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