ABSTRACT-In Laguna Madre, Texas, USA, a monospecific brown tide bloom began in January 1990 and was still persisting at the time of this writing Immediately following the start of the bloom, abundance, biomass and diversity of benthos declined, and have remained low for 6 yr. O n e explanation for the decline is that the brown tide organism is a poor food source. To determine whether the brown tide was incorporated into the estuarine food web, benthic invertebrates and fish were studied 14 mo after the bloom onset using stable carbon isotope ratios. Fish and benthos were collected from 2 areas, a seagrass habitat in Laguna Madre, and a muddy bottom habitat in the adjacent Alazan Bay. The muddy bottom fauna had a strong brown tide signature, indicating the incorporation of brown tide or brown tide detritus into the food web. The higher-biomass seagrass-fauna had heavier isotope values, reflecting incorporat~on of seagrass carbon in addition to brown tide. The top predators, Sciaenops ocellatus and Pogonjas cromis, have different niches, but were able to switch food sources and thrive during the brown tide bloom. Brown tide appears to b e able to support a n estuarine food web, but at the expense of benthic diversity. The loss of benthic diversity could be due to allelopathy or the inability of some species to assimilate brown tide Habitats with extensive seagrass beds maintain higher productivity and divers~ty than muddy habitats. However, seagrass habitats are endangered because brown tide reduces light levels, inhibits seagrass growth, and is causing seagrass decline.

This study identifies the strongest occupational risk factors and risk factor interactions in the development of indicators associated with cumulative trauma disorders (CTD). Suggestions for minimizing the occurrence of indicators associated with onset of CTD are presented. Five Occupational risk factors and six risk factor interactions were evaluated to determine their contribution to accepted indicators of the onset of CTD, including exertion, discomfort, difficulty, and fatigue. Taguchi's level-analysis procedure was used to design a 16-trial hammering experiment and to analyze the results. From the hypothesized occupational risk factors, repetition was found to have the strongest effect on the values of the physiological and subjective indicators of the onset of CTD.