Overview

The central theme of the center’s Aquatic application area continues to be the creation and application of a new genre of wireless sensing system that will generate and test novel hypotheses about the processes that control the distribution, growth and demise of aquatic microbial populations.  The long-term goal of this research group is to model and predict the dynamics of these populations. A fundamental requirement is to correlate environmental driving forces with microorganismal abundances at spatial and temporal scales relevant to the microorganisms.  In turn, this requirement calls for in situ sensing systems that can rapidly respond to and characterize ephemeral or emerging biological events.

NAMOS. In the center’s initial years, we began by examining network designs and components in a laboratory testbed.  In 2005 and 2006, we constructed and deployed a full-scale distributed sensing system in Lake Fulmor on the James Reserve.  We subsequently designed and constructed a unique ‘hybrid’ system, NAMOS, which comprises a wireless buoy sensing system and a robotic surface vehicle capable of sensing and sampling. This system represents a conscious effort to obtain both high-resolution temporal information on pertinent environmental parameters (provided by the network of static buoys) and high-resolution spatial data from specific locales during periods of interest (using the capabilities of the robotic boat).

Our systems can generate contextual information on a variety of physical, chemical and biological features of a water body and intensively observe particular locales during interesting transient events. This is only possible because we use information streaming from the buoys to guide the boat.  This distributed system has been deployed multiple times in Lake Fulmor (James Reserve) to study plankton dynamics.  The development of NAMOS and its successful use in Lake Fulmor has resulted in a template for the design and construction of sensing systems that can be used in other settings.  Our immediate goal is the adaptation of NAMOS to two coastal marine ecosystems.

Coastal Deployments. The first is King Harbor in Redondo Beach, California.  This coastal embayment suffered microalgal blooms and consequent fish kills in 2005.  Algal blooms reoccurred in 2006 without fish kills.  We will deploy a network of stationary sensors in the harbor during spring-summer of 2007 that will characterize the environmental factors leading to microalgal blooms and fish kills. (City official have speculated that low oxygen concentration resulting from high algal biomass causes the fish kills.)  Because microalgal blooms are currently unpredictable, we will monitor data streaming from sensors to identify impending blooms, at which time we will conduct an array of experimental analyses and mobilize the robotic sensor boat.

This work has provides important theoretical insights into both the design and implementation of environmental sensing systems and the environmental factors leading to harmful algal blooms.  In addition, the project has practical importance because it will provide government officials in City of Redondo Beach with the information they need to make an informed decision regarding remediation and prevention of future events.  A major unanswered question regarding recent increases of HABs and other contamination events in this region is how human activities on land affect the occurrence and severity of these events.  Finally, we feel that our collaboration with the City of Redondo Beach is an excellent template for how CENS can assist other coastal municipalities in using distributed sensing systems to address issues surrounding coastal water quality.

A second, and larger-scale implementation of a distributed sensing system in the coastal ocean is being conducted in conjunction with a NOAA-funded (Monitoring and Event Response for Harmful Algal Blooms) program entitled Rapid Analysis of Pseudo-nitzschia & Domoic Acid, Locating Events in near-Real Time.  Here, we use CENS hardware, software, and overall approaches in coastal waters near LA Harbor to study the environmental factors leading to toxic algal blooms caused by phytoplankton species that produce the powerful neurotoxin domoic acid.  This project brings together CENS- and non-CENS investigators to develop and deploy a network of coastal sensor buoys.  The project will employ an autonomous submarine (a Webb glider) whose movements and activities will be controlled by information gathered by the static sensor buoys, in a manner similar to the present control of the robotic boat in our NAMOS project.