Month: December 2019

Record High Water Levels – Why?

U.S. Army Corps Water Levels Video
Click here to proceed to a 2’49” U.S. Army Corps of Engineers video providing very clear information about why Lake Superior water levels are high.

An endless stream of articles on Superior’s record high water levels has been published. How about publishing an article on why? Why, that is, water levels are this high in the first place.

In a recent Washington Post article, meteorologist and climate scientist Kim Frauhammer nicely answers this question. A link to this excellent, in-depth article is included below. Meanwhile, here is a snapshot providing key article takeaways about “why” Superior’s water levels are so high: 

  • high levels of precipitation in the Lake Superior region over the last several months (including record precipitation for the Great Lakes Basin, April through June)
  • high rates of Superior watershed spring run-off due to high winter precipitation (the article notes an ongoing factor, the lag between precipitation, or lack thereof, and water levels).

Frauhammer touches on climate change but points out that this factor is complex, not a simple, linear factor. For example, she notes that climate is something of a double-edged sword and that:

  • the Great Lakes region has seen a 10% increase in precipitation between 1901 and 2015
  • a warm atmosphere can hold more water, leading to increased precipitation
  • conversely, warm air and water can also lead to increased evaporation, leading to an increased rate of water level decline, as observed during lower water levels in 2013.

So, what is the article’s conclusion… more record highs or rapid declines? The answer is both. According to Kim Frauhammer, expect instability, manifested through erratic year to year swings between highs and lows.

Read the full Washington Post article here.

Projected Lake Superior water levels.
What about the future? The graphic above shows projected water levels through the next 6 months into spring, 2020. U.S. Army Corps of Engineers Data Graphic.

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Sustainable Fisheries Survey

Fish tug Rosaline
The commercial fishing tug ‘Rosaline’ operating off the Black Bay Peninsula, Ontario. Photo: Infosuperior.

Lake Superior covers more of the globe than any other lake in the world, by far. Since Superior is the largest lake by surface area, it is reasonable to expect that fish from the lake would be easily available in Lake Superior communities. This is not the case.

Try going to a supermarket in Terrace Bay, Thunder Bay, Munising or Marathon to buy Lake Superior fish. Around the lake, with a few notable exceptions in the form of specialty fish shops and a handfull of restaurants, Lake Superior fish is very difficult to access. This, despite the fact that regional communities are situated beside the largest lake in the world. 

A survey being undertaken by Lakehead University and entitled, Sustainable Fisheries in the Lake Superior Region,” might help to understand how this situation could be changed for the better. 

Go directly to the “Sustainable Fisheries in the Lake Superior Region” Survey.

The project is supported by Lakehead University, the Lake Superior Living Labs Network and the Social Sciences and Humanities Research Council.

The purpose of the survey is to explore the network of people and organizations involved in all aspects of fisheries across the Lake Superior watershed (including the Canadian and US sides of the lake and Indigenous governance). Harvesting, processing, transportation, distribution, marketing, retail, consumption and waste will all be considered, in addition to policy, research, and management. Information gleaned through the survey will help to map relationships and better understand the network of organizations and institutions involved with fisheries. In essence, the survey is a stepping stone helping to build collective action towards more sustainable fisheries for the region.

Once the survey is completed, case study research will be undertaken focusing on innovative examples of how to integrate fisheries into local and sustainable food systems for the region. 

All results will be shared at a knowledge-sharing workshop in 2021, as well as in academic publications and conference presentations. 

Links:

Go Directly to the Survey

Website: Exploring Food and Fishery Systems in the Lake Superior Region


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Dec. 5th Presentation: Trekking Superior’s Ice

Many of us who live around Lake Superior have skated on the big lake’s ice. Some of us have hiked the ice to nearby islands, ice caves or points of interest. Still others have travelled even further by ice and distances of over 50 km / 31 mi. have been completed by skiers from around the lake.

At 7 p.m. on Thursday, December 5th, at the Mary J.L. Black Library in Thunder Bay, local historian Bill Skrepichuk will present an account of a much longer trek on Superior’s ice. Bill’s presentation, complete with graphics, outlines the story of over 3000 troops that trekked remote stretches of Superior’s ice in 1885. The troop movement was part of efforts by Canada’s government to move troops westward to the present day Winnipeg area to quell unrest. Various sections of the Canadian Pacific Railway around Superior’s North Shore were incomplete at the time, hence the lengthy treks over the ice, including the following stretches of Lake Superior.

  • Port Munro (just west of Marathon,) to McKellar Harbour (west of Neys Provincial Park)
  • Jackfish Bay (east of Terrace Bay) to Winston Harbour (east of Rossport)
  • Kama (east of Nipigon) to Red Rock.

Bill Skrepichuk’s presentation is extremely well researched and is based upon the book he wrote entitled, “Troop Treks of 1885: Documents and Illustrations.” Hard and soft cover copies of the book will be available at the presentation which is free of charge. Everyone is welcome.


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Available for Public Review: Draft Binational Screening Criteria for Nominated Chemicals of Mutual Concern

Keeping the Great Lakes healthy requires binational efforts when it comes to Chemicals of Mutual Concern. Photo: Infosuperior.

Canada and the United States each have policies and mandates that deal with the management of toxic substances and chemicals and their release into the Great Lakes Basin. In Canada, this is covered by the Chemicals Management Plan under the Canadian Environmental Protection Act, 1999. In the United States, it is the Toxic Substances Control Act that deals with these matters. The two countries have previously identified 8 contaminants that require cooperative binational efforts to manage the severity and extent of their potential contamination. These are known as Chemicals of Mutual Concern (CMCs).

Defining Criteria With Public Input

How exactly do these chemicals become designated as CMCs? To make a consistent framework for this decision, under Annex 3 of the Great Lakes Water Quality Agreement, Environment and Climate Change Canada and the U.S. Environmental Protection Agency have drawn up a set of 6 criteria that are described in The Draft Binational Screening Criteria for Chemicals of Mutual Concern. This document is currently available for public review. Comments and questions will be accepted until Dec 16, 2019.

Binational.net: Draft Binational Screening Criteria for Nominated Chemicals of Mutual Concern Available for Public Review


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[Research] Invasive Mussels Complicate Efforts to Reduce Mercury in Great Lakes Food Chain

Zebra Mussels are making it harder for native fish species to get nutrients and researchers at the University of Wisconsin-Madison are finding that this is leading to fish that are enriched in mercury despite efforts by Canada and the U.S. to reduce mercury loading in the Great Lakes. USFWS Photo.

Mercury is a naturally occurring element which poses several challenges when incorporated into fish as a contaminant, methylmercury. When released to the environment from the earth’s crust, either via natural degassing processes or due to anthropogenic activities like burning fossil fuels, mercury enters into a complex cycle, interacting with other elements and forming a variety of compounds. It can remain in the atmosphere for 6-12 months before being deposited in a water soluble form. Water soluble mercury can then be converted to the highly toxic and bioaccumulative methylmercury, which can cause both long-term and short-term damage to kidneys, the brain, and developing foetuses, when consumed in significant amounts by humans.

A new study published in the November 2019 issue of the “Proceedings of the National Academy of Science” shows that Canadian and U.S. reductions of mercury inputs to the Great Lakes (mercury emissions went down 60% between 1990 and 2005 in the U.S., and 85% between 1990 and 2010 in Canada) hasn’t been reflected in reduced mercury in fish to the extent that might have been expected. Through stable isotope ratio analysis in fish and sediment samples from 1978 to 2012, the researchers of Mercury source changes and food web shifts alter contamination signatures of predatory fish from Lake Michigan (Lepak et. al) discovered that an initial decline in mercury concentrations in fish immediately after efforts to reduce domestic mercury inputs did not continue at the expected rate into the 90s and 2000s. An explosive increase of invasive dreissenid mussel populations in the region, zebra mussels in the 90s and quagga mussels in the 2000s, coincided with this stunted rate of mercury reductions in fish. The researchers suggest that this may be due to the impact of invasive species on food web pathways.

Infosuperior spoke with lead author Ryan Lepak, postdoctoral researcher at the UW–Madison Aquatic Sciences Center (ASC), over email to get a better idea of what this research tells us about the Great Lakes ecosystem and shifting mercury sources.


Lead author Ryan Lepak at work, testing Lake Michigan sediment for mercury. Photo courtesy of Ryan Lepak.

Q:  Your research found that reducing the mercury load on the Great Lakes hasn’t been reflected in reduced mercury in fish because of the effect of invasive species on what foods are available to fish. Is it possible to estimate how long it will take for the reduced mercury emissions to be depicted in the food chain if we take these findings into consideration?

Ryan Lepak: As you might know from the many examples worldwide, we cannot begin to predict the interactions invasive species might have on the trophic structure of a lake and the energy pathways fish use to survive. Contaminants like mercury are closely linked to these pathways adding an increased level of complexity. That said, here’s what we’re sure of:

  1. Without reductions to mercury emissions in the past, [mercury levels in] fish today would be even higher (we know this because the air, water and sediment mercury are all lower now than they were 20 years ago.)
  2. Mercury is an element and unlike many contaminants (like organic chemicals) it cannot be destroyed. Human activities have increased the amount of mercury cycling in the world and we’re highly unlikely to ever achieve zero mercury fish.

That said, it is reassuring to find that our strategies to reduce mercury in the environment is actually resulting in quicker declines locally than we’d ever expect. (See: PNAS: Zheng et al., Observed decrease in atmospheric mercury explained by global decline in anthropogenic emissions)


Photo courtesy of Ryan Lepak

Q: In the news release from University of Wisconsin Sea Grant, it is explained that dreissenid mussel invasion of the Great Lakes has pushed fish to seek food sources that are more enriched in methylmercury from the lake bottom and nearshore environments. What makes these food sources more enriched in methylmercury?

Ryan Lepak: In many lakes, the bottom is enriched in methylmercury because the microbes that make methylmercury from mercury do their work in the absence of dissolved oxygen. Lake Michigan does not have an appreciable layer of water lacking oxygen. Instead, fish are now eating items from the bottom and nearshore that are nutritionally less valuable and they are working harder to find a meal thus becoming leaner, which in the fish world is bad. The rate of change to these nutritional/diet/energy pathways is changing faster than we are reducing mercury loading to the lake, leading to the false impression that fish [mercury levels] are increasing. In fact, to compare mercury concentrations between fish now and in the past you need to consider how lifestyle changes have impacted the overall well being of the fish. Presently, because of invasive species, lake trout are growing slower and therefore a fish at 400 mm I collect today might be 3-4 years older than a 400 mm fish from 1995. With increased age comes increased time to accumulate mercury.

Q: So fish are having to consume more food that is contaminated with mercury to meet their energy needs and they are becoming leaner because they have to work harder for that energy, which results in higher concentrations of mercury in the fish than would be present if they did not have to adjust their eating habits. Do we know what the concentrations of Mercury in the dreissenid mussels are, relative to what is found in the fish?

Ryan Lepak: They’re actually quite low, maybe 1/10th the amount. 

Q: What is the biggest take-away from your research?

Ryan Lepak: The important story here is that using carbon, nitrogen and mercury fingerprinting (isotopes) we are able to identify shifts in sources of mercury to lake trout following the removal of major mercury sources regionally. Without that aid, we would assume that mercury controls do not work if we solely looked at mercury concentrations in fish through time. In fact what we’ve learned is that the great lakes benefit greatly from local mercury reductions and that invasive species have altered contaminant cycling and bioaccumulation pathways in a considerable way. This highlights the tremendous value of programs focused on monitoring and archiving. Environment Canada and the Swedish hold the only such archives in the world. It’s ironic, collectively we’ve focused intensely on reducing chemicals in the Great Lakes (for good reason) to improve chemical burden on fish for human and wildlife safety while largely ignoring the biological “contaminants” (invasive species). Now we’re finding that due to invasive species, the chemical burden on a similar sized fish is greater, not because we’ve mismanaged chemical loading/inventories but because the biology of the system has changed. 

Ryan Lepak and his co-authors’ research allows us to better understand and monitor Mercury contamination in the Great Lakes food web. They show that we cannot solely focus on the total amount of mercury emissions, but must also look at how these emissions reach the fish we eat through a dynamic system where invasive species are having a major impact on food availability for native fish populations.

References

Lepak, Ryan F., et al., “Mercury source changes and food web shifts alter contamination signatures of predatory fish from Lake Michigan.” Proceedings of the National Academy of Sciences Nov 2019, 116 (47) 23600-23608; DOI: 10.1073/pnas.1907484116

Zhang, Yanxu, et al., “Observed decrease in atmospheric mercury explained by global decline in anthropogenic emissions.” Proceedings of the National Academy of Sciences Jan 2016, 113 (3) 526-531; DOI: 10.1073/pnas.1516312113

Links:

University of Wisconsin Sea Grant News Release – Aquatic invasive species are short-circuiting benefits from mercury reduction in the Great Lakes

2005 Water Quality Association Mercury Fact Sheet

EPA Mercury Emissions: The Global Context

IJC 2015 Article – Reducing Great Lakes Mercury Contamination: Regional Efforts May Not Be Enough


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