|Lomas, Michael W.||Bermuda Institute of Ocean Sciences (BIOS)||Principal Investigator, Contact|
|Bates, Nicholas||Bermuda Institute of Ocean Sciences (BIOS)||Co-Principal Investigator|
|Knap, Anthony||Bermuda Institute of Ocean Sciences (BIOS)||Co-Principal Investigator|
|Lipschultz, Fredric||National Aeronautics and Space Administration (NASA) HQ (NASA HQ)||Co-Principal Investigator|
|Nelson, David M.||Institut Universitaire Européen de la Mer (IUEM)||Co-Principal Investigator|
|Gegg, Stephen R.||Woods Hole Oceanographic Institution (WHOI)||BCO-DMO Data Manager|
New Production - Particle Interceptor Trap (PIT) Flux
Detailed methods for all data collected as part of this study can be found in one of the three
publications arising from this study (references given below). This contains information on
analytical machines and certified standards where applicable.
Sample QA/QC procedures followed those of the Bermuda Atlantic Time-series Study (BATS).
At the point of collection, any leaking niskin bottles were noted on the master cast sheets
and samples were taken from a different niskin fired at the same depth as the leaking bottle.
No data are reported for leaking Niskin bottles. During sample analysis standard curves and/or
certified standards were carefully examined to ensure that they were consistent with expectations
and accurate. Next, data were plotted as depth profiles and compared to a quality control window
for the February/March period at BATS. The QC window consisted of the upper and lower 95% confidence
limits based upon all data collected at BATS during February/March from 1989-2005. If our data
fell well within these bounds it was considered 'acceptable'. For those data that fell near or
outside the QC window, we went back to the original data run to ensure there was no miscalculation
or other error. If nothing was found, then we examined other data from that niskin to see if other
samples are in question. If no obvious error or problem was found, the data were considered OK and
in the range of extremes that this study hoped to observe.
Sample accuracy and precision. Sample accuracy was assessed by using certified standards, for those
measurements where standards are available (dissolved oxygen, nutrients, salinity, dissolved inorganic
and organic carbon). Certified standards were run with each analytical run and compared to long term
control charts for respective analyses. Samples were not run until certified standards were shown to
be accurate for that analytical run. Sample precision was determined by analyzing replicate samples
(not replicate analyses on the same sample) and therefore is higher than analytical precision due to
the inclusion of sampling error. At the concentrations observed during this study, sample precision
was <5% for stock measurements and <10-15% for rate measurements. Some analyses, namely dissolved
oxygen and salinity, were much better and often had a sample precisions <1%. These precision estimates
are consistent with the long term QA/QC seen with the BATS program.
The provided data files are complete matrices and therefore not every sample (columns) will be taken
from every Niskin fired (rows). Data that were either not collected, or were associated with leaking
Niskins, or were found to be in error for other reasons are denoted by "-nd" in the spreadsheets.
Detailed information on phytoplankton analysis.
Lomas, M.W., Roberts, N., Lipschultz, F., Krause, J.W., Nelson, D.M., and Bates, N.R. 2009.
Biogeochemical responses to late-winter storms in the Sargasso Sea. IV. Rapid succession of
major phytoplankton groups.
Deep Sea Research I, 56: 892-909.
Detailed information on all silica cycle measurements.
Krause, J.W., Nelson, D.M., and Lomas, M.W. 2009. Biogeochemical responses to late-winter
storms in the Sargasso Sea. 2009. II. Increased rates of biogenic silica production and export.
Deep Sea Research I, 56: 861-875.
Maiti, K., Benitez-Nelson, C.R., Lomas, M.W., and Krause, J. W. 2009. Biogeochemical responses
to late-winter storms in the Sargasso Sea. IV. Comparison of Export Production by 234Th and
Deep Sea Research I, 56: 875-892.
Detailed information on general biogeochemical measurements.
Lomas, M.W., Lipschultz, F., Nelson, D.M., and Bates, N.R. 2009. Biogeochemical responses
to late-winter storms in the Sargasso Sea. I. Pulses of new and primary production.
Deep Sea Research I, 56: 843-861.
Most of the data given in this dataset are not derived variables and are calculated using reasonably
standard equations as given in the appropriate reference above. The one exception is CTD data.
Raw CTD data were processed using SBE-Data Processing software using configuration and calibration
files provided by the Shipboard Science technician. Sensors were calibrated shortly before each cruise,
however, most sensor data were 'calibrated' using data collected in this project. Manual determinations
of dissolved oxygen, salinity and HPLC Chlorophyll a, once passing the above QA/QC steps, were taken
as correct. CTD sensor data was regressed against the appropriate manual variable. In all cases save 1,
regression statistics were very strong and linear, and represent an offset (y-intercept) and drop in
sensitivity (slope of the regression). CTD data were corrected to manual measurements using the regression
data and it is this corrected data that is given in the associated data files. OCE399-3 had a problem
with the dissolved oxygen sensor that could not be resolved so only manual oxygen data are reported for
Only nutrient analyses were close to analytical method detection limits (MDL). MDLs were estimated as 3x
the standard deviation of the lowest standard used for the analysis and are 1.5nM for nitrate and nitrite
using a standard autoanalyzer with a 1m fiber optic flow cell, ~20nM for phosphate on a standard autoanalyzer,
and <100nM for Si(OH)4 by manual analysis and a 10cm cuvette. Samples below the MDL are reported as calculated
for the reason that they somewhere between the MDL and a true zero; we consider listing them as either to be
incorrect. Carbon productivity rate measurements, particularly at the base of the euphotic or below, on
occasion are negative due to subtraction of the dark incubated sample from the light incubated sample.
This was not considered below the MDL because there is a reasonable explanation for negative values.
These measurements were ~14h deployments and it is possible that at very low light there can be less 14C
in the light bottles due to grazing, than in the dark bottles that are subtracted from the light bottles.
Moreover, light and dark respiration rates are not the same and therefore this correction is not a perfect
correction for inherent respiration by the autotrophs.
- Parameter names modified to conform to BCO-DMO convention
- CruiseId, date, time, lat, lon added from event log
|station||CTD drop number||integer|
|date||date operation occurred (GMT)||YYYYMMDD|
|time||time operation occurred (GMT)||HHMM|
|lon||Longitude position (West is negative)||decimal degrees|
|lat||Latitude position (South is negative)||decimal degrees|
|year||year of cruise||YYYY|
|deployment||PITS spar deployment number||integer|
|depth||depth where particle interceptor trap was suspended||meters|
|POC||particulate organic Carbon||millimoles/meter^2/day|
|PON||particulate organic Nitrogen||millimoles/meter^2/day|
|Dataset-specific Instrument Name|| |
Particle Interceptor Trap
|Generic Instrument Name|| |
Sediment Trap - Particle Interceptor
|Dataset-specific Description|| |
MLML Particle Interceptor Sediment Trap (MLML = Moss Landing Marine Laboratory)
|Generic Instrument Description|| |
A Particle Interceptor Trap is a prototype sediment trap designed in the mid 1990s to segregate 'swimmers' from sinking particulate material sampled from the water column. The prototype trap used 'segregation plates' to deflect and segregate 'swimmers' while a series of funnels collected sinking particles in a chamber (see Dennis A. Hansell and Jan A. Newton. September 1994. Design and Evaluation of a "Swimmer"-Segregating Particle Interceptor Trap, Limnology and Oceanography, Vol. 39, No. 6, pp. 1487-1495).
|Start Date|| |
|End Date|| |
New Production During Winter Convective Mixing Events: A Missing Component of Current Estimates Cruise Summary In 2004 the New Production research group conducted a 30-day research cruise in the Sargasso Sea from February 15th to March 15th. The primary objective of this cruise was to study the biological response to the passage of winter storms. From Julian Day 66.5 to 74, we 'caught' a significant storm event and were indeed able to follow the biological response. Original cruise data are available from the NSF R2R data catalog
|Start Date|| |
|End Date|| |
New Production During Winter Convective Mixing Events: A Missing Component of Current Estimates Original cruise data are available from the NSF R2R data catalog
|Start Date|| |
|End Date|| |
New Production During Winter Convective Mixing Events: A Missing Component of Current Estimates Note the break in the cruise was due to the loss of the CTD. Returned to Bermuda to pick up a spare CTD that had been flown in from WHOI. Original cruise data are available from the NSF R2R data catalog