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2018

Stable isotopes

Articles 1 - 10 of 10

Full-Text Articles in Physical Sciences and Mathematics

Stable Isotope Geochemistry Of Bioapatite, Amanda E. Drewicz Dec 2018

Stable Isotope Geochemistry Of Bioapatite, Amanda E. Drewicz

Boise State University Theses and Dissertations

The Cenozoic Era was a time period where dynamic shifts in climate created for both warm-wet greenhouse environments of the mid-Miocene Climatic Optimum (MMCO), and cool-dry, glacial periods of the late Pleistocene. The Cenozoic is close to our own time period, and although past climate reconstructions cannot be used as direct analogs for future climate change, understanding previous environmental responses can help inform policy surrounding future climate change. Presented here are climate reconstructions of the interior western United States, from two different geologic time periods. Each had a different climate, that differed greatly from modern day environments. The use of …

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A Multidecade Experiment Shows That Fertilization By Salmon Carcasses Enhanced Tree Growth In The Riparian Zone, Thomas P. Quinn, Helfield M. James, Catherine S. Austin, Rachel A. Hovel, Andrew Godard Bunn Nov 2018

A Multidecade Experiment Shows That Fertilization By Salmon Carcasses Enhanced Tree Growth In The Riparian Zone, Thomas P. Quinn, Helfield M. James, Catherine S. Austin, Rachel A. Hovel, Andrew Godard Bunn

Environmental Sciences Faculty and Staff Publications

As they return to spawn and die in their natal streams, anadromous, semelparous fishes such as Pacific salmon import marine‐derived nutrients to otherwise nutrient‐poor freshwater and riparian ecosystems. Diverse organisms exploit this resource, and previous studies have indicated that riparian tree growth may be enhanced by such marine‐derived nutrients. However, these studies were largely inferential and did not account for all factors affecting tree growth. As an experimental test of the contribution of carcasses to tree growth, for 20 yr, we systematically deposited all sockeye salmon (Oncorhynchus nerka) carcasses (217,055 individual salmon) in the riparian zone on one …

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Impact Of Climate Change On The Transition Of Neanderthals To Modern Humans In Europe, Michael Staubwasser, Virgil Drăgușin, Bogdan P. Onac, Sergey Assonov, Vasile Ersek, Dirk L. Hoffman, Daniel Veres Sep 2018

Impact Of Climate Change On The Transition Of Neanderthals To Modern Humans In Europe, Michael Staubwasser, Virgil Drăgușin, Bogdan P. Onac, Sergey Assonov, Vasile Ersek, Dirk L. Hoffman, Daniel Veres

School of Geosciences Faculty and Staff Publications

Two speleothem stable isotope records from East-Central Europe demonstrate that Greenland Stadial 12 (GS12) and GS10—at 44.3–43.3 and 40.8–40.2 ka—were prominent intervals of cold and arid conditions. GS12, GS11, and GS10 are coeval with a regional pattern of culturally (near-)sterile layers within Europe’s diachronous archeologic transition from Neanderthals to modern human Aurignacian. Sterile layers coeval with GS12 precede the Aurignacian throughout the middle and upper Danube region. In some records from the northern Iberian Peninsula, such layers are coeval with GS11 and separate the Châtelperronian from the Aurignacian. Sterile layers preceding the Aurignacian in the remaining Châtelperronian domain are coeval …

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High-Dimensional Isotope Relationships, Yuyang He Aug 2018

High-Dimensional Isotope Relationships, Yuyang He

LSU Doctoral Dissertations

High-dimensional isotope relationships describes the relationships of two or more element or position-specific (PS) elements in the same molecule or ion. It provides us more powerful tools to study reaction mechanisms and dynamics. Chapter 1 is about dual or multiple stable isotope relationship on δ-δ (or δ'-δ') space. While temporal data sampled from a closed-system can be treated by a Rayleigh Distillation Model (RDM), spatial data should be treated by a Reaction-Transport Model (RTM). Here we compare the results of a closed-system RDM to a RTM for systems with diffusional mass transfer by simulating the trajectories on nitrate's δ'18 …

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Estimating Watershed Residence Times In Artificially-Drained Landscapes And Relation To Nutrient Concentrations, Emma Beck, Lisa Welp, Alexandra L. Meyer Aug 2018

Estimating Watershed Residence Times In Artificially-Drained Landscapes And Relation To Nutrient Concentrations, Emma Beck, Lisa Welp, Alexandra L. Meyer

The Summer Undergraduate Research Fellowship (SURF) Symposium

Nutrient runoff from agricultural lands feeds harmful algae blooms that create a variety of problems in freshwater ecosystems. In order to reduce the effects of this nutrient runoff, Best Management Practices (BMPs) are being put in place in agricultural lands. Most of these BMPs focus on slowing down the flow of water through the watershed to give nutrient concentrations time to deplete before the water flows to the stream or river. However, the effectiveness of these BMPs are highly unknown and the process of monitoring nutrient runoff is often complex and costly. The data in this study consists of 7 …

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Kinetic Processes And Stable Isotopes In Cave Dripwaters As Indicators Of Winter Severity, Vasile Ersek, Bogdan P. Onac, Aurel Perșoiu Aug 2018

Kinetic Processes And Stable Isotopes In Cave Dripwaters As Indicators Of Winter Severity, Vasile Ersek, Bogdan P. Onac, Aurel Perșoiu

School of Geosciences Faculty and Staff Publications

We examine how the stable isotope composition of meteoric water is transmitted through soil and epikarst to dripwaters in a cave in western Romania. δ2H and δ18O in precipitation at this site are influenced by temperature and moisture sources (Atlantic and Mediterranean), with lower δ18O in winter and higher in summer. The stable isotope composition of cave dripwaters mimics this seasonal pattern of low and high δ18O, but the onset and end of freezing conditions in the winter season are marked by sharp transitions in the isotopic signature of cave dripwaters of …

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Evaluation Of Trace-Metal And Isotopic Records As Techniques For Tracking Lifetime Movement Patterns In Fishes, Jennifer E. Granneman Jul 2018

Evaluation Of Trace-Metal And Isotopic Records As Techniques For Tracking Lifetime Movement Patterns In Fishes, Jennifer E. Granneman

USF Tampa Graduate Theses and Dissertations

The focus of this work was on the use of otolith microchemistry and fish eye lens chemical profiles to measure fish movement and provided indirect support for the use of otolith microchemistry to examine exposure to crude oil. Chapter 1 provides an introduction to the applications of otolith microchemistry and eye lens isotopic profiles. In the second chapter, which examined associations between metal exposure and lesion formation in fishes collected after the Deepwater Horizon (DWH) oil spill, I did not observe any change in oil-associated metal concentrations in otoliths coinciding with the timing of the DWH oil spill. This suggests …

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Stable Isotope Analysis Reveals Different Trophic Niche Spaces For Wild And Hatchery Origin Juvenile Chinook Salmon In The Nisqually Delta, Melanie Davis, Isa Woo, Christopher S. Ellings, Sayre Hodgson, Susan De La Cruz Apr 2018

Stable Isotope Analysis Reveals Different Trophic Niche Spaces For Wild And Hatchery Origin Juvenile Chinook Salmon In The Nisqually Delta, Melanie Davis, Isa Woo, Christopher S. Ellings, Sayre Hodgson, Susan De La Cruz

Salish Sea Ecosystem Conference

Hatchery programs have been used as a conservation tool to bolster declining Chinook salmon (Oncorhynchus tshawytscha) populations throughout much of the Salish Sea. In many watersheds, hatchery fish are released concurrently with the natural-origin population, thus raising the potential for density dependent effects via depleted prey resources, territorial behavior, and movement into sub-optimal habitats. Competition during the critical period for early marine growth and survival might have detrimental effects for wild Chinook salmon populations, highlighting the potential importance of a productive delta habitat mosaic. We used an integrated diet approach with stomach content and stable isotope analyses to evaluate differential …

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Has Primary Productivity Declined In The Strait Of Georgia Since The 1970s?, Sophia Johannessen Apr 2018

Has Primary Productivity Declined In The Strait Of Georgia Since The 1970s?, Sophia Johannessen

Salish Sea Ecosystem Conference

A strong decline in phytoplankton productivity has been proposed as a principal cause of the decline in salmon survival in the Strait of Georgia over the last four decades. The best estimate of total annual primary productivity in the Strait in the 1970s was 280 gC m-2 yr-1 (Harrison et al., 1983). We tested whether or not primary productivity had declined since that time by calculating recent productivity from regional nitrogen budgets. We constructed the budgets using measurements (collected 2001-2011) of dissolved and particulate nitrogen and stable isotopes of nitrogen in seawater, river water, sinking particles, bottom sediments, atmospheric deposition, …

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The Role Of Logmat Biofilm In The Spirit Lake Ecosystem After The Eruption Of Mt. St. Helens, Emma Sevier Jan 2018

The Role Of Logmat Biofilm In The Spirit Lake Ecosystem After The Eruption Of Mt. St. Helens, Emma Sevier

Summer Research

Spirit Lake, on the flanks of Mount St. Helens, was dramatically altered as a result of the eruption in 1980, and over the past 37 years the lake ecosystem has recovered in a rapidly evolving volcanic landscape. While Spirit Lake is similar in many ways to other alpine oligotrophic lakes, it is unique because approximately 20% of the lake’s surface remains covered with floating log mats from trees felled during the eruption. The undersides of the logs provide a substrate for biofilm (periphyton) that is primarily comprised of algae, diatoms, and cyanobacteria. Due to the sheer amount of log-based surface …

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