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Principal Investigators:
Joe Salisbury (PI, UNH)
Penny Vhalos (PI, UCONN)
Meg Graustein (UCONN)
Jennifer St.Louis (UNH)
Amanda Plagge (UNH) |
Official Cruise Website
Joe Salisbury, Ph.D student Amanda Plagge and MS student
Jennifer St. Louis recently returned to UNH after participation in the Gulf
of Mexico and East Coast Carbon Cruise. The cruise started in Galveston, TX
on July 10, ended in Boston on August 4, and was the first comprehensive,
synoptic survey of inorganic carbon, nutrients and other biogeochemical
parameters for these coastal waters These efforts were implemented in
support of the North American Carbon Program (NACP) and was supported by
the NOAA/OAR and the NOAA GCC (Global Carbon Cycle) programs. The major
objective is the determination of air-sea carbon dioxide fluxes in North
American coastal regions. The NOAA Atlantic Oceanographic and Meteorological
Laboratory (AOML) is the lead institution for the cruise. UNH was one of
nine U.S. universities participating in this effort.
The UNH-UCONN team had several science-research objectives.
First we sought to measure surface distributions of dissolved organic
carbon (DOC) and its colored fraction (CDOC) to characterize how land
fluxes may be influencing the distribution of these constituents.
Second, we sought to determine if the surface coastal ocean could
be organized into optical domains that would aid in the estimation
of inorganic carbonate parameters (e.g. pCO2) from satellite platforms.
Our third objective was to collect a comprehensive spatial dataset of
carbonate parameters and inorganic ions for Jen’s Thesis. Her work
seeks to understand the contribution of pelagic calcification to overall
coastal ocean productivity.
Discrete water samples were also collected for analysis of
dissolved organic and inorganic carbon, total alkalinity and
pH, nutrients, fluorometric chlorophyll, HPLC chlorophyll, CDOM
absorption, and caffeine. The suite of measurements will help
us to connect results from our ongoing (2004-present) Western
Gulf of Maine sampling efforts to the larger Gulf and to address
several key issues related to coastal margin carbon dynamics.
UNH-UCONN Measurements:
Underway sampling
An integrated suite of underway-surface parameters was
measured using the ship’s uncontaminated seawater supply.
Approximately 6 liters per minute were diverted to flow sequentially
through a 'bio-optics' sensor suite, consisting of an Aanderra
Thermosalinograph, an Aanderra dissolved oxygen sensor, a Satlantic
ISUS Nitrate sensor and WetLabs ‘Eco-triplet” product consisting
of: fluorescence of colored organic; stimulated chlorophyll
fluorescence and particle scattering at 660nm. The flow data were
monitored and most sensors provided a reasonable range of data.
Sensors were “blanked” periodically with DI water. Corrections for
sensor drift will be applied at UNH. Periods when sensors apparently
failed or gave suspicious data were logged and the logs will be used
to cull the data.
Discrete Samples:
Dissolved Organic Carbon
DOC samples were collected using two slightly different sampling
protocols for investigators (Joe Salisbury (UNH) and Penny Vlahos
(UCONN)). Approximately 250 samples were collected for the UNH lab
and 150 samples for the UCONN. Samples were taken at the surface,10m,
below the thermocline and at the bottom. Nitrile gloves were worn and
either silicon tubing was used to draw samples, or samples were drawn
directly from the Niskin nipple into triple rinsed polycarbonate or
glass bottles. Samples for UCONN were filtered using a nominal 0.7
µm pore size glass fibre filter (GFF) into acid washed 60 ml glass
bottles with Teflon caps. UNH samples were filtered with a peristaltic
pump with silica tubing through a Whatman 0.2 µm Polycap AS filter
at low pressure. All UNH samples were frozen immediately after
collection. UCONN samples were fixed with phosphoric acid and
refrigerated in the ship’s cooler. Analysis will occur at the
respective labs (below). For analysis the samples are thawed and
acidified (UNH), then sparged with oxygen to remove inorganic carbon.
The organic carbon is combusted and converted to carbon dioxide,
which is measured by a non-dispersive infrared detector.
UNH samples will be analyzed either by the Wm. MacDowell Lab at
UNH or the Craig Carlson Lab, University of California Santa Barbara,
UCSB. The UCONN samples will be run at Vlahos Lab.
Colored Dissolved Organic Matter (CDOM)
Approximately 250 CDOM samples were collected. They were filtered
using the Whatman 0.2 µm Polycap AS (same filter and procedure as the
DOC samples above) into a 125 ml amber glass bottle and refrigerated
immediately. Three depths were typically sampled; surface, below the
mixed layer and (less often) within the mixed layer. Analysis will be
completed the University of Georgia by Heather Reader (Bill Miller’s Lab)
, using a dual beam spectrophotometer.
Methane
Air samples were drawn from the Texas A&M equilibrator (under
light pressure) via a needle, into clean, evacuated and sealed 100ml
glass bottles. Approximately 300 surface samples were taken along the
cruise track. Methane will be analyzed at Dr. Ruth Varner’s Lab (UNH)
using a Gas Chromatograph.
Ca++, Sr++, Mg++
Samples for Calcium and Strontium and Magnesium analysis were taken
at the surface at all stations, at 10m at approximately 1/2 the stations,
and periodically from the underway water. We sampled with Nitrile gloves
directly into 300ml triple DI-rinsed, then triple sample-rinsed polyethylene
bottles. The bottles were stored in the ship’s cooler shortly after
sampling. At UNH the samples will be filtered with Whatman GFF filters
(which are retained for further analysis) and the filtrate analyzed either
by Atomic Absorption or Induced Coupled Plasma analysis by Jennifer
St. Louis, in Karen VonDamm’s “Hot-water” Lab at UNH. Filters will
be desiccated then placed in clean, combusted 50ml glass bottles filled
with 1M HCl. The filtrate will be diluted with DI water and further
analyzed to determine the concentration of particulate Ca++, Sr++
and Mg++.
DIC
Periodic underway samples were taken for dissolved inorganic carbon.
Approximately 100 samples were collected. We typically did not sample on
stations where the AOML group provided coverage. The purpose of these
sampling efforts were to collect underway surface data in interesting
low-salinity or high chlorophyll regions not captured on the transect
stations. Duplicate samples were drawn from the underway outflow into
20ml Teflon-capped glass bottles, poisoned with 0.1l saturated HgCl2
and refrigerated. Samples will be analyzed at J. Salisbury’s Lab (UNH)
using an Apollo Scientific DIC analyzer based on Li-COR IR detector
technology.
13DIC
Samples were taken by Meg Graustein for 13DIC at the surface,
10m below the thermocline and at the bottom at odd-numbered stations.
Samples were taken from the Niskin using a silicon tube into triple
sample-rinsed glass bottles. Samples were then stored in the ship’s
cooler. Samples will be analyzed at the Vhalos Lab (UCONN) using a
mass spectrometer.
POC
Meg Graustein of UCONN took particulate organic carbon samples
(surface, 10m, below the thermocline and bottom) at every other station.
Water was sampled via silicon tubing into triple-rinsed glass bottles.
Between 80 and 200ml were filtered through pre-combusted Whatman GFF
0.45nm filters. The filters were taken off of the filtering apparatus,
folded into quarters, wrapped in aluminum foils and frozen. The samples
will be analyzed post-cruise at the Vhalos Lab (UCONN).
Large Volume Air sampling:
We collected air samples during steam time from one transect to another
to map out atmospheric concentrations of Currently Used Pesticides and
Perfluorinated organic compounds. A large volume air sampler was fitted
with a pre-combusted 0.45 nominal GFF for particulates and a poly-urethane
foam plug impregnated with C-18. During these sampling periods we collected
4 L of surface water from the in-line pumping system to extract for the
same compounds in near surface waters and determine potential fluxes.
