Geology topics

M.C. Black

Publications and source records attributed to M.C. Black.

4 recordsLinked to original sources

USGS2016

Effects of urban land-use on largescale stonerollers in the Mobile River Basin, Birmingham, AL

During the spring and fall of 2001 and the spring of 2002 a study was conducted to evaluate the health of the largescale stoneroller ( Campostoma oligolepis) populations in streams along an urban land-use gradient. Sites were selected from a pool of naturally similar sub-basins (eco-region, basin size, and geology) of the Mobile River basin (MRB), using an index of urban intensity derived from infrastructure, socioeconomic, and land-use data. This urban land-use gradient (ULUG) is a multimetric indicator of urban intensity, ranging from 0 (background) to 100 (intense urbanization). Campostoma sp. have been used previously as indicators of stream health and are common species found in all sites within the MRB. Endpoints used to determine the effects of urban land-use on the largescale stoneroller included total glutathione, histology, hepatic apoptosis, condition factor and external lesions. Liver glutathione levels were positively associated with increasing urban land-use (r 2 = 0.94). Histopathological examination determined that some abnormalities and lesions were correlated with the ULUG and generally increased in prevalence or severity with increasing urbanization. Liver macrophage aggregates were positively correlated to the ULUG. The occurrence of nucleosomal ladders (indicating apoptotic cell death) did not correspond with urban intensity in a linear fashion. Apoptosis, as well as prevalence and severity of a myxozoan parasite, appeared to have a hormetic dose–response relationship. The majority of the biomarkers suggested fish health was compromised in areas where the ULUG ≥ 36.

Alabama↗

USGS2010

Hematocrit and plasma osmolality values of young-of-year shortnose sturgeon following acute exposures to combinations of salinity and temperature

Little is known about the physiological capabilities of young-of-year (YOY) shortnose sturgeon. In this study, plasma osmolality and hematocrit values were measured for YOY shortnose sturgeon following 48-h exposures to 12 different combinations of salinity and temperature. Hematocrit levels varied significantly with temperature and age, and plasma osmolalities varied significantly with salinity and age. Plasma osmolality and hematocrit values were similar to previously published values for other sturgeons of similar age and size in similar treatment conditions. ?? 2010 Springer Science+Business Media B.V.

Fish Physiology and Biochemistry↗

USGS2009

The Asian clam Corbicula fluminea as a biomonitor of trace element contamination: Accounting for different sources of variation using an hierarchical linear model

In the present study, specimens of the invasive clam, Corbicula fluminea, were collected above and below possible sources of potentially toxic trace elements (As, Cd, Cr, Cu, Hg, Pb, and Zn) in the Altamaha River system (Georgia, USA). Bioaccumulation of these elements was quantified, along with environmental (water and sediment) concentrations. Hierarchical linear models were used to account for variability in tissue concentrations related to environmental (site water chemistry and sediment characteristics) and individual (growth metrics) variables while identifying the strongest relations between these variables and trace element accumulation. The present study found significantly elevated concentrations of Cd, Cu, and Hg downstream of the outfall of kaolin-processing facilities, Zn downstream of a tire cording facility, and Cr downstream of both a nuclear power plant and a paper pulp mill. Models of the present study indicated that variation in trace element accumulation was linked to distance upstream from the estuary, dissolved oxygen, percentage of silt and clay in the sediment, elemental concentrations in sediment, shell length, and bivalve condition index. By explicitly modeling environmental variability, the Hierarchical linear modeling procedure allowed the identification of sites showing increased accumulation of trace elements that may have been caused by human activity. Hierarchical linear modeling is a useful tool for accounting for environmental and individual sources of variation in bioaccumulation studies. ?? 2009 SETAC.

Environmental Toxicology and Chemistry↗

USGS1994

Plasma chloride and gill epithelial response of channel catfish to infection with Ichthyophthirius multifillis

Because infection with Ichthyophthirius multifiliis has been reported to result in osmotic stress, genesis of the plasma chloride and chloride cell response of channel catfish Ictalurus punctatus to the infection was studied from day 0 to day 7 postexposure (PE). Parasite population densities ranged from 0.08 to 0.22 trophonts per gill filament during days 1–5 PE and increased to 2.1 at day 7 PE. Population increases were the result of infection by a new generation of infective theronts and reproduction by the parasite on the host. Mean plasma chloride concentrations of fish were not significantly different among days 0–5 PE (range of means, 93.01–97.87 meq/L), but by day 7 PE the mean had declined significantly, to 83.73 meq/L. Maintenance of relatively stable plasma chloride concentrations for 5 d was associated with chloride cell proliferation. The number of interlamellar filament chloride cells had significantly increased by day 1 PE, and the number of chloride cells in the lamellae had significantly increased by day 5 PE. No further increase had occurred by day 7 PE. Vacuolization of chloride cells, examined by electron microscopy, became more common as infection progressed, and many chloride cells appeared to be degenerating by day 5 PE.

Journal of Aquatic Animal Health↗