Person-specific dynamics between negative emotions and suicidal thoughts.

INTRODUCTION: Recent technology has enabled researchers to collect ecological momentary assessments (EMA) to examine within-person correlates of suicidal thoughts. Prior studies examined generalized temporal dynamics of emotions and suicidal thinking over brief periods, but it is not yet known how variable these processes are across people. METHOD: We use data EMA data delivered over two weeks with youth/young adults (N = 60) who reported past year self-injurious thoughts/behaviors. We used group iterative multiple model estimation (GIMME) to model group- and person-specific associations of negative emotions (i.e., fear, sadness, shame, guilt, and anger) and suicidal thoughts. RESULTS: 29 participants (48.33%) reported at least one instance of a suicidal thought and were included in GIMME models. In group level models, we consistently observed autoregressive effects for suicidal thoughts (e.g., earlier thoughts predicting later thoughts), although the magnitude and direction of this link varied from person-to-person. Among emotions, sadness was most frequently associated with contemporaneous suicidal thoughts, but this was evident for less than half of the sample, while other emotional correlates of suicidal thoughts broadly differed across people. No emotion variable was linked to future suicidal thoughts in >14% of the sample, CONCLUSIONS: Emotion-based correlates of suicidal thoughts are heterogeneous across people. Better understanding of the individual-level pathways maintaining suicidal thoughts/behaviors may lead to more effective, personalized interventions.

Dirt cheap: an experimental test of controls on resource exchange in an ectomycorrhizal symbiosis.

To distinguish among hypotheses on the importance of resource-exchange ratios in outcomes of mutualisms, we measured resource (carbon (C), nitrogen (N), and phosphorus (P)) transfers and their ratios, between Pinus taeda seedlings and two ectomycorrhizal (EM) fungal species, Rhizopogon roseolus and Pisolithus arhizus in a laboratory experiment. We evaluated how ambient light affected those resource fluxes and ratios over three time periods (10, 20, and 30 wk) and the consequences for plant and fungal biomass accrual, in environmental chambers. Our results suggest that light availability is an important factor driving absolute fluxes of N, P, and C, but not exchange ratios, although its effects vary among EM fungal species. Declines in N : C and P : C exchange ratios over time, as soil nutrient availability likely declined, were consistent with predictions of biological market models. Absolute transfer of P was an important predictor of both plant and fungal biomass, consistent with the excess resource-exchange hypothesis, and N transfer to plants was positively associated with fungal biomass. Altogether, light effects on resource fluxes indicated mixed support for various theoretical frameworks, while results on biomass accrual better supported the excess resource-exchange hypothesis, although among-species variability is in need of further characterization.

Mild Cognitive Impairment, But Not HIV Status, is Related to Reduced Awareness of Level of Cognitive Performance Among Older Adults.

OBJECTIVE: Self-assessment of cognitive abilities can be an important predictor of clinical outcomes. This study examined impairments in self-assessments of cognitive performance, assessed with traditional neuropsychological assessments and novel virtual reality tests among older persons with and without human immunodeficiency virus (HIV) and mild cognitive impairment (MCI). METHODS: One hundred twenty-two participants (82 persons with HIV; 79 MCI+) completed a traditional neuropsychological battery, DETECT virtual reality cognitive battery, and self-reported their general cognitive complaints, depressive symptoms, and perceptions of DETECT performance. Relationships between DETECT performance and self-assessments of performance were examined as were the correlations between general cognitive complaints and performance. These relations were evaluated across HIV and MCI status, considering the associations of depressive symptoms, performance, and self-assessment. RESULTS: We found no effect of HIV status on objective performance or self-assessment of DETECT performance. However, MCI+ participants performed worse on DETECT and traditional cognitive tests, while also showing a directional bias towards overestimation of their performance. MCI- participants showed a bias toward underestimation. Cognitive complaints were reduced compared to objective performance in MCI+ participants. Correlations between self-reported depressive symptoms and cognitive performance or self-assessment of performance were nonsignificant. CONCLUSIONS: MCI+ participants underperformed on neuropsychological testing, while overestimating performance. Interestingly, MCI- participants underestimated performance to approximately the same extent as MCI+ participants overestimated. Practical implications include providing support for persons with MCI regarding awareness of limitations and consideration that self-assessments of cognitive performance may be overestimated. Similarly, supporting older persons without MCI to realistically appraise their abilities may have clinical importance.

Practical Guide to Measuring Wetland Carbon Pools and Fluxes.

Wetlands cover a small portion of the world, but have disproportionate influence on global carbon (C) sequestration, carbon dioxide and methane emissions, and aquatic C fluxes. However, the underlying biogeochemical processes that affect wetland C pools and fluxes are complex and dynamic, making measurements of wetland C challenging. Over decades of research, many observational, experimental, and analytical approaches have been developed to understand and quantify pools and fluxes of wetland C. Sampling approaches range in their representation of wetland C from short to long timeframes and local to landscape spatial scales. This review summarizes common and cutting-edge methodological approaches for quantifying wetland C pools and fluxes. We first define each of the major C pools and fluxes and provide rationale for their importance to wetland C dynamics. For each approach, we clarify what component of wetland C is measured and its spatial and temporal representativeness and constraints. We describe practical considerations for each approach, such as where and when an approach is typically used, who can conduct the measurements (expertise, training requirements), and how approaches are conducted, including considerations on equipment complexity and costs. Finally, we review key covariates and ancillary measurements that enhance the interpretation of findings and facilitate model development. The protocols that we describe to measure soil, water, vegetation, and gases are also relevant for related disciplines such as ecology. Improved quality and consistency of data collection and reporting across studies will help reduce global uncertainties and develop management strategies to use wetlands as nature-based climate solutions. Supplementary Information: The online version contains supplementary material available at 10.1007/s13157-023-01722-2.

Filter-feeders have differential bottom-up impacts on green and brown food webs.

Nutrient recycling by consumers can strongly impact nutrient availability for autotrophic and heterotrophic microbes, thus impacting functions such as primary production and decomposition. Filter-feeding freshwater mussels form dense, multispecies assemblages in aquatic ecosystems and have been shown to play a critical role in nutrient cycling. Mussel excretion can enhance benthic primary production and influence algal species composition. However, the role of mussels in brown or detritus-based food webs and species-specific differences has received considerably less attention. Here, using mesocosm experiments, we assessed how three species of freshwater mussels that occupy three different phylogenetic tribes influenced benthic algal accrual, ecosystem metabolism, cotton strip decomposition, leaf litter (Acer saccharum) decomposition, and litter-associated fungal biomass measured as ergosterol. Additionally, we measured mussel excretion and biodeposition rates and assessed the stoichiometry (C:N, C:P, and N:P) of the benthic algae, cotton strips, and leaf litter. In comparison to controls without mussels, generally, mussel treatments had higher benthic algal biomass composed of more diatoms, higher gross primary productivity and net ecosystem production rates, and higher cotton strip tensile strength loss, but there was not a difference in ecosystem respiration rates, leaf litter decomposition rates, or fungal biomass. Benthic algae had lower C:N and higher N:P in mussel treatment tanks and cotton strip C:N was lower in mesocosms with mussels. Our results suggest that nutrient regeneration by mussels most strongly regulates green food webs, with some impacts to brown food webs, suggesting that consumers have interactive effects on microbial functioning in freshwaters.

Functional importance and diversity of fungi during standing grass litter decomposition.

Although microbial participation in litter decomposition is widely known within terrestrial soils, the role and significance of microorganisms during the aerial standing litter phase of decomposition remains poorly investigated. We examined the fungi inhabiting standing leaf litter of Schizachyrium scoparium and Schizachyrium tenerum in a Longleaf Pine savanna ecosystem and estimated their contribution to litter decomposition. We identified fungal phylotypes associated with leaf litter and quantified leaf C mass loss, fungal biomass production, and microbial respiration during decomposition. These data were used to construct budgets estimating C flow into and through fungi. Significant losses in S. scoparium (55%) and S. tenerum (67%) leaf C mass were observed during standing decomposition along with concomitant increases in fungal biomass, which reached a maximum of 36 and 33 mgC/g detrital C, respectively. Cumulative fungal production during decomposition totaled 99 ± 6 mgC/g initial detrital C in S. scoparium and 73 ± 5 mgC/g initial detrital C in S. tenerum, indicating that 18 and 11% of the litter C was converted into fungal biomass, respectively. Corresponding estimates of cumulative fungal respiration totaled 106 ± 7 and 174 ± 11 mgC/g initial detrital C in S. scoparium and S. tenerum, respectively. Next generation sequencing identified several fungal phylotypes, with the majority of sequences belonging to the Ascomycota (Dothideomycetes) and Basidiomycota (Agaricomycetes). Fungal phylotypes were similar between litter species and changed over time, showing a successional pattern. These findings extend our understanding of fungal processes to standing litter in terrestrial ecosystems, and highlight the quantitative importance of fungi in C cycling processes.

Emotion regulation processes linking peer victimization to anxiety and depression symptoms in adolescence.

Difficulties with emotion regulation can take many forms, including increased sensitivity to emotional cues and habitual use of maladaptive cognitive or behavioral regulation strategies. Despite extensive research on emotion regulation and youth adjustment, few studies integrate multiple measures of emotion regulation. The present study evaluated the underlying structure of emotion regulation processes in adolescence using both task- and survey-based measures and determined whether differences in these emotion regulation latent factors mediated the association between peer victimization and internalizing psychopathology. Adolescents aged 16-17 years (n = 287; 55% female; 42% White) recruited in three urban centers in the United States completed baseline and follow-up assessments 4 months apart. Three models of emotion regulation were evaluated with confirmatory factor analysis. A three-factor model fit the data best, including cognitive regulation, behavioral regulation, and emotional reactivity latent factors. Task-based measures did not load onto these latent factors. Difficulties with behavioral regulation mediated the association between peer victimization and depression symptoms, whereas cognitive regulation difficulties mediated the association with anxiety symptoms. Findings point to potential targets for intervention efforts to reduce risk for internalizing problems in adolescents following experiences of peer victimization.

Ectomycorrhizal fungal mycelia turnover in a longleaf pine forest.

Elucidation of the patterns and controls of carbon (C) flow and nitrogen (N) cycling in forests has been hindered by a poor understanding of ectomycorrhizal fungal mycelia (EFM) dynamics. In this study, EFM standing biomass (based on soil ergosterol concentrations), production (based on ergosterol accrual in ingrowth cores), and turnover rate (the quotient of annual production and average standing biomass estimates) were assessed in a 25-yr-old longleaf pine (Pinus palustris) plantation where C flow was manipulated by foliar scorching and N fertilization for 5 yr before study initiation. In the controls, EFM standing biomass was 30 ± 7 g m(-2) , production was 279 ± 63 g m(-2)  yr(-1) , and turnover rate was 10 ± 3 times yr(-1) . The scorched × fertilized treatment had significantly higher EFM standing biomass (38 ± 8 g m(-2) ), significantly lower production (205 ± 28 g m(-2)  yr(-1) ), and a trend of decreased turnover rate (6 ± 1 times yr(-1) ). The EFM turnover estimates, which are among the first reported for natural systems, indicate that EFM are a dynamic component of ecosystems, and that conventional assessments have probably underestimated the role of EFM in C flow and nutrient cycling.

Discrimination in Degradability of Soil Pyrogenic Organic Matter Follows a Return-On-Energy-Investment Principle.

A fundamental understanding of biodegradability is central to elucidating the role(s) of pyrogenic organic matter (PyOM) in biogeochemical cycles. Since microbial community and ecosystem dynamics are driven by net energy flows, then a quantitative assessment of energy value versus energy requirement for oxidation of PyOM should yield important insights into their biodegradability. We used bomb calorimetry, stepwise isothermal thermogravimetric analysis (isoTGA), and 5-year in situ bidegradation data to develop energy-biodegradability relationships for a suite of plant- and manure-derived PyOM (n = 10). The net energy value (ΔE) for PyOM was between 4.0 and 175 kJ mol(-1); with manure-derived PyOM having the highest ΔE. Thermal-oxidation activation energy (Ea) requirements ranged from 51 to 125 kJ mol(-1), with wood-derived PyOM having the highest Ea requirements. We propose a return-on-investment (ROI) parameter (ΔE/Ea) for differentiating short-to-medium term biodegradability of PyOM and deciphering if biodegradation will most likely proceed via cometabolism (ROI < 1) or direct metabolism (ROI ≥ 1). The ROI-biodegradability relationship was sigmoidal with higher biodegradability associated with PyOM of higher ROI; indicating that microbes exhibit a higher preference for "high investment value" PyOM.

Mosquito Larvae in Tires from Mississippi, United States: The Efficacy of Abiotic and Biotic Parameters in Predicting Spatial and Temporal Patterns of Mosquito Populations and Communities.

Container systems, including discarded vehicle tires, which support populations of mosquitoes, have been of interest for understanding the variables that produce biting adults that serve as both nuisances and as public health threats. We sampled tires in six sites at three times in 2012 across the state of Mississippi to understand the biotic and abiotic variables responsible for explaining patterns of larvae of common species, species richness, and total abundance of mosquitoes. From 498 tires sampled, we collected >58,000 immatures representing 16 species, with the most common species including Aedes albopictus (Skuse), Culex quinquefasciatus (L.), Orthopodomyia signifera (Coquillett), Aedes triseriatus (Say), Toxorhynchites rutilus septentrionalis (Coquillett), and Culex territans (Walker) accounting for ∼97% of all larvae. We also documented 32 new county records for resident species and recent arrivals in the state, including Aedes japonicus japonicus (Theobald) and Culex coronator (Dyar & Knab). Cluster analysis, which was used to associate sites and time periods based on similar mosquito composition, did reveal patterns across the state; however, there also were more general patterns between species and genera and environmental factors. Broadly, Aedes was often associated with factors related to detritus, whereas Culex was frequently associated with habitat variables (e.g., tire size and water volume) and microorganisms. Some Culex did lack factors connecting variation in early and late instars, suggesting differences between environmental determinants of oviposition and survival. General patterns between the tire environment and mosquito larvae do appear to exist, especially at the generic level, and point to inherent differences between genera that may aid in predicting vector locations and populations.

Priming in the microbial landscape: periphytic algal stimulation of litter-associated microbial decomposers.

Microbial communities associated with submerged detritus in aquatic ecosystems often comprise a diverse mixture of autotrophic and heterotrophic microbes, including algae, bacteria, protozoa, and fungi. Recent studies have documented increased rates of plant litter mass loss when periphytic algae are present. We conducted laboratory and field experiments to assess potential metabolic interactions between natural autotrophic and heterotrophic microbial communities inhabiting submerged decaying plant litter of Typha angustifolia and Schoenoplectus acutus. In the field, submerged plant litter was either exposed to natural sunlight or placed under experimental canopies that manipulated light availability and growth of periphytic algae. Litter was collected and returned to the laboratory, where algal photosynthesis was manipulated (light/dark incubation), while rates of bacterial and fungal growth and productivity were simultaneously quantified. Bacteria and fungi were rapidly stimulated by exposure to light, thus establishing the potential for algal priming of microbial heterotrophic decay activities. Experimental incubations of decaying litter with 14C- and 13C-bicarbonate established that inorganic C fixed by algal photosynthesis was rapidly transferred to and assimilated by heterotrophic microbial decomposers. Periphytic algal stimulation of microbial heterotrophs, especially fungal decomposers, is an important and largely unrecognized interaction within the detrital microbial landscape, which may transform our current conceptual understanding of microbial secondary production and organic matter decomposition in aquatic ecosystems.

Characterizing the momentary association between loneliness, depression, and social interactions: Insights from an ecological momentary assessment study.

Evidence suggests that loneliness causes people to feel more depressed. It is unknown, however, why this association occurs and whether momentary versus chronic experiences of loneliness are implicated. Theoretical accounts suggest that momentary feelings of loneliness produce two competing motivations: social reaffiliation and social withdrawal. Social affiliation is protective against depression; social withdrawal, in contrast, is a risk factor. Thus, engaging in frequent and high-quality interactions following experiences of loneliness may protect against subsequent depression. We tested this hypothesis using a random-interval experience sampling design (5x/day/day, 14 days; Nobs = 6568) with a racially/ethnically diverse sample of adults with elevated depression symptoms (N = 102). Momentary loneliness was associated with depressed mood at the same time point and âˆ¼2.5h and âˆ¼5h later. Frequency and quality of social interaction did not moderate these associations. Findings suggest that momentary feelings of loneliness may be an important target for clinical intervention.

A Scoping Review of Suicide Prevention Interventions for Lesbian, Gay, Bisexual, Transgender, Queer, and Other Sexual and Gender Minority Individuals.

Purpose: This scoping review summarizes the literature on suicide-specific psychological interventions among lesbian, gay, bisexual, transgender, queer, and other sexual and gender minority (LGBTQ+) people to synthesize existing findings and support future intervention research and dissemination. Methods: Electronic databases PsycInfo and PubMed were searched for reports of psychological intervention studies with suicide-related outcome data among LGBTQ+ people. A total of 1269 articles were screened, and 19 studies met inclusion criteria (k = 3 examined suicide-specific interventions tailored to LGBTQ+ people, k = 4 examined nontailored suicide-specific interventions, k = 11 examined minority stress- or LGBTQ+ interventions that were not suicide-specific, and k = 1 examined other types of interventions). Results: Synthesis of this literature was made challenging by varied study designs, and features limit confidence in the degree of internal and external validity of the interventions evaluated. The only established suicide-specific intervention examined was Dialectical Behavior Therapy, and minority stress- and LGBTQ-specific interventions rarely targeted suicidal thoughts and behaviors (STBs). Nevertheless, most interventions reviewed demonstrated support for feasibility and/or acceptability. Only five studies tested suicide-related outcome differences between an LGBTQ+ group and a cisgender/heterosexual group. These studies did not find significant differences in STBs, but certain subgroups such as bisexual individuals may exhibit specific treatment disparities. Conclusion: Given the dearth of research, more research examining interventions that may reduce STBs among LGBTQ+ people is critically needed to address this public health issue.

Distress among undergraduates: Marginality, stressors and resilience resources.

Objective: This study addresses mental health concerns among university students, examining cumulative stress exposure as well as resilience resources. Participants: Participants were 253 first- and second-year undergraduate students (age = 18.76; 49.80% male, 69% students of color) enrolled at a large western US university. Methods: Data were obtained from a cross-sectional online survey examining marginalized statuses and multiple stressors alongside coping responses, adaptive self-concept, and social support as predictors of stress, anxiety, and depression. Results: Multivariate regressions demonstrated significant associations between stress exposures and lower levels of resilience resources with each mental health indicator (with substantial R2 of.49-.60). Although stressor exposures accounted for significant increases in mental health concerns, their exploratory power was attenuated by resilience resources (e.g., beta decreases from.25 to.16). Conclusions: Better understanding cumulative adversity/resilience resource profiles, particularly among marginalized students, can help universities in prioritizing institutional support responses toward prevention and mitigating psychological distress.

An Automated Virtual Reality Program Accurately Diagnoses HIV-Associated Neurocognitive Disorders in Older People With HIV.

Background: HIV-associated neurocognitive disorders (HANDs) remain prevalent despite antiretroviral therapy, particularly among older people with HIV (PWH). However, the diagnosis of HAND is labor intensive and requires expertise to administer neuropsychological tests. Our prior pilot work established the feasibility and accuracy of a computerized self-administered virtual reality program (DETECT; Display Enhanced Testing for Cognitive Impairment and Traumatic Brain Injury) to measure cognition in younger PWH. The present study expands this to a larger sample of older PWH. Methods: We enrolled PWH who were ≥60 years old, were undergoing antiretroviral therapy, had undetectable plasma viral loads, and were without significant neuropsychological confounds. HAND status was determined via Frascati criteria. Regression models that controlled for demographic differences (age, sex, education, race/ethnicity) examined the association between DETECT's cognition module and both HAND status and Global Deficit Score (GDS) derived via traditional neuropsychological tests. Results: Seventy-nine PWH (mean age, 66 years; 28% women) completed a comprehensive neuropsychological battery and DETECT's cognition module. Twenty-five (32%) had HAND based on the comprehensive battery. A significant correlation was found between the DETECT cognition module and the neuropsychological battery (r = 0.45, P < .001). Furthermore, in two separate regression models, HAND status (b = -0.79, P < .001) and GDS impairment status (b = -0.83, P < .001) significantly predicted DETECT performance. Areas under the curve for DETECT were 0.78 for differentiating participants by HAND status (HAND vs no HAND) and 0.85 for detecting GDS impairment. Conclusions: The DETECT cognition module provides a novel means to identify cognitive impairment in older PWH. As DETECT is fully immersive and self-administered, this virtual reality tool holds promise as a scalable cognitive screening battery.

Identifying person-specific coping responses to suicidal urges: A case series analysis and illustration of the idiographic method.

INTRODUCTION: Suicide is a leading cause of death. One challenge to prevention efforts is the wide phenomenological heterogeneity in suicidal urges, thoughts, and behaviors across individuals at risk. Despite this heterogeneity, most suicide research estimates group-level effects by averaging across people as if they were the same, preventing detection of person-specific factors that may modulate risk and be key to effective prevention. The goal of the present study is to illustrate the idiographic (i.e., person-specific) approach and highlight its utility for suicide research. METHODS: We implemented a case series approach using three cases from a subset of psychiatrically hospitalized adolescents who provided intensive longitudinal data on daily urges and coping behavior after discharge following a suicide attempt. For illustration, person-specific, bidirectional links between suicidal urges and coping behavior were modeled across a series of cases using a vector autoregression approach. RESULTS: The relationship between suicidal urges and coping differed across the three individuals, who were presented to exhibit the range of this variability in the presence/absence and magnitude of effects. CONCLUSIONS: Individuals who report similar suicidal risk levels likely respond in individualized ways to suicidal urges (e.g., use different coping strategies), necessitating personalized assessment and treatment. We discuss implications for future suicide research.

Cross-Study, Cross-Method Associations Between Negative Urgency and Internalizing Symptoms.

There is a small body of research that has connected individual differences in negative urgency, the tendency to report rash actions in response to negative emotions, with self-report depressive and anxiety symptoms. Despite the conceptual overlap of negative urgency with negative emotionality, the tendency to experience frequent and intense negative emotions, even fewer studies have examined whether the association of negative urgency with internalizing symptoms hold when controlling for negative emotionality. In the current study, we estimated the bivariate association between negative urgency and internalizing symptoms, tested whether they remained significant after partialling out negative emotionality, and tested whether these effects generalized to real-time experiences of negative emotions. We used data from five independent samples of high school and college students, assessed with global self-report (n = 1,297) and ecological momentary assessment (n = 195). Results indicated that in global self-report data, negative urgency was moderately and positively associated with depressive and anxiety symptoms, and the partial association with depressive symptoms (but not anxiety symptoms) controlling for negative emotionality remained significant and moderate in magnitude. This pattern was replicated in ecological momentary assessment data. Negative urgency may convey risk for depressive symptoms, independent of the effects of negative emotionality.

A meta-analysis on the affect regulation function of real-time self-injurious thoughts and behaviours.

Prominent theories suggest that self-injurious thoughts and behaviours are negatively reinforced by decreased negative affect. The present meta-analysis quantifies effects from intensive longitudinal studies measuring negative affect and self-injurious thoughts and behaviours. We obtained data from 38 of the 79 studies (48%, 22 unique datasets) involving N = 1,644 participants (80% female, 75% white). Individual-participant data meta-analyses revealed changes in affect pre/post self-injurious thoughts and behaviours. In antecedent models, results supported increased negative affect before nonsuicidal self-injurious behaviour (k = 14, 95% CI 0.09 to 0.31) and suicidal thoughts (k = 14, 95% CI 0.03 to 0.19). For consequence models, negative affect was reduced following nonsuicidal self-injurious thoughts (k = 6, 95% CI -0.79 to -0.44), nonsuicidal self-injurious behaviours (k = 14, 95% CI -0.73 to -0.19) and suicidal thoughts (k = 13, 95% CI -0.79 to -0.23). Findings, which were not moderated by sampling strategies or sample composition, support the affect regulation function of self-injurious thoughts and behaviours.

Brown meets green: light and nutrients alter detritivore assimilation of microbial nutrients from leaf litter.

In aquatic detrital-based food webs, research suggests that autotroph-heterotroph microbial interactions exert bottom-up controls on energy and nutrient transfer. To address this emerging topic, we investigated microbial responses to nutrient and light treatments during Liriodendron tulipifera litter decomposition and fed litter to the caddisfly larvae Pycnopsyche sp. We measured litter-associated algal, fungal, and bacterial biomass and production. Microbes were also labeled with 14 C and 33 P to trace distinct microbial carbon (C) and phosphorus (P) supporting Pycnopsyche assimilation and incorporation (growth). Litter-associated algal and fungal production rates additively increased with higher nutrient and light availability. Incorporation of microbial P did not differ across diets, except for higher incorporation efficiency of slower-turnover P on low-nutrient, shaded litter. On average, Pycnopsyche assimilated fungal C more efficiently than bacterial or algal C, and Pycnopsyche incorporated bacterial C more efficiently than algal or fungal C. Due to high litter fungal biomass, fungi supported 89.6-93.1% of Pycnopsyche C growth, compared to 0.2% to 3.6% supported by bacteria or algae. Overall, Pycnopsyche incorporated the most C in high nutrient and shaded litter. Our findings affirm others' regarding autotroph-heterotroph microbial interactions and extend into the trophic transfer of microbial energy and nutrients through detrital food webs.

College from home during COVID-19: A mixed-methods study of heterogeneous experiences.

This mixed-method study examined the experiences of college students during the COVID-19 pandemic through surveys, experience sampling data collected over two academic quarters (Spring 2019 n1 = 253; Spring 2020 n2 = 147), and semi-structured interviews with 27 undergraduate students. There were no marked changes in mean levels of depressive symptoms, anxiety, stress, or loneliness between 2019 and 2020, or over the course of the Spring 2020 term. Students in both the 2019 and 2020 cohort who indicated psychosocial vulnerability at the initial assessment showed worse psychosocial functioning throughout the entire Spring term relative to other students. However, rates of distress increased faster in 2020 than in 2019 for these individuals. Across individuals, homogeneity of variance tests and multi-level models revealed significant heterogeneity, suggesting the need to examine not just means but the variations in individuals' experiences. Thematic analysis of interviews characterizes these varied experiences, describing the contexts for students' challenges and strategies. This analysis highlights the interweaving of psychosocial and academic distress: Challenges such as isolation from peers, lack of interactivity with instructors, and difficulty adjusting to family needs had both an emotional and academic toll. Strategies for adjusting to this new context included initiating remote study and hangout sessions with peers, as well as self-learning. In these and other strategies, students used technologies in different ways and for different purposes than they had previously. Supporting qualitative insight about adaptive responses were quantitative findings that students who used more problem-focused forms of coping reported fewer mental health symptoms over the course of the pandemic, even though they perceived their stress as more severe. These findings underline the need for interventions oriented towards problem-focused coping and suggest opportunities for peer role modeling.