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

- 6. Trout Lake, Boulder Junction, WI. Photo: Adam Hinterthuer
- 7. Lake Tomahawk, Onieda County, WI. Photo: Laura Hermann
- – Measuring water clarity in Long Lake, Fond du Lac County. Photo: Eddie Heath, Onterra, LLC
- – 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.

