Leaving aquaculture ponds ‘out-to-dry’ has implications for nitrous oxide budgets

Researchers from China and the UK have demonstrated that the dormant period of shrimp farming, when aquaculture ponds are drained and left ‘out-to-dry’ for half a year, is associated with increased nitrous oxide emissions. The global aquaculture industry is currently growing at a rate that surpasses most other food sectors, yet the potential climatic impacts from increased greenhouse gas production has implications for the sustainability of this farming system. Through an extended field campaign of nitrous oxide measurements, emissions from the dry-period of aquaculture ponds made up the vast majority of total nitrous oxide emissions. As a previously unaccounted for part of the pond farm greenhouse gas budget, this dry phase of the aquaculture period is too large to be ignored.

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Modelling nitrous oxide emissions from agriculture once fertilizer leaves the field

Countries need to keep track of their national greenhouse gas emissions in an effort to meet targets to combat climate change. Even though carbon dioxide gets most of the attention, nitrous oxide is the most potent of the top three greenhouse gases that contribute to current global warming, having 300 times the warming strength of carbon dioxide. In many countries agriculture is the largest source of nitrous oxide emissions. Keeping track of these emissions after they leave the farm fields via water pathways is difficult.

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Double trouble: how floods after bushfire affect the health of our rivers

Between Christmas 2019 and the  2020 New Year, forested mountain ranges across drought-stricken areas in Eastern Australia came alight, with fires ravaging 11 million hectares of bush (Eucalyptus woodlands and rainforests) – a size comparable to England’s land area. These megafires threw the states of New South Wales and Victoria into a state of emergency. The bushfire crisis took a sudden turn when heavy rainfall flooded the scorched land in the span of just two weeks. Unfortunately, while rainfall might appear to be a blessing in light of the megafires, the resulting floods were ultimately not sweet relief for rivers. 

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Not so blue anymore: how dead mangroves burden coastal carbon sinks

Mangrove forests have been feeling the pressure of climate change. With heat waves and low rainfall, many mangroves along a 1000 km stretch of coastline in northern Australia have been wiped out. However, the dead trees are living on by contributing large methane emissions which has consequences to global mangrove carbon stores and climate change. Read on to find out how the living dead remain active methane emitters.

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