The AlgaeWatch On-Line Fluorometer as Used by the Santa Clara Valley Water District in California

The AlgaeWatch On-Line Fluorometer provides a continual indication of the algal biomass in water, thus allowing for the early detection of algal blooms, detection of nuisance species, and a measure of daily and seasonal fluctuations in the algal community. The Santa Clara Valley Water District (SCVWD) has been using the AlgaeWatch system since 2005 and presently owns multiple instruments installed at various reservoirs and treatment plants. Grab samples from the facilities are taken periodically and sent to the in-house laboratory for algal speciation and algal count measurements. The AlgaeWatch used at the Penitencia Water Treatment Plant (PWTP) measures the relative Chlorophyll a content of the pre-treated water which is received mainly from the Sacramento-San Joaquin Delta via the South Bay Aqueduct (SBA). This facility can treat up to 40 million gallons of water per day and measures other water quality parameters such as turbidity and pH at the pre-treatment sampling point.

The Turner Designs AlgaeWatch installed at the pre-treatment sampling point. The AlgaeWatch is typically cleaned and calibrated twice per month.	Water treatment tanks (flocculation basins) at the Santa Clara Valley Water District Penitencia facility.

The PWTP is a conventional water treatment plant with coagulation, flocculation, sedimentation, ozonation, and filtration processes. Pre-treated water is first injected with coagulant chemicals and then mixed with flocculator paddles to turn undesirable particles in the water into bigger denser flocs; which settles away in the sedimentation basins. In the final stage, filters composed of granular activated carbon and sand remove the remaining particles in the 'settled' water. A high chlorophyll a measurement by the AlgaeWatch can be an indication that an algal bloom is occurring along the SBA. As a result, the filters may be taking on an increased load during an algal bloom and have to be washed more often.

Many thanks to Lotina Nishijima and Karla Guevarra and the Santa Clara Valley Water District for their contributions to this article. Information on the Santa Clara Valley Water District can be found at http://www.valleywater.org.

Water Column Characterization Using a C3 Submersible Fluorometer

Introduction
The C3 Submersible Fluorometer's performance was evaluated by Dr. Jason G. Smith from Moss Landing Marine Laboratories, CA. Evaluation consisted of vertical profiling at Monterey Wharf II, which is located within Monterey Bay, CA (Figure 1). The main interest was testing the C3's capacity for characterization of local environments by describing vertical distributions of fluorescent properties and turbidity (side scatter).

Figure 1: Monterey Wharf II sampling station located within Monterey Bay, CA.

C3 Submersible Fluorometer Configuration
The C3 Submersible Fluorometer was configured with 3 sensors (chlorophyll, phycocyanin, and turbidity), a temperature probe, a pressure sensor for measuring depth, and a submersible battery pack used for depth profiling eliminating the need for extended cables. The C3 Submersible Fluorometer is rated for a depth of 600meters and can operate at temperatures from -2 to 50 degrees Celsius. It is able to store 480,000 data points and has a maximum sampling rate of 1 second.

Monterey Wharf II Profiling
Profiles were made in September on the 4th, 11th, 18th, and 25th in 2008. The last profile was taken on December 18th, 2008, when the water conditions were observed as being as close to blue as possible for the coastal environment. Each profile was taken between 9:30 and 10:30 am (PST), by hand, while trying to control the drop and raise rates to a few inches per second. Fixed 5 second holds were made to characterize layers at 0.25 - 0.5 meter depth intervals. Average maximum depth for this location is 8 meters and temperatures ranged from about 13 - 17 degrees Celsius in September to 12 degrees Celsius in December.

Profiling Data
The two physical water parameters measured during profiling were turbidity, recorded as NTU, and Temperature. Relative Fluorescence Units (RFU) were recorded for Chlorophyll (Chl) and Phycocyanin (PC). All data were binned per 0.5 meter intervals, averaged, and plotted vs. depth.

Turbidity, which is a measure of light scatter, primarily from suspended solids, ranged from 6-15 NTU for water column depths <7 meters indicating a relatively uniform distribution of suspended solids through most of the water column. From 7 - 8 meters depth, turbidity values ranged from 12 - 90 NTU. The largest turbidity concentrations were measured near the bottom during ebb tides and may have been due to soft sediment disruption during flood tides.

Temperature data provided information on water column stratification and changing thermoclines. Thermoclines are an indication of a stratified water column (i.e. layered water masses). Changes in temperature during profiling are used to identify thermoclines which may help researchers determine mixing rates between layers, look at settling rates, provide information related to localization of biological activity, etc. The C3 Submersible Fluorometer recorded two sharp thermoclines for the month of September, the first at 2 meters on 9/4/08 and the other at 5 meters on 9/25/08. As the month progresses there is an observed breakdown and gradual return of a thermocline at 5 meters. The C3's highly sensitive temperature probe was useful in tracking temperature changes (thermoclines) through the water column, providing evidence for the possible movement of water masses and tidal influence for this location.

Figure 2: Temperature profiles taken at Monterey Wharf II.

Relative Fluorescence Measurements for Chl and PC proved useful in tracking bloom activity and determining algal groups. PC:Chl ratios were calculated from fluorescence responses to determine if PC-containing algae were present within the algal community. Lab analysis indicated the presence of the dinoflagellate (Akashiwo sanguinae) and diatoms as dominant groups in the population.

The largest PC:Chl ratios coincided with a small dinoflagellate (A. sanguinae) bloom localized at the 2 meter thermocline on 9/4/08. This might suggest the presence of some PC-containing algae, such as cryptophytes, comingling with dinoflagellates. As the thermocline was disrupted the following week, the Chl signal from 0 - 5 meters increased. Diatoms were the dominant group during this profile and there was a noted decrease in PC:Chl ratios near the surface. The C3 recorded a very large Chl signal on 9/18/08 corresponding to a dinoflagellate bloom that must have occurred around this date. The lowest PC:Chl ratios were calculated during this bloom event. As the dinoflagellate bloom faded, the PC:Chl ratios remained low. A final profile taken in December showed little fluorescence response from both Chl and PC.

Figure 3: Profiles at MWII for chlorophyll (left) and PC:Chl ratios (right) showing progression and declination of a dinoflagellate (Akashiwo sanguinae) bloom.

Conclusion
The C3 Submersible Fluorometer was used for profiling at MWII during the month of September and December. Data retrieved from C3 profiles showed it's ability to detect changes in algal abundance, track an algal bloom, and characterize the water column. Calculating PC:Chl ratios from C3 recorded fluorescence responses throughout the water column provided information on the distribution of different algal groups within the algal community. The C3's fast sampling rate and robust memory allow users to collect detailed information to help characterize their aquatic system or local environment. Turner Designs thanks Dr. Jason G. Smith for taking the time to rigorously test the C3 Submersible Fluorometer and collect these data profiles.

Question:
Should I be using plastic or glass cuvettes for my application?

Answer:
The first thought that might come to mind is, "the more expensive the material, the better the results". For certain applications that might be correct but that's not always the case. You probably wouldn't believe me if I told you plastic cuvettes, in some applications, are as good as quartz. Well…take a look at the following plot:

The r-squared value of a regression through these points is 0.99998. These are turbidity data measured with the Trilogy using a single plastic 10x10mm square plastic cuvette. The calculated Minimum Detection Limit (MDL) is <0.05 NTU. The purpose of this test was to show that a $0.74 10x10mm plastic cuvette works just as well as a $160.00 10x10mm glass cuvette for measuring turbidity using the Trilogy.

My purpose in mentioning this isn't to get everyone to start using plastic cuvettes exclusively. There are applications that require the use of glass over plastic such as extracted chlorophyll measurements that deal with solvents which will degrade plastic and cause errors in measurement. Also, measuring refined oils in water requires quartz glass because it is able to pass deep UV wavelengths better than standard glass or plastic.

With application requirements aside, researchers have the ability to greatly increase the accuracy of measurements by eliminating large sources of error, such as using multiple cuvettes or test tubes and positioning the sample holder. If these errors are eliminated, then any material chosen for sample measurement can provide you with stable and accurate readings.

The table below includes optical specifications of different materials supplied by Turner Designs for use with sample measurement. Typical Optical Transmission % for Polystyrene 10x10mm square plastic cuvettes (P/N: 7000-957), Methacrylate 10x10mm square plastic cuvettes (P/N: 7000-959), and 12x75mm round bottom Borosilicate Glass test tubes (P/N: 10-029A).

SCUFA Trade-in Program

SCUFA owners can now trade in their instruments for a credit toward the purchase of a new C3 Submersible Fluorometer. The C3 was developed with input from many of our SCUFA users. It incorporates one, two, or three optical sensors ranging from the ultraviolet to the infrared spectrum. Each C3 comes with a factory-installed temperature sensor and has a depth rating of 600 meters. Optional mechanical wiper and pressure sensor are also available. Large internal memory and all-plastic housing make the C3 ideal for extended deployments.

Per new shipping regulations, we will no longer be able to ship SCUFA lithium batteries making this an ideal time to trade in your SCUFA. To take advantage of this program please complete the online quote request form and indicate the serial number of the instrument you wish to trade in.

TD-700 Trade-In Program

TD-700 owners can now trade in their instruments for a credit toward the purchase of a new Trilogy Laboratory Fluorometer. The Trilogy is a compact, multifunctional laboratory instrument that can be used for making fluorescence, absorbance and turbidity measurements using the appropriate snap-in module. A color touch screen with simple menus makes for an intuitive user interface. The Trilogy offers the stability and reliability of a solid-state instrument. It enables absorbance and turbidity measurements, features that were not previously available on the TD-700. We've also added applications such as Optical Brighteners, Phosphate, Nitrate and Silicate.

To take advantage of this program please complete the online quote request form and indicate the serial number of the instrument you wish to trade in.

Our international distributors have been authorized to offer the trade-in programs in their respective countries.

C3/C6 Firmware and Software Update

On July 1, 2009, Turner Designs released software and firmware version 2.02 for the C3 Submersible Fluorometer and C6 Multi-Sensor Platform. If your instrument's firmware and/or C-soft software are older than version 2.02, we recommend upgrading with the latest versions to maximize instrument performance and ensure that the latest functions are available.

Firmware and software upgrades and instructions on how to upgrade your instrument(s) can be found at the following website: http://www.turnerdesigns.com/t2/sw/main.html

If you require technical assistance when upgrading instruments, firmware and/or software, please contact Turner Designs' technical support line at 408-212-4063.

Turbidity Standards Now Available for C3, Cyclops-7, and Trilogy

AMCO/GFS Chemicals tested and approved turbidity standards for use with the C3, Cyclops-7, Trilogy, and C6 Multi-Sensor Platform using C-7s. Standards can be purchased directly from GFS Chemicals utilizing the information below.

Via Phone:
877-534-0795 (U.S. and Canada)
740-881-5501 (International)

Via Email:
Sales: sales@gfschemicals.com
International Sales: pat@gfschemicals.com

Part Number 8507 - 100 NTU Standard for Turner Designs C series
Part Number 8506 - 10 NTU Standard for Turner Designs C series

Part Number 8503 - 100 NTU Standard for Turner Designs Trilogy
Part Number 8502 - 10 NTU Standard for Turner Designs Trilogy

New Cables for PhytoFlash, Cyclops, C6 and C3

Interface cables, in various lengths, are now available as standard cables for the PhytoFlash, Cyclops-7, C6 and C3 Submersible Fluorometers. To request a quote please visit the respective product page on our website.

Don't forget to check out our Knowledge Database. It is a robust search engine if you have technical questions about Turner Designs' products or applications.

Your feedback and input are not only welcome but also essential for us to continually improve our KDB. Please feel free to use the Add case link at the bottom of the main screen to submit ideas for future articles or suggest inclusion of information you feel would be of interest. Also the Feedback link provides a means to contact the technical support team on any question you have regarding Turner Designs products or services.