Spring-neap variation in fecal pellet properties within surficial sediment of the York River stuary, Virginia

Abstract

Fecal pellet abundance was measured within the upper seabed of the York River Estuary as part of a larger study investigating relationships between fine sediment aggregates and bed erodibility. Sedimentalogical surveys were conducted twice a month during the spring and summer of 2011 to coincide with spring or neap tidal cycles. Particle size distributions were determined by sieving the sediment using three methods: 1) typical grain size analysis, 2) gentle agitation with seawater, 3) gentle agitation with deionized water. Each method used four sieves (150, 90, 63 and 45 microns) to constrain the size abundance of the particles. The study found that resilient fecal pellets comprised up to ~30% of the total sediment within the top centimeter of the seabed, and abundance was not directly related to spring-neap tidal cycles. There was a tendency, however, for larger pellets to persist around neap tide, perhaps because stronger currents at spring tide were more likely to break apart the largest pellets. Also, a greater mass of pellets was preserved when seawater rather than deionized water was used during sieving

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