Althea Marks

Althea Marks

Althea Marks
Graduate Student, M.S. Biology expected 2019

Althea’s CV

Graduate Thesis Committee:
Dr. Danielle Zacherl (CSUF) Dr. Paul Stapp (CSUF), Dr. Douglas Eernisse (CSUF), Dr. Ted Grosholz (UC Davis)

Research Interests
I am interested in the physical and biological services that coastal habitats provide such as water filtration, habitat creation, and shoreline stabilization. My B.S. Environmental Science (University of New Hampshire) focused on watershed water quality, which meshes with my graduate research on water quality services provided by oyster habitat on the west coast.

The Olympia oyster (Ostrea lurida) is native from British Columbia to Baja California, and a main component to living shoreline projects in San Francisco Bay, Newport Bay, and San Diego Bay. Oysters are a key component to these projects because they are considered foundation species which provide several ecosystem services. Oysters settle and grow on top of each other in aggregations called reefs or beds. These structures form complex three-dimensional habitat for other organisms and attenuate wave energy that erodes shorelines. Oysters are also suspension feeders that remove particulate matter from the water column. However, the filtration services of Olympia oyster habitat is understudied, and the filtration services provided by living shoreline projects is unknown.

The Pacific oyster (Crassostrea gigas) is a feral non-native oyster also present in many west coast bays and estuaries. It was introduced in the early 1900s for aquaculture to replace Olympia oyster harvest following a population crash. The Pacific oyster is a larger and more robust filter feeder, and may contribute substantially (both feral and cultivated populations) to the overall filtration budget to bays and estuaries.

I am measuring the in situ (field) filtration rates of both Olympia oyster habitat and cultivated Pacific oysters in:

  • San Diego Bay, CA (Pacific oyster aquaculture structures)
  • Newport Bay, CA (Upper Newport Bay Living Shorelines Project)
  • San Francisco Bay, CA (San Rafael Living Shorelines Project)
  • Port Eliza Bay, BC, Canada (natural high density beds for comparison)

This research will answer the following questions:

  1. How do community composition and filter feeder density affect filtration rates of oyster habitat?
  2. How do water quality parameters (temperature, salinity, turbidity, chlorophyll, and water flow speed) vary and affect oyster habitat filtration rates?
  3. What is the filtration capacity of C. gigas aquaculture operations in San Diego Bay?

Pilot studies are starting Fall 2017, and primary data collection will begin early 2018.

Research Funding Provided By:
The National Geographic Society
California State University Fullerton