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Postcards from the Field

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The Global Lake Ecological Observatory Network (GLEON) is supported in part by the National Science Foundation (NSF) under Grant Number DBI RCN 0639229 and MSB 1137327, 1137353 and other generous donors. This blog receives technical support from the Center for Limnology (CFL) at University of Wisconsin-Madison and Cary Institute of Ecosystem Studies. Any information, opinions, findings, and conclusions or recommendations expressed in this blog are those of the individual author(s) and do not necessarily reflect the views of NSF, CFL, Cary Institute, GLEON or GLEON Student Association (GSA).


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GLEONite students and postdocs have been working on some exciting research projects this past year, so we invited them to send us “Postcards from the Field.” Below, we share with the Global Lake Ecological Observatory Network (GLEON) community insights into some of these projects with a rapid tour around the globe (starting on the left and moving right by longitude in the map below) to get ready for the GLEON 19 All Hands’ Meeting. We’re looking forward to seeing you at Mohonk Lake soon! -GLEON Student Association

Sampling locations of the research ventures. We start at the left location and move right sequentially by longitude.

Sarah Burnet taking a sediment core from Willow Creek Reservoir, Oregon, USA

Sarah Burnet (PhD student)
University of Idaho, Idaho, USA

Sediment cores were collected from 30 sites in Willow Creek Reservoir, located in Heppner, Oregon. The cores were returned to the University of Idaho to be sectioned and analyzed for particle size analysis as well as nutrient content. We hope to determine the spatial distribution of these parameters to improve our understanding of the reservoir and potential lake management applications.


Ashley Mickens (left) and Tanner Williamson (right) collecting data from experimental mesocosms.

Tanner Williamson (PhD student) & Ashley Mickens (REU student)
Miami University of Ohio, Ohio, USA

Storms are expected to become more frequent and intense over the next century, and we were curious about what this might mean for things like nutrient cycling and ecosystem metabolism, so we decided to sample Acton Lake (a eutrophic reservoir) at a high frequency and fine spatial scale during storm events, which generated some pretty cool data. This then led to us wondering if we could experimentally simulate storm events in aquatic mesocosms to test some potential mechanisms behind the patterns we were observing in Acton Lake. In the summer of 2017, we simulated storm events in experimental aquatic mesocosms at Miami University’s Ecology Research Center. The specific intent of this NSF DDIG funded project was to examine how sediment detrital pools modulate ecosystem resilience following episodic perturbations.


A 360 degree photo of Ryan McClure collecting ebullition samples on Falling Creek Reservoir, VA, USA

Ryan McClure (PhD student)
Virginia Tech, Virginia, USA

The ultraportable greenhouse gas analyzer (UGGA) is cool! It reports methane, carbon dioxide, and water vapor simultaneously in the most bombproof case available. The UGGA uses unique laser absorption technology called Off-Axis Integrated Cavity Output Spectroscopy. We use the UGGA to determine the diffusive effluxes of dissolved methane and carbon dioxide in reservoirs, both spatially and temporally. One of our goals is to catch seasonal turnover in a reservoir to get a sense of how hypolimnetic oxygen influences carbon storage.


Kiyoko Yokota deploying a buoy on Otsego Lake, NY, USA.

Kiyoko Yokota (Assistant Professor)
State University of New York (SUNY) at Oneonta & Biological Field Station, New York, USA

Kiyoko’s work examines phytoplankton dynamics and anthropogenic influences (pollutants such as microplastics, changing climate, etc.) on food webs.

We deployed a temperature and light sensor chain in spring, from which we generated the very first high resolution heat and light map for Otsego Lake. Then in July the new autonomous buoy system funded by an NSF grant arrived, and we deployed it at the deepest point of the lake (z ~50 m), where manual sampling has been occurring for the last few decades, which meant jumping through multiple hoops in terms of local stakeholder permissions and also deployment logistics. We hope to use the new high-resolution data to supplement existing long term data and to further research food web dynamics on the lake now that we also are better equipped for fisheries research. We also have provided existing long term data to a couple of GLEON projects and participated in the coordinated nutrient limitation experiment through the Northeastern North America GLEON.


Sunrise sampling by Allison Hrycik on Shelburne Pond, VT, USA

Allison Hrycik, (PhD student)
University of Vermont, Vermont, USA

Allison is interested in how winter conditions (snow and ice cover) shape phytoplankton communities, and how those changes carry through to the rest of the year.

During the sampling event in the photo we had two tasks for the day and began around sunrise (hence the coffee in my hand). First, we took water quality samples (nutrients, phytoplankton, zooplankton, temperature, DO, etc.) as part of an ongoing monitoring program on Shelburne Pond that started in 2014. We sample the lake manually year-round: every week during open water and every other week during ice cover. We also have a high-frequency buoy that takes measurements throughout the open water season. Shelburne Pond is a small, hyer-eutrophic, polymictic system. Several other people have used this data set for various reasons, but my focus is examining how plankton communities differ under the ice and into the open water season depending on winter severity. Second, we collected fish (yellow perch and golden shiners) for my labmate Natalie Fores’ project. She is examining cyanotoxin uptake into fish muscle and liver tissue. We set gill nets once per month to collect samples for her project.


Amanda Gavin deploying temperature arrays in Crystal Pond, ME, USA

Amanda Gavin (MS student)
University of Maine, Maine, USA

Amanda studies the biogeochemical response of Maine lakes to chemical and physical change.

During the sampling day in the photo we deployed high frequency temperature arrays in a series of lakes to explore the relationship between DOC concentrations and stratification dynamics.



Belén Alfonso collecting sediment samples at La Salada, Argentina.

María Belén Alfonso (PhD student)
Instituto Argentino de Oceanografía, CONICET-UNS, Bahia Blanca, Argentina

Belén researches the influence of the discharge from the Colorado River in the presence of contaminants in La Salada shallow lake (Argentina).

Last summer, the IADO (Instituto Argentino de Oceanografía) team went to La Salada lake to perform preliminary research about the presence of persistent organic compounds (POC’s) as organochlorine pesticides (OP’s) and hydrocarbons aromatic polycyclic (HAP’s) in sediments samples.

This analysis was made under the framework of the SAFER (Sensing the Americas’ Freshwater Ecosystem Risk from Climate Change) and PAMPA2 (Argentinean Project of Monitoring and Prospecting the Aquatic Environment) projects. The main objectives of both projects are to employ lake ecosystems as “sentinels” of climate variability and watershed processes and investigate their interaction with other stressors to assess risks to ecosystem services.


Núria Catalán measuring carbon dioxide efflux in reservoirs in Spain, as part of the DryFlux project.

Núria Catalán (Postdoctoral Researcher)
Catalan Institute for Water Research (ICRA), Girona, Spain

Núria’s research focuses on carbon biogeochemistry of inland water ecosystems.

This photo is from the DryFlux project, which is a part of GLEON. The locations are in reservoirs in Lleida, Catalan Pyrenees and Teruel, Spain. We measured CO2 efflux from and characterized dry reservoir sediments.




Peter Isles by mountain lakes in Jämtland, Sweden

Peter Isles (Postdoctoral Researcher)
Umeå University, Umeå, Sweden

Peter’s research focus is on aquatic biogeochemistry, lake nutrient stoichiometry, land lake biogeochemistry. This summer Peter was sampling mountain lakes in Jämtland, Sweden to look at changes in nutrient stoichiometry in different food web compartments, and how that stoichiometry is affected by gradients of climate, nitrogen deposition and DOC. This was part of a larger research project focused on regime shifts in boreal and subarctic lakes driven by climate changes and browning.


Marieke Frassl and colleagues preparing to collect samples on Lake Poyang, China as part of the DryFlux project.

Marieke Frassl (Postdoctoral Researcher)
Helmholtz Centre for Environmental Research (UFZ), Leipzig, Germany

I was traveling to China with a colleague of mine to deploy a monitoring buoy in Lake Chaohu. However, a few days before I left, another colleague came over and asked me, if I could do some CO2-flux measurements in China and join the GLEON Dryflux project. Of course we could! That way, we did not only deploy the buoy, but also traveled to Lake Poyang. We had two days to have a look at this exciting lake and sample CO2 fluxes, soil moisture and temperature. Thanks to all our Chinese colleagues for organising this spontaneous sampling campaign and for the great and successful time!


Samiullah Khan (left) and Dr. Chris Moy (right) taking a sediment core from Lake Hayes, New Zealand.

Samiullah Khan (PhD student)
University of Otago, Dunedin, New Zealand

Our research goal from sampling was to ascertain historical dynamics of food web components using paleolimnological methods such as eDNA, fossils of Daphnia and phytoplankton pigments. The food web of Lake Hayes (from photo) was historically altered during the 1870s, particularly when two alien carnivorous fish species i.e. Brown Trout (Salmo trutta) and Perch (Perca fluviatilis) were introduced. Lake Hayes has severely reduced abundances of two diadromous fish species, the climbing galaxias or koaro (Galaxias brevipinnis) a potential inverti- plantivore, and longfin eel (Anguilla dieffenbachii) a predator.

As a result of biodiversity alteration and high nutrient influx from the farmlands in the catchment, the lake has faced episodic cyanobacterial blooms and hence a seasonally anoxic hypolimnion. Trout and perch fisheries in the lake were successfully established until very recent unsustainable practices and disturbances in the lake and associated streams that have left the system with a stunted and largely planktivorous perch population and reduced abundances of larger piscivorous perch and brown trout. As a restoration measure, the nutrient concentration in Lake Hayes has been substantially reduced through catchment management but eutrophication still persists due to internal nutrient cycling.

Postcards from the Field” was compiled and edited by Jonathan Doubek, a Ph.D. Candidate in the Department of Biological Sciences, fellow in the Interfaces of Global Change at Virginia Tech, and co-chair for the GLEON Student Association.


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