Research at LSPA

Two major areas of current research at LSPA include a blue-green algae (Gloeotrichia enchinulata) called Gloeo, which appears in oligatrophic lakes such as Lake Sunapee. A second research topic is that of mercury movement and transformation in the ecological systems. 

Gloeo

Lake Sunapee Scientists' Research on Gloeotrichia
In the first of a series of serendipitous events leading to today’s "Gloeo Gang", an undergraduate Cayelan Carey contacted Lake Sunapee Protective Association (LSPA). At the time, Research Director Kathleen (Kak) Weathers, based at the Cary Institute of Ecosystem Studies, was working with  LSPA on a sabbatical project on watershed-level nutrient cycling. She suggested that Cayelan pursue the question of why novel and unexpected cyanobacterial blooms were occurring in the low-nutrient lake.

Cayelan enthusiastically agreed, and so began the "Gloeo Gang" from just three initial collaborators (including herself, her undergrad adviser Kathy Cottingham, and Kathleen Weathers). The three published a paper together in the Journal of Plankton Research, covering results from that first summer of 2005 and speculating that recruitment from dormant stages (the “seed bank”) of Gloeotrichia in the lakebed sediments during seasonal mixing might play an important role in the blooms.  But they wondered how repeatable was this single-season study from one year to the next in Lake Sunapee? And: What was going on in other oligotrophic lakes in the region?   

The "Gloeo Gang" grew in scope and in size to include the other co-authors on the spotlighted article (Holly Ewing and Meredith Greer from Bates College), as well as a number of student researchers. They meet regularly and have, to date, collected weekly phytoplankton data every summer for 10 years from Lake Sunapee. They have studied a number of other lakes as well.

What Influences the Observable Presence of Gloeotrichia
The inference thus far is that mixing of the water column influences the annual likelihood of Gloeotrichia blooms, probably because greater mixing increases recruitment of cyanobacteria from the sediments.  Regional climatic variability could be the ultimate driver of how much mixing happens from one year to the next. Cayelan says that one of the most important take-home messages is that long-term monitoring is essential to get a handle on natural variability.  

A Research Paper

Spatial and temporal variability in recruitment of the cyanobacterium Gloeotrichia echinulata in an oligotrophic lake was published in the Journal of Freshwater Science (FWS). The authors: Cayelan Carey, Kathleen Weathers, Holly Ewing, Meredith Greer and Kathryn Cottingham are all familiar local scientists and part of the "Gloeo Gang".

 

Mercury

The Research Effort

Members of LSPA's  Scientific Advisory Committee (Nick Baer, Colby-Sawyer College and Celia Chen, Dartmouth College as principal investigators together with Kathy Cottingham of Dartmouth College, Holly Ewing of Bates College and Kathy Weathers of the Cary Institute) collaborated on mercury research around the Lake Sunapee area. The research was supported from NH-INBRE grant as well as from the National Institute of Environmental Health Sciences, NSF, ME-INBRE and Bates College research funds for chemical analyses, research technician assistance, and data management support.  At the 2014 Annual Meeting of LSPA, Nick Baer, Colby-Sawyer College Assoc. Professor of Biology and LSPA Board member, gave a presentation on "Diving into aquatic research: Examining mercury moving through the Lake Sunapee Watershed ", explaining important mercury research conducted in the Sunapee Watershed.

Mercury - Why the Concern

It has been known for years ("Mad Hatter" syndrome in the 1880s) that mercury is toxic to humans; in many cases through consumption of fish. Environmental Protection Agency (EPA) Fish advisories have increased six-fold nation-wide in the last 15 years. It is important to understand how mercury progresses from its source to the fish we eat.

The primary source for the New England region is the burning of fossil fuels from the mid-west . This sends inorganic mercury into the atmosphere, from which it can be deposited into aquatic systems, such as lakes, streams, and wetlands.  In the aquatic systems, methylmercury is chemically formed from inorganic mercury in plant roots and microorganisms. This transformation process from inorganic mercury to methymercury is called methylation. Variables such as the concentration of dissolved organic carbon (DOC), pH levels and even sunlight can have a strong effect on the mercury in an ecosystem.

Its Transformation

Methylmercury is the only form of mercury that can be accumulated in the muscle and fatty tissue of fish. Accumulated levels of methylmercury become higher as the fish grow, and levels are magnified up the food web as larger fish eat smaller fish, a process called biomagnification.  Once the methylmercury is formed, it is first obtained by microorganisms, then proceeds into macroinvertebrates (aquatic "bugs") then into fish and other predators, and then into humans who eat the fish.

The Research Results

The research evaluated the amounts of methymercury in an ecosystem, considering several variables, such as dissolved organic carbon (DOC). For the research team, which included many students, numerous hours were spent collecting water and animal samples, then testing them in the lab for methymercury. Over 77,000 specimens of invertebrates were analyzed!  Even the Rock Bass Derby fish were analyzed! The results showed that as DOC increases so does surface water mercury.  The data also suggested that DOC chemistry may intervene in exactly how methymercury accumulates in the food chain.