The application of metaproteomics to understand why Phaeocystis pouchetii is on the rise in Cape Cod Bay

Mak Saito, Marine Chemistry & Geochemistry
Sara Bender, Marine Chemistry & Geochemistry


2014 COI Funded Project


In Cape Cod Bay, the marine alga Phaeocystis pouchetii blooms each spring and is considered a nuisance species.  Its presence is hypothesized to be antagonist to higher trophic levels, although the mechanisms behind this relationship remain unclear.  In the bay, long-term trends provided by the Massachusetts Bay Water Authority time-series indicate that P. pouchetii blooms have increased in frequency and abundance in this region since 2000; in tandem, resident diatom populations are generally decreasing (Jiang et al.  2014).  While physical processes, such as the Gulf of Maine intrusion (Jiang et al.  2007), have been connected to P. pouchetii blooms in Massachusetts Bay, phytoplankton in Cape Cod Bay do not appear to be as affected by this current, adding additional mystery to annual bloom formation.  This proposal seeks to identify the triggers that drive the seasonal P. pouchetii bloom in Cape Cod Bay using metaproteomic approaches and to determine what underlying metabolic machinery may be responsible for its success.  Findings will help to explain differences in the timing and strength of the bloom observed in the time-series and to provide valuable information into the present and future health of Cape Cod Bay.

The proposed research would be the first study to apply a metaproteomic approach to investigate Phaeocystis bloom formation and decline in the field, and the first application of molecular-based tools to study P. pouchetii in Cape Cod Bay.  Eukaryotic metaproteomic studies, which provide a snapshot of all detectable proteins present in an environmental sample at a given point in time, provide a high-resolution overview of dynamic algal communities.  Changes in relative protein abundance will be coupled to the more than 20-year dataset consisting of bulk nutrient measurements, chlorophyll a, and phytoplankton cell counts for the bay to determine what factors initiate the spring Phaeocystis bloom, and why bloom characteristics vary on an annual and inter-annual basis.  The proposed research will provide new tools for studying and monitoring an ecologically relevant and nuisance algal species in Cape Cod Bay and provide useful information for regional stakeholders, including the Provincetown Center for Coastal Studies and the scientists involved in the Massachusetts Bay System monitoring program.  Findings from the proposed research will also be used to strengthen new collaborations with local researchers.