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Vertebral Chemistry Distinguishes Nursery Habitats of Juvenile Shortfin Mako in the Eastern North Pacific Ocean

Benjamin R. LaFreniere1, Oscar Sosa-Nishizaki2, Sharon Z. Herzka2, Owyn Snodgrass3, Heidi Dewar3, Nathan Miller4, R.J. David Wells5,6, John A. Mohan1,5

  1. School of Marine and Environmental Programs, University of New England, 11 Hills Beach Road, Biddeford, Maine04005, USA
  2. Departamento de Oceanografia Bioliogica, Centro de Investigacion Cientifica y de, Educacion Superior de Ensenada(CICESE), 3918 Carretera Tijuana-Ensenada, Ensenada, Baja California 22860, Mexico
  3. National Marine Fisheries Service, Southwest Fisheries Science Center, 8901 La Jolla Shores Drive, La Jolla, California92037, USA
  4. Jackson School of Geosciences, University of Texas at Austin, 2275 Speedway Stop C9000, Austin, Texas 78712, USA
  5. Department of Marine Biology, Texas A&M University at Galveston, 1001 Texas Clipper Road, Galveston, Texas 77553,USA
  6. Department of Ecology and Conservation Biology, Texas A&M University, College Station, Texas 77843,USA

The ability to determine the origin of highly migratory species allows fishery managers to better understand how nursery habitats contribute to adult populations. In this study, opportunistically sampled vertebrae from juvenile Shortfin Mako were sourced from two distinct nurseries in the  eastern  North  Pacific. Mineralized vertebral cartilage was analyzed to determine concentrations of selected elements (Li, Mg, Mn, Zn, Sr, Ba, standardized to Ca) using laser ablation inductively coupled plasma mass spectrometry, targeting growth bands at specific life stages. This technique allowed for investigations into shifts between past and recent life through development. Results suggested limited regional movements between nursery grounds, but local shifts in coastal habitat and/or feeding as juveniles grow. This study revealed the potential for using vertebral chemistry for characterizing regional differences and local shifts between habitats of migratory sharks in the California Current.

This project was funded by the Texas A&M CONACYT Collaborative Research Program (Project 2016-026). We thank the recreational and commercial fishermen for providing vertebrae samples. All samples were opportunistically harvested and were not targeted for this study.

“Early Life History and Nursery Habitat Use of Hudson River Striped Bass”

Kohma Arai

The University of Maryland Center for Environmental Science


Juvenile fishes depend on nurseries that are both proximate and distant to natal habitats, although drivers that cause juveniles to utilize different nurseries remain unclear. Striped bass exhibits partial migration and diverse habitat use during their early life which could arise from threshold responses associated with early life conditions. The principal nursery region of the Hudson River (HR) striped bass population occurs in freshwater and oligohaline habitats in the lower HR. Juveniles are also prevalent in distant polyhaline habitats in the western Long Island Sound (WLIS) outside the HR. Here, we used otolith chemistry and microstructure to assess the influence of early life history attributes and environmental drivers on early dispersal behaviors of HR striped bass. We hypothesize that (i) brackish water migrants collected in the lower HR and WLIS will originate from cohorts of earlier hatch dates, and (ii) early dispersal is a conditional response, triggered by slower growth and external forces. Nursery habitat use of age-0 juveniles collected throughout the HR and WLIS in August 2020 was assessed through otolith microchemistry (Mg, Mn, Sr, Ba) using Laser Ablation ICPMS analysis given the strong salinity gradient across HR and WLIS nurseries. Hatch dates and early growth were estimated through otolith microstructure and compared between freshwater residents and brackish water migrants. The influence of temperature and freshwater flow conditions on early dispersal were also assessed. Otolith microstructure analysis indicated that brackish water migrants hatched almost two weeks earlier compared to freshwater residents. Migrants also showed higher early growth despite early hatch dates and experiencing lower temperature conditions. Migrants experienced significantly higher flow conditions during their early life stages, which could be associated with early dispersal behaviors. Understanding the mechanisms underlying early dispersal and WLIS recruitment is important to support long-term persistence of the HR striped bass, which supports one of the most important fisheries in US Atlantic waters.

2022 American Fisheries Society Meeting presentation


Monitoring a unique karst system over two-years to elucidate hydroclimate variables influencing the geochemistry of surface and subsurface waters

SEKHON, Natasha1, BANNER, Jay L.2, BREECKER, Daniel O.1, TREMAINE, Darrel M.3 and MILLER, Nathan1, (1)Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX 78712, (2)Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX 78712; Environmental Science Institute, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX 78712, (3)Environmental Science Institute, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX 78712; Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX 78712

Near entrance temperate latitude stalagmites may record seasonal growth and geochemical variations associated with hydroclimate variability. Monitoring the cave system can establish empirical relationships between hydroclimate variables and geochemical proxies and growth rate. We present results from a two-year (2017-2019 CE) bimonthly monitoring campaign at Sitting Bull Falls (SBF) Cave and its watershed in remote SE New Mexico. SBF Cave is continuously fed by a surface spring/stream that terminates into a surface pool perched 4m above the cave. In this sense, the cave potentially integrates changes in the entire watershed, and thus its stalagmites may provide unique information regarding temporal changes in watershed-scale processes. Surface (spring and stream samples) and subsurface (cave dripwaters) waters were analyzed for trace element concentrations and O and H isotope values. Cave calcite accumulated on plates placed under cave drip sites were analyzed for growth rate. Cave ventilation was monitored via cave-air temperature, CO2 concentrations, and relative humidity.Our monitoring results demonstrate year-round cave ventilation and calcite growth in SBF Cave. Dripwater O and H isotope values deviate from the Global Meteoric Water Line consistent with evaporation, likely occurring in the epikarst, on the cave ceiling, or both. Co-variation of ln(Sr/Ca) and ln(Mg/Ca) in surface and subsurface waters is quantitatively accounted for by prior calcite precipitation (PCP). Subsurface waters are more PCP-evolved than surface waters. Co-variation between ln(Sr/Ca) and ln(Mg/Ca) of cave dripwaters, which is commonly used as an aridity proxy in stalagmites, might be a result of PCP occurring in both the watershed and the cave. Lastly, the water-calcite distribution coefficient of Mg for a site nearest to the cave entrance has a strong correlation with seasonal temperature variability (r2 = 0.67). Thus, we hypothesize that low/high Mg/Ca ratio couplets may aide in constraining seasonal geochemical cyclicity of near-entrance stalagmites. Taken together, we show processes in the watershed influencing the geochemical variability of cave dripwaters.

Recorded presentation

Age validation using periodicity of annulus formation and hardpart microconstituents in black sea bass (Centropristis striata)


Ben Frey – U. Maryland Center for Environmental Science

Abstract: Without accurate age interpretation or validation, serious errors in the management and understanding of fish populations can occur. This study employs a novel approach to age validation using trace element microconstituent analysis of otoliths. The optical zones of annuli are hypothesized to be the result of seasonal changes in organic content and experienced temperature, either of which can result in cycles of trace elements associated with annulus formation. Using electron microprobe and Laser Ablation ICPMS analyses, we tested for periodicity in otolith Ca, Cu, P, Sr, Mg, Mn and Zn and the synchrony of periodicity with annulus zonation (opaque and translucent zones). Initial tests were conducted for black sea bass, a species for which yearly annulus formation has been validated. Periodicities in elemental profiles were identified using a Lomb-Scargle periodogram analysis that allowed for unequally spaced measurements. Periodic components were tested for significance using Fourier series harmonic filtering. Component periods and intensities were compared between each elemental series. Candidate elements identified through this analysis of black sea bass otoliths will be useful for planned applications on Atlantic monkfish, for which no validated ageing procedure exists.

Video presentation

Ontogenetic patterns of elemental tracers in the vertebrae cartilage of coastal and oceanic sharks

AFS Annual Meeting 2021

Mariah Livernois – Texas A&M Galveston

Abstract: As predators, coastal and oceanic sharks play critical roles in shaping ecosystem structure and function, but most shark species are highly susceptible to population declines. Effective management of vulnerable shark populations requires knowledge of species-specific movement and habitat use patterns. Since sharks are often highly mobile and long-lived, tracking their habitat use patterns over large spatiotemporal scales is challenging. However, the analysis of elemental tracers in vertebral cartilage can describe a continuous record of the life history of an individual from birth to death. This study examined trace elements (Li, Mg, Ca, Mn, Zn, Sr, and Ba) along vertebral transects of five shark species with unique life histories. From most freshwater-associated to most oceanic, these species include Bull Sharks (Carcharhinus leucas), Bonnethead Sharks (Sphyrna tiburo), Blacktip Sharks (C. limbatus), Spinner Sharks (C. brevipinna), and Shortfin Mako Sharks (Isurus oxyrinchus). Element concentrations were compared across life stages to infer species-specific ontogenetic patterns of habitat use and movement. Bull Sharks exhibited clear ontogenetic changes in elemental composition matching expected changes in their use of freshwater habitats over time. Bonnethead Shark elemental composition did not differ across ontogeny, suggesting residence in estuarine/coastal regions. The patterns of elemental composition were strikingly similar between Spinner and Blacktip Sharks, suggesting they co-occur in similar habitats across ontogeny. Mako shark elemental composition was mostly stable over time, but some ontogenetic shifts occurred that may be due to changes in migration patterns with maturation. The results presented in this study enhance our understanding of the habitat use and movement patterns of coastal and oceanic sharks, and advance the utility of vertebral chemistry as a tool for examining shark life history traits.

Video presentation


Stalagmite 2D chemical mapping of seasonal growth layers

Heather Gunn – Spring 2021 Honors Thesis

GSA Abstract: Central Texas caves feature slow-growth (<10-100 µm/yr) stalagmite records as old as 70 ka that span glacial and deglacial hydroclimate cycles. Monitoring efforts in these caves indicate: calcite growth occurs mainly during cold seasons when cave-air CO2 concentrations are lowered by ventilation; drip waters have interannual epikarst residence times; calcite accumulation rate follows drip rate. In moisture-limited settings such as central Texas, drip rates likely proxy the epikarst volume of recharge precipitation. Associated stalagmites may therefore preserve millennial-scale records of recharge variation as growth band thickness. To accurately reconstruct hydroclimate, resolving seasonal growth variation is key, but seasonal growth bands are often not visible by conventional petrography. Confocal laser fluorescence microscopy (CLFM) can reveal growth bands as fluorescent couplets, but this technique is time consuming and results vary. If fluorescence variations parallel elemental variations during seasonal growth, 2D chemical mapping of stalagmite growth banding by LA-ICP-MS may provide a complementary or superior approach for hydroclimate reconstructions.

To assess this hypothesis, we performed 2D chemical mapping on a well-dated central Texas stalagmite (CWN-4) across the ~14.65 ka transition from Heinrich Stadial 1 to Bølling-Allerød interstadial (HBT), a rapid deglacial warming episode. U-series constraints indicate a substantial increase in calcite accumulation rate across HBT. Elements analyzed (Mg, Al, P, Ca, Co, Ni, Cu, Zn, Sr, Y, & Ba) were selected for their associations with fluorescence, water-rock interaction, and/or prior calcite precipitation. Sr and Ba most effectively displayed stratigraphic enrichment/depletion cycles corresponding with CLFM imagery over the same map areas and are consistent with seasonal cycles driven by ventilation. The number of enrichment cycles closely correspond with predicted annual growth rates by bracketing U-series ages. The thickness of resolved growth couplets increases above HBT interval using both LA-ICP-MS and CLFM, supporting that recharge volume increased in central Texas following the HBT. These findings support that highly resolved hydroclimate reconstructions may be possible with 2D chemical mapping by LA-ICP-MS.

GSA presentation (video)

GSA presentation (power point)

Reconstructing life histories of white sharks using vertebral chemistry

John Mohan – University of New England

AFS Meeting Abstract: Sharks exhibit enigmatic movement patterns including long-distance migrations and deep diving behavior that can be difficult to characterize. Ontogenetic characteristics of many shark species, such as late maturity age, slow growth, increased longevities, and low reproductive output, make shark populations especially vulnerable to human exploitation. Conservation and management efforts rely on understanding the complex life histories of highly migratory sharks, including movements, age, growth and feeding patterns. The mineralized vertebral cartilage in sharks is useful for estimating age, as growth bands are deposited over time and encompass the complete life history, including in utero development. This study reconstructs the environmental histories and feeding patterns of migratory white sharks (Carcharodon carcharias) by utilizing natural chemical biomarker (trace elements and stable isotopes) proxies contained in vertebral cartilage growth bands. Vertebrae samples of white sharks were collected opportunistically from coastal Mexican artisanal fisheries in the Pacific (N=12 juveniles) and the Gulf of California (N=3 subadults). Vertebrae were sectioned to expose the growth bands and elemental profiles were quantified from the vertebral focus to the edge using laser ablation ICP MS, encompassing the complete life history. Elemental patterns will be compared between capture locations and between juveniles and subadults to investigate ontogenetic shifts in habitat use. Chemical records contained in vertebral cartilage holds promise to advance our understanding of migratory shark life histories.

Video presentation here

Download Powerpoint presentation here


Identifying spatial heterogeneity in the elemental concentration of Early Jurassic dinosaur bones

Sample localities, Early Jurassic Kayenta Formation near Gold Spring, AZ.

Adam Marsh – Ph.D. candidate

Supervisor: Tim Rowe

Fossil bone records a wealth of data used to explore the evolutionary history of vertebrate life, the growth and development of individuals during their lifetime, and the taphonomic processes that occur before organismal remains become a part of the fossil record. As geochemical technology advances, fossil bone is becoming increasingly useful in investigating how organic and inorganic chemistry affect the interaction between the rock and fossil records. Direct in-situ techniques like LA-ICP-MS allow researchers to ask questions surrounding groundwater interactions, provenance, trace element uptake, and even radiometric dates of fossil bones. These Early Jurassic dinosaur bones, belonging to the long-necked Sarahsaurus aurifontanalis and meat-eating Dilophosaurus wetherilli, are built from hydroxylapatite that comprises the mineral phase of bone tissue, providing structure to the collagen, osteocytes, blood vessels, and nerves in the bone that has long since decomposed. Five line scans were performed on each of the two thin sections of dinosaur bones while analyzing for 29Si , 31P, 55Mn, 57Fe, 86Sr, 89Y, 137Ba, 208Pb, 232Th, and 238U.

Inverse distribution of Mn (blue) and Fe (red) along a laser line traverse. Altered (oxidized) bone areas are Fe-rich.

Inverse distribution of Mn (blue) and Fe (red) along a laser line traverse. Altered (oxidized) bone areas are Fe-rich.

Elemental concentrations generally decrease moving towards the centers of each bone. The decrease in the concentration of P towards the middle of the bone may suggest differing degrees of recrystallization in the fossil bone. Higher concentrations around the outside of the bone indicate more recrystallization and hence, a higher degree of fossilization. Phosphorus is the most abundant isotope in the bone (between 150,000 and 180,000 ppm), which is to be expected, as it is a major component of bioapatite. Strontium easily substitutes for Ca in bioapatite, and the relative ratios of P and Sr behave similarly through each line. The permineralized pore spaces are filled with calcite and are depleted in Mn, Fe, Y, Ba, and U.  The relative concentrations of Mn and Fe share an inverse relationship throughout the analyses. Reflected light microscopic images confirm that highly oxidized regions of the bones are bright red where oxidized iron is found in high concentrations. Barium is enriched in the meduallary cavity of the bones where secondary barite has crystallized. Thorium is the least concentrated analyte measured in the bones and is found almost exclusively in the outer centimeter and in larger vacuities. Uranium concentrations are fairly uniform across the bone thin sections but are quite enriched at about 1,000 ppm. The concentration of Pb is much more variable, which would cause direct U-Pb dating of the bioapatite in fossil bone to result in inaccurate dates. These line scans highlight the open-system behavior of bone and provide insight into the preservational history of these organismal remains since their burial in the Early Jurassic.

REE Analysis of Anhydrite Veins in Porphyry Copper Deposits

Microsampling anhydrite veins from an exploration core sample. Through the use of a low uptake rate nebulizer, we are able to obtain complete elemental surveys (including the REEs) by solution mode ICP-MS from small (milligram) samples.

Microsampling anhydrite veins from an exploration core sample. Through the use of a low uptake rate nebulizer, we are able to obtain complete elemental surveys (including the REEs) by solution mode ICP-MS from small (milligram) samples.

Mark Cloos – Advisor

Aaron Hantsche – Undergraduate, Jackson School of Geosciences

Porphyry copper deposits are created by hydrothermal mineralization as fluids from the intrusive body precipitate metal-rich minerals. These sulfur rich systems have anhydrite in the veined mineral assemblage, as well as quartz, pyrite, and chalcopyrite. Using dissolved anhydrite from veins from the Ertsberg Mining District, Papua, Indonesia, we have conducted a solution ICP-MS study to obtain rare earth element (REE) concentrations. The concentrations, normalized to chondrite, have been compared with REE patterns from the intrusive bodies in the district.

My study is focused on the REE evolution of the fluid and how that can be used to determine relative distance between a vein and a source body. Anhydrite patterns with higher La/Yb appear to be further removed from the source.  Anhydrite REE patterns also show distinct positive and negative europium anomalies. This occurs because at high temperatures in aqueous solutions, europium occurs in a divalent state; at low temperatures, europium is more stable in a trivalent state. Anhydrite takes available divalent europium into its structure creating positive anomaly. At lower temperatures, further from the source, europium concentrations have been depleted resulting in a negative anomaly.

This means that REE patterns in anhydrite can be used as exploration tools for tracking intrusions in porphyry mining districts. Anhydrite sampling could provide an easy method to indicate preferential direction for exploratory drilling for ore prospects.

Fish Otoliths as Natural Geochemical Records

Sectioned polished otolith with faint horizontal line showing laser transect from core to edge.

Sectioned polished otolith with faint horizontal line showing laser transect from core to edge.

Walther Fish Ecology Lab

John Mohan, UT Marine Science Institute

Otoliths (oto=‘ear’; lith=‘stone) are biogenic carbonates that functioning as hearing organs in teleost fish and accrete permanent growth bands on daily to annual timescales.  The elemental composition of fish otoliths are derived from the ambient environment and influenced by physiology, providing detailed chemical chronologies of specific life stages and the types of environments fish encounter.  The trace elements Sr and Ba are thought to be incorporated into otoliths by substituting for Ca during precipitation of the CaCO3 crystal lattice.  Dissolved Sr:Ca and Ba:Ca ratios vary with salinity and differ between freshwater, estuarine, and marine environments.  The Walther Lab measures dissolved elemental ratios in water samples using solution-based ICP MS to characterize spatial and temporal variation in the environment.  Laser ablation ICP MS is then used measure elemental ratios in carbonate otoliths to obtain chemical chronologies that span the entire life of individual fish.  Understanding relationships between otoliths and water chemistries, allows us to test hypothesis related to fish migration at the individual and population level.  This research combines the natural time-keeping properties of fish otoliths and the analytical capabilities of ICP MS to address research questions in the field of fisheries ecology.


a.)  Atlantic croaker Micropogonias undulatus, b.) croaker otolith with dashed redline showing transverse sectioning plane, c.)  sectioned polished otolith with dashed yellow line showing laser transect from core to edge, d. lifetime elemental profile of Sr:Ca (blue) and Ba:Ca (red) with life stage- specific habitats indicated above, e.) dissolved Sr:Ca and f.) Ba:Ca ratios versus salinity for estuarine (squares) and marine (diamonds) water samples.

a.) Atlantic croaker Micropogonias undulatus, b.) croaker otolith with dashed redline showing transverse sectioning plane, c.) sectioned polished otolith with dashed yellow line showing laser transect from core to edge, d. lifetime elemental profile of Sr:Ca (blue) and Ba:Ca (red) with life stage- specific habitats indicated above, e.) dissolved Sr:Ca and f.) Ba:Ca ratios versus salinity for estuarine (squares) and marine (diamonds) water samples.

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