Sinking Particle Flux in the Central Pacific

 

The Hawaii Ocean Time-series (HOT) program studies a region of the central Pacific ocean (the North Pacific Subtropical Gyre) near Hawaii.  This region is part of one of the great ocean deserts: low-nutrient regions with very low food web productivity and low abundances of most organisms.  The HOT program has been going to this site almost every month since 1988.  Among other measurements, they have been measuring sinking particle flux using drifting sediment traps.  These drifting sediment traps are essentially fancy buckets that the scientists deploy on a rope attached to a surface float.  They let the sediment traps drift for a period of days while collecting all particles that sink into the sediment traps.  They then measure the total mass and elemental composition of collected particles in order to estimate (among other things) the flux of carbon into the deep ocean.  While they have deployed the sediment traps, the scientists also make other measurements to try to understand which chemical, physical, and ecological processes drive carbon export.  The scientists make this data freely available and if you want to download it for yourself you can access it at the Biological and Chemical Oceanography Data Management Office website.

 

Please note that in this dataset the letters "NaN" means that a measurement was not taken.  Time-series evolve over time and logistical issues (e.g., 20-foot waves and 40-knot winds) can make it impossible to make every measurement every time.

 

HOT Particle Flux Data.xlsx

 

Data Columns:

 Cruise = the number of the HOT cruise from which the data came

 Day = day of the month

 Month = month of the year

 Year

 Depth = depth at which the sediment trap was deployed

 Surface Temperature = temperature at at the surface above the sediment trap (unit = degrees Celsius)

 Surface Nitrate = Nitrate concentration at the surface ocean above the sediment trap (unit = micromoles nitrate per kilogram seawater).  NItrate is the most abundant nitrogen-containing nutrient available to phytoplankton.

 Surface Phosphate =  Phosphate concentration at the surface ocean above the sediment trap (unit = micromoles phosphate per kilogram seawater).  Phosphate is the most abundant phosphorus-containing nutrient available to phytoplankton.

 Surface Chlorophyll a = Chlorophyll a concentration at the surface ocean above the sediment trap (unit = milligrams of chlorophyll per meter cubed of seawater). Chlorophyll a is the most important photosynthetic pigment found in nearly all plants and phytoplankton.

 Vertically-integrated Chlorophyll a = The sum of all chlorophyll a in a vertical column above the sediment trap (unit = milligrams of chlorophyll per meter squared of seawater).

 Surface primary productivity = bicarbonate uptake by phytoplankton at the surface above the sediment trap (units = milligrams of carbon per meter cubed of seawater per day).

 Vertically-integrated primary productivity = The sum of all primary productivity in a vertical column above the sediment trap (unit = milligrams of carbon per meter squared of seawater per day).

 Mass Flux = total mass of sinking particles that were collected in the sediment trap (units = milligrams per meter squared per day)

 Carbon Flux = organic carbon flux of sinking particles that were collected in the sediment trap (units = milligrams of organic carbon per meter squared per day)

 Nitrogen Flux = total nitrogen in sinking particles that were collected in the sediment trap (units = milligrams of nitrogen per meter squared per day)

 Phosphorus Flux = total phosphorus in sinking particles that were collected in the sediment trap (units = milligrams of phosphorus per meter squared per day)

 Silica Flux = total biogenic silicon in sinking particles that were collected in the sediment trap (units = milligrams of silicon per meter squared per day)

 Particulate Inorganic Carbon Flux = total particulate inorganic carbon sinking particles that were collected in the sediment trap (units = milligrams of inorganic carbon per meter squared per day).  Particulate inorganic carbon is mostly in calcium carbonate contained in the shells and skeletons of organisms like coccolithophores and foraminifera.