Stream metabolism Stream metabolism is a measure of the amount of energy produced and consumed by food webs. It estimates rates of gross primary production (GPP) by algae and aquatic plants as well as rates of heterotrophic respiration (i.e. carbon consumption, ER) by microorganisms. During 2014-15 and 2015-16 there were no Commonwealth environmental watering actions specifically targeting in-channel metabolism responses, although environmental flows did pass down the river channel while being delivered elsewhere. Long-term watering plans for the Murrumbidgee River (Commonwealth of Australia 2015) forecast in-channel deliveries of Commonwealth environmental water to support habitat and food sources and promote increased movement, recruitment and survival of native fish and other aquatic biota. In the absence of targeted environmental water deliveries we investigated the relationship between stream metabolism and river flows during 2014-15 and 2015-16 and discuss these findings with regard to future deliveries of Commonwealth environmental water. Summary of watering actions and outcomes MEP and Watering Action Measured Was the Acquittal (s) in 2015/16 outcomes Evaluation expected Report questions outcome Expected achieved outcomes Provide flows, including restoring natural flow events that Rates of No in-channel What did CEW are affected metabolism low watering actions, contribute to by river Commonwealth compared with patterns and rates water influenced regulation other river of decomposition? hydrology due to and/or systems. transit of water for extraction, to Negative Unknown What did CEW floodplain assets support relationship resulting in the contribute to habitat and between flow presence of patterns and rates food sources and channel freshes of primary and promote metabolism at throughout the productivity? increased monitoring period. Narrandera. movement, recruitment and survival of native fish. Main findings from the Stream Metabolism monitoring program Rates of metabolism in the Murrumbidgee River are consistently low
Stream metabolism Stream metabolism is a measure of the amount of energy produced and consumed by food webs. It estimates rates of gross primary production (GPP) by algae and aquatic plants as well as rates of heterotrophic respiration (i.e. carbon consumption, ER) by microorganisms. During 2014-15 and 2015-16 there were no Commonwealth environmental watering actions specifically targeting in-channel metabolism responses, although environmental flows did pass down the river channel while being delivered elsewhere. Long-term watering plans for the Murrumbidgee River (Commonwealth of Australia 2015) forecast in-channel deliveries of Commonwealth environmental water to support habitat and food sources and promote increased movement, recruitment and survival of native fish and other aquatic biota. In the absence of targeted environmental water deliveries we investigated the relationship between stream metabolism and river flows during 2014-15 and 2015-16 and discuss these findings with regard to future deliveries of Commonwealth environmental water. Summary of watering actions and outcomes MEP and Acquittal Report Expected outcomes Evaluation questions Watering Action (s) in 2015/16 Measured outcomes Was the expected outcome achieved Provide flows, including restoring natural flow events that are affected by river regulation and/or extraction, to support habitat and food sources and promote increased movement, recruitment and survival of native fish. What did CEW contribute to patterns and rates of decomposition? What did CEW contribute to patterns and rates of primary productivity? No in-channel watering actions, Commonwealth water influenced hydrology due to transit of water for floodplain assets resulting in the presence of channel freshes throughout the monitoring period. Rates of metabolism low compared with other river systems. Negative relationship between flow and metabolism at Narrandera. Unknown Main findings from the Stream Metabolism monitoring program Rates of metabolism in the Murrumbidgee River are consistently low