In this paper, the dynamics of primary production in the Daly River in tropical Australia are investigated. We used the diurnal-curve method for both oxygen and pH to calculate photosynthesis and respiration rates as indicators of whole-river productivity. The Daly River has maximum discharges during the summer, monsoonal season. Flow during the dry season is maintained by groundwater discharge via springs. The study investigated how primary production and respiration evolve during the period of low flow in the river (April–November). The relationship between primary production and the availability of light and nutrients enabled the role of these factors to be assessed in a clear, oligotrophic tropical river. The measured rate of photosynthesis was broadly consistent with the estimated mass of chlorophyll associated with the main primary producers in the river (phytoplankton, epibenthic algae, macroalgae, macrophytes). A significant result of the analysis is that during the time that plant biomass re-established after recession of the flows, net primary production proved to be ~4% of the rate of photosynthesis. This result and the observed low-nutrient concentrations in the river suggest a tight coupling between photosynthetic fixation of carbon and the microbial degradation of photosynthetic products comprising plant material and exudates.
Abstract ‘Muddy glee’ by Bracken and Mawdsley made an important contribution to highlighting gender discrimination in fieldwork and the heterogeneity of fieldwork experiences. In the past couple of years, the ability of many researchers to engage in fieldwork has also changed dramatically due to the COVID‐19 pandemic. Here, we reflect on Bracken and Mawdsley's paper and our own experiences and perspectives of fieldwork in recent years. We discuss a previous paper we co‐authored (entitled ‘Pushing the limits’: experiences of women in tropical peatland research), and the benefits that these papers (e.g., ‘Muddy glee’ and ‘Pushing the limits’) may provide. We highlight the value of sharing personal experiences in science (which is often seen as an ‘objective’ space), and how writing for ourselves can be an empowering and community‐building act.
With air pollution remaining a significant problem in many regions globally, an increasing number of environmentally conscious entrepreneurs have been taking initiatives to combat this issue, accompanied by a growing environmental awareness among the general public. To test the strength of this relationship, we use individual-level information from an enterprise survey in China in 2018 and conducted instrumental variable analyses to study the impact of air pollution on the green innovation behaviours of non-agricultural entrepreneurs. The results indicate that, on average, a one standard deviation increase in PM2.5 concentration is associated with a 4.3 percentage points increase in green innovation (or a 11.9 percentage points increase in green innovation intensity). Entrepreneurs' gambling preferences could potentially mediate the relationship between air pollution and green innovation, while expected firm income and actual firm income may act as suppressors. Specifically, entrepreneurs who launch their businesses following the implementation of environmental policies are more likely to adopt green innovation practices. This study provides insight into why there is a growing trend of environmentally-conscious entrepreneurs in regions with high levels of air pollution.
The role of citizen science in environmental monitoring has received interest in the research community over the last decade, with citizen scientists playing a key role in engaging with and gathering scientific evidence to support natural resource management. Likewise, the involvement of citizen science in aquatic research is growing. One area of aquatic research where there has been successful application of citizen science is in support of plastic-pollution research. Plastic-pollution research benefits from support by citizen scientists both because of the ubiquity of plastic within our environments, requiring data to be collected from a wide geographical area, and because of the need for systemic behavior change at both individual and societal levels. Recent studies highlight citizen science contributions to plastic-pollution research within marine systems, but our knowledge is limited about how citizen science can support limnetic plastic-pollution research, with no known published systematic reviews. The involvement of citizen science within freshwater monitoring has been widely discussed, but most peer-reviewed literature focuses on commonly targeted water-quality parameters (e.g., nutrients). This is not surprising given that freshwater plastic waste is a newly emerging field of interest; thus, the support of citizen science in this research area is only just beginning. This review is the 1st to explore the status of freshwater citizen science focused on plastic pollution. Based on a synthesis of 12 peer-reviewed publications, we considered the environmental and geographic extent of the research, research scope, methods, involvement of citizen science, and data quality. We also discuss how citizen science can contribute to emerging issues in freshwater science. Through our review we found that the use of citizen science within the field of freshwater plastic-pollution research remains rare, with most projects following the contributory model of citizen participation. Additionally, methods and standardized approaches for citizen recruitment, engagement, and training were limited in the peer-reviewed literature. Greater transparency of methods and approaches used will be key to opening up the potential for citizen science within this evolving research field. This review can be used as a starting point for researchers to develop their own freshwater plastic-waste monitoring programs involving citizen scientists.
Abstract We examined the relationship between thermal preference (selected body temperature or “Tsel") and microhabitat temperature of a nocturnal, alpine weta Hemideina maori (Orthoptera: Anostostomatidae), in the southern part of New Zealand. To examine diel variation in thermal preference, we measured Tsel five times over a 24‐h period in the laboratory and compared these temperatures to weta microhabitat temperatures in the wild. Tsel ranged from 4.3 to 29.3°C, but the distribution of temperatures was skewed, towards the cooler end of the thermal gradient, with an overall median and mean of c. 13°C. The frequency of Tsel values was bimodal, with peaks at a relatively narrow range of cool temperatures between 5 and 8°C (33%) and at a slightly broader range of warmer temperatures between 13 and 21 °C (52%). Tsel values did not vary with time of day, but differed significantly between individuals. Comparisons with microhabitat temperature showed that weta at 1250 m a.s.l. on the Rock and Pillar Range, Otago, had only limited opportunity to achieve Tsel and this was only possible during daylight hours, when weta are normally inactive.
Abstract. Intact tropical peatlands are dense long-term stores of carbon. However, the future security of these ecosystems is at risk from land conversion and extensive peatland drainage. This can enhance peat oxidation and convert long-term carbon sinks into significant carbon sources. In Southeast Asia, the largest land use on peatland is for oil palm plantation agriculture. Here, we present the first annual estimate of exported fluvial organic carbon in the drainage waters of four peatland oil palm plantation areas in Sarawak, Malaysia. Total organic carbon (TOC) fluxes from the plantation second- and third-order drains were dominated (91 %) by dissolved organic carbon (DOC) and ranged from 34.4 ± 9.7 C m−2 yr−1 to 57.7 %, 16.3 g C m−2 yr−1 (± 95 % confidence interval). These fluxes represent a single-year survey which was strongly influenced by an El Ninõ event and therefore lower discharge than usual was observed. The magnitude of the flux was found to be influenced by water table depth, with higher TOC fluxes observed from more deeply drained sites. Radiocarbon dating on the DOC component indicated the presence of old (pre-1950s) carbon in all samples collected, with DOC at the most deeply drained site having a mean age of 735 years. Overall, our estimates suggest fluvial TOC contributes ∼ 5 % of total carbon losses from oil palm plantations on peat. Maintenance of high and stable water tables in oil palm plantations appears to be key to minimising TOC losses. This reinforces the importance of considering all carbon loss pathways, rather than just CO2 emissions from the peat surface, in studies of tropical peatland land conversion.
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