Chlorophyll a class of molecules found in plant cells that convert the energy of sunlight to food in the process known as photosynthesis. Cholinesterase – an enzyme found in animals that regulates nerve impulses. Cholinesterase inhibition is associated with a variety of acute symptoms such as nausea, vomiting, blurred vision, stomach cramps, and rapid heart rate, paralysis, convulsions, and death. Chlorosis – yellowing or blanching of the leaves of plants due to loss of chlorophyll from causes other than lack of light. Chronic exposure – exposures that extend over the average lifetime or for a significant fraction of the lifetime of the species (for a rat, chronic exposure is typically about 2 years). Chronic exposure studies are used to evaluate the carcinogenic potential of chemicals and other long-term health effects. Chronic reference dose (RfD) – an estimate of a lifetime daily exposure level for the human population, including sensitive subpopulations, that is likely to be without an appreciable risk of deleterious effects. Chronic RfDs are specifically developed to be protective for long-term exposure to a compound (7 years to lifetime). Chronic toxicity – the ability of a substance or mixture of substances to cause harmful effects over an extended period, usually upon repeated or continuous exposure sometimes lasting for the entire life of the exposed organism. Clay soil – soil material containing more than 40 percent clay, less than 45 percent sand, and less than 40 percent silt. Clear cut – harvesting all the trees in one area at one time. Code of Federal Regulations (CFR) – document that codifies all rules of the executive departments and agencies of the federal government. It is divided into fifty volumes, known as titles. Title 40 of the CFR (referenced as 40 CFR) lists all environmental regulations, including regulations for U.S. EPA pesticide programs (40CFR Parts 150-189). Coliform – microorganisms found in the intestinal tract of humans and animals. Their presence in water indicates fecal pollution and potentially dangerous bacterial contamination by disease-causing microorganisms. Confidential Business Information (CBI) – information submitted to U.S. EPA by a pesticide registrant to fulfill requirements for pesticide registration that contains trade secrets or commercial or financial information that has been claimed as confidential by its source. U.S. EPA has special procedures for handling such information. Conifer – an order of the Gymnospermae, ...
Chlorophyll a concentration as a direct measure of phytoplankton abundance.
Chlorophyll. Very few studies identified in the literature focus on using CS for measuring or estimating chlorophyll-a in lakes for water quality (2 out of 108 reviewed) and only 2 out of 25 CS projects were identified which aimed to measure chlorophyll-a, both at sub-national scale: Waquoit BayWatchers (WBB) and URI Watershed Watch (URIWW)). URIWW volunteers sample waterbodies, samples are then sent for chlorophyll-a analysis at a certified lab. No information was available on how WBB collect their data, but both CS projects are closely linked to local official monitoring of specific water. The two studies indicate that the process of collecting water samples for chlorophyll-a analysis is something volunteers could seemingly easily undertake. The model of using certified labs should ensure high quality data, highlighting an approach that could be used for cal/val of chlorophyll-a algorithms. There are some developing technologies, which may make more direct data collection of chlorophyll-a data by citizens possible in the near future. Xxxxxxxxxx et al. (2017a) developed the SmartFluo, an extension for smartphones, which enables the attachment of a cuvette for measuring chlorophyll fluorescence using a smartphone camera. This makes in-field measurements possible, eliminates costs for lab analysis and shipping as well as decreases any errors generated by any delay in lab analysis and shipping the samples. More sophisticated (and well financed) CS schemes could incorporate portable sensors, such as the BBE AlgaeTorch, which measures total phytoplankton chlorophyll-a, cyanobacterial chlorophyll-a and turbidity in real time along with GPS coordinates. These are generally easy to use devices, which take little training to use. For example, as part of the Loch Leven long-term monitoring programme, a volunteer from the local fishery uses an algal torch to record data during spring, summer and autumn seasons from a boat at several locations in the lake at least weekly. The volunteer is also provided with a calendar of the dates and times that the ESA Sentinel satellites are passing over, to sample on any cloud-free day. This is a time demanding job for a volunteer, which is only possible because of the well-established relationship between the volunteer and a specialist water quality research group (UKCEH). However, coordination of this sort of volunteer arrangement at several sites, particularly for regions where cal/val data is missing, may be a solution to deliver high qual...
Chlorophyll. There were 68 platforms available in CMEMS measuring in-situ Chlorophyll during the last year in the European Seas, with a distribution by type of platform shown in Table 5. Note there were 50 Profiling Floats measuring in-situ Chlorophyll. See in Figure 7 the geographical distribution of platforms among the different basins.
Chlorophyll. Chlorophyll measurements were used as the main indicator for the algae growth during the experiment. In hindsight it would have been more accurate to compare the chlorophyll values to the algae count and dry weight values from the start. This would provide more comprehensive indications about the actual biomass in the tank. Chlorophyll levels have shown strong correlation with both dry weight and turbidity values. However, the values tend to vary more than the two latter, sometimes resulting in misleading results compared to biomass and turbidity measurements. During the first phases of the experiment, the CTD device was calibrated to a low chlorophyll range between 0-25 µ −1. This resulted in lower than realistic chlorophyll values on 9.-, 10.-, and 19. Apr. When calibrated to the low range, the device provides more accurate data at lower chlorophyll levels, but is unable to measure higher values than the set range. Due to lack of knowledge about the calibration of the chlorophyll sensor, the reason for the stagnated values went unnoticed until after the measurements on 10. Apr. The CTD-device was recalibrated to measure between the range of 0- 75 µ −1, after the measurements were conducted on the 19. Apr., which was the day the device was returned from service. There may be several explanations for the varying chlorophyll values. Xxxx variations of cell chlorophyll content in S. costatum can cause measurements to differ throughout the nychthemeron. Varying light conditions also affect the chlorophyll cell content, as S. Costatum produce more chlorophyll in lower light conditions (Anning et al., 2000) to maintain the photosynthesis. Also a denser culture would cause less light to penetrate the water, leading to a higher chlorophyll content in the algae as the biomass content increases. Difference between bucket and tank values 120,0 100,0 80,0 60,0 40,0 20,0 0,0 16:48:00 04:48:00 16:48:00 04:48:00 16:48:00 04:48:00 Time Tank values Bucket values Chlorophyll µg/l FIGURE 172 THE CHLOROPHYLL VALUES MEASURED IN THE TANK AND IN THE BUCKET THROUGH THE NYCHTHEMERON During the nychthemeron measurement, the bucket measurements provided unrealistic low results. The chlorophyll values measured in the bucket was much lower than the corresponding values in the tank, as shown in figure 42. The tank values are represented with the blue plots, and the bucket values with the orange plots. The reason for the flat tank values at 73 µg l-1, is due to the measuring range of t...
