scholarly journals Buoyancy control in ammonoid cephalopods refined by complex internal shell architecture

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
David J. Peterman ◽  
Kathleen A. Ritterbush ◽  
Charles N. Ciampaglio ◽  
Erynn H. Johnson ◽  
Shinya Inoue ◽  
...  
Keyword(s):  
Surface Tension ◽  
Water Retention Capacity ◽  
Functional Explanation ◽  
Retention Capacity ◽  
Biomechanical Stress ◽  
Liquid Retention ◽  
3D Printed ◽  
Functional Explanations ◽  
Hydrophilic Coatings ◽  
The Impact

AbstractThe internal architecture of chambered ammonoid conchs profoundly increased in complexity through geologic time, but the adaptive value of these structures is disputed. Specifically, these cephalopods developed fractal-like folds along the edges of their internal divider walls (septa). Traditionally, functional explanations for septal complexity have largely focused on biomechanical stress resistance. However, the impact of these structures on buoyancy manipulation deserves fresh scrutiny. We propose increased septal complexity conveyed comparable shifts in fluid retention capacity within each chamber. We test this interpretation by measuring the liquid retained by septa, and within entire chambers, in several 3D-printed cephalopod shell archetypes, treated with (and without) biomimetic hydrophilic coatings. Results show that surface tension regulates water retention capacity in the chambers, which positively scales with septal complexity and membrane capillarity, and negatively scales with size. A greater capacity for liquid retention in ammonoids may have improved buoyancy regulation, or compensated for mass changes during life. Increased liquid retention in our experiments demonstrate an increase in areas of greater surface tension potential, supporting improved chamber refilling. These findings support interpretations that ammonoids with complex sutures may have had more active buoyancy regulation compared to other groups of ectocochleate cephalopods. Overall, the relationship between septal complexity and liquid retention capacity through surface tension presents a robust yet simple functional explanation for the mechanisms driving this global biotic pattern.

scholarly journals Time Dependent Influence of Rotating Magnetic Field on Bacterial Cellulose

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Karol Fijałkowski ◽  
Rafał Rakoczy ◽  
Anna Żywicka ◽  
Radosław Drozd ◽  
Beata Zielińska ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Bacterial Cellulose ◽  
Water Retention ◽  
Rotating Magnetic Field ◽  
Water Retention Capacity ◽  
Water Molecules ◽  
Retention Capacity ◽  
Exposure System ◽  
The Impact ◽  
Water Holding

The aim of the study was to assess the influence of rotating magnetic field (RMF) on the morphology, physicochemical properties, and the water holding capacity of bacterial cellulose (BC) synthetized by Gluconacetobacter xylinus. The cultures of G. xylinus were exposed to RMF of frequency that equals 50 Hz and magnetic induction 34 mT for 3, 5, and 7 days during cultivation at 28°C in the customized RMF exposure system. It was revealed that BC exposed for 3 days to RMF exhibited the highest water retention capacity as compared to the samples exposed for 5 and 7 days. The observation was confirmed for both the control and RMF exposed BC. It was proved that the BC exposed samples showed up to 26% higher water retention capacity as compared to the control samples. These samples also required the highest temperature to release the water molecules. Such findings agreed with the observation via SEM examination which revealed that the structure of BC synthesized for 7 days was more compacted than the sample exposed to RMF for 3 days. Furthermore, the analysis of 2D correlation of Fourier transform infrared spectra demonstrated the impact of RMF exposure on the dynamics of BC microfibers crystallinity formation.

scholarly journals Evaluation of the short-term effect of tillage practices on soil hydro-physical properties

2019 ◽  
Vol 52 (1) ◽  
pp. 43
Author(s):  
Omid Bahmani
Keyword(s):  
Physical Properties ◽  
Water Retention ◽  
Total Porosity ◽  
Field Capacity ◽  
Water Retention Capacity ◽  
Model Parameters ◽  
Retention Capacity ◽  
Tillage Practices ◽  
Available Water ◽  
The Impact

<p><strong> </strong>Tillage is one of the most important practices that have a significant influence on the soil hydro-physical properties. In this study, the impact of the type and number of input variables with five different methods of the Retc model to predicting the moisture retention curve and soil water content in three surfaces tillage NT (No-tillage), CP (Chisel Plough) and MP (Moldboard Plough) and the impact of tillage systems on soil hydro-physical properties were evaluated. According to results, when the field capacity and wilting point moisture was added to input data in Retc to predict the moisture curve model parameters, the EF was increased in MP (0.977, 0.95) and CP (0.891, 0.86) treatments compare the NT (0.665, 0.608). The Mualem–Van Genuchten model can describe satisfactorily the simulation of soil physical properties. The S-index, which was also affected by tillage, was greater than 0.066 in all tillage treatments, indicating good soil physical quality. Results indicated that NT had the highest and lowest values of bulk density (1.55 Mgr.m<sup>-3</sup>) and total available water (TAW) (0.038 m.m<sup>-1</sup>), respectively, and the differences between NT and MP in total porosity was significant. Overall, in most soil layers, tillage practices affected the porosity and total available water in the order MP &gt; CP &gt; NT. Water retention curves indicated that the water retention capacity was greater in tilled than in no-tilled and saturated hydraulic conductivity values were greater in tilled treatments than in NT soil.</p>

scholarly journals The conservation agriculture in northwest of Morocco (Merchouch area): The impact of no-till systems on physical properties of soils in semi-arid climate

2021 ◽  
Vol 234 ◽  
pp. 00037
Author(s):  
Abdelali El Mekkaoui ◽  
Rachid Moussadek ◽  
Rachid Mrabet ◽  
Said Chakiri ◽  
Ahmed Douaik ◽  
...  
Keyword(s):  
Conservation Agriculture ◽  
Biological Properties ◽  
Water Retention Capacity ◽  
Arid Zones ◽  
Arid Environments ◽  
Retention Capacity ◽  
No Till ◽  
Significant Difference ◽  
The Impact ◽  
Semi Arid

Conservation agriculture (CA) is characterized by three principles: minimum tillage, even the total absence of tillage in the case of direct seeding (NT), permanent soil cover by mulch, and diversification of crops. Its main objective is to control soil degradation by conserving the physical and biological properties and fertility of the soil, which leads to an improvement in productivity, while preserving the environment. Conventional tillage (CT) used in the arid and semi-arid environments of Morocco (particularly in the study site area of Merchouch) compromise the productivity of established crops in these regions. The work presented consists in the study of the impact of NT on the physico-chemical properties of the soil, especially organic matter (SOM), bulk density (BD), soil moisture (θg), and structural stability (SS) in semi-arid zones. The results show that the use of the NT system positively influences the accumulation of SOM, especially at the soil surface horizon (0-5cm). Concerning θg, there is a significant difference between the two treatments (NT and CT) at the average of the three depths and especially at the horizon 20-40 cm so NT increases the water retention capacity. This study also shows that the mean weight diameter (MWD) of the 3 tests (water, ethanol, and rehumectation) is higher for NT compared to CT. This shows that no-till helped to build a good soil structure over time, which is highly desirable for improving agricultural productivity and conserving natural resources, especially water.

Chemical and physical properties of two tropical soils treated with sewage sludge compost

1969 ◽  
Vol 83 (3-4) ◽  
pp. 103-121
Author(s):  
Gustavo A. Martínez ◽  
José L. Guzmán ◽  
Miguel A. Vázquez ◽  
Luis E. Rivera ◽  
Agenol González
Keyword(s):  
Sewage Sludge ◽  
Environmental Protection Agency ◽  
Salt Content ◽  
Organic Matter Content ◽  
Water Retention Capacity ◽  
Retention Capacity ◽  
Sludge Compost ◽  
Sewage Sludge Compost ◽  
Compost Facility ◽  
The Impact

The effects of sewage sludge compost applications on a Mollisol and an Ultisol of Puerto Rico were evaluated. Experimental rates were control (0 compost), 37, 74, and 148 t/ha/yr, which were to be applied during a three year period. In addition, a treatment consisting of a single application of 445 t/ha was included to assess the impact of single massive applications vs. continuous applications of compost. Results here presented pertain exclusively to the project's first year. The compost was obtained from the sewage sludge compost facility of Puerto Rico's Solid Waste Management Authority in Arecibo. The material was predominantly inorganic and exhibited a high soluble salt content, which diminished its quality. Compost additions caused significant pH increases in both soils. The effects were more noticeable on the Ultisol (Corozal clay), where pH increased from 4.55 in the control to 6.45 with the lowest compost treatment. The electrical conductivity of both soils increased considerably with compost additions, sometimes approaching limits considered detrimental to support crop growth. The organic matter content of both soils also increased with compost additions. This increase had a positive effect on their water retention capacity. Nitrogen contributions from the compost were minimal. However, significant increases in the levels of phosphorus were observed in both soils. Compost additions caused significant increases in the levels of EDTA extractable metals (i.e., Cu, Zn, Cd, Cr, Fe). However, elements regulated by the U.S. Environmental Protection Agency (e.g., Cd, Pb, Cr) were added in amounts well below the established limits, and thus were not a reason for concern.

scholarly journals Physical characteristics affecting the infiltration of high intensity rainfall into a soil profile

2014 ◽  
Vol 9 (No. 3) ◽  
pp. 104-110 ◽  
Author(s):  
L. Koutný ◽  
J. Skoupil ◽  
D. Veselý
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Profile ◽  
High Intensity ◽  
Water Retention Capacity ◽  
Catchment Management ◽  
Suction Pressure ◽  
Infiltration Capacity ◽  
Retention Capacity ◽  
The Impact

Flooding caused by intensive precipitation has been in the centre of attention of both general public and scientists. From the flood risk management perspective, an integrated approach to catchment management is necessary, in particular with regards to water retention capacity. Our research has been focused on the high intensity rainfall, its short duration, and an adequate infiltration capacity into the soil profile in the upper parts of the catchment, the same as on the impact of soil characteristics such as moisture content and suction pressure, in particular. The five-year research period in two sub-catchments &ndash; Červ&iacute;k A and B &ndash; in the Beskydy Mts. enabled monitoring of about 300 events, and seventy of them with higher rainfall intensity were selected for further analysis. The analysis showed that the retention of an intensive precipitation was positively dependent on the instantaneous soil moisture and suction pressure. A continuous monitoring of these properties made it possible to quantify the potential runoff and the tendency to cause flooding. The analysis also showed an inverse situation in terms of the relationship between retention (and consequently runoff), suction pressure, and soil moisture content. It was therefore necessary to eliminate these by proposing suitable preventive bio-technical measures.

scholarly journals Carbon capacity of gray forest soils in the Chechen Republic

2022 ◽  
Vol 42 ◽  
pp. 02006
Author(s):  
Rustam Gakaev
Keyword(s):  
Water Retention ◽  
Forest Ecosystems ◽  
Dead Wood ◽  
Great Influence ◽  
Exchange Capacity ◽  
Microbial Populations ◽  
Water Retention Capacity ◽  
Negative Consequences ◽  
Retention Capacity ◽  
The Impact

Common areas of research needed to measure soil carbon include: (1) the impact of forest management, (2) the impact of climate change, and (3) the impact of increased carbon dioxide. The organic matter of the soil has a great influence on the productivity of the site due to its effect on the physical (bulk density, water retention capacity), biological (microbial populations) and chemical (cation exchange capacity) properties of soils. Recently, there have also been claims of the benefits of dead wood for forest ecosystems. However, as with all nutrients, too much carbon in the soil can have negative consequences, especially with regard to nitrogen immobilization.

scholarly journals Validation of Cryogenic Vacuum Extraction of Pore Water from Volcanic Soils for Isotopic Analysis

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2214
Author(s):  
Diego Rivera ◽  
Karen Gutierrez ◽  
Walter Valdivia-Cea ◽  
Mauricio Zambrano-Bigiarini ◽  
Alex Godoy-Faúndez ◽  
...  
Keyword(s):  
Water Retention ◽  
Hydrological Cycle ◽  
Water Retention Capacity ◽  
Vacuum Extraction ◽  
Initial Water Content ◽  
Soil Water Retention ◽  
Retention Capacity ◽  
Initial Water ◽  
Cryogenic Vacuum ◽  
The Impact

Andean headwater catchments are key components of the hydrological cycle, given that they capture moisture, store water and release it for Chilean cities, industry, agriculture, and cities in Chile. However, knowledge about within-Andean catchment processes is far from clear. Most soils in the Andes derive from volcanic ash Andosols and Arenosols presenting high organic matter, high-water retention capacity and fine pores; and are very dry during summer. Despite their importance, there is little research on the hillslope hydrology of Andosols. Environmental isotopes such as Deuterium and 18-O are direct tracers for water and useful on analyzing water-soil interactions. This work explores, for the first time, the efficiency of cryogenic vacuum extraction to remove water from two contrasting soil types (Arenosols, Andosols) at five soil water retention energies (from −1500 to −33 kPa). Two experiments were carried out to analyse the impact of extraction time, and initial water content on the amount of extracted water, while a third experiment tested whether the cryogenic vacuum extraction changed the isotopic ratios after extraction. Minimum extraction times to recover over 90% of water initially in the soil samples were 40–50 min and varied with soil texture. Minimum volume for very dry soils were 0.2 mL (loamy sand) and 1 mL (loam). After extraction, the difference between the isotope standard and the isotopic values after extraction was acceptable. Thus, we recommend this procedure for soils derived from volcanic ashes.

scholarly journals Effect of Unimodal and Bimodal Soil Hydraulic Properties on Slope Stability Analysis

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1674
Author(s):  
Hsin-Fu Yeh ◽  
Tsien-Ting Huang ◽  
Jhe-Wei Lee
Keyword(s):  
Hydraulic Conductivity ◽  
Slope Stability ◽  
Water Content ◽  
Water Retention ◽  
Water Retention Capacity ◽  
Retention Capacity ◽  
Seepage Analysis ◽  
Hydraulic Behavior ◽  
Conductivity Function ◽  
The Impact

Rainfall infiltration is the primary triggering factor of slope instability. The process of rainfall infiltration leads to changes in the water content and internal stress of the slope soil, thereby affecting slope stability. The soil water retention curve (SWRC) was used to describe the relationship between soil water content, matric suction, and the water retention characteristics of the soil. This characteristic is essential for estimating the properties of unsaturated soils, such as unsaturated hydraulic conductivity function and shear strength. Thus, SWRC is regarded as important information for depicting the properties of unsaturated soil. The SWRC is primarily affected by the soil pore size distribution (PSD) and has unimodal and bimodal features. The bimodal SWRC is suitable for soils with structural or dual-porous media. This model can describe the structure of micropores and macropores in the soil and allow the hydraulic behavior at different pore scales to be understood. Therefore, this model is more consistent with the properties of onsite soil. Few studies have explored the differences in the impact of unimodal and bimodal models on unsaturated slopes. This study aims to consider unimodal and bimodal SWRC to evaluate the impact of unsaturated slope stability under actual rainfall conditions. A conceptual model of the slope was built based on field data to simulate changes in the hydraulic behavior of the slope. The results of seepage analysis show that the bimodal model has a better water retention capacity than the unimodal model, and therefore, its water storage performance is better. Under the same saturated hydraulic conductivity function, the wetting front of the bimodal model moves down faster. This results in changes in the pressure head, water content, and internal stress of the soil. The results show that the water content and suction stress changes of the bimodal model are higher than those of the unimodal model due to the difference in water retention capacity. Based on the stability of the slope, calculated using the seepage analysis, the results indicate that the potential failure depth of the bimodal model is deeper than that of the unimodal model.

scholarly journals The use of the linear reservoir concept to quantify the impact of changes in land use on the hydrology of catchments in the Andes

2004 ◽  
Vol 8 (1) ◽  
pp. 108-114 ◽  
Author(s):  
W. Buytaert ◽  
B. De Bièvre ◽  
G. Wyseure ◽  
J. Deckers
Keyword(s):  
Land Use ◽  
Land Use Changes ◽  
Base Flow ◽  
Population Pressure ◽  
Water Retention Capacity ◽  
Residence Times ◽  
Retention Capacity ◽  
Mean Residence Times ◽  
Linear Reservoir ◽  
The Impact

Abstract. The high Andes region of South Ecuador (The Páramo) is characterised by a cold and wet climate. Most soils of the Páramo region are Andosols and Histosols, with a very high water retention capacity that is affected irreversibly by drying. This key property of Páramo soils buffers catchment outflow, resulting in an almost uniform outflow pattern which, notwithstanding the variability in rainfall, can be very variable in space and time. These soils serve as the most important reservoir of drinking and irrigation water for the densely populated inter-Andean depression region. The Páramo has long served only as an extensive grazing area but recent population pressure and land scarcity have increased cultivation. Two small Páramo catchments (about 2 km2) were monitored intensively for precipitation and discharge for over a year to assess the effect of such land-use changes on the hydrological properties. One catchment is in an undisturbed area and grazed intensively while in the other, local farmers started intensive drainage for cultivation of potatoes about five years ago. The linear reservoir concept has been used to assess the overall retention capacity of the catchments in terms of both peak response and base flow. In this model, every catchment is considered as a series of independent parallel reservoirs, each characterised by mean residence times (T). In every catchment, three major mean residence times can be distinguished. In the undisturbed catchment, an immediate response, characterised by a T of 5.4 hours, is followed by a slower response with a T of 44.3 h. The base flow has a mean T value of 360 h. The response of the cultivated catchment is similar with T values of 3.6 h, 27.2 h and 175 h, respectively. As a result, in the disturbed catchment, water release is about 40% faster than in the undisturbed catchment, so that the base flow falls rapidly to lower levels. The linear reservoir model is a simple way of quantifying the impact of land use changes on the water regulation capacity of Páramo catchments. Keywords: linear reservoir, Páramo, mountain hydrology, land use changes, Ecuador

Sign in / Sign up

Export Citation Format

Share Document