Record Details
A seasonal study of sediment reworking by Neotrypaea californiensis in Yaquina Bay, Oregon
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | A seasonal study of sediment reworking by Neotrypaea californiensis in Yaquina Bay, Oregon |
| Names |
Fritz, Cara E.
(creator) Wheatcroft, Robert A. (advisor) |
| Date Issued | 2002-04-02 (iso8601) |
| Note | Graduation date: 2002 |
| Abstract | A year-long field study was undertaken to investigate the influence of a number of physical and biological factors, specifically temperature, organic carbon content, and shrimp population dynamics on sediment reworking rates by the ghost shrimp Neotrypaea calforniensis. Because of its role as a structuring agent in estuaries along the West Coast, it is important to understand the factors that impact shrimp reworking rates. At a site in the intertidal of Yaquina Bay, Oregon, measurements of sediment reworking (via direct entrapment of sediment ejected from burrows) were taken at monthly intervals over the course of a 15-month period. Abiotic (temperature, organic carbon content) and biotic parameters (shrimp size, density) were measured concurrently. Rates of reworking normalized to shrimp biomass/m² varied over the year, with lows in the winter months and a peak in August. This pattern corresponds closely to temperature fluctuations. Although a deep subsurface deposit feeder, the close correspondence between reworking activity and temperature indicates that Neotrypaea is in close contact with conditions at the sediment surface. Taking into consideration the decrease in shrimp abundance over the year, the amount of sediment reworked over a given area ranged from 2.7 to 41.0 g dry sediment/hr/m². The peak in overall reworking for this site was in early spring, which has implications for recruitment of benthic organisms. Observations on food availability at feeding depths and sediment turnover rates, from direct entrapment and a heavy mineral tracer experiment, suggest that the ghost shrimp may obtain nutritional material using methods aside from ingesting particles that are subducted to depth. |
| Genre | Thesis/Dissertation |
| Topic | Bay ghost shrimp -- Oregon -- Yaquina Bay |
| Identifier | http://hdl.handle.net/1957/22928 |
