walk on soils frequently, but we seldom observe them. Soils are massive, even though they are porous. Soil 1m (40 inches) deep over an area of 1 hectare (2.5 acres) might weigh 10,000–15,000 metric tons. It is teeming with life. There are trillions, or quadrillions, of living organisms (mostly microorganisms), representing thousands of species, in each square meter of soil (Metting 1993). In fact, species diversity, or number of species, may be greater below ground than above ground. We seldom see these organisms because we seldom look below ground or dig into it. The many worms and insects one finds digging in a garden are a small fraction of the species in soils because the greatest diversity of soil-dwelling species exists among microscopic insects, mites, roundworms (or nematodes), and fungi. Even though individual organisms in soils are mostly very small or microscopic, the total mass of living organisms in a hectare of soil, excluding plant roots, may be 1–5 or 10 metric tons. More than one-half of that biomass is bacteria and fungi. Living microorganism biomass generally accounts for about 1%–5% of the organic carbon and about 2%–6% of the nitrogen in soils (Lavelle and Spain 2001). The upper limit of soil is the ground surface of the earth. The lower limit is bedrock for engineers, or the depth of root penetration for edaphologists. Unconsolidated material that engineers call soil can be called “regolith” (Merrill 1897, Jackson 1997) to distinguish it from the soil of pedologists and edaphologists. Regolith may consist of disintegrated bedrock, gravel, sand, clay, or other materials that have not been consolidated to form rock. Pedologists investigate the upper part of regolith, where changes are effected by exchanges of gases between soil and aboveground atmosphere and by biological activity. This soil of pedologists may coincide with that of edaphologists or include more regolith. In fact, the lower limit of soil that pedologists investigate is arbitrary, unless this limit is a contact with bedrock that is practically impenetrable with pick and shovel.

scholarly journals The influence of long- and short-term volcanic strain on aquifer pressure: a case study from Soufrière Hills Volcano, Montserrat (W.I.)

2020 ◽  
Vol 223 (2) ◽  
pp. 1288-1303
Author(s):  
K Strehlow ◽  
J Gottsmann ◽  
A Rust ◽  
S Hautmann ◽  
B Hemmings
Keyword(s):  
Water Level ◽  
Pore Pressure ◽  
Crustal Deformation ◽  
Water Levels ◽  
Short Term ◽  
Soufriere Hills Volcano ◽  
Soufrière Hills Volcano ◽  
Water Level Changes ◽  
Soufriere Hills

Summary Aquifers are poroelastic bodies that respond to strain by changes in pore pressure. Crustal deformation due to volcanic processes induces pore pressure variations that are mirrored in well water levels. Here, we investigate water level changes in the Belham valley on Montserrat over the course of 2 yr (2004–2006). Using finite element analysis, we simulate crustal deformation due to different volcanic strain sources and the dynamic poroelastic aquifer response. While some additional hydrological drivers cannot be excluded, we suggest that a poroelastic strain response of the aquifer system in the Belham valley is a possible explanation for the observed water level changes. According to our simulations, the shallow Belham aquifer responds to a steadily increasing sediment load due to repeated lahar sedimentation in the valley with rising aquifer pressures. A wholesale dome collapse in May 2006 on the other hand induced dilatational strain and thereby a short-term water level drop in a deeper-seated aquifer, which caused groundwater leakage from the Belham aquifer and thereby induced a delayed water level fall in the wells. The system thus responded to both gradual and rapid transient strain associated with the eruption of Soufrière Hills Volcano (Montserrat). This case study gives field evidence for theoretical predictions on volcanic drivers behind hydrological transients, demonstrating the potential of hydrological data for volcano monitoring. Interrogation of such data can provide valuable constraints on stress evolution in volcanic systems and therefore complement other monitoring systems. The presented models and inferred results are conceptually applicable to volcanic areas worldwide.

Sedimentary Cladocera as indicators of past water-level changes in shallow northern lakes

2011 ◽  
Vol 75 (3) ◽  
pp. 430-437 ◽  
Author(s):  
Liisa Nevalainen ◽  
Kaarina Sarmaja-Korjonen ◽  
Tomi P. Luoto
Keyword(s):  
Water Level ◽  
Lake Level ◽  
Water Levels ◽  
Sediment Record ◽  
Inference Model ◽  
Water Level Changes ◽  
Long Term Changes ◽  
Lower Water Level ◽  
The Relationship

AbstractThe usability of subfossil Cladocera assemblages in reconstructing long-term changes in lake level was examined by testing the relationship between Cladocera-based planktonic/littoral (P/L) ratio and water-level inference model in a surface-sediment dataset and in a 2000-yr sediment record in Finland. The relationships between measured and inferred water levels and P/L ratios were significant in the dataset, implying that littoral taxa are primarily deposited in shallow littoral areas, while planktonic cladocerans accumulate abundantly mainly in deepwater locations. The 2000-yr water-level reconstructions based on the water-level inference model and P/L ratio corresponded closely with each other and with a previously available midge-inferred water-level reconstruction from the same core, showing a period of lower water level around AD 300–1000 and suggesting that the methods are valid for paleolimnological and -climatological use.

scholarly journals Reviews and Syntheses: Ocean acidification and its potential impacts on marine ecosystems

2015 ◽  
Vol 12 (13) ◽  
pp. 10939-10983 ◽  
Author(s):  
K. M. G. Mostofa ◽  
C.-Q. Liu ◽  
W. D. Zhai ◽  
M. Minella ◽  
D. Vione ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Algal Blooms ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Marine Organisms ◽  
Atmospheric Co2 ◽  
Algal Toxins ◽  
Seawater Ph ◽  
Potential Impact ◽  
Insight Into

Abstract. Ocean acidification, a complex phenomenon that lowers seawater pH, is the net outcome of several contributions. They include the dissolution of increasing atmospheric CO2 that adds up with dissolved inorganic carbon (dissolved CO2, H2CO3, HCO3−, and CO32−) generated upon mineralization of primary producers (PP) and dissolved organic matter (DOM). The aquatic processes leading to inorganic carbon are substantially affected by increased DOM and nutrients via terrestrial runoff, acidic rainfall, increased PP and algal blooms, nitrification, denitrification, sulfate reduction, global warming (GW), and by atmospheric CO2 itself through enhanced photosynthesis. They are consecutively associated with enhanced ocean acidification, hypoxia in acidified deeper seawater, pathogens, algal toxins, oxidative stress by reactive oxygen species, and thermal stress caused by longer stratification periods as an effect of GW. We discuss the mechanistic insights into the aforementioned processes and pH changes, with particular focus on processes taking place with different time scales (including the diurnal one) in surface and subsurface seawater. This review also discusses these collective influences to assess their potential detrimental effects to marine organisms, and of ecosystem processes and services. Our review of the effects operating in synergy with ocean acidification will provide a broad insight into the potential impact of acidification itself on biological processes. The foreseen danger to marine organisms by acidification is in fact expected to be amplified by several concurrent and interacting phenomena.

scholarly journals Instrumentation issues and problems in earth dams (Case Study; Shah Qasim Dam in Yasouj, Iran)

2020 ◽  
Vol 33 (02) ◽  
pp. 737-745
Author(s):  
Amir Behshad
Keyword(s):  
Water Level ◽  
Water Levels ◽  
Critical Conditions ◽  
Earth Dams ◽  
Water Level Changes ◽  
East Of Iran ◽  
Accurate Comparison ◽  
Safety And Stability ◽  
Over Time

Installation and monitoring of instrumentation is one of the practical methods for controlling safety and stability of earth dams. Piezometers existing in dam body and dam abutments are one of the various types of precision instruments used in dams, which indicate the height of water level in different parts of the dam. In order to evaluate the performance of piezometers of Shah Qasim Dam in Kohgiluyeh and Boyerahmad province (in south east of Iran), we compare water level changes in piezometer and water level changes in the dam lake over time. In this paper, the above mentioned dam is modelled using the SEEP/W software, then after imposing boundary conditions, water levels are computed at various points. For more accurate comparison, water level changes are plotted in transverse and longitudinal piezometers over time. The results of analysis indicate significant increase of permeability in vicinity of some piezometers. The piezometers BX4, BX14, BX13 and SP6, and the region near them, as well as piezometers SP24 and SP18 and their surrounding area, have critical conditions which should be inspected as soon as possible.

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