Inland waters play an active role in the global carbon cycle and emit large volumes of the greenhouse gases (GHGs), methane (CH4 ) and carbon dioxide (CO2 ). A considerable body of research has improved emissions estimates from lakes, reservoirs and rivers but recent attention has been drawn to the importance of small, artificial waterbodies as poorly quantified but potentially important emission hotspots. Of particular interest are emissions from drainage ditches and constructed ponds. These waterbody types are prevalent in many landscapes and their cumulative surface areas can be substantial. Furthermore, GHG emissions from constructed waterbodies are anthropogenic in origin and form part of national emissions reporting, whereas emissions from natural waterbodies do not (according to Intergovernmental Panel on Climate Change guidelines). Here, we present GHG data from two complementary studies covering a range of land uses. In the first, we measured emissions from nine ponds and seven ditches over a full year. Annual emissions varied considerably: 0.1-44.3 g CH4 m-2 year-1 and -36-4421 g CO2 m-2 year-1 . In the second, we measured GHG concentrations in 96 ponds and 64 ditches across seven countries, covering subtropical, temperate and sub-arctic biomes. When CH4 emissions were converted to CO2 equivalents, 93% of waterbodies were GHG sources. In both studies, GHGs were positively related to nutrient status (C, N, P), and pond GHG concentrations were highest in smallest waterbodies. Ditch and pond emissions were larger per unit area when compared to equivalent natural systems (streams, natural ponds). We show that GHG emissions from natural systems should not be used as proxies for those from artificial waterbodies, and that artificial waterbodies have the potential to make a substantial but largely unquantified contribution to emissions from the Agriculture, Forestry and Other Land Use sector, and the global carbon cycle.

Science fields, including tropical peatland research, are facing persistent under-representation of women. In this perspective piece, we explore, as women at different stages of our career, our personal experiences of 'what is it like to be a woman working in tropical peatland science'? We collected our responses and analysed them thematically. Although we come from a variety of different backgrounds and cultures, our responses all dealt with common issues, such as from practical challenges of being women in the field, persistent sexism, issues of harassment to navigating the politics of research as a woman. The peat swamp is seen as a site of rebellion against traditional gender roles. Senior female role models were also vital for us all, which highlights that mentoring schemes in aquatic and wetland research, as in other science fields, need further consideration and investment. Continuing to improve gender balance is central to effecting a positive change in research culture, and we stress that the issue of the 'bravado' surrounding fieldwork needs to be further explored and challenged. By pushing these 'limits' both in the field and in the academy, we will not only produce a more equal and compassionate working environment, but also ultimately improve our science.

The rise of palm oil as the world's most consumed vegetable oil has coincided with exponential growth in palm oil research activity. Bibliometric analysis of research outputs reveals a distinct imbalance in the type of research being undertaken, notably a disproportionate focus on biofuel and engineering topics. Recognizing the expansion of oil palm agriculture across the tropics and the increasing awareness of environmental, social, and economic impacts, we seek to reorientate the existing research agenda toward one that addresses the most fundamental and urgent questions defined by the palm oil stakeholder community. Following consultation with 659 stakeholders from 38 countries, including palm oil growers, government agencies, non-governmental organizations, and researchers, the highest priority research questions were identified within 13 themes. The resulting 279 questions, including 26 ranked as top priority, reveal a diversity of environmental and social research challenges facing the industry, ranging from the ecological and ecosystem impacts of production, to the livelihoods of plantation workers and smallholder communities. Analysis of the knowledge type produced from these questions underscores a clear need for fundamental science programmes, and studies that involve the consultation of non-academic stakeholders to develop "transformative" solutions to the oil palm sector. Stakeholders weremost aligned in their choice of priority questions across the themes of policy and certification related themes, and differed the most in environmental feedback, technology and smallholder related themes. Our recommendations include improved regional academic leadership and coordination, greater engagement with private and public stakeholders in Africa, and Central and South America, and enhanced collaborative efforts with researchers in the major consuming countries of India and China.

Fluvial fluxes of dissolved organic carbon (DOC) may represent an important loss for terrestrial carbon stores in the tropics. However, there is currently limited guidance on the preservation of tropical water samples for DOC analysis. Commonly employed preservation techniques such as freezing or acidification can limit degradation but may also alter sample properties, complicating DOC analysis. We examined the effects of cold storage at 4 °C on DOC concentration and quality in water samples collected from a tropical peat catchment. Samples were stored in the dark at 4 °C for periods of 6–12 weeks. Freeze/thaw experiments were also made. Mean DOC concentrations in samples stored for six weeks at 4 °C were 6.1 % greater than in samples stored at ambient room temperature (33 °C) over the same period. Changes in DOC concentrations, in two sample sets, during cold storage were 2.25 ± 2.9 mg L-1 (8 %) to 2.69 ± 1.4 mg L-1 (11 %) over a 12-week period. Freeze/thaw resulted in alterations in the optical properties of samples, and this in turn altered the calculated DOC concentrations by an average of 10.9 %. We conclude that cold storage at 4 °C is an acceptable preservation method for tropical DOC water samples, for moderate time periods, and is preferable to freezing or storage at ambient temperatures.