Freshwater ecosystems produce methane, a potent greenhouse gas, and ponds on agricultural land are particularly strong emitters. Dr Malerba and colleagues used maps of agricultural ponds and compiled data on their emissions to produce assessments of methane emissions from agricultural ponds for both the USA and Australia. They found emissions twice as high as were initially being accounted for under national inventories, highlighting the need to account for this source in national inventories.
Alice Drinkwater (Sat,) studied this question.