Sedimentation and barnacle recruitment and growth in a shallow coastal lagoon of south Texas

Gray, John Jack

Sedimentation and barnacle recruitment and growth in a shallow coastal lagoon of south Texas

Date

2014-09-29

Authors

Gray, John Jack

Description

According to the United States Environmental Protection Agency, one of this nation’s greatest concerns to the receiving waters of an aquatic system is the impairment of water quality due to sediment transport. Thus, an aquatic system whose receiving waters are subject to unrestrained sediment transport from a spoil bank, which is an unstabilized depository for sediment acquired during a dredge, should be a concern. In this study an attempt was made to assess sedimentation and its effect on the life cycle of sessile aquatic life over a year. South Bay was chosen for the study site because it is adjacent to an active spoil bank and close to Mexiquito Flats, a site not associated with an active spoil bank. Barnacles were chosen to be studied as an indicator of sedimentation because barnacles are a sessile aquatic filter feeding animal that have been shown to be affected by sediment transport, a precursor to sedimentation. Balanus eburneus Gould, 1841 was studied for recruitment and growth and a second barnacle, B. amphitrite Darwin 1854, was studied for recruitment only. Forty stations in South Bay were each installed with clay pads and cylinders from which sedimentation and barnacle recruitment and growth data were collected, respectively, and eight stations in Mexiquito Flats Measurement of sedimentation was collected at four and six month intervals and barnacle recruitment and growth collected as close to a per monthly basis as possible. Sedimentation appears to be occurring in both sites but differences between sites was not significant. Sedimentation in South Bay did not exhibit a decreasing trend with increasing distance from the spoil bank shore or exhibit any relation with barnacle recruitment or growth. Recruitment and growth followed seasonal patterns with v increasing recruitment of B. eburneus in May and September and of B. Amphitrite in May only. Growth of B. eburneus increased during the warmer months.
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