The workshop focused on the potential of optical instrumentation to determine in situ (1) biomass and (2) rate processes of zooplankton. The workshop concluded that optical instrumentation will be required in conjunction with acoustics to quantify biomass, distribution and composition of zooplankton populations and communities. Optics and acoustics complement each other in studying spatial and temporal distributions of zooplankton; acoustics quantify the size distribution whereas optics are useful for taxonomic identification . This combination significantly enhances the probability of success of U.S. GLOBEC field studies of the interaction of zooplankton populations with their biotic and physical environments. The high spatial and temporal resolution of optical methods, plus continuous observation, make them an ideal tool for quantifying rate processes of juvenile and adult zooplankton, operating on scales from microns to meters. Two- and eventually three-dimensional, non-intrusive in situ observations should lead to a better understanding of rates of feeding, swimming and predation. Optics can also be applied to quantify other variables such as the distribution, abundance and types of potential zooplankton prey (both chlorophyll and non-chlorophyll containing) at the same time and in the same water parcel that the distribution and abundance of the zooplankton are measured.
Recommendations resulting from the workshop include the following: (1) Integrate acoustical, optical and physical sensors to simultaneously obtain from the same parcel of water information on zooplankton abundance and species composition, as well as the distribution of potentially controlling biological and physical variables. (2) Develop in situ configurations of sensors that can make non-invasive optical observations of zooplankton rate processes and biological and physical variables which control these rates. (3) Develop small, non-intrusive sensor platforms that can be used to follow small aggregations of zooplankton over time while rate processes are being measured. (4) Develop techniques for integrating multiple sensors into a sampling system that can be used to (a) identify and select locations for high resolution measurements and to (b) interrelate those measurements to rate processes and physical structures measured at other time and space scales. (5) Develop image analysis techniques that provide real-time, or near-realtime, identification of organisms from video images collected in measurements of both biomass and rate processes.