Assessing Ocean Acidification and Hypoxia impacts in Oregon

Hello Everyone! My name is Kaegan Scully-Engelmeyer and I am thrilled to have joined the Oregon Sea Grant Scholars as the 2021-22 Ocean Acidification and Hypoxia (OAH) Fellow with the Oregon Department of Environmental Quality (DEQ). Since starting this fellowship in December I have joined the water quality assessment team at DEQ and have been supporting the coordination and organization of a recently formed OAH scientific-technical workgroup. The workgroup has been convened to assist DEQ in developing procedures for assessing the biological impacts of OAH in Oregon’s territorial waters (which extend three nautical miles from the shoreline). In this post I’ll give a simplified overview of Ocean Acidification and Hypoxia as water quality stressors, and then share some of the details of DEQ’s water quality assessment process. In future posts I’ll get more in depth about each of these areas.

Ocean Acidification and Hypoxia as water quality stressors (simplified):

Ocean Acidification (OA): As carbon dioxide (CO2) is released into the atmosphere, around 30% of it is stored in the ocean. In the simplest terms, Ocean Acidification refers to a series of carbonate chemistry reactions in which increasing levels of CO2 in the ocean lowers the pH of the water. This change in chemistry has been shown to negatively impact certain types of ocean dwelling species, particularly those that form a calcified shell. In recent years OA research has seen a swift rise in the coastal and oceanographic scientific community, as scientists work to understand current and future impacts to ocean health and ocean-reliant economies.

Hypoxia: Hypoxia in this case refers to low dissolved oxygen conditions. In Oregon’s marine waters these conditions occur mainly because of a process called upwelling, wherein low oxygen/nutrient rich water from deep in the ocean is brought into the upper water column. As nutrient rich water is exposed to light, phytoplankton (microscopic plants) bloom and their resulting decomposition uses oxygen, lowering the amount of dissolved oxygen available in the water column. As you can guess, these low oxygen conditions can have a negative impact on aquatic species. These processes are naturally occurring phenomena here off the coast of Oregon, but in recent years climatic shifts controlling the extent and duration of upwelling have led to longer upwelling seasons, expanding the area and duration of these low oxygen events.

If you’re interested, here is link to two short videos that dive a little deeper into these processes and how they relate to Oregon, I highly recommend checking them out.

Water quality assessment:

The Water Quality Assessment Program at DEQ is responsible for assessing and reporting to the U.S. Environmental Protection Agency (EPA) on the condition of Oregon’s surface waters every two years. The water quality assessment team relies on water quality data collected internally at DEQ as well as data and information submitted during a public call for data. These data are assessed and compared to existing water quality criteria to determine if a waterbody is not meeting the criteria or impaired. A list of impaired waters is submitted to EPA as a part of the DEQ’s Integrated Report every two years. If you’re interested in a more detailed breakdown, DEQ’s assessment team created a great story map that walks through the assessment and Integrated Report process.

DEQ does not (yet) have a defined procedure to assess the impacts of OAH on biological life in Oregon’s marine waters. As you can imagine, it is a uniquely challenging endeavor to assess biological impacts related to OAH conditions in an environment such as the ocean, one that is constantly changing and influenced by so many large-scale processes and factors. This is why the assistance of this technical workgroup is so critical in developing a robust and scientifically sound assessment procedure. We’ve had one full workgroup meeting so far and are currently working in a subgroup format to develop a draft assessment procedure to workshop with larger group. Thus far working with the assessment team at DEQ and the technical workgroup members from across the region has been an excellent experience, and I am looking forward to continuing to make progress towards OAH assessment procedures.

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