The setting of numeric instream objectives (effects-based criteria) and catchment limits for major agricultural stressors, such as nutrients and fine sediment, is a promising policy instrument to prevent or reduce degradation of stream ecosystem health. We explored the suitability of assemblage thresholds, defined as a point at which a small increase in a stressor will result in a disproportionally large change in assemblage structure relative to other points across the stressor gradient, to inform instream nutrient and sediment objectives. Identification and comparison of thresholds for macroinvertebrate, periphyton, and bacterial assemblages aimed at making the setting of objectives more robust and may further provide a better understanding of the underlying mechanisms of nutrient and fine sediment effects. Gradient forest, a novel approach to assemblage threshold identification based on regression-tree-based random forest models for individual taxa, allowed inclusion of multiple predictors to strengthen the evidence of cause and effect between stressors and multispecies responses. The most prominent macroinvertebrate and periphyton assemblage threshold across the nitrogen (N) gradient was located at very low levels and mainly attributed to declines of multiple taxa. This provided strong evidence for stream assemblages being significantly affected when N concentrations exceed reference conditions and for effects cascading through the ecosystem. The most prominent macroinvertebrate assemblage threshold across a gradient of suspended fine sediment was also located at very low levels and attributed to declines of multiple taxa. However, this threshold did not correspond with periphyton assemblage thresholds, suggesting that the sensitivity of macroinvertebrate assemblages is unrelated to sediment effects on periphyton assemblages. Overall, the spectrum of N concentrations and fine sediment levels within which these stream assemblages changed most dramatically were relatively narrow given the wide gradients tested. We conclude that assemblage thresholds can inform the setting of generic instream nutrient and sediment objectives for stream ecosystem health. For example, the most stringent objective for instream N concentration should be set at values similar to reference concentrations for full protection of sensitive taxa or overall stream biodiversity. To avoid severe degradation of stream biodiversity, the least stringent N objective should stay well below the point where significant turnover subsided.

Summary In stream ecosystems, bacterial communities play an important role in nutrient and energy cycling processes as they are among the most numerous and active organisms at the basal trophic level of the stream food web. Bacterial communities in stream biofilms have been shown to correlate well with different catchment land use and therefore provide an opportunity for the development of a novel ecological indicator of stream ecosystem health. In this study, a bacterial community index (BCI) model was developed and validated using a national data set of biofilm bacterial community profiles collected from 223 streams across seven geographical regions in New Zealand. The six‐component BCI model was generated using the partial least squares regression method to associate the multivariate bacterial community profile with the macroinvertebrate community index, which is a well‐established indicator of stream health. Despite strong regional clustering of the bacterial community profiles, the BCI was indicative of the level of disturbance in the catchment, as shown by significant correlations with a wide range of independent indicators of water quality, macroinvertebrate community data, ecosystem functioning and catchment land‐use data. The BCI was able to explain 35% of the variation in a multi‐metric index incorporating ten common ecological parameters, suggesting that the stream bacterial communities could provide useful information about the ecosystem integrity. The BCI provides a novel ecosystem assessment tool, which can be used to complement existing stream health measures in the management of anthropogenic impacts on freshwater streams and rivers.

BackgroundWhile a subgroup of patients with exacerbations of chronic obstructive pulmonary disease (COPD) clearly benefit from antibiotics, their identification remains challenging. We hypothesised that selective assessment of the balance between the two dominant bacterial groups (Gammaproteobacteria (G) and Firmicutes (F)) in COPD sputum samples might reveal a subgroup with a bacterial community structure change at exacerbation that was restored to baseline on recovery and potentially reflects effective antibiotic treatment.MethodsPhylogenetically specific 16S rRNA genes were determined by quantitative real time PCR to derive a G:F ratio in serial sputum samples from 66 extensively-phenotyped COPD exacerbation episodes.ResultsCluster analysis based on Euclidean distance measures, generated across the 4 visit times (stable and exacerbation day: 0,14 and 42) for the 66 exacerbation episodes, revealed three subgroups designated HG, HF, and GF reflecting predominance or equivalence of the two target bacterial groups. While the other subgroups showed no change at exacerbation, the HG cluster (n = 20) was characterized by G:F ratios that increased significantly at exacerbation and returned to baseline on recovery (p<0.00001); ratios in the HG group also correlated positively with inflammatory markers and negatively with FEV1. At exacerbation G:F showed a significant receiver-operator-characteristic curve to identify the HG subgroup (AUC 0.90, p<0.0001).ConclusionsThe G:F ratio at exacerbation can be determined on a timescale compatible with decisions regarding clinical management. We propose that the G:F ratio has potential for use as a biomarker enabling selective use of antibiotics in COPD exacerbations and hence warrants further clinical evaluation.

We sought to test whether stream bacterial communities conform to Rapoport's Rule, a pattern commonly observed for plants and animals whereby taxa exhibit decreased latitudinal range sizes closer to the equator. Using a DNA sequencing approach, we explored the biogeography of biofilm bacterial communities in 204 streams across a ∼1000 km latitudinal gradient. The range sizes of bacterial taxa were strongly correlated with latitude, decreasing closer to the equator, which coincided with a greater than fivefold increase in bacterial taxonomic richness. The relative richness and range size of bacteria were associated with spatially correlated variation in temperature and rainfall. These patterns were observed despite enormous variability in catchment environmental characteristics. Similar results were obtained when restricting the same analyses to native forest catchments, thereby controlling for spatial biases in land use. We analysed genomic data from ∼500 taxa detected in this study, for which data were available and found that bacterial communities at cooler latitudes also tended to possess greater potential metabolic potential. Collectively, these data provide the first evidence of latitudinal variation in the range size distributions of freshwater bacteria, a trend which may be determined, in part, by a trade-off between bacterial genome size and local variation in climatic conditions.

The COVID-19 pandemic and related lock downs have accelerated the need for online and remote teaching within university settings. However, due to the abrupt nature of the pandemic, many academic staff were not prepared for this forced transition. This study aimed to understand how the pandemic affected academics at a New Zealand university, with regards to their transition to emergency remote teaching. Specifically, it explores the challenges as well as benefits academics experienced during this transition. Recommendations for future online learning are also made. Academic staff (N = 67) at a New Zealand University completed an anonymous online survey. Quantitative data were analyzed statistically using descriptive and inferential statistics, while qualitative data were analyzed thematically. Major challenges experienced included miscommunication from the university, concerns about student access to technology, finding a quiet space to work, lack of digital competence skills, too much screen-time, managing work hours, and work/life balance. Benefits included enhanced flexibility, enhanced teacher creativity, increasing autonomy of learners, and reduced commute time. Looking forward, academic staff desired future teaching to include blended learning and virtual immersion. New strategies of working remotely are being explored to facilitate teaching and learning while catering to the preferences and skills of both educators and students. Our findings honor the considerable agility of academic staff who sought to sustain and enhance excellence in remote education. At an institutional level our findings point to the need for staff to be supported by their institutions as they further refine their work within new-found spaces.