This Small Business Innovation Research (SBIR) Phase I project will investigate the feasibility of an accurate low cost in-situ solid-state multi-spectral absorption meter for measurement of water properties. Current commercially available instruments are limited in their accuracy in real world conditions due to their design and are also expensive due to the use of costly components such as lamps, filter wheels, spectrometers, etc. This project will explore the use of a novel patented construction method that in combination with LEDs, optics, and photodiodes gives scientists an accurate and low cost research tool to measure absorption in-situ over a variety of wavelengths. The instrument will be insensitive to interfering parameters (e.g. scattering) and easy to maintain in the field. If successful this new method of measure water properties will help communities determine the health of natural water resources. Measuring the absorbance of water is a fundamental measurement for aquatic researchers. Light penetrating water is diminished almost exponentially with depth with an accompanying change in the energy spectrum. These changes affect phytoplankton life directly, so an understanding of the absorption properties for bodies of water is significant for determining the ability to support the growth of phytoplankton. Multi-spectral absorption can also be used to determine the constituents of water, distinguishing between water, dissolved yellow substances, phytoplankton, etc. Most measurements of absorption have been done on samples using a laboratory instrument, but there is an ongoing need to measure absorbance in- situ which allows researchers to gather much more data efficiently. A more accurate in-situ absorption meter dramatically improves the quality of the data that scientists can generate and reduces the amount of time they spend correcting for interfering parameters
