The purpose of this dissertation was to investigate the usefulness and limitations of radioactive tracers as a tool for the study of microbial-meiofaunal trophic interactions under near-natural conditions. / Three methods of delivering labeled substrates to natural cores of sediments were compared. Slurried sediments disrupted the sedimentary structure and significantly altered uptake of labeled substrates by copepod species. Thus, disruption of sedimentary structure can significantly alter microbial-meiofaunal interactions and influence the results of grazing studies. / The ($\sp3$H) -thymidine technique for measuring bacterial production was evaluated. The metabolic fate of labeled thymidine in a coastal marine sediment was not consistent with assumptions necessary for measuring bacterial production or its consumption by meiofauna. / Microautoradiography was used to demonstrate that sedimentary microalgae and heterotrophic bacteria can be selectively labeled with ($\sp{14}$C) -bicarbonate and labeled organic substrates, respectively. / A study was performed to determine if radioactivity measured in copepods from grazing experiments was the result of ingestion of labeled microorganisms or the result of uptake by non-feeding processes. Uptake of label by copepods from ($\sp{14}$C) -bicarbonate was due almost exclusively to grazing on microalgae. Uptake of label by copepods from ($\sp{14}$C) -acetate, however, resulted from activity by epicuticular bacteria and was not due to ingestion of labeled bacteria. / Considered collectively, the results of these studies indicate that, when nondisruptive methods of label introduction are used, ($\sp{14}$C) -bicarbonate can be used as a reliable tracer of grazing on microalgae. Labeled organic substrates, however, do not appear to be a valid tracer form consumption of heterotrophic bacteria. Specifically, uptake by epicuticular bacteria associated with copepods account for essentially all of the radioactivity that is associated with copepods. / Source: Dissertation Abstracts International, Volume: 50-08, Section: B, page: 3250. / Major Professor: David Thistle. / Thesis (Ph.D.)--The Florida State University, 1989.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_78059 |
| Contributors | Carman, Kevin R., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 133 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
Page generated in 0.0023 seconds