Methods

The University of Washington Tacoma Estuaries class conducted oceanographic survey throughout varies basins in the Puget Sound during the months of March, April, and May 2023. The basins that were sampled during spring quarter consisted of: Commencement Bay, Quartermaster Harbor, Main Basin and the San Juan Islands. At each basin, water samples were collected and analyzed for water properties using a Seabird CTD, Niskin and Thoreson bottles, Secchi disk, and a phytoplankton tow net (20um). On the larger vessels a Seabird CTD and Rossette was used. Sediments and microplastics were collected at some stations using a Van veen and microplastics manta net respectively. CTD data included temperature, salinity, density, dissolved oxygen, fluorescence and transmissivity. Discrete water samples data consisted of dissolved oxygen, chlorophyll-a, nutrients (nitrate, nitrite, ammonia, phosphate, and silicate), and phytoplankton were collected at both surface depths and bottom depths. A Secchi disk was lowered to determine the light layer. A phytoplankton tow net was lowered to 10 meters to analyze phytoplankton abundance near the surface. Sediments samples were obtained via a Van veen being lowered to the bottom at selected stations. At various stations microplastics were collected via a surface tow manta net (335 um). Lastly zooplankton vertical net tows (211 um) were done to collect samples from the water column. A verticla zooplankton net tow was done in the main basin from 140 m to 40 m at two stations and two vertical zooplankton net tows were done in the San Juans from 75 m to the surface.

All water samples were taken back to the University of Washington Tacoma Oceanography/Limnology Lab for water properties analysis. Main Basin and San Juan Islands sample analyses were done onboard the research vessel and the Friday Harbor Lab respectively.

This class website focuses on reporting and analyzing the results from the water samples collected throughout the quarter.

Field Methods Standard Operating Procedures

The Weelander

Vessel used for Com-bay & QMH

RV Rachel Carson

(from the Rachel Carson Oceanography site)

Vessel used for Main Basin

RV Kittiwake

(from FHL information website)

Vessel used for San Juan Island

Seabird 19 CTD

CTD being lowered, from The Weelander

CTD Rosette

CTD Rosette being lowered, from RV R.C.

CTD Rosette

CTD Rosette, from RV Kittiwake

Niskin Bottle

Clint H. preparing the Niskin bottle prior to water sampling on The Wheelander.

Dissolved Oxygen

Dissolved oxygen water sample being taken from CTD rosette on the Rachel Carson.

Chlorophyll

Chlorophyll water sample being collected from CTD rosette on the Rachel Carson.

Nutrients

Arthur W. collecting nutrients sample, using a syringe and filter.

Secchi Disk

Natasha W. prepares to lower Secchi disk for turbidity reading.

Phytoplankton Net

Tai N. straightens out phytoplankton net before lowering into the water.

Zooplankton Net

Arthur W. & Michael P. monitors zooplankton net as its lowered.

Microplastics Net

Microplastics tow net is lowered and dragged behind the RV Rachel Carson.

Van Veen

Michael P. lowers a Van Veen for sediment sampling off The Wheelander.

Zooplankton Collection

Gracelyn S. & Tim W. collects zooplankton sample from net.

Sieving Microplastics

Microplastic sample is pour through multiple sieves prior to data analysis.

Collecting Sediments

Gracelyn S. collects sediments samples from Van Veen.

Laboratory Standard Operating Procedures

UWT Laboratory

Oceanography Lab at University of Washington - Tacoma

RV Rachel Carson

Wet Laboratory onboard the RV Rachel Carson.

Friday Day Harbor

Laboratory on San Juan - Friday Harbor

Microscopes

Microscopes secured in dry lab of RV Rachel Carson.

Chlorophyll Analysis

Devices onboard the RV Rachel Carson used for chlorophyll analysis.

Dissolved Oxygen Analysis

Devices onboard the RV Rachel Carson used for dissolved oxygen analysis.

Counting Phytoplankton

Arthur W. & Mateo S. counting phytoplankton samples onboard the RV Rachel Carson.

Laboratory methods used are as follows. All dissolved oxygen procedures followed the Winkler titration method found in The accuracy of the Winkler method for dissolved oxygen (Carpenter, 1965). All chlorophyll procedures followed the method outlined in A Practical handbook of seawater analysis (Strickland, 1972). All nutrients were run by the UW Seattle Marine Chemistry Lab. Phytoplankton procedures followed best practices in A taxonomic guide to some common marine phytoplankton (Horner, 2002). Laboratory methods for phytoplankton were unique to our class. Net samples were counted on a Sedgewick slide for only one transect and the total count of phytoplankton would be recorded. As for the discrete sample of phytoplankton, multiple transects would be counted until a total count of 100 phytoplankton was reached. Sediment protocol followed the PSA Beckman Coulter LS 13 320 manual. Microplastics procedures used followed the Laboratory methods for the analysis of microplastics in the marine environment (Masura, 2015)

Paged Developed by Tai Nguyen

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