Presentation on theme: "Chlorophyll Measurements"— Presentation transcript:
1 Chlorophyll Measurements Melissa CarterScripps Institution of Oceanography
2 Red tide this summerThis summer in La Jolla and most of the Southern California Region we experienced a very dramatic red tide that lasted over a month at this intensity.As you can see from the photo, the bloom is patchy and appears to be the highest near the coastline.To give you some perspective on this photo the pier is ~1000ft / or 300m long.So how does this bloom compare to other years and are how does it compare to waters further offshore?
3 What is chlorophyll? …and why is it important? Ocean productivityPhytoplankton dynamicsHarmful algal bloomsOcean productivity…
4 How do we measure chlorophyll? Satellite imageryIn-situ fluorometryDiscrete samples
5 Chlorophyll Time Series from Scripps Pier, 1983-2000 and 2005 Mean3.00Median1.38Standard Deviation10.32Range218.93Minimum0.02Maximum218.95Count1919Here is the Scripps Pier Chlorophyll time seriesThe x axis is time in years and the y is a log scale of chlorophyll conc.But, before we look into those questions, let me tell you a little bit about the data that we collect for this time series These are twice weekly measurements of surface chlorophyll concentration using a standard chlorophyll extraction technique . Each data point represents an averaged conc. from duplicate samples analyzed with a fluorometer. The other parameters that we measure include: temperature, salinity, nitrate, phosphate, silicate and environmental conditions such as weather, water and any changes in biological conditions. We also collect a whole water sample and net tow in order to determine the species composition of the phytoplankton in our sample.There is a gap in the time series from Oct 2000 until Feb due to a loss in funding for this program, however we have received new funding from SCCOOS….We have collected over 1900 samples with the long-term mean of those sample at 3 mg/m3 with a standard deviation of mg/m3. If you remove the bloom events the standard deviation is 2.05 over a total of 1886 samples and the mean is 2 mg/m3.Over the entire time series, the maximum chlorophyll concentration measured was in March 1995 at mg /m3 in . This summer the maximum chlorophyll concentration was the 2nd highest recorded over the 17 year time series, just at 200 mg/m3.There appears to be a slight increasing trend starting in 1995 and our most current data is consistent with this.McGowan et al., unpubl. data