Challenges of diabetes prevention in the real world : results and lessons from the Melbourne diabetes prevention study

OBJECTIVE: To assess effectiveness and implementability of the public health programme Life! Taking action on diabetes in Australian people at risk of developing type 2 diabetes. RESEARCH DESIGN AND METHODS: Melbourne Diabetes Prevention Study (MDPS) was a unique study assessing effectiveness of Life! that used a randomized controlled trial design. Intervention participants with AUSDRISK score ≥15 received 1 individual and 5 structured 90 min group sessions. Controls received usual care. Outcome measures were obtained for all participants at baseline and 12 months and, additionally, for intervention participants at 3 months. Per protocol set (PPS) and intention to treat (ITT) analyses were performed. RESULTS: PPS analyses were considered more informative from our study. In PPS analyses, intervention participants significantly improved in weight (-1.13 kg, p=0.016), waist circumference (-1.35 cm, p=0.044), systolic (-5.2 mm Hg, p=0.028) and diastolic blood pressure (-3.2 mm Hg, p=0.030) compared with controls. Based on observed weight change, estimated risk of developing diabetes reduced by 9.6% in the intervention and increased by 3.3% in control participants. Absolute 5-year cardiovascular disease (CVD) risk reduced significantly for intervention participants by 0.97 percentage points from 9.35% (10.4% relative risk reduction). In control participants, the risk increased by 0.11 percentage points (1.3% relative risk increase). The net effect for the change in CVD risk was -1.08 percentage points of absolute risk (p=0.013). CONCLUSIONS: MDPS effectively reduced the risk of diabetes and CVD, but the intervention effect on weight and waist reduction was modest due to the challenges in recruiting high-risk individuals and the abbreviated intervention

TRY plant trait database – enhanced coverage and open access

Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

Organic Matter Stoichiometry Influences Nitrogen and Phosphorus Uptake in a Headwater Stream

The concept of nutrient spiraling combines the geological, hydrological, and biological processes that influence nutrient cycling in streams. Spiraling studies have demonstrated connections between metabolic and nutrient cycles, organic matter (OM) dynamics, and hydrologic controls. Most spiraling studies have addressed the dynamics of a single element. However, nutrients do not move through ecosystems in isolation. Recent models have used ecological stoichiometric theory to couple N and P cycles, but empirical data to support these conceptual frameworks are generally lacking. We investigated the relationship between N and P uptake and the extent to which OM stoichiometry was related to the relative uptake of N and P in a headwater stream across 2 seasons. In addition, we explored whether our results were consistent with theoretical predictions derived from ecological stoichiometry and consumer–resource imbalances. We found that higher respiration led to higher NH4+ and P uptake rates. NH4+ and P uptake were strongly correlated, but the nature of this relationship shifted with a seasonal change in the dominant OM to fresh leaf litter in autumn. OM stoichiometry was a strong predictor of relative nutrient uptake (NH4∶SRP uptake ratios). Seasonal input of low N∶P leaf litter led to relatively higher NH4+ uptake from the water column, which caused a shift in relative nutrient uptake but did not alter the strength of the coupling. Our results indicate that stoichiometric imbalances between nutrient consumers and resources have a strong influence on nutrient uptake in streams. Moreover, stoichiometric models of consumer–resource imbalances between microbes and dominant OM substrates accurately captured N and P uptake dynamics in our study system. Integrating stoichiometry with metabolic controls provides insights into nutrient dynamics and acts as a framework to link N and P cycles

Benthic diatoms as indicators of eutrophication in tropical streams

Diatoms are frequently used as indicators of eutrophication in temperate systems, but little is known about their application to impacted African tropical systems. Five streams located within Gombe Stream National Park and five streams supporting human settlements draining into Lake Tanganyika, East Africa, were investigated for species composition, richness and diversity of epilithic algae. In addition, a trophic diatom index (TDI) developed for monitoring European rivers was applied to these tropical systems. 54 specific and infraspecific diatom taxa representing 20 genera were identified for all sites with Achnanthes s.l., Gomphonema and Navicula s.l. being the most common genera. Species richness varied between 10 and 21 in disturbed streams and 13 and 19 in undisturbed streams. Nutrients were significantly enriched in streams draining the deforested watersheds but indices of diversity and evenness (Shannon H, J and Simpson-Yule D, E) did not show any significant differences between streams in forested and deforested watersheds. Significant differences were observed between pooled data for the TDI between forested and deforested watersheds. Analysis of percent pollution tolerant diatom taxa indicates that organic pollution of streams in deforested watersheds may be contributing to eutrophication. This study shows that African diatoms, cosmopolitan or resembling well-known North American and European taxa, allows for trophic indices tailored to the autecological preferences of species to be applied to new regions, although intensive studies on these African taxa will lead to more accurate results. Measures of species-richness and diversity, historically used to describe the state of an ecosystem, may not be suitable to evaluate streams which are not grossly polluted. © 2006 Springer

A Model for using Environmental Data‐Driven Inquiry and Exploration to Teach Limnology to Undergraduates

Limnologists are increasingly using large volumes of data, both from high-frequency sensors as well as long-term studies, to address new research questions. Undergraduate students, i.e., future limnologists and informed citizens, need quantitative reasoning skills and tools to be able to analyze these large datasets. However, most undergraduate curricula typically remains focused on small-scale local studies, potentially contributing to many students’ inability to see the applicability of their classroom experiences (Prokop et al. 2007). In response, we have developed undergraduate teaching modules that integrate the use of high-frequency and long-term datasets from many lakes around the world. Here, we describe two modules that are designed to increase conceptual understanding of climate change and lake metabolism while simultaneously improving quantitative reasoning, building data manipulation skills, and highlighting the inherent variability in real data (Fig. 1). These two modules were developed by a team of limnologists and education researchers committed to improving environmental data literacy in undergraduate classrooms as part of the Environmental Data-Driven Inquiry and Exploration Project (Project EDDIE; http://www.projecteddie.org). In addition to describing the modules, we also share both the students’ and instructors’ experiences during module implementation, and highlight the potential for scaling these modules across different skill levels, both within and across different types of institutions. Our experience suggests that students appreciate the value of high-resolution and long-term data, and that working with large datasets cements the “real world” application of basic freshwater ecology concepts

Spatial and Temporal Variability in the Amount and Source of Dissolved Organic Carbon: Implications for Ultraviolet Exposure in Amphibian Habitats

The amount, chemical composition, and source of dissolved organic carbon (DOC), together with in situ ultraviolet (UV-B) attenuation, were measured at 1–2 week intervals throughout the summers of 1999, 2000, and 2001 at four sites in Rocky Mountain National Park (Colorado). Eight additional sites, four in Sequoia and Kings Canyon National Park/John Muir Wilderness (California) and four in Glacier National Park (Montana), were sampled during the summer of 2000. Attenuation of UV-B was significantly related to DOC concentrations over the three years in Rocky Mountain (R2 = 0.39, F = 25.71, P \u3c 0.0001) and across all parks in 2000 (R2 = 0.44, F = 38.25, P \u3c 0.0001). The relatively low R2 values, however, reflect significant temporal and spatial variability in the specific attenuation per unit DOC. Fluorescence analysis of the fulvic acid DOC fraction (roughly 600–2,000 Daltons) indicated that the source of DOC significantly affected the attenuation of UV-B. Sites in Sequoia–Kings Canyon were characterized by DOC derived primarily from algal sources and showed much deeper UV-B penetration, whereas sites in Glacier and Rocky Mountain contained a mix of algal and terrestrial DOC-dominated sites, with more terrestrially dominated sites characterized by greater UV-B attenuation per unit DOC. In general, site characteristics that promoted the accumulation of terrestrially derived DOC showed greater attenuation of UV-B per unit DOC; however, catchment vegetation and soil characteristics, precipitation, and local hydrology interacted to make it difficult to predict potential exposure from DOC concentrations

Century-Long Warming Trends in the Upper Water Column of Lake Tanganyika

Lake Tanganyika, the deepest and most voluminous lake in Africa, has warmed over the last century in response to climate change. Separate analyses of surface warming rates estimated from in situ instruments, satellites, and a paleolimnological temperature proxy (TEX86) disagree, leaving uncertainty about the thermal sensitivity of Lake Tanganyika to climate change. Here, we use a comprehensive database of in situ temperature data from the top 100 meters of the water column that span the lake’s seasonal range and lateral extent to demonstrate that long-term temperature trends in Lake Tanganyika depend strongly on depth, season, and latitude. The observed spatiotemporal variation in surface warming rates accounts for small differences between warming rate estimates from in situ instruments and satellite data. However, after accounting for spatiotemporal variation in temperature and warming rates, the TEX86 paleolimnological proxy yields lower surface temperatures (1.46 °C lower on average) and faster warming rates (by a factor of three) than in situ measurements. Based on the ecology of Thaumarchaeota (the microbes whose biomolecules are involved with generating the TEX86 proxy), we offer a reinterpretation of the TEX86 data from Lake Tanganyika as the temperature of the low-oxygen zone, rather than of the lake surface temperature as has been suggested previously. Our analyses provide a thorough accounting of spatiotemporal variation in warming rates, offering strong evidence that thermal and ecological shifts observed in this massive tropical lake over the last century are robust and in step with global climate chang

Century-Long Warming Trends in the Upper Water Column of Lake Tanganyika

Lake Tanganyika, the deepest and most voluminous lake in Africa, has warmed over the last century in response to climate change. Separate analyses of surface warming rates estimated from in situ instruments, satellites, and a paleolimnological temperature proxy (TEX86) disagree, leaving uncertainty about the thermal sensitivity of Lake Tanganyika to climate change. Here, we use a comprehensive database of in situ temperature data from the top 100 meters of the water column that span the lake’s seasonal range and lateral extent to demonstrate that long-term temperature trends in Lake Tanganyika depend strongly on depth, season, and latitude. The observed spatiotemporal variation in surface warming rates accounts for small differences between warming rate estimates from in situ instruments and satellite data. However, after accounting for spatiotemporal variation in temperature and warming rates, the TEX86 paleolimnological proxy yields lower surface temperatures (1.46 °C lower on average) and faster warming rates (by a factor of three) than in situ measurements. Based on the ecology of Thaumarchaeota (the microbes whose biomolecules are involved with generating the TEX86 proxy), we offer a reinterpretation of the TEX86 data from Lake Tanganyika as the temperature of the low-oxygen zone, rather than of the lake surface temperature as has been suggested previously. Our analyses provide a thorough accounting of spatiotemporal variation in warming rates, offering strong evidence that thermal and ecological shifts observed in this massive tropical lake over the last century are robust and in step with global climate chang