|SEARCH||THE COURTSHIP OF EVA AND BOB|
Passive Water Samplers and Basic Observation Buoys (BOBs) for Monitoring Water Quality in Long Island Sound
The Science Challenge – Pollutant and Biological Time Series Observations
The necessity to monitor the ocean and Great Lakes for extended periods of time has never been greater. As populations and industry continue to grow in and around coastal watersheds, a range of anthropogenic impacts pose a growing threat to the aquatic environment. Stressors to the environment include climate change, overfishing & harvesting, nutrient loading, hypoxia, introduction of invasive species, pollution, ocean acidification and harmful algal blooms, to name a few. In addition, natural perturbations such as severe storms, tsunamis, sediment erosion, excess runoff and surge can play a significant role in the health of the oceans.
To understand the individual and collective impacts of these myriad factors requires that we measure a wide range of variables at time and space scales that are adequate to measure the natural and human-induced variability. This has been the motivating factor for the development of both the National Science Foundation’s (NSF) sponsored Ocean Observing Initiative (OOI) and the National Oceanic and Atmospheric Administration (NOAA) sponsored Integrated Ocean Observing System (IOOS).
The Technology Solutions
The ability to sample the coastal ocean for contaminants is an ever-increasing challenge for water quality managers. Typical water quality sampling has been accomplished through discrete grab sampling at single or multiple points in the water. These approaches provide a snapshot of water quality in space and time, and measurements are therefore subject to variability in the environment that could impact the concentration of a contaminant at the time of sampling.
Recently, passive sampling technologies have been developed that provide a means to measure contaminant levels over a longer time frame and average the concentration of the contaminant over the period the sampler is deployed. Passive samplers work by providing a substrate that has been impregnated with reference compounds that correspond to contaminants targeted for measurement. When deployed, these samplers equilibrate the contaminants in the environment with the receiving marker over a period of time to provide an averaged concentration of the contaminant. One compound that has been used, identified by Dr. Penny Vlahos at the University of Connecticut as a viable substrate, is Ethylene Vinyl Acetate (EVA).
Basic Ocean Buoys
A Basic Observation Buoy (BOB) is a floating platform with capacity to carry a suite of environmental sensors. A BOB can be moored to the bottom in open water or tied to a dock in coastal waters. Based on concepts developed by Doug Levin, Ph.D., located at NOAA’s IOOS (Integrated Ocean Observing System) Program Office, BOB is an exciting collaborative being developed to link scientists and educators. The project allows teachers and students to become directly involved with longer-term monitoring of the environment based upon a simple technology of their own design and construction. To date, the BOB project has centered around precollege to undergraduate level student-designed, built and deployed buoys that host data collection, storage, and in some cases transmission capabilities.
COSEE-TEK staff reviewed the original BOB design and engineered a new design to effectively support the EVA passive samplers and settling plates. The modified design relied upon more affordable commercial fishing trawl floats to provide the same level of buoyancy and, for the benefit of this project, provided a more compact, cost effective solution for ocean observation. .
Biological Settling Plates
One of the simplest approaches to understand spatial and temporal variability in the development of coastal subsea communities is through the deployment of settling plates that mimic the natural hard substrates that many coastal invertebrates occupy during the adult phase of their life cycle. By instituting both a long-term and short-termdeployment strategy, it is possible to follow the seasonal trend of organismal and community developmentas well as the variability of larvae in the water column for discrete periods throughout the year. The settling plates can range in size and material, simply providing a hard surface (oriented facing down in the water column) upon which marine invertebrates will settle.
Drs. Robert Whitlatch and John Hamilton of the University of Connecticut have been monitoring the dynamics of settlement in Long Island Sound for over a decade using PVC plates that are 10 cm x 10 cm and marked with a 1 cm x 1 cm grid. This allows for rapid assessment of the percentage of the plate that has been covered by the settled organisms.
The Teacher Technology Experience – The Courtship of EVA and BOB
Dr. Penny Vlahos of the University of Connecticut’s Department of Marine Sciences led this Teacher Technology Experience (TTE). The TTE began with an orientation to long-term monitoring, passive samplers and settling plates. Teachers then had the opportunity to construct their own COSEE-TEK BOB that they would deploy during the school year. The TTE also involved recovering the passive samplers and settling plates deployed two weeks earlier. These EVA samplers were installed, along with four long-term and four short-term settling plates on the redesigned COSEE-TEK BOBs. Three BOBs were deployed, one located in the Thames River, one south of Pine Island, and one tied to the dock at UConn Avery Point.
In addition to their BOB, teachers were provided with a cage to hold three passive samplers, 12 settling plates and an Onset “Hobo” long term temperature and light monitoring device. The teachers deployed their BOB with the EVA samplers and settling plates in their local waters following the summer TTE. The EVA’s will be retrieved/redeployed on a monthly interval in the fall, which will be adequate for the EVA sensor to adsorb the contaminants of interest.
To date, two participating teachers have deployed their BOBs and have returned one set of EVA samplers for analysis in Dr. Vlahos’s lab. They also have collected temperature and salinity data at each of the BOB sites. The EVA sensors are being analyzed by a UConn undergraduate student who is also leading the EVA sensor preparation, data collection and mass spectrometer analysis in Dr. Vlahos’ lab.? The teachers will have the opportunity to bring small teams of students from their school to Dr. Vlahos’s lab and be immersed in the technologies, procedures and results of the data analysis.
The location, images and data from the initial three BOBs deployed by COSEE-TEK partner, Project Oceanology, have been plotted using Google Earth and are available on the COSEE-TEK website. As the two schools in Long Island Sound come on line, the location and data from their BOBs will also be plotted using Google Earth to promote the exploration, analysis and comparison of the data in a geospatial context by the teachers and students. The COSEE-TEK website will be an interactive repository for this data, allowing the teachers to download and upload data to a Google Docs server.