Science Seminar Series

August 7, 2020 10:30 a.m.

Climate science and action for Maine’s coast and coastal communities

Dr. Heather Leslie,
Director of University of Maine Darling Marine Center
Associate Professor University of Maine, School of Marine Sciences

With featured host: 

Cassaundra Rose, Ph.D.
Senior Science Analyst & Climate Council Coordinator
Maine Governor’s Office of Policy Innovation and the Future

Dr. Leslie serves as co-lead of the Maine Climate Council’s Coastal and Marine Working Group. Together with 37 other leading scientists, resource managers, municipal officials, and other experts from across the state, she worked over the last year to develop strategies to cut carbon emissions and enhance community resilience in Maine’s coastal communities across the state. These strategies will be considered as part of Maine’s Climate Action Plan, which the Council will deliver to the Legislature in December 2020. Dr. Leslie will summarize the latest science and detail the coastal and marine strategies developed thus far, particularly those that relate to aquaculture, fisheries and other industries vital to Maine’s working waterfront and coastal communities. Participants will be invited to share their questions and concerns and to participate in the next phases of the Council’s work.

July 24, 2020 10:30 a.m.

Untangling the links between ocean life, the global carbon cycle, and future climate

Dr. Margaret Estapa
Assistant Professor of Geosciences, Skidmore College
Assistant Professor of Chemical Oceanography, University of Maine, Darling Marine Center

Alyson Santoro (UCSB)Estapa and colleagues retrieving a neutrally-buoyant sediment trap aboard the R/V Revelle in the north Pacific Ocean in 2018

The global ocean acts as a “sponge” for atmospheric carbon dioxide, including human emissions.  One of the processes that allow this is called the biological carbon pump, which starts when tiny single-celled, plant-like organisms grow and absorb carbon dioxide through photosynthesis.  When these organisms die or get eaten, some of that carbon stays in the ocean and sinks into deeper water.  Over long periods of time this transfer keeps carbon dioxide out of the atmosphere.  However, scientists are still working out which organisms are the most important, and how they might react as the ocean warms, becomes more acidic and loses its wintertime sea ice cover.  Will ocean biology keep contributing to ocean carbon uptake in the future?  Since 2017, Dr. Estapa has been part of NASA study that is exploring these links through a series of expeditions at sea.  She will talk about the clues her team has discovered in the North Pacific, and the questions they hope to answer closer to home, in the North Atlantic.


July 10, 2020 10:30 a.m.

Maine’s changing lobster fishery: some direct and indirect impacts of climate change

Dr. Robert Steneck
Professor of Oceanography, Marine Biology and Marine Policy, University of Maine, Darling Marine Center


The American lobster (Homarus americanus) fishery is not only Maine’s most valuable marine resource, it is also the most valuable species harvested in the United States.  Maine’s lobster is perhaps the only species in the world to have been heavily fished for well over a century but is doing better in recent years than ever before with record landings in 2016.  One might think this is a fishery with few worries now or in the future.  However, challenges for this fishery have never been greater.  Today, the economic impact of COVID-19, international trade problems, concerns about the northern right whale and bait shortages all weigh heavily on everyone who fishes for lobsters on the Maine coast.  While many of those concerns will hopefully be resolved in the next several years, a less conspicuous but a longer-term concern relates to climate change.  The warming Gulf of Maine has generally improved conditions for baby lobster abundance but big changes may be occurring to where lobsters live.

Starting in the 1980s, Steneck and his students conducted SCUBA diving surveys of lobsters to determine in which habitats they were most abundant.  From 1989 to 1999 Steneck’s team found lobsters were primarily in shallow water– living in shelters within boulder fields.  In 2019, Steneck and his students re-examined lobster populations and found them to be more spread out on ledge and sediment habitats but not concentrated in boulder fields as they had been.  The research team also observed a thick carpet of non-native (invasive) seaweed – some of which was rotting on the sea floor.  Steneck’s team is now exploring the possibility that small pockets of low oxygen due to rotting seaweed and warmer sea temperatures may be causing lobsters to avoid boulder field shelters.  Since large predatory fish such as cod are now rare along the coast of Maine, there is little negative consequence to lobsters that choose not to shelter in place. However, this is only the start of what may become a much larger study of the indirect effects of our changing Gulf of Maine.