The lower Neuse River estuary is a wind driven, highly productive system suffering from significant perturbation. Algal "blooms", suppressed dissolved oxygen, anoxia and consequent fish kills have plagued this reach of the Neuse for many years.
North Carolina State University (NCSU) Center for Applied Aquatic Ecology (CAAE) researchers Dr. Robert Reed and David Toms, under the supervision of Dr. Howard Glasgow, have developed a real time remote monitoring (RTRM) program in the lower Neuse River estuary, that includes a network of autonomous and realtime data acquisition stations with surface to bottom sensor profiling. This program is collecting the data necessary to characterize physicochemical and biological response of the Neuse River in the presence of natural and anthropogenic phenomena.
Sensor fouling and consequent drift and failure have been the single most significant obstacles to the operation of this program. In the past, the NCSU team was forced to visit each deployment station and clean, recondition and recalibrate each of the Hydrolab Series 4 sondes as often as every four days (Figure 1). This high degree of maintenance caused Glasgow and team to search for alternatives in mulitparameter technology and brought them to YSI and the 6600 EDS (Extended Deployment System).
In order to evaluate the 6600 EDS, the NCSU team collocated an EDS and Hydrolab Series 4 sonde at one of their deployment stations. The results (figures 1, 2, 3) were impressive. The 6600 EDS remained accurate and reliable throughout the deployment without requiring cleaning or recalibration. The Hydrolab system required frequent cleaning and recalibration to remain within reasonable agreement with reference measurements which were made with another Hydrolab.
Dr. Reed reported that the 6600 EDS will save their program valuable time and money that can be spent on expanding the program and working toward the restoration and protection and of the water quality of the Neuse River http://waterquality.ncsu.edu.
Figure 1. Data document YSI 6600 EDS DO system accuracy and stability during continuous deployment in high fouling conditions. Note frequency of Hydrolab recalibration.
Figure 2. Data depict YSI 6600 EDS pH system accuracy and stability during continuous deployment in high fouling conditions. Note frequency of Hydrolab recalibration.
Figure 3. Data depict stability and accuracy of YSI turbidity system. YSI turbidity data were proven to be more representative of actual conditions.
In 1991 YSI, Inc. made the first significant advance toward providing accurate DO measurements in the presence of fouling with the development of the Rapid Pulse™ dissolved oxygen system. Rapid Pulse DO continues to outperform thick-membrane or stirring- dependant technology in any environment. In the mid-nineties, YSI pioneered the employment of wiped sensor technology in multiparameter sondes and introduced their now widely successful wiped chlorophyll and turbidity sensors. Carrying wiped technology to the next level, YSI has developed what is arguably the single most important advancement in deployable sonde technology since the beginning of sonde deployment: the 6600 EDS (Extended Deployment System). The 6600 EDS, with Clean Sweep™ technology, prevents fouling of the Rapid Pulse™ DO sensor as well as the pH sensor. Integral wipers continue to facilitate unprecedented performance from YSI’s chlorophyll and turbidity sensors.
PERFORMANCE SPECIFICATIONS
|
Dissolved Oxygen
% Saturation
|
Range
|
0-500%
|
|
Resolution
|
0.1%
|
|
Accuracy
|
0-200%: ±2% of reading or 0.2 mg/1,
whichever is greater; 200-500%: ±6%
of reading
|
|
Dissolved Oxygen mg/l
|
Range
|
0-50 mg/l
|
|
Resolution
|
0.01 mg/l
|
|
Accuracy
|
0-20 mg/1: ±2% of reading or 0.2 mg/l, whichever is greater; 20-50 mg/1: ±6% of reading
|
|
Conductivity
|
Range
|
0-100 mS/cm
|
|
Resolution
|
0.001-0.1 mS/cm (range dependent)
|
|
Accuracy
|
±0.5% of reading 0.001 mS/cm
|
|
Salinity
|
Range
|
0-70 ppt
|
|
Resolution
|
0.01 ppt
|
|
Accuracy
|
±1% of reading or 0.1 ppt, whichever
is greater
|
|
Temperature
|
Range
|
-5 to 45 °C
|
|
Resolution
|
0.01°C
|
|
Accuracy
|
±0.15°C
|
|
pH
|
Range
|
0-14 units
|
|
Resolution
|
0.01 unit
|
|
Accuracy
|
±0.2 unit
|
|
ORP
|
Range
|
-999 to 999 mV
|
|
Resolution
|
0.1 mV
|
|
Accuracy
|
±20 mV
|
|
Chlorophyll
|
Range
|
0-400 ug/l
|
|
Resolution
|
0.1 ug/l Chl; 0.1% FS
|
|
Turbidity
|
Range
|
0-1,000 NTU
|
|
Resolution
|
0.1 NTU
|
|
Accuracy
|
±5% of reading or 2 NTU, whichever
is greater
|
|
Depth, Shallow
Non-vented
|
Range
|
0-30 ft (0-9m)
|
|
Resolution
|
0.001 ft (0.001m)
|
|
Accuracy
|
±0.06ft (±0.02m)
|
|
Depth, Middle
Non-vented
|
Range
|
0-200 ft (0-61m)
|
|
Resolution
|
0.001 ft (0.001m)
|
|
Accuracy
|
±0.4ft (±0.12m)
|
|
Vented Level
|
Range
|
0-30 ft (0-9m)
|
|
Resolution
|
0.001 ft (0.001m)
|
|
Accuracy
|
0-10 ft (0-3m): ±0.01ft (0.003m)
|
|
10-30ft (3-9m): ±0.06ft (0.01m)
|
If you would like more information about the 6600EDS, please visit the YSI website at www.ysi.com, or call YSI Sales at the following locations:
NE Region: Kevin McClurg, 800-363-3269, ext. 225
SE Region: Kyle Waits, 866-216-2662
Central Region: Rick Fielder, 800-765-4974, ext. 363
Western Region: David Lee, 916-421-5199