To quantify the relationships between burrow density class, burrow opening density, and 
shrimp density, spatially coincident “baseline” samples were collected at 90 random sites 
throughout Yaquina estuary. Shrimp density was determined by hydraulically excavating a 
megainfaunal core barrel (40 cm diameter x 100 cm depth) using a suction-dredge, and washing 
the core barrel contents through a 3 mm mesh to retain burrowing shrimp and other large 
infauna. 
Stable Isotope Data 
Macroalgae samples were collected monthly during 2003 and 2004 from five locations 
along the salinity gradient ranging from polyhaline to oligiohaline conditions. Algal material 
was collected from hard substrates to eliminate contamination from any additional nutrient 
sources other than the water column. Five replicates of healthy macroalgae were collected from 
each sampling site. Samplers wore sterile lab gloves while collecting to prevent contamination. 
Each algae sample was washed thoroughly in RO water, frozen and lyophilized. The dried 
material was ground into a fine powder for isotope analysis. Grinding mortar and pestles were 
thoroughly rinsed with acetone and allowed to completely dry between samples (QAPP 02.01, 
2002 ). 
The EPA Integrated Stable Isotope Research Facility (ISIRF) analyzed the samples for 
6 I5 N according to SOP CL-6 (1999). Nitrogen isotope ratios were measured on macroalgae 
samples combusted in a Carla Erba elemental analyzer (model # 1108) equipped with a 4 meter 
poraplot Q gas chromatograph column directly coupled to an isotope ratio mass spectrometer 
operating in a continuous flow mode (Delta S, Finnigan MAT, San Jose, CA, USA). This 
continuous flow mode also provides a direct measurement of nitrogen content. Protocol and 
methods for operation of the mass spectrometer are all based on published approaches that have 
been verified through multiple approach analyses and inter-lab comparisons. A concentration, 
calibration and reference standard were run at the beginning, mid and end of each run. 
Additionally, a spike, concentration standard and blank were run every ten samples. Standard 
material included NBS tomato leaves (1573) for concentration standard; NBS spinach (1570) for 
reference standard; NIST Com Stalk for calibration standard and spike recovery. 
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