Marine Mammals and Friends Abstracts
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Water Quality Considerations and Life Support System Design for Cephalopods
Barrett L. Christie, Dallas Zoo Watch Video (Login required) Full Abstract
The captive management of cephalopods necessitates the maintenance of water quality within precise ranges. Cephalopods have a microvillus epidermis that is one cell layer thick and contains many pores, increasing the overall surface area. The increased surface area and permeability make cephalopods highly sensitive to the chemistry and bacterial load of surrounding water. In addition to an inherent chemical sensitivity, cephalopods also possess increased metabolic rates; as much as two to three times higher than teleost fishes. As such, cephalopods produce increased amounts of nitrogenous wastes (NH3/NO2) which must be oxidized by nitrification in closed systems below 0.10 mg/L. Cephalopods are also highly sensitive to nitrate concentrations well below acceptable thresholds for fishes (50-80 mg/L). Thus, life support strategies must address these particular aspects of water quality to ensure animal welfare. Decades of laboratory culture have provided insights into the most effective filtration components to meet the unique demands of these animals. Life support systems in laboratories and public aquaria typically employ mechanical filtration followed by foam fractionation, biofiltration, activated carbon, and sterilization before returning water to the exhibit. Filtration strategies designed with the unique physiology of cephalopods in mind are best suited to meet their stringent needs for water quality and facilitate good husbandry. |
Disinfection Byproduct Speciation and Pathways Resulting from Ozone or Chlorine Application in Seawater Systems
Craig Adams, Utah State University Watch Video (Login required) Full Abstract
Treatment of seawater (and artificial seawater formulations) in marine aquaria with ozone result in a mixture of disinfection byproducts (e.g., trichloramine and tribromamine). Due to the high concentration of chloride in seawater, ozone can degrade to free chlorine species (i.e., hypochlorous acid/hypochlorite; or HOCl/OCl-). Depending on the bromide concentration in solution, both ozone and chlorine addition can lead to the formation of free bromine species (i.e., hypobromous acid/hypobromite; or HOBr/OBr-). Free chlorine and bromine both react with other constituents in seawater (including ammonia) to form many disinfection byproducts including haloamines (e.g., trichloramine (NCl3) and tribromamine (NBr3).), trihalomethanes, haloacetic acids and other species. In this project, a suite of analytical methods were developed, validated and used to study the formation of disinfection byproducts in varied seawater treatment scenarios. Analytical methods included liquid chromatography, gas chromatography, and ion chromatography coupled with mass spectrometry and other detectors (in addition to titrimetric and other methods). Analytical methods were used to examine the concentration of both inorganic and organic disinfection byproducts under a wide range of treatment conditions both in laboratory and full-scale systems. In addition, kinetic chemical models were developed to predict the formation of varied chlorinated and brominated species during ozone and chlorine treatment. Specific results of the chemical modeling were validated using chemical analyses, and more recent methods are currently being used to validate the formation of other disinfection byproduct species. |
Management of Chloramines in Marine Mammal Pools
Dr. Howard Dryden, Dryden Aqua Watch Video (Login required) Full Abstract
No Abstract. |
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Management of Marine Mammal Pools without Direct Chlorine Addition
Chris Nguyen, National Aquarium Watch Video (Login required) Full Abstract
Marine Mammal pool waters require disinfection to minimize viability of disease causing fecal bacteria emanating from the mammalian gut. To mitigate ill health effects of oxidant exposure to megafauna, off-pool disinfection processes are used, which reduce oxidant demand within the pool. However, a low concentration of oxidant is usually maintained in the pool itself. For over ten years, control of infectious organisms has been managed in the National Aquarium’s Dolphin Discovery pool without chlorine addition. A portion of infectious organisms is removed via fractionation, and a portion is destroyed via ozone disinfection. Approximately 10% of water treatment flow is exposed to an applied ozone dose of 0.3 mg/L in contact chambers. Foam fractionators process approximately 33% of the recirculation flow. Fractionator flow can be, but is not always, treated with an applied ozone dose of 0.03 mg/L. Although ozone quickly converts to chlorine in solution, ozone is preferred over direct chlorine injection because of its ability to improve watercolor, its ability as a micro flocculent and it's greater effectiveness in destroying infectious organisms. These are features that chlorine cannot provide or cannot provide as well as ozone. Total chlorine as measured by DPD is maintained in the pool at 0.10 – 0.15 mg/L. Coliform counts are consistently maintained at an MPN <3. |
By Products of Disinfection in Life
Support Systems Ed Latson MS, DVM, Central Park Aquatic Health Watch Video (Login required) Full Abstract
No Abstract. |