The goal of this research is to investigate the role of environmental factors, such as climate, in controlling Bering Sea productivity, particularly the productivity of walleye pollock. We are collecting sinking particulate matter using automated, time-series sediment traps. The collected material is analyzed for C and N stable isotopic composition and for lipids, such as wax esters and sterols, that are characteristic of specific source organisms. Similar analyses of plankton are also being done, and, by comparing the sediment trap and zooplankton results, we will obtain information on the source of the trapped material and on the food web which generates the sinking material. The question of what processes allow the preservation of organic matter in marine sediments, for time spans of millions of years, has long puzzled scientists.
Bacteria are normally very efficient at breaking down detrital organic matter.
One hypothesis is that adsorption of organic molecules to sediment minerals, such as clays or iron oxides, prevents bacterial decay. The effects of adsorption to on the decomposition rate of organic substances have been a focus of work in my laboratory for over 15 years. During that time, we have found that adsorption decreases the decomposition rate of free amino acids, peptides, and proteins. Recent research, being conducted in collaboration with Research Associate Susan Sugai and Ph.D. student Xiaoling Ding, is investigating groups of organic molecules that appear to have the properties necessary for adsorptive preservation. Selected Publications Alexander, V., S. M. Henrichs, and H. J. Niebauer.