NOAA - Great Lakes Environmental Research Laboratory
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Site: e78M-Central Basin
Latitude: 42.11667
Longitude: -81.25000
Total Depth (m): 23.0
CONTACT: Mark A. Teece mteece@esf.edu
Data Collection: Sarah FitzPatrick
General Date, Depth, and Temperature Info
| Temperature (oC) | Depth (m) | OP # 1 | OP # 2 | ||||||
| Date | JDay | Epi | Meta | Hypo | Epi | Meta | Hypo | ||
| 14 May 05 | 134 | 7.8 | 7.7 | 7.6 | 2.0 | 12.0 | 21.2 | LGF2005-134.22 | |
| 9 Jun 05 | 160 | 21.2 | 15.2 | 9.6 | 1.0 | 8.5 | 15.5 | LGF2005-160.51 | LGF2005-160.52 |
| 18 Jul 05 | 199 | 25.2 | 19.0 | 10.5 | 1.0 | 15.7 | 20.7 | LGF2005-199.34 | LGF2005-199.35 |
| 10 Aug 05 | 222 | 26.1 | 14.3 | 12.9 | 1.0 | 17.5 | 21.0 | LGF2005-222.46 | LGF2005-222.47 |
| 9 Sep 05 | 252 | 22.9 | 20.1 | 13.7 | 1.0 | 21.0 | 22.5 | LGF2005-252.034 | LGF2005-252.035 |
Water samples were collected from a rosette aboard the R/V Lake Guardian from site e78 on the dates listed. OP#1 refers to the initial rosette cast in which samples were taken from the metalimnion and hypolimnion (with the exception of May which also included the epilimnion). OP#2 refers to the water sample collected at 1 m from the rear of the boat using a submergible pump (June-September). All temperature and depth data was collected from a CTD cast.
Seston was collected on a 47mm GF/F filter aboard the ship, frozen, and then freeze dried after returning to the lab. Fatty acid analysis was performed on seston filters from each month and each depth at this station.
The standards used in these analyses were a C19 acid (nonadecanoic acid-MW 298.5 g/mol) and a C17 alcohol (1-heptadecanol-MW 256.471 g/mol).
The original standard made was:
20mg C19 acid / 50 mL iso octane = 0.4 g / L
20mg C17 ol / 50 mL iso octane = 0.4 g / L
This was diluted to 25 mL using 1.5 mL of original standard
(20 mg / 50 mL) * 1.5 mL = 0.6 mg / 25 mL = 0.024 mg / mL
This is called Sarah's Standard
This is the same as 0.024 ug / uL and 100 uL was used in each sample so there is a total of 2.4 ug of C19 and C17 standards in each sample.
The one exception was in June, where the original standard was used and 200uL was added to each sample giving a total of 80 ug of C19 and C17 in each sample.
The general GC conditions included:
GC Make Shimadzu GC-17A
Column HP-5 (crosslinked 5% PH ME Siloxane) 30m x 0.25mm x 0.25mm
Injector Temp 280 oC
Detector hydrogen flame ionization
Detector Temp 300 oC
Temperature Setup 60 oC for 1 minute
***increased to 141 oC at 15 oC min-1
***increased to 300 oC at 5 oC min-1
***remained here for 25 mins
Column Flow 0.52 mL/min He
A GCMS was also used:
GC Make Shimadzu GCMS-QP5050
Column XTI-5 (30m x 0.25mm x 0.25mm )
Spectra Recorded 50-550amu
Injector Temp 280 oC
Detector Temp 280 oC
Temperature Setup 60 oC for 1 minute
***increased to 140 oC at 15 oC min-1
***increased to 300 oC at 4 oC min-1
***remained here for 30 mins
Column Flow 1.2 mL/min He
Stable carbon and nitrogen isotopes were measured on GF/F filters for seston
Instrument Costech Elemental Analyzer 4010 coupled to a ThermoFinnigan Delta XL Plus isotope ratio mass spectrometer
via a ThermoFinnigan Conflo III interface Calibrated relative to NIST and NBS standards
Mark Teece
SUNY-ESF
(315)470-4736
