Tag Archives: GLEON

CFL’s Crowd-Sourced Secchi Slideshow: Happy Earth Day!

We asked, and you answered! It’s Earth Day and we’re continuing our shout out to the inventor of limnology’s most ubiquitous instrument. (Full captions to photos are posted below)

Click on images above for slideshow. Fuller captions describing images are provided below:


1 – Pietro Angelo Secchi, dropped the first disk off the side of the Papal Yacht in 1865. Image courtesy: University of Toronto

2 – 150 years later, a disk descends into Lake Mendota’s green, over-productive waters. Photo: Adam Hinterthuer, University of Wisconsin-Madison

3 – Secchi off a sailboat. Image: National Library of Australia

4 – Claude Reeves, Auburn University’s Area Extension Specialist demonstrates a Secchi at the Wiregrass Research and Extension Station in Southeast Alabama. Photo: Rusty Wright, Auburn University (CFL Phd, 1993).

5 – Secchi on a stick is recommended for pond management where a clarity target of 18-24 inches is ideal to achieve a good ratio of fish versus algae. Photo: Rusty Wright, Auburn University

6 – Kids help Trout Lake Station’s Noah Lottig read the winter Secchi depth on Trout Lake. Photo: Adam Hinterthuer

7 – Citizen scientist Tim Plude monitors the Secchi depth of Lake Tomahawk in Wisconsin’s Oneida County. Photo: Laura Herman, Wisconsin DNR

8 – Volunteers participating in the (NY) Citizens Statewide Lake Assessment Program will collect over 1000 Secchi readings this year. Photo: Nancy J. Mueller, Manager NYS Federation of Lake Associations, Inc.

9 – NYCSLA volunteers take Secchi depth readings in Java Lake in Western New York. Photo: Nancy J. Mueller.

10 – Unexpected “soupy” water awaited researchers this winter on Lake Monona. Photo: Ted Bier

11 – Stephen Eiser holds Secchi disks in both basins of Long Lake at the University of Notre Dame Environmental Research Center in Northern Michigan. An impermeable curtain prevents water flow between the basins. The East basin receives the majority of dissolved organic carbon load and has become darker in color the past two years. Photo: Jake Zwart

  1. – Measuring water clarity in Long Lake, Fond du Lac County. Photo: Eddie Heath, Onterra, LLC

13 – Large algae blooms are more common towards the end of the summer when water temperatures are warm. They’re also more prevalent in lakes with high inputs of nutrients from farm fertilizer and urban runoff. Photo: Eddie Heath, Onterra, LLC

14 – Off the coast of Belize, Carrie Cow Bay research station managers take Secchi readings near the Carribean coral reef. They’ve documented a decline in water clarity. Photo: Smithsonian National Museum of Natural History

15 – Kate Hamre, a graduate student in Cayelan Carey’s lab at Virginia Tech takes a sample at Falling Creek Reservoir (a GLEON site) in Virginia. Photo: Alex Gerling.

16 – On the shores of Lake Mendota, Center for Limnology post-doc, Hilary Dugan, holds a cookie made in honor of the Secchi disk’s 150th anniversary. Photo: Hilary Dugan

17 – On the slightly more frozen shores of Trout Lake, Center for Limnology post-doc, Jessica Corman, holds a similar cookie in tribute of the big day. Photo: Jessica Corman

  1. – A wolf holds a Secchi “disk,” in honor of the tool’s 150th birthday. Photo: Stephanie Schmidt, Alaska Department of Fish and Game.


16. Lake Mendota, Madison, WI. Photo: Hilary Dugan.

16. Lake Mendota, Madison, WI. Photo: Hilary Dugan.

Field Samples: The Art (and Science) of Wrangling ‘Big Data’

Field Samples is a weekly Q&A asking researchers what they’ve been up to and what they’ve learned. Today, information manager/data scientist extraordinaire, Corinna Gries, talks the brave new world of “big data.”

Who are you, where are you from, and how did you get here? 

CorinnaGriesI am Corinna Gries, Information Manager for the North Temperate Lakes Long-Term Ecological Research (NTL LTER) site.  I was born and raised in Hamburg, Germany and went to school in Kiel, Germany where I received a PhD in Botany. How I got here is a long story that involves an early interest in databasing and programming, a self-taught career change while still doing botanical ecophysiology research, and a stop as information manager for the Central Arizona Pheonix LTER site.

Pretend we just boarded an elevator and you only have a one-minute ride to tell me about your work – can you capture it a few sentences? 

I archive data, which is sort of like running a museum or library for data. That is, the data are not in drawers, on shelves, or in display cases, but in a database and displayed on the web for everybody to find, download and use. This is a somewhat new discipline, called Information Management, Information Science, or lately Data Science and involves a fair amount of technical as well as science domain understanding. Continue reading

Video: Going Global with Freshwater Science

GLEON fellowship students ask questions during the summer workshop. Photo: A. Hinterthuer

GLEON fellowship students ask questions during the summer workshop. Photo: Grace Hong

“Okay, now we’re going to do a little role playing,” the moderator announced to the room. “We need a customer and a shopkeeper, would anyone like to read a script?”

After a little coercion, two reluctant thespians assumed their roles and launched into an exchange, trading lines like “How much for that brass dish, sir?” and “You drive a hard bargain, young lady.”

The exercise is designed to help multiple stakeholders learn how to achieve what might be called “win/win” resolutions and is taken from the book “Getting to Yes: Negotiating Agreement Without Giving In.”

It would be easy to mistake this for some sort of corporate seminar. But it was actually a workshop for the Global Lake Ecological Observatory Network (GLEON), an international group of ecologists, hydrologists, information technologists and computer scientists all working together to answer some big global questions about our inland waters. Continue reading

Spring Blitz! Global Collaboration Gets to the Bottom of Plankton Diversity

As spring moves to summer, an unprecedented scientific collaboration is sending researchers around the globe scrambling into their boats and simultaneously heading out onto the world’s lakes. It’s called “Spring Blitz,” and, from Wisconsin to Florida to Switzerland, scientists are out monitoring everything from water temperature to dissolved oxygen to plankton communities as lakes in the northern hemisphere warm up and settle in to their stratified summer conditions.

Center for Limnology (and GLEON) researchers, Paul Hanson and Cayelan Carey head out on Lake Mendota to collect samples for Spring Blitz. Photo: A. Hinterthuer

Center for Limnology (and GLEON) researchers, Paul Hanson and Cayelan Carey head out on Lake Mendota to collect samples for Spring Blitz. Photo: A. Hinterthuer

Most lakes in temperate climates undergo stratification during the warmer months. As the surface water warms, it becomes less dense and “floats” on the cold water below it and, eventually ,the water column of the lake is divided into distinct sections, the warm upper layer (epilimnion to science-minded folks) and the cold bottom layer (hypolimnion).

Emily Sylvia and other GLEON team members collect samples on Lake Annie, south of Orlando, Florida

Emily Sylvia and other GLEON team members collect samples on Lake Annie, south of Orlando, Florida

This is the first year of the project, which is organized by the Global Lake Ecological Observatory Network, a grass-roots collection of limnologists, ecologists, engineers and IT professionals collaborating to build a better understanding of the world’s freshwater ecosystems. Paul Hanson, co-chair of the GLEON steering committee and faculty member at the Center for Limnology, says this late spring is pushing researchers to their limits. Continue reading

Lake Life Ramping Back Up, Clear Water Phase on Its Way

A trip out sampling on Lake Mendota this morning yielded a robust catch of the zooplankton (tiny animal), Daphnia, a miniscule, yet voracious crustacean that goes to town on phytoplankton (tiny plant) populations that are blooming throughout the upper reaches of the water column.

Spring plankton community, Lake Mendota from Center for Limnology on Vimeo.

Eventually we’ll see so many Daphnia eating so many tiny green phytoplankton, that the waters will become crystal clear. This fleeting “clear water” phase will only last until the surface waters warm and send Daphnia down below hunting for cooler waters. Then the opposite of “clear water” will occur as blue green algae (cyanobacteria) blooms that we know all too well on Mendota take over. Unfortunately, these are just as unpalatable to any grazers in the lake as they are to those of us watching the green scums from the shore…

The sampling was part of the Global Lake Ecological Observatory Network’s “Spring Blitz,” an unprecedented limnological effort to simultaneously monitor spring transitions on lakes around the globe. More to come on that next week. Stay tuned!

The CFL's Paul Hanson and Cayelan Carey take measurements on Lake Mendota as part of the Global Lake Ecological Observatory Network's "Spring Blitz" monitoring project.

The CFL’s Cayelan Carey and Paul Hanson take measurements on Lake Mendota as part of the Global Lake Ecological Observatory Network’s “Spring Blitz” monitoring project.