Vermont Lakes
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Lake Willoughby, Orleans County, looking toward the south.
22 August 2011. Image source:

Northern Vermont showing Orleans, Essex and Caledonia Counties. The Canadian Province of Québec is above the yellow line near the top of the image; the Connecticut River runs along the right border of the image. Four lakes have our current focus: Crystal (C), Willoughby (W), Seymour (S) and Memphremagog (M). Image source: Google Earth.

What's growing in your lake? Vermont Lakes presents a seasonal calendar of the phytoplankton of selected lakes of northern Vermont, emphasizing diatoms, along with sketches of their evolution and ecology.

We have a general knowledge of the predominant and larger plants and animals with which we share the land -- from mosses, ferns, grasses and maples to worms, beetles and vertebrates. We are aware of seasonal changes in our environments, especially terrestrial ones -- of weather, of plant growth and flowering, of animal activity and migrations. We are embedded in these natural rhythyms of life. This calendar seeks to extend that appreciation to the common photosynthetic microorganisms of the fresh waters around us by promoting an interest in similar seasonal and long-term changes in the microorganisms of lakes and exploring how these microorganisms have been shaped by natural selection to live in the open water of lakes.

The Vermont Lakes calendar is intended neither to provide an extensive listing of the species present in these lakes nor to guide the identification of the phytoplankton of these lakes. Our aim is primarily educational with the calendar providing a platform to present important and interesting aspects of the biology of these microorganisms and the ecology of lakes.

The calendar consists of sets of annotated microscope field images of the phytoplankton of specific lakes from throughout the year. The images emphasize abundant and common representative species and provide links to sketches about them. Links to the phytoplankton of specific lakes are provided by clicking on the map image at the left of this page or selecting a lake from the drop-down menu at the top of this page.

A brief introduction to "How to use the Vermont Lakes calendar" is provided.

Lakes have been sampled periodically from 2011 to 2015. Sampling resumed in early April 2015, when the ice was out (finally!). RKE 1 May 2015


Coeloshpaerium naegelianum Chrysosphaerella longispina Chrysosphaerella longispina Ceratium hirundinella Ceratium hirudinella Mallomonas caudata Mallomonas caudata Lyngbya birgei Lyngbya biregei Lyngbya birgei Dinobryon sertiularia Peridinium sp. (dead) Mallomonas caudata Mallomonas caudata Dinobryon sertularia Asterionella formosa Fragilaria crotonensis Fragilaria crotonensis Peridinium so. (dead) Peridinium sp. (dead)

Phytoplankton of Kieser Pond, Caledonia County, Vermont. 7 August 2011.

Full size image


The "Lakes" menu at the top of the page provides access to the Vermont Lakes calendar. Select a lake and, when the lake's page loads, select a sampling date. Lake calendars may also be accessed from the map of northern Vermont toward the top of this page.

The Vermont Lakes calendar presents sets of annotated microscope field images of the phytoplankton of specific lakes on specific dates. A representative image (reduced to 25% of the normal size displayed on these pages) of a typical microscope field from the calendar is shown on the left. The image is a serial-focus image, one which we developed specifically for routine use on these pages to approximate what we see in our microscopes.

The "focus" bar is an invisible zone which runs the full width of the image but is constrained vertically to its top 10% and bottom 10% (delimited by horizontal black lines only in the representative image on the left).

As the cursor moves from left to right across this focal zone, simulation of focussing down through the field (away from the viewer) is displayed; right-to-left cursor movement simulates the focus moving upwards toward the viewer.

The right-most portion of the focus zones displays a composite image, if we have included one.

To freeze your view of any slice of the field or the composite image simply exit the current focal zone vertically with the cursor in either direction, while that slice is displayed.

A scale bar sits in the lower right corner of the images.

Try the full size image.

Clicking on a lake's name (in large font) in the top-left corner of the page links to descriptive, physical, topographical and other information about the lake.

Each set of images is accompanied along its left margin below the lake's name by information about the sample for the date shown (figure on immediate left).

The numbers of microscopic image fields for that date are displayed below the date field. Field 1 will load initially; to change the field displayed for that date simply click on another field number.

Below the field numbers is a list of the dominant species of phytoplankton in the sample for that date, encompassing all fields, arranged by major groups. Each species name is linked to an independent page with images and information about the species. The named are color-coded with respect to the major taxa to which they belong.

Also, the names of species are provided for many individuals in the sample image as the cursor is moved over them - the cursor will change from an arrow to a hand with a pointing finger. Clicking on the individual displays information about that species on the right side of the web page. Not all individuals in a field are labelled.
Each species has a single letter superscipt indicating its relative abudance in the sample

The sample overview provides brief notes about sample for the given date in the frame on the far-right of the page (not shown here).

Page updated 10 May 2015
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Cite any and all works on this website as derived from

Seymour Lake Lake Memphremagog Lake Willoughby Crystal Lake