Physical Sciences and Mathematics Commons^™

Isotopic Ecology Of Bison And Bootherium At Big Bone Lick, Kentucky, Frances Stephenson

Electronic Theses and Dissertations

Big Bone Lick (BBL) is a late Pleistocene and Holocene fossil locality in the Ohio River valley of Kentucky. This study utilized stable isotopes (δ¹³C, δ¹⁸O, and ⁸⁷Sr/⁸⁶Sr) in tooth enamel to reconstruct mobility and diet in Bison, as well as diet in Bootherium bombifrons. Isotopic results from seven Bison and two B. bombifrons are reported. Results suggest Pleistocene Bison and Bootherium occupied different dietary niches. Although both had C3-dominated diets, Bison occupied more open environments than B. bombifrons. Two bison from the late Holocene deposit had diets that consisted …

Volatile Cycling And Metasomatism In Flat-Slab Subduction Zones Of The Central Andes, Coleman Hiett

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Flat-slab subduction, where an oceanic plate subducts horizontally below a continental margin for hundreds of kilometers, is an enigmatic but prevalent tectonic configuration in which chemical cycling and alteration of the continental plate is poorly constrained. Geochemical investigations in regions of modern and ancient flat-slab subduction in the Central Andes afford an opportunity to study this process. Certain elements naturally occur with varying number of neutrons in their nuclei (isotopes), and measurements of isotope ratios within geologic materials inform on chemical sources and geologic processes. This research leverages stable isotope analyses and other geochemical tools to investigate volatiles and other …

Cryogenic Ridges: A New Speleothem Type, Bogdan P. Onac, Daniel M. Cleary, Oana A. Dumitru, Victor J. Polyak, Ioan Povara, Jonathan G. Wynn, Yemane Asmerom

International Journal of Speleology

Cryogenic cave carbonates have been described from several formerly or presently glaciated karst caves. In most of these occurrences, they precipitated as loose grains or aggregates with various morphologies and sizes. Here, we report on a new speleothem type (cryogenic ridges) identified in Sohodoalele Mici Cave (SW Romania) within a large chamber near the entrance shaft. This study was motivated by the presence of a network of calcite ridges over the stalactites’ surface and by the observation that during winter, these speleothems are covered by a thin ice layer. The higher δ¹⁸O (−3.5 to –1‰) and …

Levels Of Autotrophy And Heterotrophy In Mesophotic Corals Near The End Photic Zone, Amy Carmignani, Veronica Z. Radice, Kathryn M. Mcmahon, Alex I. Holman, Karen Miller, Kliti Grice, Zoe Richards

Biological Sciences Faculty Publications

Mesophotic corals live at ~30-150 m depth and can sustain metabolic processes under light-limited conditions by enhancing autotrophy through specialized photoadaptations or increasing heterotrophic nutrient acquisition. These acclimatory processes are often species-specific, however mesophotic ecosystems are largely unexplored and acclimation limits for most species are unknown. This study examined mesophotic coral ecosystems using a remotely operated vehicle (Ashmore Reef, Western Australia at 40–75m depth) to investigate the trophic ecology of five species of scleractinian coral (from genera Leptoseris, Pachyseris, and Craterastrea) using stable isotope analyses (δ¹³C and δ¹⁵N) of host and symbiont tissues …

Larval Ecology Of Atlantic Bluefin Tuna (Thunnus Thynnus): New Insights From Otolith Microstructure, Biotic, And Abiotic Analyses From The Gulf Of Mexico And Mediterranean Sea, Estrella Malca

All HCAS Student Capstones, Theses, and Dissertations

Atlantic bluefin tuna (ABT), Thunnus thynnus, spawn in the Gulf of Mexico (GoM) and the Mediterranean Sea (MED). Spawning occurs within narrow temporal and environmental parameters. Efforts to characterize growth of ABT in wild conditions revealed a wide range of growth variability during the early life stages. This series of studies examined potential biotic and abiotic influences of larval growth from seven ABT cohorts, and identified several key drivers of growth for this commercially valuable species. A detailed investigation of larval dynamics using otolith microstructure was conducted as follows. First, companion growth curves and stable isotope analysis from the same …

Using Stable Isotope Analyses To Assess The Trophic Ecology Of Scleractinian Corals, Michael P. Lesser, Marc Slattery, Keir J. Macartney

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Studies on the trophic ecology of scleractinian corals often include stable isotope analyses of tissue and symbiont carbon and nitrogen. These approaches have provided critical insights into the trophic sources and sinks that are essential to understanding larger-scale carbon and nitrogen budgets on coral reefs. While stable isotopes have identified most shallow water (<30 m) corals as mixotrophic, with variable dependencies on autotrophic versus heterotrophic resources, corals in the mesophotic zone (~30–150 m) transition to heterotrophy with increasing depth because of decreased photosynthetic productivity. Recently, these interpretations of the stable isotope data to distinguish between autotrophy and heterotrophy have been criticized because they are confounded by increased nutrients, reverse translocation of photosynthate, and changes in irradiance that do not influence photosynthate translocation. Here we critically examine the studies that support these criticisms and show that they are contextually not relevant to interpreting the transition to heterotrophy in corals from shallow to mesophotic depths. Additionally, new data and a re-analysis of previously published data show that additional information (e.g., skeletal isotopic analysis) improves the interpretation of bulk stable isotope data in determining when a transition from primary dependence on autotrophy to heterotrophy occurs in scleractinian corals.

Snapshots Of Coastal Ecology During Glacial And Deglacial Intervals: A Multiproxy Assessment Of Northern Gulf Of Mexico Sediment Cores, Kendall Emilie Brome

LSU Master's Theses

Terrestrial ecosystems along exposed continental shelves during times of relatively low sea level and glaciation are rarely preserved due to the mechanically erosive nature of marine transgression and regression. In this study, I investigate the geochemical and palynological characteristics of two well-preserved sites in the northern Gulf of Mexico (NGOM) to determine the ecologic settings and subsequent mechanisms of preservation in this region. Both sites contain preserved terrigenous sediments of previously exposed coastal margins; the first is located at the Alabama Underwater Forest (~13 km south of Gulf Shores, AL, at ~15 mbsl), and optically stimulated luminescence dates to 72–56 …

Establishment Of Invasive Black Carp (Mylopharyngodon Piceus) In The Mississippi River Basin: Identifying Sources And Year Classes Contributing To Recruitment, Gregory W. Whitledge, Patrick T. Kroboth, Duane C. Chapman, Quinton E. Phelps, Wes Sleeper, Jennifer Bailey, Jill A. Jenkins

United States Geological Survey: Staff Publications

Black Carp (Mylopharyngodon piceus) was imported to the USA to control aquaculture pond snails. This species has escaped captivity and occurs in parts of the Mississippi River, several tributaries, and floodplain lakes, which is concerning due to potential competition with native fishes and predation on native mussels, many of which are imperiled. However, Black Carp captures have primarily been incidental by commercial fishers, and evidence of reproduction in the wild is limited. The objectives of this study were to assess relative abundance of aquaculture- origin and wild Black Carp using ploidy and otolith stable isotope analysis, identify spatial …

Red Drum (Sciaenops Ocellatus) Trophic Web Reconstruction Using Stable Isotopes In Two Systems In The Northwestern Gulf Of Mexico, Elizabeth Mogus Garcia

Theses and Dissertations

Estuaries act as nurseries for many important fishes, including predators like Red Drum (Sciaenops ocellatus). Using gut content and stable isotope analyses to better understand juvenile S. ocellatus’ diet and role within the trophic web, a full year of data was collected on a quarterly basis to illustrate a change in diet based on resource availability at two study sites and for two non-overlapping S. ocellatus sizes. Panopeidae and Penaeidae were the most abundant prey items found in S. ocellatus stomachs for both sizes, sites, and four quarters representing over 50% of the diet. Stable isotope analyses …

Halogen And Non-Traditional Isotope Geochemistry Of Planetary And Terrestrial Materials, Anthony Gargano, Zachary Sharp, Justin Simon, Charles Shearer, Adrian Brearley, James Day

Earth and Planetary Sciences ETDs

This dissertation presents the advances in non-traditional isotope geochemistry of planetary and terrestrial materials encompassing chlorine, sulfur, and zinc isotopes, as well as halogen geochemistry. A wide breadth of materials was studied throughout the completion of this work including iron meteorites, achondrites, chondrites, Apollo lunar samples, as well ancient marine chert, and carbonate sediments. Much of the focus involved the development of a method capable of simultaneously measuring the halogen contents and chlorine isotope compositions of geological materials. Here, I present these data sets to broadly characterize the process of devolatilization of planetary materials, and specifically the problem of ‘halogen-poisoning’ …

Elucidating The Sources Supplying Aerosol Iron, Zinc, And Cadmium To The Surface Of The North Pacific Ocean With Stable Isotopes, Zach B. Bunnell

USF Tampa Graduate Theses and Dissertations

Transition metals, such as iron (Fe), zinc (Zn) and cadmium (Cd), are found at just trace amounts within the global oceans yet are vital for many biological functions of phytoplankton. As a result, these metals influence the ocean’s efficacy for carbon sequestration. Atmospheric dust is the primary input of Fe to various surface waters and may also supply Zn and Cd to oligotrophic surface waters. Here, I present Fe, Zn, and Cd isotope data from the US North Pacific GEOTRACES Section GP15 (Alaska-Tahiti) from the low-dust season (Sept. – Nov. 2018). Using this data and aerosol enrichment factors, I show …

Intra-Population Variation Of Hair And Fingernail Stable Hydrogen, Oxygen, Carbon And Nitrogen Isotopes In London, Ontario, Canada Residents During The Covid-19 Pandemic, Sawyer C E Rowe

Electronic Thesis and Dissertation Repository

Lockdowns and travel restrictions during the COVID-19 pandemic forced a significant fraction of London, Ontario, Canada residents to remain in one location for long enough to reach isotopic equilibrium with their primary drinking water source(s). This situation created ideal natural conditions for measuring the isotopic fractionation between the stable hydrogen and oxygen isotopes of drinking water and hair or nail tissues, and for determining the magnitude of intra-population variation in tissue δ²H and δ¹⁸O. Hair and nail of participants who reported exclusively drinking London municipal tap water spanned much larger δ²H and δ^{18 …}

Effects Of Glutamine Deamidation On The Oxygen Isotope Compositions Of Bone Collagen, Curtis W. Russell

Electronic Thesis and Dissertation Repository

The oxygen (O) isotope composition of mammalian collagen has the potential to provide information about the drinking water and hence geographic location and climate during the life of modern and ancient animals. An accurate and reproducible O-isotope analysis of collagen, however, has been elusive. Here, the O-isotope compositions of collagen from cortical bone of four megaherbivores were compared using two extraction procedures: the traditional Longin (HCl) method and the less commonly employed EDTA method. Preservation of O-isotope compositions was evaluated by measuring collagen peptide-chain masses, specifically the glutamine deamidation level (GDL). The EDTA method yielded collagen with a GDL of …

Accuracy And Practical Considerations For Doubly Labeled Water Analysis In Nutrition Studies Using A Laser-Based Isotope Instrument (Off-Axis Integrated Cavity Output Spectroscopy), Linda M. Reynard, William W. Wong, Noreen Tuross

Geosciences Faculty Publications and Presentations

Background: Given the utility of the doubly labeled water (DLW) method for determination of energy expenditure, additional techniques for isotope analysis of the samples are welcome. Laser-based instruments are one such new analytical tool, but their accuracy and feasibility for DLW studies are grossly understudied.

Objectives: We assessed the accuracy of laser-based isotope ratio measurements as part of the DLW method for estimation of carbon dioxide production rate (rCO₂) and total energy expenditure (TEE), in between-group comparison study designs.

Methods: Urine samples from a previous study were analyzed with a laser-based instrument [off-axis integrated cavity output spectroscopy (OA-ICOS)]. …

Determining Spatial Controls On Snow Isotopic Signature And Tracing The Snowmelt Pulse As It Moves Through Two Montane Catchments, Jenna K. Rolle

Graduate Student Theses, Dissertations, & Professional Papers

In this study, we investigate the spatial and temporal distribution of stable isotopes of oxygen and hydrogen in water across two mountainous catchments in west-central Montana to trace the input of snow to local soil, bedrock aquifers, and streams. Snowpack and snowmelt samples were collected throughout the winter season at ten sites selected to encompass a range of elevation, aspect, slope angle and hillslope position. Soil and bedrock wells at five of the ten sites were sampled after the initial snowmelt pulse and stream samples were collected weekly at the outlets of both catchments to trace the timing and partitioning …

The Hera Orebody: A Complex Distal (Au–Zn–Pb–Ag–Cu) Skarn In The Cobar Basin Of Central New South Wales, Australia, Corey Wall

Geosciences Faculty Publications and Presentations

The Hera Au–Pb–Zn–Ag deposit in the southeastern Cobar Basin of central New South Wales preserves calc-silicate veins and remnant sandstone/carbonate-hosted skarn within a reduced anchizonal Siluro-Devonian turbidite sequence. The skarn orebody distribution is controlled by a long-lived, basin margin fault system, that has intersected a sedimentary horizon dominated by siliciclastic turbidite, with lesser gritstone and thick sandstone intervals, and rare carbonate-bearing stratigraphy. Foliation (S1) envelopes the orebody and is crosscut by a series of late-stage east–west and north–south trending faults. Skarn at Hera displays mineralogical zonation along strike, from southern spessartine–grossular–biotite–actinolite-rich associations, to central diopside-rich–zoisite–actinolite/tremolite–grossular-bearing associations, through to the northern …

Stable Isotopes Used To Infer Trophic Position Of Green Turtles (Chelonia Mydas) From Dry Tortugas National Park, Gulf Of Mexico, United States, David C. Roche, Michael S. Cherkiss, Brian J. Smith, Derek A. Burkholder, Kristen M. Hart

Marine & Environmental Sciences Faculty Articles

Evaluating resource use patterns for imperiled species is critical for understanding what supports their populations. Here we established stable isotope (δ¹³C, δ¹⁵N) values for the endangered green sea turtle (Chelonia mydas) population found within the boundaries of Dry Tortugas National Park (DRTO), south Florida, USA. There is little gene flow between turtles sampled at DRTO and in other rookeries in Florida, underscoring the need to study this distinct population. Between 2008 and 2015 we collected multiple sample types (skin [homogenized epidermis/dermis], whole blood, red blood cells, plasma, carapace) from 151 unique green turtles, including …

Spatiotemporal Variability Of Soil Water Δ18o And Δ2h Reveals Hydrological Processes In Two Floodplain Soils, Amanda Ceming-Barbato

LSU Master's Theses

The movement of water through soil is preferential and heterogeneous. Subsurface interactions between mobile flows and the soil matrix are not uniform and are therefore difficult to predict through time and space. The use of stable isotopes of hydrogen (²H) and oxygen (¹⁸O) as conservative tracers of water movement is improving understanding of soil hydrological processes, yet field-scale observations of isotopic variability remain scarce despite implications for identifying dominant hydrologic processes. We sampled two adjacent soils at a ridge-swale topography floodplain forest to determine soil water isotopic variability at a 20 cm depth resolution in soils …

Effect Of The Hierarchical Position Of Individuals In A Medicago Sativa Stand On Shoot Respiration, M. Lötscher, Hans Schnyder

IGC Proceedings (1997-2023)

The influence of the hierarchical position on the relationship between C gains and C losses (respiration) of individuals was investigated in a alfalfa (Medicago sativa) stand. The hierarchical position that an individual occupied was defined by its height relative to the stand height. Stands were established by arranging potted individual plants at a density of 400 plants m^-2. Stands were grown in growth cabinets. ¹³C steady-state labelling was used to assess C fixation (C_new) by individuals during a photoperiod of 16 h. Respiration of shoots was measured during the following 8 h dark …

Stable Hydrogen Isotopes Of Aquatic-Emergent Versus Terrestrial Insects In Southern Ontario, Celina Y. Tang

Undergraduate Student Research Internships Conference

Aquatic-emergent insects are vectors of both contaminants and nutrients, linking the aquatic system to the terrestrial system. Aquatic-emergent insects are high in omega-3 fatty acids that benefit terrestrial aerial insectivores, such as bats and birds. With aerial insectivores on a decline, a contributing factor could be a decrease in the quality of insects. We collected insects from lakeshore and inland locations in Southern Ontario. Insects sampled included bees, wasps, ants, beetles, caddisflies, craneflies, dragonflies, marchflies, mayflies, midges, other flies, and true bugs. Insects’ wings and powdered bodies were then analyzed for stable hydrogen isotopes (d²H) in order …

A Study Of Stable Isotopes In Snow On Mt. Hood, Oregon, Maya Felix

University Honors Theses

Over the 2020-2021 Winter, event-based and end-of-season snow samples were collected on Mt. Hood near Government Camp, OR and analyzed for their stable isotopic compositions of ¹⁸O and ²H. It was found that surficial snow collected through the winter had higher variation in isotopic values than samples from a snow pit collected in spring. This suggests homogenization occurred in the snowpack over the season from snow metamorphism, sublimation, and/or melting. Homogenization of the snowpack will likely become more pronounced as temperatures increase and rain falls more often than snow due to climate change. Research that utilizes the snowpack …

Mosquito Distribution And Stoichiometric Analysis Between Open And Closed Canopies In New Orleans Cemeteries, Rachel Rogers

LSU Master's Theses

Cemetery vases represent an important container habitat for mosquito larvae. Some species, like, Aedes albopictus and Aedes aegypti, prefer container habitats, whereas others, like Culex quinquefasciatus, will opportunistically use containers. In New Orleans, these three medically important vector species (Ae. albopictus Ae. aegypti, and Cx. quinquefasciatus) co-occur, despite a demonstrated competitive advantage of Ae. albopictus to the other two. Here we test the hypothesis that canopy cover from trees could be a mediating factor in driving mosquito assemblages in New Orleans, by influencing food sources, and the microclimate experienced by mosquito larvae. Samples from seven …

Identifying Nitrogen Source And Seasonal Variation In A Black Mangrove (Avicennia Germinans) Communityof The South Texas Coast, Ashley Elizabeth Murphy, Carlos E. Cintra-Buenrostro, Alejandro Fierro-Cabo

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Black mangrove (Avicennia germinans) stands in south Texas grow in association with other autotrophic organisms including herbaceous halophytes and cyanobacterial mats. Despite the relevant ecosystem services provided by this coastal plant community, limited information exists on its functioning, in particular as it pertains to nutrient dynamics, namely nitrogen (N). Nitrogen stable isotopes were used to assess potential N sources for plant growth in this community. Plant tissue (leaves), cyanobacteria, and sediment were sampled once every season for one year. Total N in A. germinans (2.6 %) and associated saltwort (Batis maritima) (2.1 %) was higher than in cyanobacteria (0.6 %), …

Organic-Input Impacts On Soil Carbon Flux, Storage, And Budget In Conservation Agricultural Soils, Central Washington, Usa, Jessica Hartman

All Master's Theses

The increase in global atmospheric CO₂ over the last 200 years has generated an urgent need for strategies for sequestering carbon (C). Soil C, which has been depleted by land use change and agricultural practices, is a prime target for C storage. Land management practices, including no-till, cover cropping and crop rotation, and the application of C amendments such as compost and biochar, are suggested to increase C in the soil. Spoon Full Farm, near Thorp, WA, was a conventional hay farm until 2016, when management practices changed to implement some of these C sequestration strategies. A prior CWU …

Triple Oxygen Isotope Measurements (Δ'17O) Of Body Water Reflect Water Intake, Metabolism, And Δ18O Of Ingested Water In Passerines, Pablo Sabat, Seth D. Newsome, Stephanie Pinochet, Roberto Nespolo, Juan Carlos Sanchez-Hernandez, Karen Maldonado, Alexander R. Gerson, Zachary D. Sharp, John P. Whiteman

Biological Sciences Faculty Publications

Understanding physiological traits and ecological conditions that influence a species reliance on metabolic water is critical to creating accurate physiological models that can assess their ability to adapt to environmental perturbations (e.g., drought) that impact water availability. However, relatively few studies have examined variation in the sources of water animals use to maintain water balance, and even fewer have focused on the role of metabolic water. A key reason is methodological limitations. Here, we applied a new method that measures the triple oxygen isotopic composition of a single blood sample to estimate the contribution of metabolic water to the body …

The Multidisciplinary Approaches On Facies Developments And Depositional Systems Of The Bahçecik Travertines, Gümüşhane, Ne-Turkey, Rai̇f Kandemi̇r, Ezher Tagli̇asacchi̇, Mi̇ne Sezgül Kayseri̇ Özer, Di̇lek Şaffak, Fati̇h Köroğlu, Hsun-Ming Hu, Chuan-Chou Shen

Turkish Journal of Earth Sciences

The Bahçecik travertines, located in Gümüşhane (NE-Turkey) have been investigated for the first time using a multidisciplinary approach, which included sedimentological (lithofacies, depositional system), petrographic, radiometric 230Th dating, geochemical analysis (stable isotopes), palynomorphs and geophysics (GPR). A carbonate build-up, 12 m thick, was formed with some interruptions, through the middle Pleistocene period. For this study, two travertine sections (F and D) were extensively used to figure out palaeoenvironmental and palaeoclimatic proxies. The main precipitation cycles, separated by palaeosol levels, have been described and interpreted from a sedimentological perspective. The carbonate deposits consist of shrubs, crystalline crust, reed, laminated (micritic), pisoids, …

Multiple Fluid-Mineral Equilibria Approach To Constrain The Evolution Of Thermal Watersin The Hisaralan Geothermal Field, Simav Graben, Western Turkey, Ali̇ Gökgöz, Hali̇m Mutlu, Mehmet Özkul, Ali̇ Kami̇l Yüksel

Turkish Journal of Earth Sciences

In this study seasonal changes in the geochemical and stable isotope compositions of Hisaralan thermal waters in Simav Graben, western Turkey, were investigated with regards to a variety of mineral-water interactions and mixing processes. The Hisaralan and Emendere geothermal waters, with temperatures of up to 99 °C, were mostly of Na-HCO3 and Ca-HCO3 types. The δ18O and δ2H values of the Hisaralan waters ranged from -9.32‰ to -8.73‰ and -65.02‰ to -61.10‰, with maximum seasonal differences of 0.3‰ and 1.8‰. The Emendere waters were represented by a more positive range of δ2H values (-54.95‰ to -54.61‰), while their δ18O compositions …

Factors Determining Seagrass Blue Carbon Across Bioregions And Geomorphologies, Ines Mazarrasa, Paul Lavery, Carlos M. Duarte, Anna Lafratta, Catherine E. Lovelock, Peter I. Macreadie, Jimena Samper-Villarreal, Cristian Salinas, Christian J. Sanders, Stacey Trevathan-Tackett, Mary Young, Andy Steven, Oscar Serrano

Research outputs 2014 to 2021

Seagrass meadows rank among the most significant organic carbon (C_org) sinks on earth. We examined the variability in seagrass soil C_org stocks and composition across Australia and identified the main drivers of variability, applying a spatially hierarchical approach that incorporates bioregions and geomorphic settings. Top 30 cm soil C_org stocks were similar across bioregions and geomorphic settings (min-max: 20–26 Mg C_org ha⁻¹), but meadows formed by large species (i.e., Amphibolis spp. and Posidonia spp.) showed higher stocks (24–29 Mg C_org ha⁻¹) than those formed by smaller species (e.g., Halodule, Halophila, …

Stable Isotopes Of Water Reveal Differences In Plant – Soil Water Relationships Across Northern Environments, Matthew J. Kohn, James P. Mcnamara

Geosciences Faculty Publications and Presentations

We compared stable isotopes of water in plant stem (xylem) water and soil collected over a complete growing season from five well‐known long‐term study sites in northern/cold regions. These spanned a decreasing temperature gradient from Bruntland Burn (Scotland), Dorset (Canadian Shield), Dry Creek (USA), Krycklan (Sweden), to Wolf Creek (northern Canada). Xylem water was isotopically depleted compared to soil waters, most notably for deuterium. The degree to which potential soil water sources could explain the isotopic composition of xylem water was assessed quantitatively using overlapping polygons to enclose respective data sets when plotted in dual isotope space. At most sites …

Can Stable Isotopes From Tree Rings Improve Our Understanding Of Past Variability In The Southern Annular Mode?, Zachary Grzywacz

Graduate Theses, Dissertations, and Problem Reports

Few annually dated stable isotope records exist across Oceania. In mid- to high-latitude locations in South America, tree-ring stable isotopes provide information about past climate dynamics such as the Southern Annular Mode (SAM). The SAM drives latitudinal shifts in Southern Hemisphere westerly winds, influencing temperature and moisture delivery across the mid- to high-latitudes, including Tasmania. Combinations of paleoclimate proxies from across the Southern Ocean might provide insight into dynamic processes like the SAM that are difficult to measure with a single proxy. Measuring stable carbon and oxygen isotope ratios from tree rings in Tasmania could provide complementary data to contribute …