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Influence of ontogenetic development, temperature, and pCO2 on otolith calcium carbonate polymorph composition in sturgeons

Changes to calcium carbonate (CaCO 3 ) biomineralization in aquatic organisms is among the many predicted effects of climate change. Because otolith (hearing/orientation structures in fish) CaCO 3 precipitation and polymorph composition are controlled by genetic and environmental factors, climate change may be predicted to affect the phenotypic plasticity of otoliths. We examined precipitation of otolith polymorphs (aragonite, vaterite, calcite) during early life history in two species of sturgeon, Lake Sturgeon, (Acipenser fulvescens) and White Sturgeon (A. transmontanus), using quantitative X-ray microdiffraction. Both species showed similar fluctuations in otolith polymorphs with a significant shift in the proportions of vaterite and aragonite in sagittal otoliths coinciding with the transition to fully exogenous feeding. We also examined the effect of the environment on otolith morphology and polymorph composition during early life history in Lake Sturgeon larvae reared in varying temperature (16/22 °C) and pCO 2 (1000/2500 µatm) environments for 5 months. Fish raised in elevated temperature had significantly increased otolith size and precipitation of large single calcite crystals. Interestingly, pCO 2 had no statistically significant effect on size or polymorph composition of otoliths despite blood pH exhibiting a mild alkalosis, which is contrary to what has been observed in several studies on marine fishes. These results suggest climate change may influence otolith polymorph composition during early life history in Lake Sturgeon.

54 ENVIRONMENTAL SCIENCES↗

Temperature-dependent oxygen isotope fractionation in otoliths of juvenile Chinook salmon ( Oncorhynchus tshawytscha )

Oxygen thermometry has become a widely used technique for reconstructing thermal history in calcifying organisms but interpretation can be subject to predictive error from vital effects. To better understand these processes in Chinook salmon (Oncorhynchus tshawytscha) we experimentally constructed a temperature-dependent, otolith–water fractionation relationship for oxygen isotopes (δ 18 O) by rearing post-yolk absorptive juvenile fish at nominal temperatures from 6 to 21 °C. Temperature and otolith precipitation rate had significant effects on the otolith–water δ 18 O fractionation, but somatic growth rate did not. The slope of the δ 18 O fractionation equation also differed significantly from that of synthetic aragonite. Furthermore, our results suggest the expression of kinetic effects on δ 18 O fractionation in otoliths of Chinook salmon that are increasingly constrained at higher temperatures by other physical and physiological processes involved in mineral formation. Species-specific δ 18 O fractionation equations have considerable utility to reconstruct temperature history in Pacific salmon, but applications should recognize the potential for inferential uncertainty arising from interacting vital effects.

59 BASIC BIOLOGICAL SCIENCES↗

Isotopes and genes reveal freshwater origins of Chinook salmon Oncorhynchus tshawytscha aggregations in California’s coastal ocean

The ability of salmon to navigate from the ocean back to their river of origin to spawn acts to reinforce local adaptation and maintenance of unique and heritable traits among salmon populations. Here, the extent to which Chinook salmon Oncorhynchus tshawytscha from the same freshwater breeding groups associate together in the ocean at regional and smaller-scale aggregations prior to homeward migration is evaluated. Natural variation in salmon otolith daily growth bands, strontium isotopes ( 87 Sr/ 86 Sr), and microsatellite DNA were used as intrinsic tags to link the distributions of fish caught in the ocean with their freshwater origins. Adults were caught from vessels by hook and line in small aggregations (7-18 ind.) at the same geographic location (1-24 km of coastline) and time (4-36 h) from 3 ocean regions along central California, USA. Salmon caught together in aggregations were from the same genetic group, and to a lesser extent, of the same natal origin (individual rivers or hatcheries). However, at regional scales, adult salmon mixed. Central Valley winter-run Chinook salmon caught together in the ocean varied in the duration of freshwater rearing for up to 2-3 mo prior to seaward migration, suggesting associations within the group were not established in freshwater or maintained over the lifetime of the fish. Our findings are consistent with coarser information indicating stocks are distributed differently in time and space, but larger sample sizes are required to evaluate the consistency of patterns at smaller spatial scales. This study uncovers freshwater associations prior to homeward migration, a principle and undocumented prerequisite of the collective navigation hypothesis.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

In search of the dead zone: Use of otoliths for tracking fish exposure to hypoxia

Otolith chemistry is often useful for tracking provenance of fishes, as well as examining migration histories. Whereas elements such as strontium and barium correlate well with salinity and temperature, experiments that examine manganese uptake as a function of these parameters have found no such correlation. Instead, dissolved manganese is available as a redox product, and as such, is indicative of low-oxygen conditions. Here we present evidence for that mechanism in a range of habitats from marine to freshwater, across species, and also present ancillary proxies that support the mechanism as well. For example, iodine is redox-sensitive and varies inversely with Mn; and sulfur stable isotope ratios provide evidence of anoxic sulfate reduction in some circumstances.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Reconstructing the Migratory Behavior and Long-Term Survivorship of Juvenile Chinook Salmon under Contrasting Hydrologic Regimes

The loss of genetic and life history diversity has been documented across many taxonomic groups, and is considered a leading cause of increased extinction risk. Juvenile salmon leave their natal rivers at different sizes, ages and times of the year, and it is thought that this life history variation contributes to their population sustainability, and is thus central to many recovery efforts. However, in order to preserve and restore diversity in life history traits, it is necessary to first understand how environmental factors affect their expression and success. We used otolith 87 Sr/ 86 Sr in adult Chinook salmon (Oncorhynchus tshawytcha) returning to the Stanislaus River in the California Central Valley (USA) to reconstruct the sizes at which they outmigrated as juveniles in a wetter (2000) and drier (2003) year. We compared rotary screw trap-derived estimates of outmigrant timing, abundance and size with those reconstructed in the adults from the same cohort. This allowed us to estimate the relative survival and contribution of migratory phenotypes (fry, parr, smolts) to the adult spawning population under different flow regimes. Juvenile abundance and outmigration behavior varied with hydroclimatic regime, while downstream survival appeared to be driven by size- and time-selective mortality. Although fry survival is generally assumed to be negligible in this system, >20% of the adult spawners from outmigration year 2000 had outmigrated as fry. In both years, all three phenotypes contributed to the spawning population, however their relative proportions differed, reflecting greater fry contributions in the wetter year (23% vs. 10%) and greater smolt contributions in the drier year (13% vs. 44%). In conclusion, these data demonstrate that the expression and success of migratory phenotypes vary with hydrologic regime, emphasizing the importance of maintaining diversity in a changing climate.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Vitamin D receptor deficiency impairs inner ear development in zebrafish

The biological actions of vitamin D are largely mediated through binding to the vitamin D receptor (VDR), a member of the nuclear hormone receptor family, which regulates gene expression in a wide variety of tissues and cells. Mutations in VDR gene have been implicated in ear disorders (hearing loss and balance disorder) but the mechanisms are not well established. In this study, to investigate the role of VDR in inner ear development, morpholino-mediated gene knockdown approaches were used in zebrafish model system. Two paralogs for VDR, vdra and vdrb, have been identified in zebrafish. Knockdown of vdra had no effect on ear development, whereas knockdown of vdrb displayed morphological ear defects including smaller otic vesicles with malformed semicircular canals and abnormal otoliths. Loss-of-vdrb resulted in down-regulation of pre-otic markers, pax8 and pax2a, indicating impairment of otic induction. Furthermore, zebrafish embryos lacking vdrb produced fewer sensory hair cells in the ears and showed disruption of balance and motor coordination. These data reveal that VDR signaling plays an important role in ear development. - Highlights: • VDR signaling is involved in ear development. • Knockdown of vdrb causes inner ear malformations during embryogenesis. • Knockdown of vdrb affects otic placode induction. • Knockdown of vdrb reduces the number of sensory hair cells in the inner ear. • Knockdown of vdrb disrupts balance and motor coordination.

60 APPLIED LIFE SCIENCES↗

Utica Shale Energy and Environment Laboratory Final Scientific/Technical Report

The Ohio State University (OSU) was awarded a contract on October 1, 2014, from the Department of Energy National Energy Technology Laboratory (DOE-NETL) to develop the Utica Shale Energy and Environment Laboratory (USEEL) in the Utica-Point Pleasant shale play of the Appalachian Basin. It was designed to be an environmental and technology development lab that would enable the academic, industry, government, and non-governmental organization (NGO) research communities to better understand unconventional oil and gas (UOG) engineering practices and technology to increase production and safety, and decrease environmental effects. Political and economic consequences necessitated changes in project site location and design, from the Ohio State Eastern Agricultural Research Station (EARS) and the Muskingum Watershed Conservancy District (MWCD) in east-central Ohio to a site located at an Energy Corporation of America (ECA) Marcellus drill pad in Greene County, Pennsylvania. Although the overall project progressed little beyond planning and administration before termination on September 18, 2017, significant research and MS or PhD investigations were completed or continue today. An experimental study design for site specific and regional baseline assessments was developed utilizing ecoregions, United States Geological Survey (USGS) Hydraulic Unit Code watersheds, and GIS technology and databases. This can be utilized to build a defensible and scalable management and research framework for UOG investigations that can be extrapolated for predictive and comparative analyses. The most commonly mentioned perceived risks of shale energy development identified in a socioeconomic analysis included impacts to the environment and water resources, traffic and road deterioration, and crime. Economic benefits, such as the windfall wealth to residents, job opportunities, and the demand for hotels and restaurants emerged, as the main positive impact to the community. Preliminary results of an analysis of the location and mechanisms for extremely high pore pressures of the deep Utica-Point Pleasant formations of southwestern Pennsylvania and their possible relationship to high initial production rates indicate that the overpressure is caused by a combination disequilibrium compaction and fluid expansion. Drilling fluids research designed a proof-of-concept device to evaluate desalination and solvent separation in hydraulic fracturing flowback water that could facilitate water recycling and potentially mitigate deep-well injection. A groundwater study was devised to characterize the subsurface aquifers in terms of the geological framework and groundwater chemistry, including the chemistry of dissolved gases and salts. Brines and gases associated with hydrocarbon migration in groundwater (including noble gases and hydrocarbons) were to be specifically fingerprinted for use as tracers of fluid migration. Trace element analysis of fish otoliths, using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), is being utilized to assess surface water quality. This methodology will be used to reconstruct the exposure histories of fish from watersheds and discriminate between the signatures associated with hydraulic fracturing and coal mining activities.

03 NATURAL GAS↗