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Determining the magnitude and origins of nitrogen (N) deposition in the open ocean is vital for understanding how anthropogenic activities influence oceanic biogeochemical cycles. Excess N in the North Pacific Ocean(NPO) is suggested to reflect recent anthropogenic atmospheric deposition from the Asian continent, changes in nutrient dynamics due to marine N-fixation, and/or lateral transport of nutrients. We investigate the impact of anthropogenic and marine sources on reactive N deposition in the NPO, with a focus on ammonium (NH4+), an important bioavailable nutrient, using aerosol samples (n =108) collected off the coast of China (Changdao Island). This study site is used as a proxy for continental emissions that can be exported and subsequently deposited to the ocean. The NH4+concentration of aerosol samples varied seasonally (p < 0.05), with a higher average value in winter (2.8 ±1.1 μg/m3) and spring (1.9 ±0.8 μg/m3) compared to autumn (0.7 ±0.6 μg/m3) and summer (1.4 ±0.4 μg/m3). The isotopic composition of aerosol NH4+ varied seasonally, with higher averages in spring (13.3 ±7.9‰) and summer (15.6 ±6.2‰) compared to autumn (3.2 ±2.5 ‰) and winter (3.8 ±11.4‰). These seasonal patterns in the isotopic composition of NH4+ are investigated based on correlations of aerosol chemical species, seasonal shifts in transport patterns, partitioning of ammonia/ammonium between the gas and particle phase, and continental versus marine sources of ammonia. We find that anthropogenic activities, mainly agricultural practices (e.g., volatilization, fertilizer, animal husbandry), are the primary sources of NH4+ deposited to the NPO. 

Abstract Sexual harassment in field settings brings unique challenges for prevention and response, as field research occurs outside “typical” workplaces, often in remote locations that create additional safety concerns and new team dynamics. We report on a project that has 1) trained field project participants to recognize, report, and confront sexual harassment, and 2) investigated the perceptions, attitudes, and experiences of field researchers regarding sexual harassment. Pre-campaign surveys from four major, multi-institutional, domestic and international field projects indicate that the majority of sexual harassment reported prior to the field campaigns was hostile work environment harassment, and women were more likely to be the recipients, on average reporting 2-3 incidents each. The majority of those disclosing harassment indicated that they coped with past experiences by avoiding their harasser or downplaying incidents. Of the incidences reported (47) in post-campaign surveys of the four field teams, all fell under the category of hostile work environment and included incidents of verbal, visual, and physical harassment. Women’s harassment experiences were perpetrated by men 100% of the time, and the majority of the perpetrators were in more senior positions than the victims. Men’s harassment experiences were perpetrated by a mix of women and men, and the majority came from those at the same position of seniority. Post-project surveys indicate that the training programs (taking place before the field projects) helped participants come away with more positive than negative emotions and perceptions of the training, the leadership, and their overall experiences on the field campaign. 

Concentrations and the stable isotopic composition of bulk aerosol nitrate (NO₃⁻) were quantified from two GEOTRACES cruises: (a) Alaska–Tahiti (GP15;n = 22) and (b) Peru–Tahiti (GP16;n = 17) to explore the hypothesis that a marine source influences aerosol NO₃⁻in the equatorial Pacific. The δ¹⁵N‐NO₃⁻ranged from −14.5‰–0.5‰, with lowest values furthest from the coast, primarily reflecting a shift in sources. The δ¹⁸O‐ and Δ¹⁷O‐NO₃⁻were both relatively high (65.2‰–85.4‰ and 21.4‰–30.7‰, respectively) and decreased away from continental regions, reflecting a shift in the oxidants that influence the formation of NO₃⁻. Transport modeling and co‐occurrence of low δ¹⁵N, δ¹⁸O and Δ¹⁷O provided evidence for an important influence of marine‐derived alkyl nitrates (RONO₂) on aerosol NO₃⁻formation. Based on the Δ¹⁷O, we quantified that the contribution of RONO₂to aerosol NO₃⁻can be as high as 47.5% (range 7.5%–47.5%). We also estimate an average δ¹⁵N‐RONO₂of −27.8‰ ± 23.3‰.

 

Geosciences remain one of the least diverse fields. Efforts to diversify the discipline need to address the role of hostile and exclusionary work and learning environments. A workplace climate survey distributed to five professional organizations illustrates varied experiences of earth and space scientists over a 12‐month period (pre‐COVID). A majority experienced positive interactions in the workplace. However, scientists of color, women and non‐binary individuals, scientists with disabilities, and lesbian, gay, bisexual, queer, pansexual, and asexual (LGBQPA+) scientists more frequently experienced negative interactions, including interpersonal mistreatment, discriminatory language, and sexual harassment. Geoscientists of color were more likely to experience devaluation of their work than white scientists. More than half of women and non‐binary respondents, as well as those who identify as LGBQPA+ experienced identity‐based discriminatory remarks. Disabled geoscientists were more likely to hear negative identity‐based language than those who did not disclose a disability. Overall, 14% of all respondents experienced sexual harassment in the previous year. Rates were greatest for historically excluded groups: non‐binary (51%), LGBQPA+ (33%), disabled (26%), women (20%), and geoscientists of color (17%). A majority of geoscientists reported avoiding their colleagues and almost a third considered leaving their institution or a career change. Historically excluded groups were more likely to report opting out of professional activities with potential career consequences. To address continued exclusion and low retention in the earth and space sciences, recruitment is not enough. We need to create environments that ensure opportunities for all to thrive.