Stephen Spotte

Clostridium perfringens as the Cause of Death of a Captive Atlantic Bottlenosed Dolphin (Tursiops truncatus)1

A previously healthy captive female bottlenosed dolphin (Tursiops truncatus) died suddenly. At necropsy, Clostridium perfringens was isolated from dorsal muscle, blood, left heart ventricle, thoracic fluid, and abdominal fluid. An identical strain was recovered from pool water. A male dolphin in the same pool had inflicted several “rake” marks on the dorsal surface of the female. Water-borne bacteria probably entered these lesions which served as the focus for anaerobe penetration and spread.

The type of activated carbon determines how much dissolved organic carbon is removed from artificial seawater

Abstract Four granular activated carbons (GACs) made of different materials were tested for removal of dissolved organic carbon (DOC) from artificial seawater of a recirculated aquarium. After 70 days in a continuous flow experiment, comparative removal data (grams of GAC required to remove 1 g of DOC) were coconut shell (491), hardwood (84·4), anthracite (837) and bone char (383), indicating the superior performance of hardwood. Scanning electron microscopy showed that microbial colonization of a sample material (hardwood) was slight and occurred exclusively at the surface. Biological enhancement of GAC was considered to be unimportant as a mechanism for DOC removal.

PROBIT analysis predicts hatching rates of brine shrimp Artemia sp. cysts

Abstract Thirty replicates of San Francisco Bay brine shrimp Artemia sp. cysts from one lot were weighed to 0·01 mg. The mean mass of a single cyst was 2·597 μg (±0·040 μg, 95% confidence level). Batches of 1 g from the same lot were hatched in the laboratory, and fraction hatched versus time data were fitted to a nonlinear curve using PROBIT analysis. Median time of hatch was 24·8 h with a standard error of ±3·92 h. Cysts and nauplii in 1-ml aliquots were pipetted at regular intervals and counted under a dissecting microscope. The number of cysts pipetted at the beginning of the experiment was 19% less than estimates based on the known number per volume of hatching medium, indicating that hatching data derived from pipetting procedures may contain large sampling errors. PROBIT analysis allows fraction hatched to be predicted when a particular lot of cysts is hatched under controlled conditions.

THE EFFICACY OF UV IRRADIATION IN THE MICROBIAL DISINFECTION OF MARINE MAMMAL WATER 1

A study was made on the efficacy of a commercial ultraviolet (UV) sterilizer in reducing the number of bacteria and yeasts in a saline, closed ystem marine mammal complex. UV irradiation was effective in lowering bacterial counts in the effluent of the unit (>75% reduction), but bacteria in more remote parts of the water system reached levels equal to or greater than pre-UV counts. Yeast reduction was considerably less, and a trend similar to that of the bacteria was observed in remote sections of the water system. It is concluded that UV irradiation is of limited value in the disinfection of marine mammal water. Factors contributing to the poor performance of the sterilizer were the long recycle time of the water and lack of a residual effect.

Carbonate mineral filtrants with new surfaces reduce alkalinity in seawater and artificial seawater: Preliminary findings

Abstract Silica sand (silica), coral (aragonite), and oyster shell (calcite) were ground to similar particle sizes and placed in seawater and artificial seawater (GP2 Medium). Alkalinity and pH values of the artificial seawater decreased substantially over 24 h when in contact with coral and oyster shell; the effects in seawater were minor. Once alkalinity has been reduced, the maintenance of stable pH at values typical of seawater is made more difficult. The data, which are preliminary, have practical application.