summary of data used in this report and analysis techniques are presented in Chapter 4. 
Chapter 5 provides information on spatial and temporal patterns in water quality data, including 
important factors influencing water quality distributions. Seasonal, zonal, and long-term trends 
in causal (nitrogen and phosphorous) and response (chlorophyll a, dissolved oxygen, and water 
clarity) variables are presented in Chapters 6-9. These chapters also include cumulative 
distribution functions for causal and response variables and comparison of water quality 
conditions in Yaquina Estuary to those in other Oregon estuaries. In addition, comparisons of 
observations from Yaquina Estuary to existing State of Oregon chlorophyll a and dissolved 
oxygen criteria are summarized in Chapters 7 and 8. Chapter 10 examines the usefulness of 
macroalgal biomass as a response variable for the Yaquina Estuary, including descriptions of 
seasonal, interannual, and zonal patterns in macroalgal biomass and factors which influence its 
distribution. Chapter 11 provides a description of the distribution, variability, and factors 
influencing Zostera marina habitat in the estuary as well as light requirements for this species. 
Chapter 12 provides a demonstration of using a mechanistic stress-response model for Z. marina 
to assess whether specific water clarity percentiles are protective of existing habitat. A summary 
of the results of this study and recommendations are provided in Chapter 13. 
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