Three 9.45L aquariums contained twelve 7-cm long oysters pre-exposed to ¹⁵N labeled phytoplankton (OA1, OA2, OA3,) and three aquariums had no oysters and served as controls (CA1, CA2, CA3). These aquariums were filled with 0.1micron filtered seawater and a small circulation pump was added. N₂O, ¹⁵N, and oxygen were measured initially and then aquariums sealed until oxygen had depleted to 2mgL^-1. Oysters were then harvested for their gill/mantle tissue (meat) and digestive tissue (digestive) over a period of time.

Oxygen was measured insitu using an oxygen probe. Water samples for N₂O analysis were collected with a peristaltic pump through a syringe needle directly into 12 ml exetainer that had been flushed with N₂ and preserved with KOH to a pH above 12. Approximately six ml sample was collected. N₂O concentrations in the headspace were measured on a GC-ECD.  Water samples for 15N2 samples were collected with a peristaltic pump through a syringe needle directly into 30 ml serum bottles that had been flushed with He and preserved with KOH to a pH above 12.   Approximately eight ml sample was collected. ¹⁵N₂ was analyzed by GC - Isotope Ratio Mass Spectrometry (IRMS). Oyster tissue ¹⁵N samples were collected from the aquariums from dissections. ¹⁵N was analyzed on a elemental analyzer (EA) coupled with an IRMS.