L3_NTU_Chl

50 %
50 %
Information about L3_NTU_Chl
Entertainment

Published on February 16, 2014

Author: jideshkumar007

Source: authorstream.com

Turbidity and Chlorophyll: Turbidity and Chlorophyll Lecture 3 YSI (Yellow Springs Inc): YSI (Yellow Springs Inc) https://www.ysi.com/ysi/Products YSI sensors: YSI sensors HACH - Hydrolab: HACH - Hydrolab http://www.hydrolab.com/sondes.asp Some Hydrolab sensors: Some Hydrolab sensors Turbidity: Turbidity Measure of suspended particles in water – can include inorganic (sediments) as well as organic (bacteria, plankton). High turbidity reduces light transmission (by both absorption and scattering), i.e. larger light attenuation coefficient (K). Can measure with secchi disk (secchi depth, cm) Can measure by weight (total suspended solids (TSS, mg/L) Can measure with turbidimeter = nephelometer (NTU) http://en.wikipedia.org/wiki/Turbidity NTU: NTU Nephelometric Turbidity Units (NTU) http://en.wikipedia.org/wiki/Nephelometer detector mirror A more popular term for this instrument in water quality testing is a turbidimeter . However, there can be differences between models of turbidimeters, depending upon the arrangement ( geometry ) of the source beam and the detector. A nephelometric turbidimeter always monitors light reflected off the particles and not attenuation due to cloudiness. In the United States environmental monitoring the turbidity standard unit is called Nephelometric Turbidity Units ( NTU ) Nephelometer comes from the Greek word for cloud, nephos , Turbidity standards: Turbidity standards Formazine based (carcinogenic) – typically 4000NTU stock diluted. Need to test against NIST standards. Precipitates unless stirred constantly. AMCO beads – non-toxic. Long shelf life. More expensive. Slightly different scattering properties. http://www.amcoclear.com/products/water.standards.php Some NTU numbers: Some NTU numbers DI or RO water (approx 0 NTU) Tapwater (<0.3NTU) Surface waters clear (<5NTU) Surface waters visibly turbid (10-50NTU) Silted waters from erosion (up to 1000NTU) Problems for fish/organisms (>50-100NTU) Protect benthic seagrasses (<5-10NTU) Light Limitation is the Principal Determinant of SAV Distribution Water Quality drives light limitation: Light Limitation is the Principal Determinant of SAV Distribution Water Quality drives light limitation Secchi depth (m) or attenuation coefficient (K d ) in 1/m Light-limitation depends on water quality Light is absorbed (a) and scattered (b) by water+TSS+color+chl a From mathematical models of light absorption and scattering a direct link between water quality and light available to SAV can be calculated. TSS PowerPoint Presentation: U.S. Coastal States Water-Quality Criteria for Turbidity Patrick Biber - Univ. of North Carolina, Chapel Hill Region State Criteria for saltwaters (surface WQ standards) Year Best Numerical Criterion + Exceed 25NTU 1 Exceed 5NTU 2 NE Connecticut not to exceed natural origin, use BMPs (FW <5NTU over backgrnd) 1997 NE Delaware <10NTU above background natural turbidity 1999 +10 -15 5 NE Maine no turbidity criteria 2000 NE Massachussetts free from turbidity that aesthetically objectionable or impair any use 1993 NE New Hampshire <10NTU above background natural turbidity 1999 +10 -15 5 NE Rhode Island <5NTU above background (SA), <10NTU above background (SB, SC) 1997 +5 -20 0 CEN Maryland not exceed 50NTU monthly avg, not exceed 150NTU point msr 1995? 50 25 45 CEN New Jersey <10NTU 30 day avg, <30 NTU point msr 2002 10 -15 5 CEN New York no increase that will cause substantial visible contrast to natural conditions 1999 CEN Virginia no turbidity criteria 1997 SE Florida <29NTU above background natural turbidity 1996 +29 -4 24 SE Georgia free from turbidity that results in a substantial visual contrast due to man-made activity 2000 SE North Carolina not exceed 25NTU, if natural background >25 NTU no increase over background permitted 1996 25 0 20 SE South Carolina not exceed 25NTU provided existing uses maintained 1976? 25 0 20 GOM Alabama <50NTU above background natural turbidity 2002? +50 25 45 GOM Louisiana estuarine lakes, bays, bayous <50NTU 2000 50 25 45 GOM Mississippi <50NTU above background turbidity beyond a 750ft mixing zone at time of discharge 1995 +50 25 45 GOM Texas no substantial and persistent changes from ambient conditions 1997 PAC Alaska not exceed 25NTU, not increased Ksecchi by more than 10% 2003 25 0 20 PAC California Wastewater to oceans = 75NTU 30 day avg, 100NTU 7 day avg, max 225NTU point msr 1990 75 50 70 PAC Oregon <10% cum increase relative to upstrm control location, except in emergency/construction w BMPs 2001 PAC Washington <5NTU above background when <50NTU, <10% above background otherwise (AA, A); <10NTU above background when <50NTU, <20% above background otherwise (B, C) 1997 +5 -20 0 HA Hawaii Estuaries and embayments = geom mean <1.5NTU, 90% of time <3NTU, 98% ot time <5NTU 1992? 1.5 -23.5 -3.5 NAT FEDERAL no turbidity criteria NB: Hawaii only state that has turbidity criteria that appear to be fully protective of seagrasses to depths >1m + Numerical criterion based on background of 0 NTU 1,2 Turbidity levels associated with minimum light requirements for seagrass at 1m depth in 1. North Carolina and 2. Chesapeake Bay Calibration: Calibration Always check expiration dates. Make Formazin solutions fresh EACH time – check against a standard in turbidimeter before use. Always check 0 NTU first (DI water) Always use a standard higher than max value expected (e.g. 10 NTU or 100 NTU) ALWAYS check for AIR BUBBLES – this is the major source of error or bad data. Chlorophyll Fluorescence: Chlorophyll Fluorescence Derived from light NOT used for photosynthesis. A proxy for phytoplankton concentration (= abundance of cells) Affected by amount of photosynthesis happening as well as cell density. Can vary widely over the course of a day FOR THE SAME AMOUNT OF CELLS!!! Photosynthesis: Photosynthesis PowerPoint Presentation: Chloroplast Chlorophyll Excitation: Chlorophyll Excitation Each quantum of light absorbed by a chlorophyll molecule rises an electron from the ground state to an excited state. PowerPoint Presentation: Light reaction – Z scheme http://www.steve.gb.com/science/photosynthesis.html http://www.geosciences.unl.edu/~dbennett/physiology.html Photosynthesis: Photosynthesis 3% Light Energy “Usage”: Light Energy “Usage” Light Rct and Fluorescence: Light Rct and Fluorescence IN VIVO - LIVING CELLS: Not all light is used for photosynthesis, i.e. for electron transport in the light reaction. Depending in species, conditions, physiological state, some or most of light is converted to fluorescence (measurable) or heat (“not” measurable) IN VITRO – chl extracted with acetone: None of the above matters – fluorescence is directly proportional to chl concentration METHODS – chl extraction: METHODS – chl extraction EPA standard method 445 (fluorometric) or ESS150 (spectrophotometer) are for phytoplankton. Grind sample in solvent (90% acetone) in dark and keep cold (chl is easily destroyed!) Allow to extract overnite in fridge (4 0 C) Centrifuge or filter to remove “particles” Read Abs or Flr on machine. [Acidify with HCL – read phaeophytin and used in calculations] [Other solvents include methanol, dimethylformamide (DMF), fluorocarbon ionic surfactant Zonyl FSA, etc.] Turner TD700 fluorometer: Turner TD700 fluorometer Sensitive – use for low concentrations (very faint green color). Best for phytoplankton. Configuring the Turner Designs Model TD-700 Fluorometer for Method 445.0 Your fluorometer should be equipped with the following Turner Designs optical filter kit (or equivalent): Optical Kit: PN: 7000-961 Excitation filter: 10-050R color specification 5-60 Emission filter: 10-051R color specification 2-64 Lamp: 10-045 Daylight White Lamp http://www.turnerdesigns.com/t2/doc/appnotes/998_6000.html Turner TD700 fluorometer: Turner TD700 fluorometer Sensitive – use for low concentrations (very faint green color). Best for phytoplankton. Configuring the Turner Designs Model TD-700 Fluorometer for Method 445.0 Your fluorometer should be equipped with the following Turner Designs optical filter kit (or equivalent): Optical Kit: PN: 7000-961 Excitation filter: 10-050R color specification 5-60 Emission filter: 10-051R color specification 2-64 Lamp: 10-045 Daylight White Lamp http://www.turnerdesigns.com/t2/doc/appnotes/998_6000.html THEREFORE: THEREFORE In water quality monitoring chl fluorescence is a RELATIVE indicator of change in phytoplankton population abundance. IT IS NEVER AN ABSOLUTE MEASURE! The only “absolute” measure is to take a water sample, filter to concentrate, extract with solvent (e.g. 90% acetone), determine sample chl concentration and back-calculate to in-water chl concentration after correcting for volume filtered. Another note: Another note Usually chl samples are frozen after filtering, and run weeks or months later. THIS MAY BE A PROBLEM? A recent study in Long Island showed about a 30% decrease in extracted chl concentration of samples frozen longer than 2 weeks compared to the SAME samples if extracted immediately. NUTRIENT MANAGEMENT STRATEGIES ARE BASED LARGELY ON CHL NUMBERS… Lab: Lab Check turbidity standards. Calibrate NTU+ sensor and read water samples. Optical sensor maintenance. Test chl flr sensor with fluorophore

Add a comment

Related presentations

Related pages

ocean.st.usm.edu

ocean.st.usm.edu
Read more