Dataset: GoMX_PIT_Oceanus_8-2010
Deployment: OC468-02

GoMX Aug/ Sep 2010: PIT traps 
Methods
Eight (PIT 1 & 2, 7, & 8) to twelve (PIT 3, 4, 5, 6) columns were attached to a cross (2-3 in each of 4 directions) attached 30 m above the weight. Above the column a bungee cord connection that buffered the wave action connected to two large benthos floats and a bead of a series of small floats with a buoy at the surface. The traps, which were suspended at 150 m depth (PIT 1 to 6) or 185 m (PIT > 6) and drifted freely, were deployed at the beginning of each main station and recovered at the end. Deployment time varied around 36 hours, except PIT 7 where it was 24 h. Each trap column was 62.5 cm high, with baffles in the 9 top cm and a diameter of 6.96 cm (area 37.94 cm²).

Gels in jars fitting tightly into the columns were added at the bottom of two columns to investigate size distribution and type of sinking particles. Prior to deployment the cup with the softened gel (softened by adding a layer of 50 ‰ FSW ≥ 2 days before deployment) was fitted into the bottom of the column and overlaid first with a layer of salt-enriched water and then with FSW. The other 6 to 10 columns were filled with FSW which was under laid with 300 mL of salt-enriched water using a tube connected to a sawed off pipette.

Upon retrieval, water was drained above the gel cups, the cups removed and stored in the fridge. The upper 2/3 of the water in the other columns was also drained after particles wee allowed to settle and the lower third of all columns mixed and used for subsequent analysis of POC, PON, Isotopes. DNA content and oil signature is analyzed for selected samples only.