What is this thing floating on the lake?
This is an aquatic insect emergence trap. It collects insects as they emerge from the water as winged adults. Also attached to the emergence trap are other devices, including funnel traps and artifical substrate, for collecting invertebrates as they move through the water.
We gather and count the invertebrates captured by these traps each week to learn more about the health of the lake. Please do not disturb these collection devices, as it will limit the usefulness of our data, including our ability to predict emerging problems with the lake ecosystem.
Why are scientists collecting insects and other invertebrates?
Lakes provide essential resources including drinking water, irrigation, and recreation. However, these ecosystems face growing threats from harmful blue-green algae. Toxins produced by harmful blue-green algae – known as cyanotoxins – pose significant risks to human health, causing liver damage and promoting tumor growth. You may have seen you local lake closed in previous summers and falls. These closures are issued by the Washington Department of Health when cyanotoxins exceed safe levels. Unfortunately, over the past decade, the prevalence of cyanotoxins across the U.S. has risen by 500%. This poses a serious threat to our food supply and the quality of life in rural and tribal communities.
Figure 1: Freshwater cyanotoxin advisories and closures have risen 500% in United States in 10 years. Data from USA EPA.
Insects and other aquatic invertebrates are essential components of a healthy lake ecosystem. They provide food for fish and other larger animals, break down debris, and contribute to nutrient cycling. But while invertebrates are likely affected by cyanotoxins, the extent of these impacts remains poorly understood. This gap in knowledge lessens our ability to maintain the health and utility of our local lakes.
Invertebrate species also vary in their sensitivity to habitat degradation. For this reason, by recording what invertebrates we find in a lake, we can monitor the health of the lake quickly, cheaply, and effectively. However, we currently do not know which invertebrates are tolerant versus sensitive to cyanotoxins.
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The goal of this scientific research is to investigate the effects of cyanotoxins on aquatic invertebrates using four local lakes: Pass Lake, Lake Campbell, Lake Erie, and Heart Lake. By simultaneously monitoring the invertebrate community and cyanotoxins at these sites, we aim to 1) determine the relationship between cyanotoxins and invertebrate diversity, 2) identify potential indicator species of cyanotoxins, and 3) assess the risk that cyanotoxins adversely impact fish and other consumers of invertebrates through accumulation toxins.
Figure 2: Great Blue Heron (left) hunts for prey behind a cyanotoxin closure sign. Pass Lake, Washington.
Do you have permits for this research?
Yes! This research has been approved by the Washington Department of Fish and Wildlife, Washington State Parks, and the City of Anacortes. This project also has approval and a letter of support from Lummi Natural Resources.
Why is the lake closed?
The Washington Department of Health may close reactional access to a lake when cyanotoxins exceed safe levels. We are not responisble for these closures. Our data are not used to decide whether a lake should be closed. However, if Washington Department of Health has closed recreation access, it is because they have determined that the water contains high levels of toxins harmful to human health.