Exo-proteomics of marine dissolved organic matter

Dissolved in the whole ocean is a large pool of organic material, which contains as much carbon as there is in the form of carbon dioxide in the atmosphere. Understanding what this material is made of and the ways it is produced, removed, and recycled is critical for understanding the global cycling of carbon and other important elements. In addition to this material, millions to billions of microbes are living in every liter of seawater, and these organisms are responsible for both making and consuming organic matter. These microbes, like all living organisms, are made up of up to 20% proteins, one of the primary building blocks of life. The proteins in these cells become part of the dissolved organic material in seawater when they die, in addition to specific proteins they release to help them survive when they are alive. Thus, proteins make up a significant portion of the dissolved organic material in the ocean. For this proposed project, we will work to identify which proteins are found dissolved in seawater, both their identity and quantity, in order to gain insight into what dissolved organic material in seawater is composed of and what role microorganisms play in structuring that composition.

The goal of this project was to extract and analyze proteins dissolved in seawater. The duration of the project was cut short due to the project leader leaving Austria on 1 October 2016, but samples of dissolved organic material containing proteins were collected from hundreds of liters of seawater in the Pacific Ocean (from depths of 100 m down to 2000 m). Preliminary work on an efficient method for extracting proteins from seawater was conducted, and future work will be continued by a PhD student.