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Minimal research has been conducted on the geochemistry of acorn barnacles, yet recent studies suggest these sessile crustaceans have the potential to act as paleo-environment indicators, biomonitors of anthropogenic pollution, and tracers of marine megafauna movement. As there are nearly 900 species of acorn barnacles, it is necessary to investigate variations among species to determine their efficacy as proxies. The primary objective of this study is to compare trace metal concentrations of two extant barnacle species - Amphibalanus eburneus (ivory barnacle) and Semibalanus balanoides (northern rock barnacle) - to better understand their unique applications in the ocean sciences. Samples were collected from Manursing Island Club in Rye, New York, along the western shoreline of the Long Island Sound. Collected barnacles were photographed, and the rostro-carinal diameter of each specimen was measured to aid with identification. All barnacle plates were cleared of soft parts, sonicated in milli-Q water, brushed clean with vinegar, rinsed off, and soaked in bleach for 3 hours. Element/Ca ratios were measured using a ThermoScientific iCAPQ Quadrupole-Inductively Coupled Plasma-Mass Spectrometry (Q-ICP-MS). Li, Na, Mg, K, and Sr to Ca ratios were measured. A comparison of the K/Ca values of S. balanoides and A. eburneus was inconclusive. Additional data may be necessary to determine if there are interspecies differences within the same environment. However, Na/Ca, Li/Ca, and Sr/Ca ratios could be species-specific. S. balanoides was observed to have lower Na, Sr, and Li to Ca ratios than A. eburneus, although they were exposed to the same environmental conditions. Hence, any studies that wish to explore Na/Ca, Li/Ca, Sr/Ca in barnacles would need to target a given species or acknowledge potential offsets. Notably, S. balanoides samples collected downshore had lower Mg/Ca ratios than samples collected further upshore. This finding is not unsurprising as Mg/Ca values in barnacles have been known to be impacted by shore level. While the full extent of the utility of barnacle geochemistry is still undergoing exploration, we are just beginning to determine which potential proxies require species-specific investigations. 

The geochemistry of marine carbonates frequently reflects the environmental factors that influence their growth, such as climate and/or water quality. Barnacles are sessile crustaceans with shells that provide such environmental archiving. The bay barnacle, Amphibalanus improvisus, was found in the Hudson River at Piermont, NY and Nyack, NY and was the most abundant species identified. To expand the geographic perspective, Amphibalanus eburneus and Semibalanus balanoides barnacles were collected in Rye, NY on the Long Island Sound coast. However, this did not permit a perfect comparison as these species were not identified at the Hudson River sites. Barnacle samples were cleaned and organic matter removed with a multi-step process that included a vinegar scrub, short bleach bath, and ultrasonication in milli-Q water. Trace metals in calcium carbonate barnacle shells were analyzed via quadrupole mass spectrometer. The analysis focuses on Mg, Sr, Ba, Na, and Y to Ca ratios. There was geographic variation in barnacle Y/Ca, Ba/Ca, and Na/Ca values. This may indicate that the concentrations of these trace metals in the waters of the three places do vary, suggesting there could be potential to explore these measurements as an environmental proxy. The Mg/Ca and Sr/Ca inter-site variability was more difficult to quantify. Although Mg/Ca and Sr/Ca are known paleothermometers in other archives, more work needs to be done to determine their efficacy in these locations. Ultimately, this preliminary data and assessment shows that these metals can be recorded in barnacle shells and opens the door to future environmental- or climate-proxy development in the Hudson River and Long Island Sound. 

To address the national need to diversify the geosciences, we created the cohort-based Environmental Science Pathways Scholars Program, or E(SP)2, for undergraduates in the Environmental Science Department at Barnard College who identify as Black, Indigenous, and people of color (BIPOC), first generation, or low income. By fostering a more inclusive community in the particularly formative stages of academic and early professional development, E(SP)2 aims to support and retain a diverse cohort of students who have developed confidence in their scientific skills and identities, and who share a passion for environmental science. E(SP)2 is modeled on the Science Pathways Scholar Program [(SP)2] at Barnard College, an active and successful multidisciplinary opportunity at Barnard College. 

Abstract. The response of the hydrological cycle to anthropogenic climatechange, especially across the tropical oceans, remains poorly understood due to the scarcity of long instrumental temperature and hydrological records. Massive shallow-water corals are ideally suited to reconstructing past oceanic variability as they are widely distributed across the tropics,rapidly deposit calcium carbonate skeletons that continuously record ambient environmental conditions, and can be sampled at monthly to annualresolution. Climate reconstructions based on corals primarily use the stable oxygen isotope composition (δ18O), which acts as a proxy for sea surface temperature (SST), and the oxygen isotope composition ofseawater (δ18Osw), a measure of hydrological variability. Increasingly, coral δ18O time series are paired with time series of strontium-to-calcium ratios (Sr/Ca), a proxy for SST, from the same coral to quantify temperature and δ18Osw variabilitythrough time. To increase the utility of such reconstructions, we presentthe CoralHydro2k database, a compilation of published, peer-reviewed coral Sr/Ca and δ18O records from the Common Era (CE). The database contains 54 paired Sr/Ca–δ18O records and 125 unpaired Sr/Ca or δ18O records, with 88 % of these records providing data coverage from 1800 CE to the present. A quality-controlled set of metadata with standardized vocabulary and units accompanies each record, informing the useof the database. The CoralHydro2k database tracks large-scale temperatureand hydrological variability. As such, it is well-suited for investigationsof past climate variability, comparisons with climate model simulationsincluding isotope-enabled models, and application in paleodata-assimilation projects. The CoralHydro2k database is available in Linked Paleo Data (LiPD) format with serializations in MATLAB, R, and Python and can be downloaded from the NOAA National Center for Environmental Information's Paleoclimate Data Archive at https://doi.org/10.25921/yp94-v135 (Walter et al., 2022).