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Stream channels in the McMurdo Dry Valleys are typically wide, incised, and stable. At typical flows, streams occupy a fraction of the oversized channels, providing habitat for algal mats. In January 2012, we discovered substantial channel erosion and subsurface thermomechanical erosion undercutting banks of Crescent Stream. We sampled stream water along the impacted reach and compared concentrations of solutes to the long-term data from this stream ( ~ 20 years of monitoring). Thermokarst-impacted stream water demonstrated higher electrical conductivity, and concentrations of chloride, sulfate, sodium, suspended sediments, and nitrate than the long-term medians. These results suggest that this mode of lateral permafrost degradation may substantially impact stream solute loads and potentially fertilize stream and lake ecosystems. The potential for sediment to scour or bury stream algal mats is yet to be determined, though it may offset impacts of associated increased nutrient loads to streams. [ABSTRACT FROM AUTHOR]

Drought is a common disturbance in arid-land streams and rivers. The survival of aquatic species depends on access to refuge habitats where water quality remains high. Over the past century, modified flow regimes and altered watershed and instream characteristics have led to the extinction and endangerment of numerous fish species endemic to the southwestern United States. We assessed the water quality of potential drought refuges in the Middle Rio Grande (MRG), with an emphasis on suitability for the endangered Rio Grande Silvery Minnow (RGSM). We examined three types of potential drought refuges: three agricultural return drain outfalls; three isolated pools that remained during streamflow intermittency; and a reach with perennial flow below an agricultural diversion dam. All potential refuges are known to contain RGSM and other fishes. Two out of three drain outfalls, one out of three isolated pools, and three out of ten kilometers of perennially wetted stream below a dam met basic water quality criteria necessary to support RGSM populations. These findings suggest that refuge habitability is context dependent, that generalizations regarding the suitability of a specific refuge type should be avoided, and that careful assessment is required to determine if a specific location will support fish assemblages. Although some areas may contain water, they may represent ecological traps if fish are exposed to poor water quality conditions compared to other potential refuge habitats.

OBJECTIVES: To evaluate potential moderators of the effect of adding extended telephone monitoring (TM) and telephone monitoring and counseling (TMC) continuing care to treatment as usual (TAU) for alcoholism. Continuing care was predicted to be more effective for patients with severe substance-use histories, poor initial response to treatment, and other risk factors for relapse. METHODS: Randomized study with 18-month follow-up. Outcomes were frequency of drinking and any drinking. RESULTS: Main effects favored TMC over TAU on alcohol outcomes. However, none of the 11 variables examined moderated these effects. Conversely, main effect and moderator analyses indicated TM was more beneficial than TAU only for women and for participants with lower readiness to change. CONCLUSIONS: TMC improves drinking outcomes when added to standard care, regardless of alcohol use history, early response to treatment, or other risk factors for relapse. TM is recommended for women and less motivated patients. [ABSTRACT FROM AUTHOR]

Rates of personality disorders (PDs) in substance abusers are higher than in the general population. Comorbid PDs are believed to complicate the treatment of addicted patients: in addition to having more severe substance-use disorders and life problems, personality-disordered patients may use substances differently than their peers without Axis II diagnoses. In a sample of 339 adults receiving inpatient treatment for alcohol or drug abuse/dependence, 71.7% received Axis II diagnoses, and they presented a more severe clinical picture. They also had more self-reported "impulsive" substance use and use of drugs or alcohol in positive situations. Different groups of personality-disordered patients had different patterns of self-efficacy for abstinence for hypothetical future situations. [ABSTRACT FROM AUTHOR]

Wildfires are increasing globally in frequency, severity, and extent, but their impact on fluvial networks, and the resources they provide, remains unclear. We combine remote sensing of burn perimeter and severity, in-situ water quality monitoring, and longitudinal modeling to create the first large-scale, long-term estimates of stream+river length impacted by wildfire for the western US. We find that wildfires directly impact ~6% of the total stream+river length between 1984 and 2014, increasing at a rate of 342 km/year. When longitudinal propagation of water quality impacts is included, we estimate that wildfires affect ~11% of the total stream+river length. Our results indicate that wildfire activity is one of the largest drivers of aquatic impairment, though it is not routinely reported by regulatory agencies, as wildfire impacts on fluvial networks remain unconstrained. We identify key actions to address this knowledge gap and better understand the growing threat to fluvial networks, water security, and public health risks.

Anthropogenic increases in nitrogen (N) and phosphorus (P) concentrations can strongly influence the structure and function of ecosystems. Even though lotic ecosystems receive cumulative inputs of nutrients applied to and deposited on land, no comprehensive assessment has quantified nutrient-enrichment effects within streams and rivers. We conducted a meta-analysis of published studies that experimentally increased concentrations of N and/or P in streams and rivers to examine how enrichment alters ecosystem structure (state: primary producer and consumer biomass and abundance) and function (rate: primary production, leaf breakdown rates, metabolism) at multiple trophic levels (primary producer, microbial heterotroph, primary and secondary consumers, and integrated ecosystem). Our synthesis included 184 studies, 885 experiments, and 3497 biotic responses to nutrient enrichment. We documented widespread increases in organismal biomass and abundance (mean response = +48%) and rates of ecosystem processes (+54%) to enrichment across multiple trophic levels, with no large differences in responses among trophic levels or between autotrophic or heterotrophic food-web pathways. Responses to nutrient enrichment varied with the nutrient added (N, P, or both) depending on rate versus state variable and experiment type, and were greater in flume and whole-stream experiments than in experiments using nutrient-diffusing substrata. Generally, nutrient-enrichment effects also increased with water temperature and light, and decreased under elevated ambient concentrations of inorganic N and/or P. Overall, increased concentrations of N and/or P altered multiple food-web pathways and trophic levels in lotic ecosystems. Our results indicate that preservation or restoration of biodiversity and ecosystem functions of streams and rivers requires management of nutrient inputs and consideration of multiple trophic pathways., (© 2020 Cambridge Philosophical Society.)

Different reproductive strategies and the transition to asexuality can be associated with microbial symbionts. Whether such a link exists within mollusks has never been evaluated. We took the first steps towards addressing this possibility by performing pyrosequencing of bacterial 16S rRNA genes associated with Potamopyrgus antipodarum, a New Zealand freshwater snail. A diverse set of 60 tissue collections from P. antipodarum that were genetically and geographically distinct and either obligately sexual or asexual were included, which allowed us to evaluate whether reproductive mode was associated with a particular bacterial community. 2624 unique operational taxonomic units (OTU, 97% DNA similarity) were detected, which were distributed across ~30 phyla. While alpha diversity metrics varied little among individual samples, significant differences in bacterial community composition and structure were detected between sexual and asexual snails, as well as among snails from different lakes and genetic backgrounds. The mean dissimilarity of the bacterial communities between the sexual and asexual P. antipodarum was 90%, largely driven by the presence of Rickettsiales in sexual snails and Rhodobacter in asexual snails. Our study suggests that there might be a link between reproductive mode and the bacterial microbiome of P. antipodarum, though a causal connection requires additional study., Competing Interests: The authors have declared that no competing interests exist.

The goal was to identify factors that predicted sustained cocaine abstinence and transitions from cocaine use to abstinence over 24 months. Data from baseline assessments and multiple follow-ups were obtained from three studies of continuing care for patients in intensive outpatient programs (IOPs). In the combined sample, remaining cocaine abstinent and transitioning into abstinence at the next follow-up were predicted by older age, less education, and less cocaine and alcohol use at baseline, and by higher self-efficacy, commitment to abstinence, better social support, lower depression, and lower scores on other problem severity measures assessed during the follow-up. In addition, higher self-help participation, self-help beliefs, readiness to change, and coping assessed during the follow-up predicted transitions from cocaine use to abstinence. These results were stable over 24 months. Commitment to abstinence, self-help behaviors and beliefs, and self-efficacy contributed independently to the prediction of cocaine use transitions. Implications for treatment are discussed., (Published by Elsevier Inc.)

Objective: This study tested whether the addition of an enhanced continuing care (ECC) intervention that combined in-person and telephone sessions and began in the first week of treatment improved outcomes for cocaine-dependent patients entering an intensive outpatient program (IOP)., Method: Participants (N = 152) were randomized to IOP treatment as usual (TAU) or IOP plus 12 months of ECC. ECC included cognitive-behavioral therapy elements to increase coping skills, as well as monetary incentives for attendance. It was provided by counselors situated at a separate clinical research facility who did not provide IOP. The primary outcomes measured were (a) cocaine urine toxicology and (b) good clinical outcome, as indicated by abstinence from all drugs and from heavy alcohol use. Secondary outcomes were frequency of abstinent days, cocaine use days, and heavy drinking days. Follow-ups were conducted at 3, 6, 9, and 12 months after baseline., Results: Patients in ECC completed a mean of 18 sessions. Contrary to the hypotheses, patients in TAU had better scores on both the cocaine urine toxicology and the good clinical outcome measures than those in ECC, as indicated by significant Group × Time interactions (cocaine urine toxicology, p = .0025; abstinence composite, p = .017). These results were not moderated by substance use before or early in treatment or by IOP attendance. Results with the secondary outcomes also did not favor ECC over TAU., Conclusions: Continuing care that is not well integrated with the primary treatment program may interfere in some way with the therapeutic process, particularly when it is implemented shortly after intake.

Aims: To determine whether 18 months of telephone continuing care improves 24-month outcomes for patients with alcohol dependence. Subgroup analyses were performed to identify patients who would benefit most from continuing care., Design: Comparative effectiveness trial of continuing care that consisted of monitoring and feedback only (TM) or monitoring and feedback plus counseling (TMC). Patients were randomized to treatment as usual (TAU), TAU plus TM or TAU plus TMC, and followed quarterly for 24 months., Setting: Publicly funded intensive out-patient programs (IOP)., Participants: A total of 252 alcohol-dependent patients (49% with current cocaine dependence) who completed 3 weeks of IOP., Measurements: Percentage of days drinking, any heavy drinking and a composite good clinical outcome., Findings: In the intent-to-treat sample, group differences in alcohol outcomes out to 18 months favoring TMC over TAU were no longer present in months 19-24. There was also a non-significant trend for TMC to perform better than usual care on the good clinical outcome measure (60% vs. 46% good clinical outcome in months 19-24). Overall significant effects favoring TMC and TM over TAU were seen for women; and TMC was also superior to TAU for participants with social support for drinking, low readiness to change and prior alcohol treatments. Most of these effects were obtained on at least two of three outcomes. However, no effects remained significant at 24 months., Conclusions: The benefits of an extended telephone-based continuing care programme to treat alcohol dependence did not persist after the end of the intervention. A post-hoc analysis suggested that women and individuals with social support for drinking, low readiness to change or prior alcohol treatments may benefit from the intervention., (© 2011 The Authors, Addiction © 2011 Society for the Study of Addiction.)

The effectiveness of motivational enhancement therapy (MET) in comparison with counseling as usual (CAU) for increasing retention and reducing substance use was evaluated in a multisite randomized clinical trial. Participants were 461 outpatients treated by 31 therapists within 1 of 5 outpatient substance abuse programs. There were no retention differences between the 2 brief intervention conditions. Although both 3-session interventions resulted in reductions in substance use during the 4-week therapy phase, MET resulted in sustained reductions during the subsequent 12 weeks whereas CAU was associated with significant increases in substance use over this follow-up period. This finding was complicated by program site main effects and higher level interactions. MET resulted in more sustained substance use reductions than CAU among primary alcohol users, but no difference was found for primary drug users. An independent evaluation of session audiotapes indicated that MET and CAU were highly and comparably discriminable across sites.