Project Breathless brings together an interdisciplinary team of ecologists, economists and communication scholars to increase understanding of the impact of low oxygen dead zones in lakes and oceans. The project team focuses on how low oxygen conditions influence fish, their habitats and the food webs that support them, as well as ecosystem services, including fisheries production.
The study focuses on several species of fish and their food webs in the Baltic Sea, Gulf of Mexico and Lake Erie.
Project Breathless is supported by a grant from the U.S. National Science Foundation (award #: 1923965).
Project Breathless examines the impacts of dead zones on aquatic food webs.Image adapted from photo by Peter Ljungberg, SLU
Dead zones - or hypoxic zones - are areas of significantly reduced oxygen in oceans, estuaries and lakes. Pollution from runoff and warming waters due to climate change are leading to an increase in the occurrence of hypoxic zones worldwide.
Exploring dead zones through a fish's eyes and ears
Chemical analysis of fish eye lenses and earstones reveals impacts of low oxygen exposure.
Earstones, or otoliths, are tiny, calcified structures in fishes' ears that grow in concentric rings. The age and condition of a fish can be tracked by examining earstone growth rings. As they grow, earstones absorb trace elements from the water. The presence of the element manganese in an earstone can indicate a fish's exposure to low oxygen conditions.
The presence of methlymercury in eye lenses can also be an indicator of hypoxia. Methlymercury is a neurotoxin that is made more bioavailable under low oxygen conditions, mobilizing it into aquatic food webs.
For more details about Project Breathless research, visit our Project Details page.
breathing new life into dead zones
We know the causes of dead zones. Urbanization, loss of natural land cover, fossil fuel use and certain agricultural practices lead to runoff of fertilizers, sewage and other pollutants into our waterways. These pollutants accumulate in lakes and coastal areas and lead to algal blooms, which cause low oxygen conditions when the algae die and decompose. Climate change is increasing water temperatures, leading to larger and more severe hypoxic events.
Fortunately, many of the solutions to mitigate and adapt to climate change will also address causes of hypoxia. These include:
Reducing emissions from the energy, transportation and food sectors
Revitalizing cities to be green and sustainable
Conserving natural landscapes
Using nature-based solutions for storm water management
Using flood-proof wastewater infrastructure
Reducing agricultural runoff