Comparison of bacterial dynamics in tidal creeks of the lower Delmarva Peninsula, Virginia, USA

Abstract

ABSTRACT. Bacterial biornass, abundance, and product~vity were greater in 3 tidal marsh creeks on the Chesapeake Bay side of the lower Delmarva Peninsula than in nearby creeks of the seaside coastal lagoon complex (biomass: 462 and 71 n g C ml-'; abundance: 12 X 10' and 3.8 X 106 cells ml-l; productivity: 46 and 7.3 ng C rnl-' h-'; bayside and seaside respectively). Bacterial cell-size distributions were also significantly different between the seaside and bayside creeks, with a larger proportion of smaller cells dominating samples from the seaside creeks. Bayside and seaside concentrat~ons of total suspended solids (TSS) and dissolved organic carbon (DOC) were similar (approximately 49 m g 1.' TSS and 3.5 mg I-' DOC) The amount of organic matter (OM) and chlorophyll a was higher in the bayside creeks, while inorganic N and P concentrations were higher in the seaside creeks (OM. 9 0 a n d 3.4 mg 1 -l ; chlorophyll a. 6 0 and 4.1 g 1.'; PO," 0.2 and 1.2 FM; NH,' 0.6 and 1.2 ubI; bayside and seaside respectively). The high inorganic nutrient pools combined with the low levels of bacterial productivity suggest that bacterial production is not l~nlited by N or P in the seaside creeks and that the amount of carbon moving through the bacterial loop is much less than on the bayside. In fact, DOC turnover times were much longer for the seaside (22 d ) than for the bayside (6 d ) . Reasons for the observed differences in bacterial dynamics for the bay and seasides are not known specifically, but may be related to differences in the source of the DOC (marsh grass vs phytoplankton), grazlng on the bacterial cells, or bacterial community structure

Determining replication for discrimination among microbial communities in environmental samples using community-level physiological profiles

“…CLPP successfully discriminated among the microbial communities present in Phillips and Hungars Creeks in October 1996 and May 1997 when 10 replicates at each site were used (Fig. 1), a result which agreed with those previously observed in bacterial dynamics [16] and genetic similarity [17,18] in these two creeks. In general, the variability associated with replicates from a single container or from different containers was nearly the same for each site, although in Phillips Creek, the variance associated with the single‐container samples was slightly larger than that from the several containers.…”

“…2A). Differences in community similarity are not a direct result of differences in abundance since there is a greater difference in abundance during the warmer months [16,27] when the communities were most similar. When the raw data used to generate Fig.…”

“…The CLPP approach using BIOLOG ® technology was used to assess microbial community similarity in two well‐mixed tidal marsh creeks on the Eastern Shore of Virginia. Phillips Creek, a tidal creek of the coastal lagoon complex on the seaside of the Delmarva Peninsula, and Hungars Creek, on the Chesapeake Bay side, are separated by only 7 km of land, yet the bacterial biomass, abundance and productivity are different [16], and the communities differ genetically [17,18]. Samples were collected from each creek on two different dates (October 7, 1996 and May 22, 1997) to examine differences in the CLPP.…”

Development of a process-based nitrogen mass balance model for a Virginia (USA) Spartina alterniflora salt marsh:implications for net DIN flux

“…The VCR extends 110 km along the seaward margin of the southern Delmarva Peninsula. Our study site, Phillips Creek Marsh, is located in a mainland salt marsh of approximately 135 ha (MacMillin et al 1992) which drains into Phillips Creek. Annually tidal range at this site is approximately 1.93 m relative to mean sea level (MSL).…”

Effects of the agricultural pesticides atrazine, deethylatrazine, endosulfan, and chlorpyrifos on an estuarine microbial food web

“…Microalgae comprise approximately 30% of the annual net primary production of the North Inlet (South Carolina, USA) estuarine system [3]. Bacterial carbon productivity was measured in a Virginia tidal creek at 46 ng C/ml/h [4]. These microorganisms generally have a high cell surface area to volume ratio, and they also have the potential to accumulate or metabolize pesticides [5].…”