Effects of ghost shrimp on zinc and cadmium in sediments from Tampa Bay, FL

Marine Chemistry
By: , and 

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Abstract

This study investigated the effects that ghost shrimp have on the distribution of metals in sediment. We measured levels of HNO3-extractable zinc and cadmium in surface sediment, in ghost shrimp burrow walls and in sediment ejected by the ghost shrimp from their burrows, at five sandy intertidal sites in Tampa Bay. Ghost shrimp densities and their rate of sediment ejection were also quantified, as were sediment organic content and silt + clay content. Densities of ghost shrimp (Sergio trilobata and Lepidophthalmus louisianensis) averaged 33/m2 at our sites, and they ejected sediment at an average rate of 28 g/burrow/day. Levels of both Zn and Cd were significantly higher in burrow walls than in surface sediments. Sediment ejected by the shrimp from their burrows had elevated levels of Zn (relative to surface sediments) at one of the sites. Sediment organic content and silt + clay content were higher in burrow-wall sediments than in ejected sediment, which in turn tended to have values above those of surface sediments. Differences in levels of HNO3-extractable Zn and Cd among sediment types may be a consequence of these sediments differing in other physiochemical characteristics, though the differences in metal levels remained statistically significant for some sites after correcting for differences in organic content and silt + clay content. We conclude that the presence of ghost shrimp burrows contributes to spatial heterogeneity of sedimentary metal levels, while the ghost shrimp bioturbation results in a significant flux of metals to the sediment surface and is expected to decrease heterogeneity of metal levels in sedimentary depth profiles.

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Publication type Article
Publication Subtype Journal Article
Title Effects of ghost shrimp on zinc and cadmium in sediments from Tampa Bay, FL
Series title Marine Chemistry
DOI 10.1016/j.marchem.2006.12.014
Volume 104
Issue 1-2
Year Published 2007
Language English
Publisher Elsevier
Contributing office(s) Coastal and Marine Geology Program
Description 10 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Marine Chemistry
First page 17
Last page 26
Country United States
State Florida
City Tampa Bay
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