Thematic Goal 2: Harmful and Shifting Species

How do species that are harmful or new to an aquatic ecosystem contribute to reshaping ecosystem structure, its overall biological functions, and the dominant trophic interactions within associated food webs? Rapid changes in the abundance and distribution of a species, along with expansion or contraction of its geographic range, are some of the primary indicators that ecosystems may be changing in response to regional or global phenomena. It has been hypothesized that climate-based forcing is an underlying driver of many of these changes for both micro- and macro-organisms in the Gulf of Maine (GoM). Recently, the GoM coastal ecosystem and many inland waters have experienced harmful algal and cyanobacterial blooms (HABs) with increasing frequency, duration, and type, as well as disruptive range-expansion (or in some cases range-losses) of species ‘on the move’ – which may be linked to rapidly warming temperatures in this region. 

Under this theme, Maine-eDNA researchers aim to identify the community and biogeochemical processes that underlay the emergence and outcomes of harmful marine and freshwater blooms. The researchers will use eDNA approaches to characterize harmful blooms, the planktonic communities associated with their emergence (and decline), and their ecosystem consequences. They will also leverage the accessibility of eDNA sampling to engage citizen scientists and in turn expand bloom detection and monitoring to scales that will improve our understanding of blooms on the time and spatial scales they actually occur.

A second goal will help our researchers characterize species range shifts now occurring in the greater GoM kelp forest ecosystem, a system defined by a steep oceanographic thermal gradient and rapid regional warming.  By leveraging the power of eDNA to detect species often not seen in traditional net or diver surveys, they seek to elucidate the putative causes of these shifts, and develop predictive models to forecast geographic range shifts among native and non-native taxa. This goal will be achieved by (a) comparatively studying eDNA of key species inhabiting kelp forests that span from the warm leading edge to the core of forest distribution in the region, (b) employing controlled field experiments, and (c) using computational approaches including statistical models, eDNA network analyses, and machine learning. 

A key benefit of both projects will be improved surveillance and early warning systems for harmful or shifting taxa as they emerge in the region, improving Maine’s short-term ability to quantify and manage these threats (or even new species opportunities), and their impacts on ecosystem services. Ultimately, data generated by the two projects under Thematic Goal 2 will be applied to new models and accessible forecasting tools to improve future mitigation, prevention, and/or avoidance strategies.