Data and code for: Temporal and Spatial Variation in Temperature and Oxygen at the Microscale: Key Niche Axes for Aquatic Life

Data on water temperature and water oxygenation were collected in four different water bodies (i.e. sites), two running and two standing. WaterbodiesThese were all located on private lands in Devon (UK, 50°29'N 3°48'W). Running waters were the river Mardle, which originates on Dartmoor and discharges into the river Dart and a small first order stream, which discharges into the river Mardle. Standing waters comprised a duckpond in a forest and a sun-exposed reservoir, both close to Buckfastleigh. Water loggersHandy Polaris Loggers (OxyGuard) were deployed in each site. Periodically these were retrieved, read out, calibrated, serviced and redeployed during the period from December 23rd 2011 to July 17th 2012. Loggers were placed such that they measured the oxygen conditions in the water column, 5-10 cm above the sediment, at a depth of 20-40 cm (note that this is equivalent to the open water microhabitat sampled below). Spot measurementsWe also performed spot measurements to characterise microhabitat conditions during 5 field visits (Table S1). On each visit, water temperature and water oxygenation were measured across representative microhabitats in each site. Typically, 3-5 microhabitats would be measured, and each type of microhabitat would be measured at 5 different spots in the waterbody (i.e. replicates) in the morning and in the afternoon. Spot measurements were made in the littoral zone at a depth up to ~40 cm, and replicate measurements were made in close proximity of one another (within a few meters along the shoreline). Since all four water bodies were quite shallow (< 2 m), no attempt was made to characterise the vertical gradient. Instead, measurements were focussed on the shallow, littoral zone, where insolation is highest and where the vast majority of macroinvertebrates reside. Over these 5 field visits, we collected 775 spot measurements (3-5 microhabitats x morning and afternoon x 5 replicates x 4 sites x 5 visits). We used a battery powered, portable Fibox 3 LCD Trace oxygen meter with a temperature sensor and a DP-PST3 optical oxygen sensor, the end of which is covered in a steel tube to protect both the sensor material and the optical fiber (PreSens GmBH, Germany).