Calcification rates from pH experiments on Lophelia pertusa specimens collected from the Norwegian Skagerrak and the Gulf of Mexico (Lophelia OA project) on 2016-09-20 (NCEI Accession 0278866)

Acquisition Description:
Acquisition Description for Tisler Reef Data:

Net calcification was measured using the total alkalinity anomaly (Smith & Key 1975; Ohde & Hossain 2004). Corals were individually placed in closed glass chambers (220 ml) in a water bath that maintained temperature to +/-0.2 degrees C during all trials. To avoid hypoxia or the severe reductions of pH during incubations, ambient air was continuously bubbled into the chambers at a slow rate (1-2 bubbles s-1). This also provided adequate circulation within the chamber. A 60 ml water sample was collected by syringe before and after the incubation period, and measured for total alkalinity in duplicate. The respiration rate of each colony was measured as oxygen consumption in a 400 ml closed acrylic chamber during hour-long incubations. Dissolved oxygen concentrations were measured in umol L-1 using a Strathkelvin 782 dual oxygen meter and SI130 microcathode electrode. The feeding rate of each colony was measured as the capture rate of adult Artemia salina during a one-hour period in 0.8 L incubation chambers containing a starting prey density of 125 Artemia L-1.

Acquisition Description for Gulf of Mexico Data:

The buoyant weight of each colony was obtained at the start and end of the two-week experimental period by weighing fragments submerged in seawater and attached by a hook to an analytical balance (Denver Instrument, precision of 0.1 mg). The respiration rate of each colony was measured as oxygen consumption in an 800 ml closed acrylic chamber during hour-long incubations. Dissolved oxygen concentrations were measured in umol L-1 using a Strathkelvin 782 dual oxygen meter and SI130 microcathode electrode. The feeding rate of each colony was measured as the capture rate of adult Artemia salina during a one-hour period in 0.8 L incubation chambers containing a starting prey density of 125 Artemia L-1.