Award: OCE-1205232

Every teaspoon of seawater is home to millions of microscopic organisms that are the engines driving biological activity in the ocean. They form the base of food webs that sustain fisheries and are responsible for recycling nutrients required for life (e.g. carbon, hydrogen, nitrogen, oxygen, phosphorus, iron, and sulfur). They directly influence EarthÆs climate by altering the concentrations of carbon dioxide, methane, nitrous oxide and other gases in the oceans and in the atmosphere. There are thousands of different types of microorganisms in the oceans, each performing different and critical functions that are required to maintain life on Earth. The underlying forces that determine the abundance, distribution and activity of these microorganisms are largely unknown. In this one year award for a pilot study, we have brought together oceanographic researchers from different disciplines to identify the key factors that determine the abundance, distribution and activity of marine microorganisms. In addition to the principal investigators (Morris, Ingalls and subcontract Twining), collaborators drew from 14 different research groups in the geochemistry and molecular biology communities. The geochemistry community typically studies the end result of biological activity that has occurred over days to many years. The molecular biology community typically studies cellular processes that are occurring on the scale of minutes to hours. These researchers also often use different techniques for collecting marine samples. Geochemists typically worry about contaminating their samples with metallic or organic compounds from the ship and sampling equipment, while biologists are concerned with contamination from other organisms (like humans). This project is among the first efforts to bring together these disparate communities to identify mechanisms underlying biogeochemical process at an interface between two distinct environments in the North Pacific. PIs and collaborators carried out a 6 day cruise starting in Seattle and heading northwest into the Pacific Ocean. We reached the low chlorophyll high nutrient waters of the north Pacific Subarctic gyre, where the waters are characterized by low biological productivity despite the relatively large quantities of unused nutrients (nitrogen and phosphorous) present. The cruise returned to costal waters along a well established transect that crosses an open ocean to coastal oceanographic boundary. We used genomics, transcriptomics, proteomics, metabolomics and metallomics to determine which microbial types were present and active at six stations, and the extent to which they were deficient in biologically necessary trace metal nutrients. We have generated a large dataset that we, along with the broader community, are mining for clues about the state of the biological community and the environment. Some preliminary highlights include molecular studies indicating that the organisms along our transect are responding to very different conditions. For example, the phytoplankton at the station furthest from shore displayed signs that the scarcity of iron was causing physiological stress. Also, the metal content of different types of phytoplankton differed significantly. Such differences in cellular metallomes indicate that there were differences in the biochemical cellular processes occurring in different cell types. These may occur in response to the environment, and they may also have implications for how cells alter their environment. Proteomic analyses revealed between 600 and 1,000 proteins in each sample and suggest that there were shifts in microbial communities and activities. Specifically, open ocean and coastal communities were dominated by different groups of microorganisms that expressed different proteins for nutrient uptake and utilization. We also have found clues about the presence and activity of organisms through analyzing the variety of organic molecules prese...