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Changes in Marine Biological Sciences

Dunaliella tertiolecta cultures grown under high (left) and low (right) irradiance. Photograph is courtesy of Dr.Assaf Sukenik

Dunaliella tertiolecta cultures grown under high (left) and low (right) irradiance. Photo is courtesy of Dr.Assaf Sukenik

Over the past decade, there has been a quiet revolution in marine biological sciences. Whereas students in the early 1980’s and before would probably been exposed to biochemistry and physiology courses in their undergraduate curricula, most students would not have received training in molecular biology or biophysics. In the mid 1980’s, recognizing the potential of these latter disciplines in helping to address key questions in biological oceanography and marine biology, several federal agencies, especially ONR, NSF, and DOE developed research and training programs in “molecular ecology”. Such programs were extraordinarily successful in microbiology, and today it is difficult to conceive of training a marine microbiologist without fundamental skills in molecular biology.

These skills have radically changed our notions about diversity and activity of marine prokaryotes, and have been invaluable in elucidating evolutionary trees and the origins of biogeochemical cycles. However, the application of similar techniques to primary production, nitrogen fixation, and other rate determining processes in aquatic as well as terrestrial ecosystems has lagged. The EBME program provides a laboratory in the Institute of Marine and Coastal Sciences at Rutgers University that addresses these issues.

Importance of Interdisciplinary Communication

Graduate research and training on photosynthesis and primary production in aquatic ecosystems are largely based on radiocarbon uptake processes and “bio-optics”, a subdiscipline of optics that examines relationships between inherent and apparent optical properties of microscopic and macroscopic particulate matter in aquatic ecosystems. There is a parallel field of “photosynthesis research”, containing an eclectic mix of disciplines including physics, physical chemistry, biophysics, biochemistry, molecular biology, plant physiology, ecology, and geochemistry. The latter field has its own disciplinary literature, including a journal of the same name (i.e., Photosynthesis Research) as well as Biochimica Biophysica Acta (Bioenergetics), J. Biol. Chem., Biophys. J., Planta, Plant Physiol; etc. With very few exceptions, researchers in aquatic sciences working on primary production (i.e. photosynthesis), rarely interact with researchers in “photosynthesis research” and vice versa.

This intellectual schism has prevented the elucidation of fundamental phenomena documented in the aquatic sciences literature from being correctly interpreted, while simultaneously, researchers in photosynthesis have largely ignored the unparalleled genetic diversity afforded by aquatic photoautotrophs in the development of their own “paradigms”. For example, in the mid 1970’s, with the broad application of commercial fluorometers in aquatic systems, it became apparent that the fluorescence yield of chlorophyll was depressed in full sun, but rapidly increased under cloud cover and at night. The mid-day depression of fluorescence was interpreted variously as evidence of photoinhibition, diel cycles of chlorophyll within cells, etc.

In the early 1980’s, light-induced fluorescence quenching was correlated with a reversible cycle of carotenoids in higher plants, in which one form of carotenoid appeared to reduce the functional absorption cross section of the light harvesting system. It took almost a decade for that information to be transmitted to the aquatic sciences community, and to this day, many researchers are unaware of the role of the xanthophyll cycle. Research papers on the cycle in the aquatic sciences literature are extremely rare, as are laboratory studies of the cycle. The cycle is much simpler to follow in some aquatic photoautotrophs than in higher plants, some biophysicists have used diatoms or similar organisms to investigate the physical processes responsible.

Such examples of the use of nontraditional aquatic organisms for studies of fundamental processes are also extremely rare. Similarly, while molecular genetics has been extremely powerful in helping to elucidate fundamental mechanisms in photosynthetic processes, there are virtually no examples of similar approaches with ecologically relevant aquatic photoautotrophs. The lack of interdisciplinary communication has certainly impeded progress in understanding fundamental processes in aquatic systems, and arguably has led to a narrow perspective of photosynthetic processes amongst researchers in that area.

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The E.B.M.E. Approach to Education and Research

One of the major reasons for the paucity in interdisciplinary communication and collaboration can be traced to the heritage of the disciplines. Aquatic scientists usually come from backgrounds in ecology or some field of physics and have little formal training in fundamental biophysical processes or the molecular biology related to photosynthesis. Over the past two decades, we have striven to bridge these gaps. Nonetheless, with the rapid development of sophisticated techniques, based on measurements of variable fluorescence, photoacoustics, specific diagnostic proteins, and high resolution oxygen changes, we feel that it is imperative that educational institutions develop and foster the research and teaching programs required to provide the training and experimental opportunities to apply such techniques in the environmental sciences, together with the resident expertise to help train the next generation of instrumentation designers and researchers.

The research, education, and training activity within the EBME laboratory requires a significant investment in instrumentation infrastructure. Instrumentation development emphasizes biophysical applications in the environmental sciences, where the most recent developments in technology (electronics, optics, computers) are used to develop prototype instruments for research and training. Utilizing the unique aspects of EBME interdisciplinary environment, a vigorous instrumentation program has been developed that has led to the commercialization of novel biophysical instrumentation for the aquatic sciences community, as well as to the training of instrumentation engineers for the marine and environmental sciences.