Castellan, A. C. Virginia Institute of Marine Science REU, accastellan@osprey.smcm.edu

 
PHYSICAL SEDIMENT DISTURBANCE EFFECTS ON JUVENILE RECRUITMENT PROCESSES AND MACROBENTHIC COMMUNITY STRUCTURE OF MUDDY ESTUARIES
 
Physical disturbance is an important process that shapes terrestrial and aquatic community structure. Recent studies indicate that physical sediment disturbance is common in estuaries, particularly in regions such as estuarine turbidity maximum where trapped fine sediments are highly mobile. Nonetheless, physical disturbance effects on macrofaunal communities in these regions remain poorly studied. One important way physical disturbance can affect macrofaunal community structure is through recruitment processes. For example, mechanical disruption of the sediment-water interface may lead to enhanced mortality of newly recruited individuals or disturbance may create chemical signals, such as elevated NH4+ levels, that deter recruitment. In this study, macrobenthic species abundance and diversity were compared for high energy (York River) and low energy (Patuxent River) Chesapeake Bay subestuaries. Burial times for juvenile amphipods (Leptocheirus plumulous) were also measured for intact sediment cores from the York River that had sediment surface porewater NH4+ concentrations ranging from 34-97 uM. The observed macrofaunal abundance and diversity trends are consistent with the hypothesis that disturbance alters benthic community structure. Leptocheirus burrowed rapidly at all NH4+ levels tested, thus, the ammonium levels characteristic of disturbed York River sediment do not provide pre-recruitment chemical cues to deter Leptocheirus recruitment.
 
Day: Wednesday, Feb. 3
Time:
Location: Sweeney Center
 
Code: SS54WE1535S