Gloeotrichia  (GLEE-o-TRICK-ee-ah)

 

Fuzzy Balls in Panther Pond

 

Did you see all those fuzzy balls in Panther Pond last summer?  Those fuzzy balls are called Gloeotrichia echinulata.  They may have been in Panther for a long time, but have only been present in large enough numbers to be seen in Panther Pond for the past 10-20 years or so.  Last summer they were found in such large numbers that it should really be considered a bloom.  Although Gloeotrichia has been seen in moderately eutrophic to eutrophic lakes for a long time, the latest research indicates that they have only been showing up in clear lakes in the Northeast U.S. for the past 30 years. (Carey et al., 2008; Carey et al., 2009). 

 

Why are they showing up now?

 

Hypothetically speaking, since it’s unlikely that environmental conditions are so different now than they have been in the past, the most likely reason that they were not seen before is that they were not present in the lake and may have been recently transported from another lake. 

 

What does it mean for the future water quality of Panther Pond? 

 

Gloeotrichia are unlike most other algae that are found in lakes in that they don’t get their nutrient from the water column, but instead get the nutrient that they need from the bottom sediments.  They have a rather complex life cycle.  This could have serious implications for water quality.  The normal sources of nutrients, especially phosphorus is from surface water runoff or from internal recycling of phosphorus from the bottom sediment under anoxic (no oxygen) conditions.  Gloeotrichia, like algae, need sunlight and warm water to proliferate.  Last summer was very sunny and warm and was likely the immediate cause of the bloom. Research is presently being conducted to determine if Gloeotrichia will transport phosphorus from the bottom sediments to add another source of phosphorus to contribute to algae production.

- Phil Boissonneault, April 2011

 

Current Research

 

Panther Ponders have been invited to participate in a research project on gloeotrichia, being conducted by scientists at Dartmouth and Bates colleges. Details of the project are uncertain at this point, but we'll post more information here when it's available.

 

Additional information

 

http://www.lakesunapee.org/templates/science.html

 

http://www.bates.edu/ewing-environmental.xml

 

http://sites.dartmouth.edu/CottinghamLab/ecological-research/

 

Update - 2012 Annual Meeting

 

GUEST SPEAKER,  HOLLY EWING from BATES COLLEGE

Holly came to us because Phil Boissonnealut wrote an essay about gloeotrichia and put it on our website.  Holly responded. A number of Panther Ponders offered the use of their docks for sample collection, and Dr. Ewing selected several sites around the lake. She and her student assistants have been collecting water samples and setting up experiments for more than a year at these sites. Dr. Ewing, along with scientists at other institutions, have been studying gloeotrichia in a couple of dozen lakes in the northeastern U.S.

 

Prof. Holly Ewing discusses gloeotrichia

 

The biology of gloeotrichia is not thoroughly understood yet. It is classed as a cyanobacterium, and is of concern because it produces toxins which may affect the nerve system and liver, and cause skin and eye irritation. Additionally, the recent gloeotrichia blooms may indicate problems with the lake chemistry, particularly the presence of excess phosphorus. *

Core samples of bottom sediments taken from Panther Pond indicate that gloeotrichia has been in the lake for many, many years, but it has only recently become a problem as large blooms have developed in the summer.

How are we doing on Panther Pond? Not so good in 2011. Of all of the lakes in the study, Panther has had the greatest concentration of gloeotrichia during the summer blooms. (Other lakes with high gloeo counts include Belgrade Lakes and Lake Auburn, which is a public water supply.)

However, there are two positives to note:

  1. Unlike the other high-gloeo lakes in the study, Panther has a broad and healthy array of other plankton along with the gloeo.
  2. There are some hints that the situation can be reversed by controlling the limiting nutrients which gloeo uses.

 

One of the limiting nutrients is nitrogen, which it gets from the air. There’s nothing we can do about that. The other is phosphorus, which the gloeo gets from the sediments on the lake bottom (see footnote below.) The way to control, and perhaps even reverse, the gloeo blooms is to limit the amount of phosphorus going into the water, by preventing storm water runoff from carrying additional sediment into the lake. That’s what we’ve been working on for years, with the 319 grants and other conservation projects.

In short, we’re doing the right things, we just need to do more of them, and do them better. Every time we plant a vegetative buffer between an open lawn and the lake, or install infiltration trenches or steps, or put riprap around a culvert, we’re helping to defeat the gloeo. We need to keep up the efforts to identify and treat erosion sites, and do everything else we can to keep phosphorus out of the lake. [Click HERE for more information.]

Money is running out to pay for the collection of lake samples and the running of on-site experiments; but Holly and her fellow scientists are developing a smart-phone app which will allow private citizens to make gloeo observations and transmit the results to Holly’s group. Panther Ponders who have smart phones and want to try their hand as citizen-scientists can get further information by contacting PPA.

 

* A limited amount of phosphorus can be “sequestered,” or bound up in the sediments on the bottom of the lake. This phosphorus is not available to fertilize the gloeo and other algae. Over the course of the summer, small plants and animals die and sink to the bottom of the lake, where they decompose. The decomposition consumes oxygen from the water. As long as dissolved oxygen remains in the water, the phosphorus remains sequestered. However, once the oxygen is depleted, a chemical change occurs which makes the phosphorus available for gloeo and other plankton. Left unchecked, this process results in plankton blooms and, eventually, the eutrophication (read “death”) of the lake. This is why we are so concerned with measurements of dissolved oxygen at the lowest levels of the lake. Fortunately, there was never a time during the summer of 2011 when the dissolved oxygen at the lake bottom fell low enough to release phosphorus; but that was an unusual year.