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The Geoscience Education Targeting Underrepresented Populations program is a National Science Foundation funded project designed to assess the effectiveness of a multifaceted approach to increase recruitment and retention in Earth & Environmental Science (EES) majors at Weber State University (WSU) in Ogden, Utah. This program integrates a combination of early outreach to high schools, concurrent-enrollment courses, a summer bridge program, structured early undergraduate research experiences, community engaged learning, and multiple pedagogies to support a diverse student population. The focus of this presentation will be on the place-based educational approach to teaching an Earth science summer bridge program and a first-year summer research experience. These programs overlap in both time and location allowing incoming students to have peer-to-peer interactions with current EES majors. The summer bridge program runs for two weeks and provides students with an introduction to the WSU campus, available student services, initial advising, and an early collaborative research experience focused on local natural hazards and the Great Salt Lake basin water resources. Students collect water samples from Great Salt Lake, local streams, and a groundwater well field on WSU’s campus. Students then analyze major element chemistry of those samples with the help of faculty and students in the EES department using lab facilities at WSU. The summer research program is a four-week summer program for freshmen and sophomores who have declared an EES major. Students conduct in-depth field and lab research project on the Great Salt Lake ecosystem, using real-time geochemical data collected from field observatories on Antelope Island State Park. Students work as a team with a faculty lead and senior peer teaching assistants to address a research question by analyzing field station data as well as collecting and analyzing environmental chemistry and microbiology samples from the lake, including alkalinity, inorganic and organic carbon, major ions, cell counts, and photosynthetic efficiency. The summer research students also act as peer mentors for students in the Summer Bridge. All students present their research finding to friends and family at a celebratory event on the last day of both programs. We will present on the successes and challenges of the program to date and our plans to assess various components and their overall impact on student recruitment and retention in our department. 

Abstract. Field investigations of the properties of heavily melted “rotten” Arcticsea ice were carried out on shorefast and drifting ice off the coast ofUtqiaġvik (formerly Barrow), Alaska, during the melt season. While noformal criteria exist to qualify when ice becomes rotten, the objectiveof this study was to sample melting ice at the point at which its structural andoptical properties are sufficiently advanced beyond the peak of the summerseason. Baseline data on the physical (temperature, salinity, density,microstructure) and optical (light scattering) properties of shorefast icewere recorded in May and June 2015. In July of both 2015 and 2017, smallboats were used to access drifting rotten ice within ∼32 km of Utqiaġvik. Measurements showed that pore space increased as icetemperature increased (−8 to 0 ^∘C), ice salinitydecreased (10 to 0 ppt), and bulk density decreased (0.9 to0.6 g cm⁻³). Changes in pore space were characterized with thin-sectionmicrophotography and X-ray micro-computed tomography in the laboratory. Theseanalyses yielded changes in average brine inclusion number density (whichdecreased from 32 to 0.01 mm⁻³), mean pore size (whichincreased from 80 µm to 3 mm), and total porosity (increased from0 % to > 45 %) and structural anisotropy (variable, withvalues of generally less than 0.7). Additionally, light-scattering coefficientsof the ice increased from approximately 0.06 to > 0.35 cm⁻¹ as the ice melt progressed. Together, these findings indicate thatthe properties of Arctic sea ice at the end of melt season are significantlydistinct from those of often-studied summertime ice. If such rotten ice wereto become more prevalent in a warmer Arctic with longer melt seasons, thiscould have implications for the exchange of fluid and heat at the oceansurface.

 

Organic and inorganic stable isotopes of lacustrine carbonate sediments are commonly used in reconstructions of ancient terrestrial ecosystems and environments. Microbial activity and local hydrological inputs can alter porewater chemistry (e.g., pH, alkalinity) and isotopic composition (e.g., δ¹⁸O_water, δ¹³C_DIC), which in turn has the potential to impact the stable isotopic compositions recorded and preserved in lithified carbonate. The fingerprint these syngenetic processes have on lacustrine carbonate facies is yet unknown, however, and thus, reconstructions based on stable isotopes may misinterpret diagenetic records as broader climate signals. Here, we characterize geochemical and stable isotopic variability of carbonate minerals, organic matter, and water within one modern lake that has known microbial influences (e.g., microbial mats and microbialite carbonate) and combine these data with the context provided by 16S rRNA amplicon sequencing community profiles. Specifically, we measure oxygen, carbon, and clumped isotopic compositions of carbonate sediments (δ¹⁸O_carb, δ¹³C_carb, ∆₄₇), as well as carbon isotopic compositions of bulk organic matter (δ¹³C_org) and dissolved inorganic carbon (DIC; δ¹³C_DIC) of lake and porewater in Great Salt Lake, Utah from five sites and three seasons. We find that facies equivalent to ooid grainstones provide time‐averaged records of lake chemistry that reflect minimal alteration by microbial activity, whereas microbialite, intraclasts, and carbonate mud show greater alteration by local microbial influence and hydrology. Further, we find at least one occurrence of ∆₄₇isotopic disequilibrium likely driven by local microbial metabolism during authigenic carbonate precipitation. The remainder of the carbonate materials (primarily ooids, grain coatings, mud, and intraclasts) yield clumped isotope temperatures (T(∆₄₇)), δ¹⁸O_carb, and calculated δ¹⁸O_waterin isotopic equilibrium with ambient water and temperature at the time and site of carbonate precipitation. Our findings suggest that it is possible and necessary to leverage diverse carbonate facies across one sedimentary horizon to reconstruct regional hydroclimate and evaporation–precipitation balance, as well as identify microbially mediated carbonate formation.