Chapter 6 Flashcards
What two groups of aquatic animals dominate the research field?
amphibians and fish
What is the widest used amphibian in research?
Xenopus
What was developed in the toxicology field that was made as a toxicology screening assay in which chemicals are tested on the developmental stages of embryos for effects of malformation, growth inhibition, and mortality?
Frog Embryo teratogenesis Assay - Xenopus (FETAX)
what is the most common aquatic vertebrate used in biomedical research?
Zebrafish (Danio rerio)
Why are zebrafish a powerful model for studying gene function?
their internal anatomical structures are visible within the first 5 days of embryonic development
What is the primary enclosure for aquatic species?
immediate tank environment
What are most aquatic tanks made from?
polycarbonate or polysulfone plastic
what materials for tanks can result in illness and death?
metals or stainless steel
What system has individual tanks that work well for both small and large groups of animals, but need frequent changes and water changes?
static
What type of system is common in research facilities where water is recirculated but has a specific volume of water changes to introduce fresh water into the system, but can be bad if there is a water quality issue or a disease outbreak?
Recirculating systems
What system runs a constant low flow of water into and out of the tank without water circulation, but can be disruptive to species that prefer static water?
flow-through systems
How does cleaning of an aquatic system differ from rodent cage cleaning?
you cannot use detergents on aquatic systems
What is included in the primary enclosure of aquatic species?
filtration systems
an aggregate of microorganisms is desired on tank walls
true
What is one of the most important aspects of aquatic husbandry?
water quality
what is one surprising thing that amphibians are sensitive to?
latex gloves
What temperature do tropical amphibians need water at?
21C-29C (70-85F)
What temperature do temperate region amphibians need?
18-22C (65-72F)
What temperature are zebrafish colonies kept at?
24-28C (75-82F)
What is pH?
the number of hydrogen ions in a system
What does the pH scale range from, and what is neutral?
0-14, 7 is neutral
What values on the pH scale are acidic?
lower than 7
What values on the pH scale are basic/alkaline?
higher than 7
What pH do most aquatic species prefer?
6.8-7.1
How does varying pH affect ammonia in water?
ammonia becomes toxic in alkaline/basic conditions
what can you add to the water to raise the pH of water?
add sodium bicarbonate or calcium carbonate
what can you add to water to lower the pH?
glacial acetic acid and hydrochloric acid.
what must you remove from municipal water before use in tanks?
chlorine
What chemical is used in place of chlorine because it has lower levels of carcinogenic byproducts but is more toxic to aquatic life?
chloramines
What is the best way to remove chloramines?
catalytic carbon filter or treatment with sodium thiosulfate
What is the measure of the amount of dissolved salts and minerals, present as ions, within an aqueous solution, which is the flow of electricity?
conductivity
What happens if there are too many ions in the water?
the water will flow out of the animals’ body into the water
what happens if there aren’t enough ions in the water?
water will flow into the animal and cause an overload of the circulatory and excretory systems
what is the term for the flow of water across a water-permeable barrier?
osmosis
what is a measure of the amount of specific ions dissolved in water?
water hardness
what minerals can be found in harder water?
calcium, magnesium
What pH does hard water lean toward?
alkaline/basic
What is the measure of oxygen molecules in the water?
dissolved oxygen (DO)
What happens to DO when the temperature rises in the water?
oxygen will diffuse out of the water
What is gas bubble disease?
when oversaturation of water with dissolved gases causes side effects in fish or amphibians and can cause rapid death
what are methods of purifying water?
reverse osmosis, deionization, distillation
for what purpose are buffering chemicals added to an aquatic system?
to adjust the pH
what type of filters are available?
biological, mechanical, and chemical
what is an inert/stable substance, typically silicone, gravel, glass, or plastic, with a high surface are that acts as a substrate to bind large numbers of nitrifying bacteria?
biological filter
what happens to ammonia and nitrite levels when a biological filter is first added to a tank?
rise dramatically
what is ‘new tank syndrome?”
when ammonia and nitrite levels rise drastically when a biological filter is first added
what is the process of breaking down waste ammonia into less toxic byproducts?
nitrogen cycle
where does the nitrogen cycle take place?
in the biological filter
what are the less toxic byproducts of ammonia?
nitrites and nitrates
what method physically removes solid waste from the tank?
mechanical/particulate filter
what method dissolves minerals and compounds, including wastes, that may pass through the mechanical filter.
chemical filtration
what light can kill microorganisms living in a tank?
UV light
what is the germicidal spectrum for killin microorganisms but can cause mutations in DNA?
200-280 nanometers
what is the standard for the flow rate of water into and out of the tank?
usually 5-6 per hour
what type of outlets should aquatic facilities have for safety?
ground-fault circuit interrupted (GFCI)
why is backup power so important?
to prevent catastrophic death due to DO depletion
what is the best humidity for aquatic facilities?
50-80%
what light levels should you keep fish at?
100-150 lux
what light is not recommended in zebrafish rooms?
red light due to their red-sensitive cone cells
how far above the floor should electrical outlets be located?
1m
Why does the germicidal spectrum have to be in a certain wavelength range?
to cause a limitation in microorganism replication
which parameter is is acceptable to check on a weekly basis, rather than daily?
hardness (measure of calcium and magnesium in water)
