Stratification and Mixing in Coastal Waters of the Western Gulf of Maine during Summer

1968 ◽  
Vol 25 (12) ◽  
pp. 2609-2621 ◽  
Author(s):  
Edward M. Hulburt
Keyword(s):  
High Temperatures ◽  
Coastal Waters ◽  
Low Temperatures ◽  
Gulf Of Maine ◽  
Cold Water ◽  
Vertical Mixing ◽  
Tidal Mixing ◽  
Western Coast ◽  
Surface Temperatures ◽  
Light Wind

In the summers of 1966 and 1967, very low surface temperatures, about 11 C, and weakly stratified water occurred along the western coast of the Gulf of Maine at Cape Nedick, in the Sheepscot River, and off Vinalhaven Island at the mouth of Penobscot Bay. Moderately low temperatures, about 13 C, were found often between the islands of Casco Bay. These low temperatures indicate an active vertical mixing, associated with tidal currents, that transports water warmed at the surface downward and cold water upward.Where tidal mixing is reduced, offshore from Cape Ann and in the landward confines of Casco Bay, surface temperatures over 17 C and pronounced stratification occurred. When these high temperatures were observed off Cape Ann, the weather was sunny and calm, or a light wind caused very little mixing. Within Casco Bay temperatures of 17 C or more were observed during a period when fogs were prevalent, allowing heating in clear spells in the daytime and a minimum of cooling at night.

scholarly journals Environmental factors influencing cold-water coral ecosystems in the oxygen minimum zones on the Angolan and Namibian margins

2019 ◽  
Author(s):  
Ulrike Hanz ◽  
Claudia Wienberg ◽  
Dierk Hebbeln ◽  
Gerard Duineveld ◽  
Marc Lavaleye ◽  
...  
Keyword(s):  
Organic Matter ◽  
High Temperatures ◽  
Environmental Conditions ◽  
Cold Water ◽  
Tidal Mixing ◽  
Low Oxygen ◽  
Nepheloid Layer ◽  
Oxygen Minimum Zones ◽  
Oxygen Minimum ◽  
Water Coral

Abstract. Fossil cold-water coral mounds overgrown by sponges and bryozoans were observed in anoxic conditions on the Namibian margin, while mounds colonized by thriving cold-water coral reefs were found in hypoxic conditions on the Angolan margin. These low oxygen conditions do not meet known environmental ranges favoring cold-water corals and hence are expected to provide unsuitable habitats for cold-water coral growth and therefore reef formation. To explain why the living fauna can nevertheless thrive in both areas, present day environmental conditions at the southwestern African margin were assessed. Downslope CTD transects and the deployment of bottom landers were used to investigate spatial and temporal variations of environmental properties. Temporal measurements in the mound areas recorded oscillating low dissolved oxygen concentrations of 0–0.17 ml l−1 (≙ 0–9 % saturation) on the Namibian and 0.5–1.5 ml l−1 (≙ 7–18 % saturation) on the Angolan margin, which were associated with relatively high temperatures (11.8 13.2 °C and 6.4–12.6 °C respectively). Semi-diurnal barotrophic tides were found to interact with the margin topography producing internal waves with excursions of up to 70 and 130 m for the Namibian and Angolan margins, respectively. These tidal movements temporarily deliver water with more suitable characteristics to the coral mounds from below and above the hypoxic zone. Concurrently, the delivery of high quantity and quality of suspended particulate organic matter was observed, which serves as a food source for cold-water corals. On the Namibian slope organic matter indicates a completely marine source and originates directly from the surface productive zone, whereas on the Angolan margin the geochemical signature of organic material suggest an additional mechanisms of food supply. A nepheloid layer observed above the cold-water coral mound area on the Angolan margin may constitutes a reservoir of fresh organic matter, facilitating a constant supply of food particles by tidal mixing. This suggests that the cold-water coral communities as well as the associated fauna may compensate unfavorable conditions induced by low oxygen levels and high temperatures with an enhanced availability of food. With the expected expansion of oxygen minimum zones in the future due to anthropogenic activities, this study provides an example on how ecosystems could cope with such extreme environmental conditions.

Low solubility of alumina in enstatite and uncertainties in estimated palaeogeotherms

1978 ◽  
Vol 288 (1355) ◽  
pp. 471-486 ◽  
Keyword(s):  
High Temperatures ◽  
Low Temperatures ◽  
Alumina Content ◽  
Equilibrium Solubility ◽  
Low Solubility

Spurious kinks in estimated palaeogeotherms may result from small errors in the calibration of the geothermometers and geobarometers. New data indicate that the equilibrium solubility of alumina in enstatite is even less than shown by recent studies, and that the slopes (d T /d P ) of the isopleths of equal alumina content are steeper than hitherto believed. Consequently, pressures of equilibration estimated from current formulations of the orthopyroxene-garnet geobarometer will be too high at high temperatures (> 1200 °C) and too low at low temperatures.

scholarly journals Environmental temperature during early life affects the personality of mosquitofish in adulthood

2021 ◽  
Author(s):  
Haifeng Li ◽  
Xinyu ZHang ◽  
Yi Wu ◽  
Feng ZHang ◽  
CHunlin Li
Keyword(s):  
Body Length ◽  
High Temperatures ◽  
Low Temperatures ◽  
Early Life ◽  
Environmental Temperature ◽  
Phenotypic Trait ◽  
Behavioral Syndrome ◽  
Growing Up ◽  
Female Fish ◽  
Behavioral Traits

Abstract Personality has been observed in a variety of animal taxa with important implications in ecology and evolution. Exploring the influence of environmental temperature during early life on personality could help to understand the ontogeny of this phenotypic trait in animals. In this study, we reared newborn mosquitofish Gambusia affinis at high (30°C) and low (25°C) water temperatures and measured their shyness and exploration upon sexual maturity. We tested the repeatability of each behavioral trait; the correlation between them; and the effects of rearing temperature, sex, and body length on the behaviors. When growing up at low temperatures, female fish exhibited repeatability in shyness and exploration, and males exhibited marginal repeatability in shyness. However, neither of the 2 behaviors were repeatable when the fish were reared at high temperatures. There was a negative correlation between shyness and exploration, indicating that the 2 behaviors comprise a behavioral syndrome in this species. Mosquitofish reared at high temperatures were more explorative than those reared at low temperatures, while there was no difference in shyness between the 2 treatments. Body length and sex had no significant effects on the average values of the 2 behaviors. The results indicate that environmental temperature during early life could shape the personality of mosquitofish and modify the average of the behavioral traits. These findings might provide insights to understand the ontogeny of animal personality and how changes in environmental temperature influence animal dispersal by shaping their personality.

Analysis of Ferroelectric Microcapacitors by Scanning Probe Microscope

2004 ◽  
Vol 811 ◽  
Author(s):  
Nobuhiro Kin ◽  
Koichiro Honda
Keyword(s):  
High Temperatures ◽  
Low Temperatures ◽  
Evaluation System ◽  
Ferroelectric Material ◽  
Scanning Probe Microscope ◽  
Scanning Probe ◽  
Electrical Heater ◽  
Device Processing ◽  
Probe Microscope ◽  
The Impact

ABSTRACTTo develop higher density FRAM requires reducing cell size. Therefore, the size effects resulting from device processing and the material's physical properties must be measured. Therefore, analyzing the electric characteristics of a single bit cell capacitor has become important. Two known characteristics of ferroelectric material are that the Vc increases at low temperatures, and the Pr falls at high temperatures. To further evaluate the impact of temperature on ferroelectrics, we constructed a new evaluation system based on a scanning probe microscope, that can measure the electric characteristics of a single bit cell capacitor. This system can be used in the temperature range from −120 degrees to 300 degrees C. We accomplished this by circulating liquid nitrogen around a SPM stage and by using an electrical heater. We measured the electrical properties of ferroelectric microcapacitors by using a sample with IrOx/PZT/Pt structure. Our measurements revealed that 2Pr really increases at low temperatures, and Pr decreases at high temperatures. That is, we have shown that Vc increases 30% at low temperatures and Pr decreases 10% also in an actual FRAM single bit cell capacitor.

Effects of ternary additions on the deformation behavior of single crystals of MoSi2

2000 ◽  
Vol 646 ◽  
Author(s):  
Haruyuki Inui ◽  
Koji Ishikawa ◽  
Masaharu Yamaguchi
Keyword(s):  
Yield Strength ◽  
Strain Rate ◽  
Single Crystals ◽  
Creep Strain ◽  
High Temperatures ◽  
Low Temperatures ◽  
Deformation Behavior ◽  
Creep Strain Rate ◽  
Compression Creep ◽  
Ternary Additions

ABSTRACTEffects of ternary additions on the deformation behavior of single crystals of MoSi2 with the hard [001] and soft [0 15 1] orientations have been investigated in compression and compression creep. The alloying elements studied include V, Cr, Nb and Al that form a C40 disilicide with Si and W and Re that form a C11b disilicide with Si. The addition of Al is found to decrease the yield strength of MoSi2 at all temperatures while the additions of V, Cr and Nb are found to decrease the yield strength at low temperatures and to increase the yield strength at high temperatures. In contrast, the additions of W and Re are found to increase the yield strength at all temperatures. The creep strain rate for the [001] orientation is significantly lower than that for the [0 15 1] orientation. The creep strain rate for both orientations is significantly improved by alloying with ternary elements such as Re and Nb.

Consideration of the Cross-Anisotropy of Different Materials of the Asphalt Surface Layer and Temperature to Determine Pavement Responses

2021 ◽  
Vol 13 (1) ◽  
pp. 140-151
Author(s):  
Minrui Guo ◽  
Xinglin Zhou
Keyword(s):  
Surface Layer ◽  
High Temperatures ◽  
Low Temperatures ◽  
Compressive Strain ◽  
Fatigue Cracking ◽  
Element Model ◽  
Rate Of Change ◽  
Temperature Relationship ◽  
The Cross ◽  
Cross Anisotropy

The effects of the cross-anisotropy of different materials of the asphalt surface layer and the depth-temperature relationship on pavement responses and damage are investigated. A three-dimensional Finite-Element Model (FEM) of the pavement, which considers the depth-temperature relationship of the surface layer under moving tire load, is developed. Pavement damage models are established to evaluate the damage ratio for primary rutting and fatigue cracking. The results show that the compressive strain at the bottom of the surface layer increases as the temperature increases, and the cross-anisotropy (n-value) decreases, indicating that a decrease in the horizontal modulus of different materials of the surface layer increases the damage ratio for primary rutting at high temperatures. The tensile strain at the bottom of the surface layer declines as the n-value increases to 1. For the same change in the n-value, the rate of change of the damage ratio for fatigue cracking is greater at low temperatures than at high temperatures, demonstrating that the number of allowable load repetitions is more sensitive at low temperatures. In addition, the effect of cross-anisotropy and temperature on the vertical stress are larger on the top of the base than in the subbase and subgrade.

scholarly journals Towards a regional ocean forecasting system for the IBI (Iberia-Biscay-Ireland area): developments and improvements within the ECOOP project framework

Ocean Science ◽  
2012 ◽  
Vol 8 (2) ◽  
pp. 143-159 ◽  
Author(s):  
S. Cailleau ◽  
J. Chanut ◽  
J.-M. Lellouche ◽  
B. Levier ◽  
C. Maraldi ◽  
...  
Keyword(s):  
General Circulation ◽  
Large Scale ◽  
Vertical Mixing ◽  
Circulation Model ◽  
Storm Surges ◽  
Ocean General Circulation Model ◽  
Tidal Mixing ◽  
Basin Scale ◽  
Forecasting System ◽  
Ocean Forecasting

Abstract. The regional ocean operational system remains a key element in downscaling from large scale (global or basin scale) systems to coastal ones. It enables the transition between systems in which the resolution and the resolved physics are quite different. Indeed, coastal applications need a system to predict local high frequency events (inferior to the day) such as storm surges, while deep sea applications need a system to predict large scale lower frequency ocean features. In the framework of the ECOOP project, a regional system for the Iberia-Biscay-Ireland area has been upgraded from an existing V0 version to a V2. This paper focuses on the improvements from the V1 system, for which the physics are close to a large scale basin system, to the V2 for which the physics are more adapted to shelf and coastal issues. Strong developments such as higher regional physics resolution in the NEMO Ocean General Circulation Model for tides, non linear free surface and adapted vertical mixing schemes among others have been implemented in the V2 version. Thus, regional thermal fronts due to tidal mixing now appear in the latest version solution and are quite well positioned. Moreover, simulation of the stratification in shelf areas is also improved in the V2.

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