Aquatic and Amphibian Adaptations to Seasonal Climate Change
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Temperature has long been recognized as an important environmental factor in both terrestrial and aquatic ecosystems in regard to its pivotal role over biological activity (development, growth and reproduction). The response of aquatic biota to physical changes in light or photoperiod, nutrients, temperature and flow can often lead to profound changes in individual development and survival or community structure across each trophic level therefore it is important that organisms can adapt to changes in their environment.
Fish
Fish, like reptiles and amphibians, are ‘cold-blooded’ vertebrates. This means that their body temperature varies according to the temperature of their surroundings. Some Antarctic fish stay deep in the sea, where although the temperature may be –1.8C, it is a fraction warmer than the freezing point of sea water, so no ice forms inside their body. Most Antarctic fish even have their own ‘antifreeze'. During hte cold seasons some freshwater fish can also produce antifreeze like the rainbow smelt (Osmerus mordax) accumulate high levels of glycerol in winter that serve as an antifreeze. Liver glycogen is a source of glycerol during the early stages of glycerol accumulation, whereas dietary glucose and amino acids are essential to maintain rates of glycerol synthesis.
Fish
Fish, like reptiles and amphibians, are ‘cold-blooded’ vertebrates. This means that their body temperature varies according to the temperature of their surroundings. Some Antarctic fish stay deep in the sea, where although the temperature may be –1.8C, it is a fraction warmer than the freezing point of sea water, so no ice forms inside their body. Most Antarctic fish even have their own ‘antifreeze'. During hte cold seasons some freshwater fish can also produce antifreeze like the rainbow smelt (Osmerus mordax) accumulate high levels of glycerol in winter that serve as an antifreeze. Liver glycogen is a source of glycerol during the early stages of glycerol accumulation, whereas dietary glucose and amino acids are essential to maintain rates of glycerol synthesis.
Wood Frogs
Some amphibians like the wood frog endure freezing during the winter time, but only the fluids in extracellular spaces freeze.
Some amphibians like the wood frog endure freezing during the winter time, but only the fluids in extracellular spaces freeze.
Even more incredible is the fact that the wood frogs stop breathing and their hearts stop beating entirely for days to weeks at a time. In fact, during its period of frozen winter hibernation, the frogs’ physical processes—from metabolic activity to waste production—grind to a near halt. What’s more, the frogs are likely to endure multiple freeze/thaw episodes over the course of a winter.