IDBR: Development of a device to improve accuracy and reduce variability of in situ fluorometric measurements in aquatic environments

University Of Wisconsin-Milwaukee, Milwaukee WI

Investigators

Abstract

An award has been made to the University of Wisconsin-Milwaukee to develop a new device that improves automated monitoring of algal pigments in aquatic environments. The ability to monitor algal pigments such as chlorophyll and phycocyanin in lakes, rivers, and oceans is central to our understanding of aquatic ecosystems and algal ecology. Autonomous in situ fluorometric sensors allow these pigments to be measured at highly resolved timescales (minutes to hours) on a continuous basis. These sensors have advanced our understanding of processes that occur at subdaily timescales and on day/night cycles. Currently the interpretation of this sensor data is complicated by at least two major confounding variables. Fluorescent yield per unit of pigment varies by orders of magnitude due to algal light history since light exposed cells produce a lower fluorescent yield per pigment molecule. In addition, extreme variability in sensor signals (i.e. from detection limits to sensor saturation)occurs due to the heterogeneous distribution of algal cells in colonies or particles. No technology currently available addresses these issues. A device will be designed, built, and tested that significantly reduces these confounding variables. The "Chamber for Pigment Incubation and Grinding," or CPIG autonomously samples an aliquot of water, holds it in the dark for a predetermined period of time allowing for dark recovery of light exposed algal pigments and homogenizes the sample before taking fluorescent measurements using commercially available fluorometric sensors. The device accepts a variety of in situ fluorometers, is completely programmable via USB input and can interface with typical data logger/modem setups used at continuous monitoring stations globally. It is shoeboxed sized, small enough for installation on data buoys or at fixed monitoring stations and has low power requirements. In situ fluorometers are used by thousands of scientists and resource managers around the world engaged in water quality monitoring. They have the potential to reduce time-­consuming manual water sampling and costly laboratory analyses of algal pigments. The CPIG will significantly reduce two of the largest confounding variables affecting in situ fluorometric measurements making them more widely applicable at thousands of water quality monitoring sites across the globe. The project advances science education by supporting a graduate dissertation research project and engages undergraduate research fellows from underrepresented groups, including incoming freshmen and McNair Scholars. Data from the device will be deployed at monitoring stations in the U.S. and internationally, providing monitoring data for a variety of stakeholders. Furthermore, the device will be introduced to the Global Lakes Ecological Observatory (GLEON) network, a grass roots international organization composed of hundreds of scientists and students using and managing in situ sensors deployed in lakes around the world. All data produced by the CPIG testing will be immediately available for free via GLEON online databases. This project crosses disciplines as it engages undergraduate students enrolled in a marketing course within the UWM School of Business. These students will design a marketing plan for the CPIG in order to advertise, and disseminate the device to the larger scientific community while simultaneously learning about challenges in marketing scientific instruments. Funded by the Instrument Development for Biological Research (IDBR) program in the Division of Biological Infrastructure.