Updated:  May 17, 2024


Jennifer B. Korosi, Randelle C. Adano, Pham Ha Phuong Do, Roland I. Hall, Januja Jeyarajah, Emily M. Stewart, Johan A. Wiklund & Joshua R. Thienpont, Ecosystem impacts of an invasive charophyte (Nitellopsis obtusa) interpreted in a multiple stressor context using paleolimnology, Lake and Reservoir Management,

New research conducted by Dr. J. Korosi et al. provides support for anecdotal evidence that blue-green algae blooms used to occur in Lake Scugog until the 1990’s then cleared up.  Cores taken from the lake bottom clearly demonstrate differences in the sediment after the dam was installed when the lake was flooded. The cores showed evidence markers of blue-green algae blooms after that time until the 1990’s probably caused by excess nutrients from the rotting of the underlying wetland.   Current day blooms have previously been indicated to be linked to invasion by the plant-like alga, Nitellopsis obtusa or  starry stonewort.  This indication of linkage between the presence of this new invader to microcystis or blue-green algae blooms is a corroboration of earlier research conducted by Dr. Tyler Harrow-Lyle under our three year Trillium Fund grant.


Dr. Jennifer Korosi, Dr. Joshua Thienpont, Aniko Gruber, Zahraa Jaafar, Minahill Malik, Marielle Manansala, Divyam Patel, Raha Pishrow, Altrisha Rodrigues, Katherine Tse, York University, Toronto, Ontario, Canada

York University undergraduate students in the Environmental Science program partnered with the Scugog Lake Stewards to investigate lake ice decline on Lake Scugog as part of their senior capstone experience. The Environmental Science Capstone course pairs students with a community partner to tackle a real-world socio-ecological challenge by applying environmental science knowledge and tools. Over the duration of the 12-week term, students researched lake ice decline and its links to climate change, including implications for lake ecosystem health and water quality.

The results of the generalized additive model revealed that ice-off date has been declining since 1971 (R-sq. Adj. = 0.174, deviance explained = 18.7%), and that ice-off now occurs approximately 2 weeks earlier, on average, compared to pre-1970 (Figure 1). This year broke a new record for earliest ice-off, occurring on March 5 compared to the previous record of March 15 in 2012. The trend of earlier ice-off dates fits with the global pattern of lake ice decline described above, due to climate warming.    Ice in, Ice out report, J.Korosi, May ’24


  1. SLS and Dr. Andrea Kirkwood of Ontario Tech. has successfully submitted a MITACS application for partial funding for this summer’s research on a new method developed by the Kirkwood lab. using an eDNA protocol to determine the presence or absence of the charophyte starry stonewort and/or its cousin charophyte, Brittlewort or Nitella and other macrophytes. This research will take place on Lake Simcoe, Lake Scugog and other lakes.  SLS has committed $7,500 plus tax toward this work which includes $3,000 from Lake Simcoe Conservation Authority. This will be added to by lab. analysis costs contributed by Ontario Tech. U.  Whereas analysis in the past has been limited by the need to take physical samples and then painstakingly analyse them, this new methodology will hopefully be much more accurate based on water sampling any analysis only.  This is leading edge science, … and hopefully will lead to a much larger study next year and in future years to determine the full extent of Starry stonewort presence over a wide geography and lead to better knowledge of what are its limiting factors and to management methodologies.         In addition to eDNA monitoring, the grad student Flavia will collect aquatic vegetation and water samples from Lake Scugog and Lake Simcoe, so there will be additional data collected. A research assistant Amelia Rinaldi will assist with the field and lab studies this summer; Amelia is a lab alumna who is starting teachers’ college at Ontario Tech in the fall.
  2. We are planning the first of our pontoon boat trips for early June to bring researchers and new citizen science volunteers up to speed about current status of the lake and its macrophytes. Doctoral student, Flavia Breje who will be conducting the ‘Novel eDNA protocol studies for starry stonewort in Ontario lakes’ study, will accompany this first group.
  3. We are planning our first Science Social: We are inviting Dr. Sapna Sharma to speak on Climate Change on the 14th or the 21st of May in the Anglican Church Hall or the Presbyterian church.  We will have our Newsletter up and running and linked with our Instagram account by then.
  4. Invasive species: Good news.  A presentation was made to the Scugog Environmental Advisory and Climate Change Committee of the Township on Mar. 20. About what to do about the invasion of phragmites grass taking over the Beach area of Palmer Park.  Following that we receive the following note from Keiko Lui, head of SEACCC.  In terms of the invasive Phragmites at Kinsmen’s Beach and surrounding areas, our next steps include reaching out to our current contractor who has been treating phragmites on Municipal lands and internally to find out about the availability of new herbicides that can used in wet areas and what process we’d have to pursue to get it done (via the Township). We would likely already have funds to do the treatment, so it’s just a matter of process etc. Hopefully we will be able to do some education with at least one group at the site regarding this nasty problem.
  5. Lake Month: The planning of this is in a state of flux at the moment.  Consultation indicated that a more pro-active approach might be better, therefore such taglines as:  August is LAKE ACTION MONTH:  What can we all do to keep Lake Scugog Healthy …. Or AUGUST IS LAKE MONTH:  A time to share and care for Lake Scugog. 
  6. Lake Discovery Day: August 10, 2024.   The Latcham Center has been booked which includes the front lawn. Pat has a large white tent to use along with our tent and a tent from Rob.  We all need to take part, so mark your calendar.  We will also have our close partners, Kawartha Conservation, Ontario Tech., etc. We will apply for a grant from the Township to cover the cost of the Latcham and some marketing expenses.  This cannot be done until June.
  7. We have contacted the Lake Partner Program regarding having a lake Steward test Site 8 for the program and have not heard back from them. We will contact them again although it is very late.    

Resulting previous scientific publications and resources: 

All regarding studies on Lake Scugog.

  1. Erin D. Smith, Andrea E. Kirkwood, Community science to the rescue: capturing water quality data during the COVID-19 pandemic, By monitoring these lakes during the summer of 2020, a large water quality data gap was filled, and new findings about regional nutrient patterns were uncovered.
  2. Erin D. Smith, Andrea E. Kirkwood. (2022) Nearshore plankton and macroinvertebrated community structure is strongly associated with macrophyte abundance in a large lake with high shoreline development. Fundamental Applied Limnology 196/1 (2022), Learn More
  3. Tyler J Harrow-Lyle, Andrea Kirkwood. (2021) Pervasive changes to the lower aquatic food web following Nitellopsis obtusa establishment in a large, shallow lake, Freshwater Biology.  file:///C:/Users/Barbara/Desktop/GREAT%20%20INFO/Pervasive%20Changes%20to%20the%20lower%20aquatic%20food%20web.pdf
  4. Erin D. Smith, Deborah Balika, & Andrea E. Kirkwood. (2021). Community science-based monitoring reveals the role of land use scale in driving nearshore water quality in a large, shallow, Canadian lake
  5. Erin D. Smith, Deborah Balika, & Andrea E. Kirkwood. (2020). An assessment of Lake Scugog nearshore water quality and ecological condition (2017-2019)
  6. Tyler J. Harrow-Lyle & Andrea E. Kirkwood. (2020). An assessment of Lake Scugog offshore water quality and ecological condition (2017-2019)
  7. Tyler J. Harrow-Lyle & Andrea E. Kirkwood. (2020). The invasive macrophyte Nitellopsis obtusa may facilitate the invasive mussel Dreissena polymorpha and Microcystis blooms in a large, shallow lake
  8. Tyler J. Harrow-Lyle & Andrea E. Kirkwood. (2021). Low benthic oxygen and high internal phosphorus- loading are strongly associated with the invasive macrophyte Nitellopsis obtusa (starry stonewort) in a large, polymictic lake.
  9. Tyler J. Harrow-Lyle & Andrea E. Kirkwood. (2021). An ecological niche model based on a broad calcium-gradient reveals additional habitat preferences of the invasive charophyte Nitellopsis obtusa.
  10. Tyler J. Harrow-Lyle & Andrea E. Kirkwood.  (2021)  Pervasive changes to the lower aquatic food web following Nitellopsis obtusa establishment in a large, shallow lake, Freshwater Biology.
  11. Tyler J. Harrow-Lyle & Andrea E. Kirkwood. (2022). The non-native charophyte Nitellopsis obtusa (starry stonewort) influences shifts in macrophyte diversity and community structure in lakes across a geologically heterogeneous landscape, Aquatic Ecology.
  12. Tyler J. Harrow-Lyle & Andrea E. Kirkwood (2022), The non-native charophyte Nitellopsis obtusa (starry stonewort) influences shifts in macrophyte diversity and community structure in lakes across a geologically heterogeneous landscape,  Aquatic Ecology.

Additional research to be added soon.