Isle of Skye
Today as guests explored the Isle of Skye, the largest island in the Inner Hebrides, I got to explore the benthic realm beneath the waves. As is typical in the waters off Scotland, macroalgae known as kelp comprise the major plant fauna. This rich community of constantly swaying autotrophs provides not only shelter for a myriad of nektonic species but also is a major source of nourishment for higher trophic levels. One of the epifaunal species that depends on kelp such as sea lettuce (Ulva lactuca) as a food source is the sea hare (Aplysia punctata). This mollusk is basically a snail that has lost its external shell. This was an evolutionary adaptation because secreting a calcium carbonate shell takes a great amount of energy which could be used for other purposes such as growth or reproduction. However, with the loss of a hard shell, the sea hare had to devise other defense mechanisms. If irritated Aplysia can secrete a distasteful milky substance or emit a purple dye into the water column. This purple dye hides the animal and also distracts predators while the hare slowly crawls away. They get their name not from the speed at which they move, but from the fact that the rhinophores and oral tentacles on the head give this mollusk a “rabbit-like” appearance.
Today as guests explored the Isle of Skye, the largest island in the Inner Hebrides, I got to explore the benthic realm beneath the waves. As is typical in the waters off Scotland, macroalgae known as kelp comprise the major plant fauna. This rich community of constantly swaying autotrophs provides not only shelter for a myriad of nektonic species but also is a major source of nourishment for higher trophic levels. One of the epifaunal species that depends on kelp such as sea lettuce (Ulva lactuca) as a food source is the sea hare (Aplysia punctata). This mollusk is basically a snail that has lost its external shell. This was an evolutionary adaptation because secreting a calcium carbonate shell takes a great amount of energy which could be used for other purposes such as growth or reproduction. However, with the loss of a hard shell, the sea hare had to devise other defense mechanisms. If irritated Aplysia can secrete a distasteful milky substance or emit a purple dye into the water column. This purple dye hides the animal and also distracts predators while the hare slowly crawls away. They get their name not from the speed at which they move, but from the fact that the rhinophores and oral tentacles on the head give this mollusk a “rabbit-like” appearance.
