Line P Program

Present sampling

Our present sampling consists of the following:

Station type: CTD

A CTD cast is done to 2000 dbar. The standard CTD measurements are:

• Temperature
• Conductivity
• Transmissivity
• Fluorescence
• Dissolved Oxygen

No water samples are taken except for a "Surface" sample at 5 dbar for Nutrients, Salinity, and Chlorophyll.

Station type: Rosette/Bongo

A "deep rosette" cast is done down to 10 m above the ocean floor. The CTD measurements listed above are recorded. In addition, water samples are taken for:

• Dissolved Oxygen
• Dissolved Inorganic Carbon
• Alkalinity
• pH
• Nutrients (Nitrate plus Nitrite, Phosphate, Silicate)
• Salinity

These samples are collected at the following pressures: 5, 10, 25, 50, 75, 100, 125, 150, 175, 200, 250, 300, 400, 600, 800, 1000, 1250, 1500, 2000, 2500, 3000, 3500, 4000 dbar and 10 m above the ocean floor.
A "shallow rosette" cast is done down to 200 dbar.

In addition to the CTD measurements listed above, Irradiance (PAR) is also recorded. Water samples are taken for:

• DMS (Dimethylsulfide)
• DMSP-d (Dimethylsulfoniopropionate dissolved)
• DMSP-t (Dimethylsulfoniopropionate total)
• Nutrients (Nitrate plus Nitrite, Phosphate, Silicate)
• Chlorophyll
• HPLC (Phytoplankton Pigment Concentrations)

These samples are collected at the following pressures: 0, 5, 10, 15, 20, 25, 30, 40, 50, 75, 100, 175, 200, 300 dbar.
A vertical net haul is performed down to 250 m using a set of Bongos with a mesh size of 236 µm.

Principal Participants and Collaborators