| dc.contributor.author | Roegner, George Curtis. | en_US |
| dc.date.accessioned | 2014-10-21T12:38:00Z | |
| dc.date.available | 1996 | |
| dc.date.issued | 1996 | en_US |
| dc.identifier.other | AAINN15942 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55142 | |
| dc.description | The physical oceanography of a shallow estuarine system located along the Eastern Shore of Nova Scotia was studied to examine sources and tidal transport of mero- and holoplankton groups. The estuary was highly flushed and characterized the dispersive endmember of the physical retention continuum. Estuarine residence times were found to be much lower than that required for molluscan planktonic development, indicating that larvae tended to be exported from the system. Gastropod larvae exhibited especially large exports from estuary to sea. However, all groups, including bivalve larvae and holoplankton, were consistently transported between estuary and the nearshore zone. Recruitment of benthic organisms to the system is probably dependent on an allochthonous source of larvae. | en_US |
| dc.description | A laboratory flume was used to examine the transport of burrowed juvenile soft-shell clams (2 weeks post-settlement) when exposed to flow velocities typical of tidal currents measured in the field. Clams resisted erosion until the initiation of sediment transport, after which they were rapidly advected from sections of test substrate. Comparisons between living and dead clams indicated that burrowing behavior was important for maintaining position at velocities below the critical erosion velocity for sediment movement. The ability of low density, shallow-burrowing juvenile bivalves to avoid transport as bedload or resuspended particles is probably minimal during erosional periods. | en_US |
| dc.description | The effects of juvenile transport on the recruitment patterns of three estuarine bivalves (Mya arenaria, Macoma balthica, and Gemma gemma) were investigated at four sites in the Eel River estuary, Nova Scotia. The sites differed in the magnitude of horizontal current velocity and aerial exposure. Immigration of animals into experimentally defaunated sediments and monthly samples of clam populations over the three year study confirmed that all these species have the ability to recruit through juvenile transport. Transport rates were sufficient to replenish juvenile clams in defaunated plots to control values within days. | en_US |
| dc.description | Laboratory and field experiments were conducted to compare growth of juvenile clams as a function of aerial exposure. In the laboratory, growth of clams held at different levels of aerial exposure, but supplied with an equal food ration, allowed separation of the physiological effects of emersion from that of reduced feeding. In a second experiment, clams were grown at three exposure levels in the field. Both laboratory and field experiments confirmed a significant reduction in shell growth and tissue weight of clams placed at mid-intertidal exposures in comparison to those continuously immersed. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1996. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Physical Oceanography. | en_US |
| dc.subject | Biology, Oceanography. | en_US |
| dc.title | Hydrodynamic factors affecting the recruitment of bivalve molluscs in a tidally-dominated estuary. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
