Seawater Nutrient AnalysisCollaborative Efforts to Improve Environmental Monitoring
Poster Presentation
Presented by J. Woodside
Prepared by T. Smith, T. Smith
Xylem, 777 Graham Road, Suite 101, College Station, TX, 77845, United States
Contact Information: [email protected]; 19796905229
ABSTRACT
Seawater Nutrient Analysis
Seawater nutrients play a vital role in oceanic seafood chain. Quantification of these nutrients forms the foundation for understanding oceanic productivity and their analyses can be used to measure and monitor many oceanic cycles. Soluble inorganic nitrogen, phosphorous, and silicate in seawater are essential for the survival of marine organisms. A moderate amount of nutrients in seawater promotes the growth of biology and microorganisms. Inadequate amounts of nutrients restrict the growth of phytoplankton. Excessive nutrient growth is prone to cause eutrophication and lead to harmful algae blooms (HABs), and even the death of aquatic organisms. Excess nutrients in seawater can be attributed to several sources, but the crux of the nutrients in seawater comes from human activities and sources. Fertilizers run off, animal waste, and wastewater processes are the main sources of excess nutrients in seawater.
The U.S. EPA has endorsed several methods to monitor and measure nutrients in seawater. The nutrients of concern are nitrate, nitrite, ammonium, orthophosphate, and silicate. Each of these nutrients present their own challenges. Nitrogen and phosphorous naturally enter estuarine and seawater when freshwater runoffs pass over geological formations rich in nitrogen and phosphorous , or when into decomposing organic matter and wildlife waste gets flushed into rivers and streams. Silicate is of interest because of its impact on global CO2 concentrations through the combined processes of weathering of silicate minerals and transfer of CO2 from the atmosphere to the lithosphere. Silicate production can be limited by the availability of dissolved silicate. Plankton construct their exoskeletons from silica. Ammonia nitrogen is found in low concentrations in seawater. Higher levels of ammonia in seawater can be directly and indirectly toxic to many marine organisms. Large scale agricultural, animal waste, and industrial run-offs are significantly increasing ammonia concentrations in seawater and estuaries.
Several flow analysis techniques have played an important role in water analysis and monitoring. Several flow-based methods have been developed for the photometric determination of the above-mentioned nutrients. SFA (segmented flow analysis) is one of the flow-based methods that has been proven reliable and consistent over the years. This study will demonstrate the accuracy and consistency of the SFA technique to generate dependable and practical data for seawater monitoring.
