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Salt marshes provide many important ecosystem services, key among them being carbon sequestration. However, a large degree of uncertainty remains in salt marsh carbon budgets, particularly during colder months of the year when salt marsh microbial and vegetative activity is assumed to dormant. We also lack data on urban systems. In this study, we used an easily portable carbon dioxide sensor package to directly measure net carbon dioxide (CO2) fluxes throughout the winter in a temperate, urban salt marsh. We sampled across the dormant season both on normal (cold) temperature days and on days that were anomalously warm (defined here as air temperatures 2.8°C above the long-term average). We demonstrated that median (±mad) daytime CO2 fluxes doubled on the warm days, compared to cold days (1.7 ± 2 mmol m−2 h−1, 0.7 ± 1.3 mmol m−2 h−1, respectively). We also show that net CO2 emissions scaled with soil temperature. The high day-to-day variability, however, implies that infrequent or sparse measurements cannot sufficiently capture the temporal dynamics of dormant season salt marsh net CO2 fluxes. The magnitude of the net CO2 source from our sampling during the dormant season leads us to hypothesize that, as mean annual temperatures continue to increase, dormant season CO2 emissions from salt marshes will increasingly offset growing season carbon dioxide uptake. This change compromises the carbon sequestration capacity, and therefore the climate mitigation potential of these ecosystems. Future studies should focus on quantifying the impact of dormant season CO2, and other greenhouse gases on salt marsh carbon budgets.

The effect of the "Adapted-Coping with Stress" (A-CWS) intervention on social support coping was examined, using a randomized controlled trial design. The participants were 410 ninth-grade students (ages 14 to 16 years and mostly African American) living in low-resourced neighborhoods. Participants were randomly assigned 1:1 to either the A-CWS intervention or a standard care control condition. All participants were assessed at their schools before implementation of the intervention, at intervention completion, and again at 6- and 12-month post-intervention. Engagement in social support coping was examined in both intention-to-treat and treatment-as-received samples (i.e., intervention participants who attended at least 12 A-CWS treatment sessions and participants in the standard care control condition), using latent growth models. In intention-to-treat analyses, no significant treatment effects were identified. In treatment-as-received analyses, results revealed a significant association between social support coping and treatment condition; levels of social support coping decreased over time in the control condition, but they remained relatively stable in the treatment condition. The results indicate adequate intervention adherence and efficacy of the A-CWS to sustain social support coping within a sample of youth at high risk for stress exposure and associated disorders.

Few data are available to evaluate the long term effects of habitat isolation on species richness or abundances in the tropics. Barro Colorado Island (BCI), Panama, has been studied for more than 80 years since its isolation from surrounding lowland forest when the Panama Canal was constructed. Thirty-five percent of the originally present 200 resident species have disappeared. Although the loss of species is well-studied, changes in abundance that might help predict future losses have not been evaluated. One study in 1970 and the present study conducted 25 years later estimated abundances of most bird species on BCI. Comparisons indicate at least 37 species have declined by at least 50%. Twenty-six species of edge habitats are expected to decline as forest maturation proceeds, yet 11 forest species that are now rare may be lost soon. All 26 species that were present in 1970 but not detected in the mid-1990s were rare in 1970. Thus, rarity appears to be a good predictor of extinction risk in this tropical habitat fragment.

Northern Pygmy-Owls (Glaucidium gnoma) occur in mountainous regions of western North America, but their movements and seasonal patterns of distribution are poorly understood. Assumed to be altitudinal migrants, data evaluating their seasonal distributions are scarce. We quantified the seasonal distributions of Northern Pygmy-Owls across elevations in the Oregon Coast Range, USA, by using call playbacks to elicit responses. We hypothesized that pygmy-owls would be more widely distributed at higher elevations during the summer, and during the cooler winter months their distributions would shift downslope to more moderate climates. Northern Pygmy-Owls responded at all elevations and in all seasons but responded most frequently at middle elevations. The pattern of responses with respect to season and elevation was consistent in the 2 years of our study (2020-2021), suggesting that they were not altitudinal migrants in our study area during those years. However, characterizing altitudinal migration from distributions alone requires careful interpretation so we encourage further studies using tagged and tracked individuals. Received 31 January 2023. Accepted 24 September 2023. Key words: altitudinal migration, elevational distribution, seasonal distribution. Los tecolotes Glaucidium gnoma se encuentran en regiones montanosas del oeste de Norte America, pero sus movimientos y patrones de distribucion estacionales son poco entendidos. Aunque se asume que son aves migratorias altitudinales, los datos que evaluan su distribucion estacional son escasos. Cuantificamos la distribucion estacional de los tecolotes Glaucidium gnoma en distintas elevaciones en Oregon Coast Range, Estados Unidos, usando cantos pregrabados para provocar respuestas. Nuestra hipotesis fue que los tecolotes iban a estar ampliamente distribuidos en sitios de elevaciones altas durante el verano y que durante los meses mas frios del invierno su distribucion cambiaria a sitios con menor elevacion con climas mas moderados. Los tecolotes Glaucidium gnoma respondieron a los cantos en todas las elevaciones durante todas las estaciones pero respondieron mas frecuentemente en elevaciones medias. El patron de respuestas con respecto a la estacion y la elevacion fue consistente en los 2 anos de nuestro estudio (2020-2021), sugiriendo que no eran migrantes altitudinales en nuestra area de estudio durante estos anos. Sin embargo, la caracterizacion de la migracion altitudinal de las distribuciones requiere una interpretacion cuidadosa por lo que invitamos a realizar mas estudios utilizando individuos marcados y rastreados. Palabras clave: distribucion altitudinal. distribucion estacional, migracion altitudinal., Altitudinal migration is the seasonal movement of a species' population along elevational gradients (Boyle 2017). A widespread phenomenon, it has been documented in ~10% of extant bird species (Barcante et [...]

Abstract The impact of coastal acidification on sediment nitrous oxide (N2O) and methane (CH4) fluxes is largely unknown. We exposed temperate estuarine sediments to moderate (pH 7.3) and extreme (pH 6.3) acidification. Sediments were collected from two sites—one exposed to high and the other to low nitrogen loading. We demonstrate that low pH has a strong effect on greenhouse gas fluxes. The response, in terms of both magnitude and direction, was site specific. Sediments from the high nitrogen loading site exhibited increased N2O fluxes and decreased CH4 fluxes under moderate and extreme acidification. In contrast, sediments from the low nitrogen loading site exhibited decreased N2O fluxes under moderate and extreme acidification while CH4 fluxes both decreased (moderate) and increased (extreme). This study highlights the dynamic response of sediment N2O and CH4 fluxes to low pH and emphasizes the need for deeper understanding of ofcoastal acidification impacts on sediment biogeochemistry.

Success and impact metrics in science are based on a system that perpetuates sexist and racist "rewards" by prioritizing citations and impact factors. These metrics are flawed and biased against already marginalized groups and fail to accurately capture the breadth of individuals' meaningful scientific impacts. We advocate shifting this outdated value system to advance science through principles of justice, equity, diversity, and inclusion. We outline pathways for a paradigm shift in scientific values based on multidimensional mentorship and promoting mentee well-being. These actions will require collective efforts supported by academic leaders and administrators to drive essential systemic change.

Abstract The harmful alga Heterosigma akashiwo possesses a hybrid nitrate reductase (NR) enzyme, NR2-2/2HbN, which has the potential to convert NO to nitrate for assimilation into biomass. In previous research, NR transcription in H. akashiwo was induced by nitrate while NR activity was inhibited by ammonium. Here, the capacity of H. akashiwo to use NO in the presence of nitrate and/or ammonium was investigated to understand the regulation of NO assimilation. Continuous cultures of H. akashiwo were acclimated to growth on nitrate, ammonium, or a mixture of both. Aliquots from these cultures were spiked with 15N-labeled NO. The expression of genes involved in nitrogen assimilation was evaluated, as well as nitrate reductase activity and assimilation of 15N-labeled nitrogen into algal biomass. Results showed that NO induced expression and activity of NR, and upregulated expression of GOGAT regardless of the presence of other inorganic nitrogen sources, while GS expression decreased over time. Furthermore, 15NO uptake and assimilation was significantly higher in cultures acclimated for growth on ammonium compared to cultures acclimated for growth on nitrate alone. Assimilation of NO may provide H. akashiwo with a competitive advantage in N-poor environments or areas with elevated NO.

In the current era of rapid climate change, accurate characterization of climate-relevant gas dynamics-namely production, consumption, and net emissions-is required for all biomes, especially those ecosystems most susceptible to the impact of change. Marine environments include regions that act as net sources or sinks for numerous climateactive trace gases including methane (CH4) and nitrous oxide (N2O). The temporal and spatial distributions of CH4 and N2O are controlled by the interaction of complex biogeochemical and physical processes. To evaluate and quantify how these mechanisms affect marine CH4 and N2O cycling requires a combination of traditional scientific disciplines including oceanography, microbiology, and numerical modeling. Fundamental to these efforts is ensuring that the datasets produced by independent scientists are comparable and interoperable. Equally critical is transparent communication within the research community about the technical improvements required to increase our collective understanding of marine CH4 and N2O. A workshop sponsored by Ocean Carbon and Biogeochemistry (OCB) was organized to enhance dialogue and collaborations pertaining to marine CH4 and N2O. Here, we summarize the outcomes from the workshop to describe the challenges and opportunities for near-future CH4 and N2O research in the marine environment.

Low-oxygen conditions plague coastlines worldwide. At present, little is known about how the transition from normoxic to low or even no oxygen conditions alters sediment biogeochemical cycling and ultimately ecosystem functioning. Conventional sediment core incubations cannot capture rapid (

Abstract The marine nitrogen cycle is a main driver of ocean productivity and affects global climate. Despite decades of study, we still have an incomplete understanding of the role of the marine nitrogen cycle in the Earth system. While marine sediments play a major role in nitrogen cycling in the ocean, magnitudes and mechanisms are largely unconstrained. Recent research suggests that permeable sandy sediments on the highly energetic and dynamic continental shelf are key components of the marine nitrogen cycle, but data to quantify their contribution are lacking. Here, we use insights from measurements and modeling studies to substantiate the hypothesis that shelf sediments are an overlooked driver of the marine nitrogen cycle. Specifically, we propose that permeable shelf sediments are sites for intense nitrogen conversions and suggest a three‐pronged approach to address unresolved controversies.

Abstract N2 fixation is a major component of the global N cycle and has been extensively studied in open‐ocean and terrestrial ecosystems. Yet rates and ecological dynamics remain virtually unknown for the inland and coastal aquatic ecosystems (lakes, wetlands, rivers, streams, and estuaries) that connect terrestrial and marine biomes. This is due to the diversity of these habitats as well as the traditional paradigm that N2 fixation rates were low to nonexistent, and therefore not important, in these ecosystems. We identify three major research themes to advance understanding of aquatic N2 fixation: (1) the biological diversity of diazotrophs and variability of N2 fixation rates, (2) the ecological stoichiometry of N2 fixation, and (3) the upscaling of N2 fixation rates from genes to ecosystems. Coordinating research across these areas will advance limnology and oceanography by fully integrating N2 fixation into ecological dynamics of aquatic ecosystems from local to global scales.

Salt marshes provide many important ecosystem services, key among them being carbon sequestration. However, a large degree of uncertainty remains in salt marsh carbon budgets, particularly during colder months of the year when salt marsh microbial and vegetative activity is assumed to dormant. We also lack data on urban systems. In this study, we used an easily portable carbon dioxide sensor package to directly measure net carbon dioxide (CO2) fluxes throughout the winter in a temperate, urban salt marsh. We sampled across the dormant season both on normal (cold) temperature days and on days that were anomalously warm (defined here as air temperatures 2.8°C above the long-term average). We demonstrated that median (±mad) daytime CO2 fluxes doubled on the warm days, compared to cold days (1.7 ± 2 mmol m-2 h-1, 0.7 ± 1.3 mmol m-2 h-1, respectively). We also show that net CO2 emissions scaled with soil temperature. The high day-to-day variability, however, implies that infrequent or sparse measurements cannot sufficiently capture the temporal dynamics of dormant season salt marsh net CO2 fluxes. The magnitude of the net CO2 source from our sampling during the dormant season leads us to hypothesize that, as mean annual temperatures continue to increase, dormant season CO2 emissions from salt marshes will increasingly offset growing season carbon dioxide uptake. This change compromises the carbon sequestration capacity, and therefore the climate mitigation potential of these ecosystems. Future studies should focus on quantifying the impact of dormant season CO2, and other greenhouse gases on salt marsh carbon budgets. [ABSTRACT FROM AUTHOR]

AbstractTupac Shakur is remembered for many things. Rapper. Actor. Poet. Thug. Scholar. Moreover, while Shakur was “one of hip-hop’s most successful and influential artists, with more than 75 million records sold worldwide (Hess, 2007), he was also remembered as a contradiction. Known for his anthem to black womanhood, Dear Momma, Shakur was found guilty of sexual assault. As the son of Black Panther, the late Afeni Shakur, Tupac spoke out against gun violence, and yet songs such as Death Around the Corner promoted the use of violence. Beyond his enigmatic persona, his body of work, 25 years after his untimely death, still leaves questions for exploration. [ABSTRACT FROM AUTHOR]

The obesity epidemic continues to increase, with half of US women predicted to be obese by 2030. Women with obesity are at increased risk for not only cardiovascular and liver disease, but also reproductive disorders. Although mouse models are useful in studying the effects of obesity, there is inconsistency in obesity-induction methods, diet composition, and mouse strains, and studies using female mice are limited. In this study, we sought to compare the effects of a 45% high-fat diet (HFD) versus a 60% HFD on the uterine estrous cycle of nulligravid C57BL/6J mice. For 22 weeks, we placed a total of 20 mice on either a 60% HFD, 45% HFD, or each HFD-matched control diet (CD). Both HFDs produced significant weight gain, with 60% HFD and 45% HFD gaining significant weight after 2 weeks and 15 weeks, respectively. Additionally, both HFDs led to glucose intolerance, fatty liver, and adipocyte hypertrophy. Mice fed 60% HFD displayed hyperphagia in the first 12 weeks of HFD treatment. Moreover, 60% HFD-treated mice had a longer estrous cycle length and an increased percentage of estrus stage samplings compared to CD-treated mice. Estrous cycle stage-controlled 60% HFD-treated mice displayed an increased estrogen-to-progesterone ratio and decreased ovarian corpora lutea compared to CD-treated mice, which may underlie the observed estrous cycle differences. There was no significant difference between diets regarding endometrial morphology or the percent of endometrial CD45+ immune cells. Our results indicate that consideration is needed when selecting a HFD-induced obesity mouse model for research involving female reproductive health. [ABSTRACT FROM AUTHOR]