Resolution of Biological Microstructure Through In Situ Fluorescence Emission Spectra: An Oceanographic Application Using Optical Fibers

Abstract

ONE OF THE CHALLENGES we face as oceanogra-phers is the wide range of spatial and temporal scales over which we must measure the physical, biological, and chemical properties and processes in the ocean. The constraints of available tech-nologies have required discrete sample collection with bottles or nets to define the distribution of bulk biological and chemical properties and processes. These sampling constraints have confined us to a relatively coarse-scale resolution of the biological and chemical characteristics of the upper ocean. In contrast, physical oceano-graphic instrumentation has provided definition of temperature, salinity, and density over a much wider range of spatial scales, from centimeters (microscale) to thousands of kilometers (basin scale). This mismatch in sampling resolution be-tween physical and biological/chemical properties is particularly critical at the microscale, where it is likely that biological and chemical distributions and processes are constrained by finescale and mi-croscale physical processes. It is, therefore, critical to our understanding of the linkages between small-scale physics, biology, and chemistry that we address this mismatch in sampling scales through new approaches to instrumentation to measure biological microstructure. The need for sub-l-m resolution of plankton distributions has long been recognized (e.g., Cassie, 1963), and this need has become increas-ingly important as laboratory and field experi-ments have documented the complex interrelation-ships of microbes and protists in plankton ecology. Additional laboratory evidence has docu-mented the complex behavioral responses of mesozooplankton to various chemical and