Dataset: Seawater conditions monitored and recorded during two separate laboratory experiments in 2017 to acclimate krill to dissolved oxygen (DO) or pH conditions.

Two separate experiments were conducted to test the effects of acclimation to different pH or dissolved oxygen (DO) conditions on adult female Euphausia pacifica. System indicates the system that generated controlled seawater conditions with many individual krill held within one experimental system. Responses measured after the ten day acclimation (ETS activity, AARS activity, and respiration rate) are given in the Krill Physiology dataset along with the corresponding system name.

Acclimation of krill to different oxygen levels in the laboratory was done at the NOAA Mukilteo Research Station in flow-through experimental systems with independent temperature, pH, and oxygen control. Nine systems of generating controlled seawater were used, three per treatment. Target dissolved oxygen levels were 3, 5, and 9 mg DO L-1; temperature was maintained at 12 °C and pH at ~7.82. During the oxygen experiment, temperature, pH, and dissolved oxygen were monitored continuously using Omega thermistors, Honeywell Durafet III probes, and Vernier optical dissolved oxygen probes, respectively. Temperature, pH, and oxygen concentration were recorded in each system every 6 seconds, but were binned into 10 min averages.

Experimental acclimation to pH was conducted at the FHL Ocean Acidification Environmental Laboratory, using a flow-through system with pH controlled by CO2 bubbling. Target pH levels were 8.0, 7.5, and 7.2: three flow-through systems were used, one per pH treatment. Temperature was set to 12 °C and oxygen was maintained at ambient levels through bubbling, but not monitored. Temperature and pH were monitored and logged every 10 min with a Honeywell Durafet III electrode. Temperature failed to record in system 104A but this system shared a cooling unit with system 104B and was therefore likely similar.