Florence Lake Research Articles

Plasma insulin-like growth factor-1 is unrelated to female reproductive development in a wild population of Dolly Varden charr Salvelinus malma (Walbaum, 1792)

Insulin-like growth factors (IGFs) are endocrine agents that signal growth in fishes. Because of the interplay between growth and reproduction, endocrine control of the growth axis is thought to have a connection to the reproductive axis. Seasonal patterns and relationships between IGF-1, fish condition, and gonadal development were investigated in a wild population of female Dolly Varden charr Salvelinus malma (Walbaum, 1792) during the summer growing season prior to spawning. Fish were sampled from Florence Lake, Alaska on five sequential sampling trips during April–October 2006. Body and gonad morphometric measurements, and blood plasma samples were obtained for IGF-I quantification. IGF-I increased during summer with fish condition. The gonadosomatic index indicated a pattern of advancing reproductive development in one cohort of fish by August, which indicated impending spawning compared to an immature (non-reproductive) cohort. However, plasma IGF-I levels were not predictive of the sexually maturing cohort. We conclude that IGF-I is not a useful endocrine marker of advancing reproductive state in female Dolly Varden charr but does relate to fish condition during the summer growth period.

Characteristics of a Naturalized Kokanee Salmon Oncorhynchus nerka Population in Atypical Habitat

Kokanee salmon are a dwarf freshwater form of the anadromous sockeye salmon (Oncorhynchus nerka) native to the Pacific coast of North America and Asia and widely introduced in western North America as a sport and prey fish. Few kokanee salmon introductions have succeeded in eastern North America. A naturalized population of kokanee salmon has persisted for over 50 yr in Florence Lake, Wisconsin, an unlikely location given its relatively small size (21.4 ha), shallow maximum depth (7.6 m), low elevation (381 m), and southerly latitude (45.12°N). Kokanee salmon completed their entire life cycle within the lake and rarely entered an accessible coldwater inlet stream. Spawning occurred during late October and early November along the lake shoreline. Spawning redds with defending males were observed in 1–2 m of water on sand/gravel/ cobble substrate. Kokanee salmon growth in the lake was relatively rapid, and fish had a mean total length of 117 mm after their first growing season (age 0+), 212 mm after their second (age 1+), begin to mature and spawn after their third (age 2+) at 317 mm for females and 324 mm for males, and were at 344 mm for females and 354 mm for males after their fourth (age 3+). Few fish reproduced at age 4+. Despite limited oxy-thermal habitat during summer, kokanee salmon appear to thrive in Florence Lake, perhaps because of cold inflows from the inlet and springs within the lake.

Impact of aerosols on reservoir inflow: A case study for Big Creek Hydroelectric System in California

Accurate and reliable reservoir inflow forecast is instrumental to the efficient operation of the hydroelectric power systems. It has been discovered that natural and anthropogenic aerosols have a great influence on meteorological variables such as temperature, snow water equivalent, and precipitation, which in turn impact the reservoir inflow. Therefore, it is imperative for us to quantify the impact of aerosols on reservoir inflow and to incorporate the aerosol models into future reservoir inflow forecasting models. In this paper, a comprehensive framework was developed to quantify the impact of aerosols on reservoir inflow by integrating the Weather Research and Forecasting model with Chemistry (WRF-Chem) and a dynamic regression model. The statistical dynamic regression model produces forecasts for reservoir inflow based on the meteorological output variables from the WRF-Chem model. The case study was performed on the Florence Lake and Lake Thomas Alva Edison of the Big Creek Hydroelectric Project in the San Joaquin Region. The simulation results show that the presence of aerosols results in a significant reduction of annual reservoir inflow by 4-14%. In the summer, aerosols reduce precipitation, snow water equivalent, and snowmelt that leads to a reduction in inflow by 11-26%. In the spring, aerosols increase temperature and snowmelt which leads to an increase in inflow by 0.6-2%. Aerosols significantly reduce the amount of inflow in the summer when the marginal value of water is extremely high and slightly increase the inflow in the spring when the run-off risk is high. In summary, the presence of aerosols is detrimental to the optimal utilization of hydroelectric power systems.

A Comparison of Nonlethal Methods for Evaluating the Reproductive Status of Female Coastal Cutthroat Trout

Abstract Knowledge of the state of sexual development is important for management of coastal cutthroat trout Oncorhynchus clarkii clarkii, a fish species targeted for sport fishing throughout its range along the Pacific coast of North America. The purpose of this study was to compare the nonlethal methods of ultrasound imaging, body lipid content, and the measurement of plasma vitellogenin and estradiol levels for assessing the reproductive status of female coastal cutthroat trout. This was examined in a population living in Florence Lake, Alaska, during the spring–early autumn period of the annual reproductive cycle. All methods, except body lipid content, were effective at determining maturity status in either the spring (ultrasound imaging), or spring and autumn (plasma vitellogenin and estradiol). These approaches could be useful for conducting nonlethal assessments of length- or age-at-maturity on populations of coastal cutthroat trout that are small, have conservation concerns, or are heavily utilized by anglers.

California Damming

Using the ideas of culture theorist Walter Benjamin (among others), I examine the public response to two dams, Friant Dam and Florence Lake Dam, to illustrate the political and aesthetic reasons why Californians have very mixed feelings about the state's dams. The history of John Muir and Hetch Hetchy is also alluded to.

Evolution of 3.1 and 3.0 Ga volcanic belts and a new thermotectonic model for the Hopedale Block, North Atlantic craton (Canada)

A new model for evolution of the Archean Hopedale Block, based on mapping and supporting U–Pb geochronological and geochemical studies, is highlighted by (i) ca. 3.25 Ga emplacement of igneous precursors of Maggo Gneiss; (ii) &gt3.1 Ga, high-grade Hopedalian metamorphism and attendant deformation; (iii) emplacement of the Hopedale mafic dykes; (iv) 3.1 Ga deposition of Hunt River volcanic rocks; (v) ca. 3.0 Ga deposition of Florence Lake volcanic rocks; (vi) 2.88–2.96 Ga, greenschist- to amphibolite-facies Fiordian metamorphism and formation of penetrative, northeast-striking Fiordian structures; and (vii) emplacement of a suite of 2.89–2.83 Ga tonalite to granite intrusions, which partially overlap and locally postdate Fiordian metamorphism and deformation. The Hunt River and Florence Lake volcanic sequences are different in age but similar in most other respects. The former consists mainly of amphibolite-facies mafic metavolcanic rocks and lesser amounts of komatiite flows and metasedimentary and 3105 ± 3 Ma felsic volcanic rocks. The Florence Lake volcanic belt consists mainly of greenschist- to amphibolite-facies mafic metavolcanic rocks, lesser amounts of felsic metavolcanic rocks, dated at 2979 ± 1 and 2990 ± 2 Ma, komatiite flows, and rare metasedimentary rocks. The similarity of rock types, field relationships between different rock types, such as the common association of ultramafic and felsic metavolcanic rocks, and the chemistry of volcanic rocks in both belts suggest a common tectonic setting for each belt. A model involving episodic volcanism, separated by 100 Ma, in ensialic basins is consistent with the dominance of tholeiitic basalt and an abundance of pre-volcanic basement.

Paleomagnetic constraints on rotation within Mount Abbot quadrangle, central Sierra Nevada, California

The regional photolineament pattern in Mount Abbot quadrangle in the central Sierra Nevada is sigmoidal in plan view. The fractures in the southwest section of the quadrangle, near Florence Lake, strike N10°–20°E, while those in the central section, along Bear Creek, strike N50°–70°E and those in the northeast strike N25°–40°E. A paleomagnetic investigation was undertaken to determine if this sigmoidal pattern was formed by kinking of originally straight photolineaments after the rock mass cooled below the blocking temperature. If the inner limb of the kink rotated 40°–60° clockwise with respect to the outer limbs, then there should be a similar difference in the paleomagnetic declinations between the Florence Lake and Bear Creek areas. The paleomagnetic results indicate a clockwise difference in declination of 13.4°±7° of the Bear Creek area with respect to Florence Lake. Thus the sigmoidal pattern could not have formed entirely by rotation after cooling below the blocking temperature. It is also possible that the observed declination discrepancy is due to tilting, apparent polar wander, or paleomagnetic dispersion instead of rotation. Sigmoidal patterns, formed by kink folding, occur on the outcrop scale with inner limb rotations of 15°–30°; three of these kinks were sampled to test the paleomagnetic method in an area of demonstrable rotation. The data from these sites indicate that although no difference in declination is evident, a reheating event may have occurred which could have removed any rotation from the paleomagnetic record. Reheating, possibly due to the circulation of hydrothermal fluids, may have been causally related to the outcrop scale kinking, since reheating is not observed away from the outcrop scale kinks. The data further indicate that there may have been continuous deformation of the rock mass during the formation of the kinks.

Joint formation in granitic rock of the Sierra Nevada

Research Article| May 01, 1983 Joint formation in granitic rock of the Sierra Nevada PAUL SEGALL; PAUL SEGALL 1U.S. Geological Survey, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar DAVID D. POLLARD DAVID D. POLLARD 1U.S. Geological Survey, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1983) 94 (5): 563–575. https://doi.org/10.1130/0016-7606(1983)94<563:JFIGRO>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation PAUL SEGALL, DAVID D. POLLARD; Joint formation in granitic rock of the Sierra Nevada. GSA Bulletin 1983;; 94 (5): 563–575. doi: https://doi.org/10.1130/0016-7606(1983)94<563:JFIGRO>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract A single steeply dipping joint set in the Mount Givens Granodiorite, central Sierra Nevada, was studied to clarify the mechanics of fracture and joint formation in granitic rocks. The joints were filled with fluid during, or immediately following, formation; these fluids deposited epidote and chlorite within the joints. Examination of lithologic markers in outcrop and thin section demonstrates that relative displacements are normal to the joint surfaces. These observations rule out a shear origin for these joints. The measured extensional strain acommodated by joint dilation is on the order of 1 × 10−4 to 5 × 10−4. A few joints in the area exhibit small strike-slip offsets. In these joints, the mineral fillings are sheared, indicating the strike-slip motion postdated the jointing.Individual joints consist of numerous subparallel, planar segments. The lengths of joints range from metres to nearly 100 metres. Shorter joints are more abundant than longer joints. The observed distribution of joint lengths is thought to result from the elastic interaction of adjacent joints. Shorter joints are prevented from further propagation by their long neighbors. Between mapped joints, small cracks that have lengths of several centimetres are found parallel to the longer joints. These cracks represent a growth stage between grain-scale microcracks and macroscopic joints.A method is developed for estimating the tensile stress responsible for initiating joint growth. The method requires knowledge of the extensional strain accommodated by joint dilation and the spatial density of joints, both of which can be determined by field observations. Calculations based on observations of joints in the Florence Lake area indicate relative tensile stresses (average remote stress plus internal fluid pressure) of approximately 1 MPa to 40 MPa. These values of stress and estimates of initial crack length are used to estimate the quasi-static fracture toughness of the granodiorite. The calculated fracture toughnesses range from 0.04 Mpa·m1/2 to 4 Mpa·m1/2. The stress and fracture toughness estimates are compatible with existing data from laboratory fracture experiments. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Bird Banding at Florence Lake, 7340 Feet Altitude

Bird Banding at Florence Lake, 7340 Feet Altitude