Ref. No. [UMCES] CBL 2013-020
ACT VS12-03
A summary of the physical and water quality conditions experienced over the duration of
the moored deployment are presented in Table 3. Water temperature ranged from 25.3 to 29.4
°C and salinity varied from 3.9 to 9.9. Chlorophyll and CDOM are quite high at this location
and can contribute significantly to the fluorescent properties of the ambient seawater.
Table 3.
Ancillary physical and water quality conditions for the moored field deployment test conducted
in Winans Cove, Baltimore Harbor, Baltimore, MD.
Site
Temperature
(
o
C)
Salinity
Chlorophyll
(µg/L)
CDOM
A
400
, m
-1
Turbidity
(NTU)
Baltimore
Harbor
Min
25.3
3.9
2.6
1.17
1.3
Max
29.4
9.9
44.8
2.48
6.0
Mean
27.0
8.2
16.6
1.52
3.0
The time series response of the C3-CDOM, -Crude Oil, and -Refined Fuel sensors during
the moored deployment in Baltimore Harbor are shown in figures 18, 19, and 20, respectively.
During the deployment 33 discrete reference samples were collected and analyzed for total
petroleum hydrocarbons (TPH). Only three samples, one on 8/22 and two on 8/24, had any
detectable level of hydrocarbons as analyzed by TestAmerica using GC-FID. The instrument
response of the CDOM unit averaged 739 (± 55) RFU during the field deployment but no clear
response was observed corresponding to the three positive TPH detections in corresponding
reference samples (Fig. 18). The Crude Oil sensor response averaged around 920 (
±
82) RFU
over this same period and again there was no observable increased instrument response for the
three positive TPH reference sampling timepoints (Fig. 19). The Refined Fuel sensor averaged
only 22 (
±
7) RFU (Fig. 20), but did show an 8 RFU change at the highest reference TPH detect
of 35 ppb consistent with the responses observed during the COOGER trials (see Fig 26). All
three sensors exhibited a small but repeated diurnal pattern that appeared to track with
temperature. The pattern is the most obvious in Fig. 20, where the scale has been significantly
reduced and reveals a maximum level of variation. There was no apparent tracking of
instrument response by any of the sensors to concentrations of chlorophyll, CDOM, or turbidity
despite substantial variation in these parameters (Table 3 and Figs. 18-20, panel C).
Representative EEM fluorescent maps for reference samples collected on five different
dates are shown in figure 21-23, with the CDOM, Crude Oil, and Refined Fuel sensor optical
window depicted, respectively. EEM characteristics were fairly consistent over time and
fluorescence intensity maxima were much more closely matched for the CDOM and Crude Oil
configuration relative to the Refined Fuel configuration.
Cross plots of instrument response to concentrations of TPH detected by GC-FID and
predicted EEM
QSE
intensities are shown in figures 24-26. For the CDOM sensor, the average
EEM
QSE
for the reference samples yielding non-detects was 12221 (± 283) cps, compared to
12284 (±210) cps for the three positive TPH samples. For the Crude Oil sensor the average
EEM
QSE
was 27013 (± 678) for the TPH non-detect reference samples and 27194 (± 450) cps for
reported TPH detects, which although higher, was within the environmental range observed
during this deployment. Corresponding instrument responses for the CDOM (745 (± 18) vs 744
(± 17) RFU) and Crude Oil sensors (924 (± 20) vs 921 (± 16) RFU) were little changed from
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