All living things need water to survive. Did you know that all living things also need nitrogen to survive? Nitrogen is an essential nutrient and a key component of amino acids, which are the building blocks of proteins and nucleic acids (DNA and RNA). Without proteins and nucleic acids, living organisms would not be able to function and grow!
Approximately 78% of the Earth’s atmosphere is made up of nitrogen (two nitrogen atoms bonded together or N2). However, nitrogen in this form is unusable for nearly all living things. So how do we humans and other life forms obtain nitrogen? It starts in the soil where specialized bacteria “fix” atmospheric nitrogen. The nitrogen-fixing bacteria intake atmospheric nitrogen and convert it into a different form that can then be taken up by plants through their roots. Animals then get the nitrogen they need by eating plants or other animals. Finally, when organisms die, decomposers help break down organic and inorganic materials, and the nitrogen is returned to the soil. This process is known as the nitrogen cycle, but what happens when there are not sufficient levels of nitrogen in the soil?
Certain wetland environments, particularly bogs (like Shadow Lake Bog!), are habitats where oxygen and nutrient levels (i.e. nitrogen) are low because water does not flow in and out easily. Bogs receive most, if not all, of their water through precipitation. These conditions make it more difficult for decomposers to break down dead plant material quickly. When dead plant material accumulates, peat is formed, which also makes the water and soil very acidic! These unique conditions have given rise to one of the most extraordinary evolutionary adaptations: carnivorous plants. Carnivorous plants are able to absorb supplemental nitrogen from sources other than soil.
The most common carnivorous plant belongs to the Drosera genus and is known as the “sundew.” Sundews trap their insect prey with “tentacles” (trichomes) protruding from their leaves. Each trichome has a sticky gland at the tip that produces nectar, perfect for attracting and trapping prey. Once an insect is stuck, the trichomes coil around, and digestive enzymes get to work to extract nutrients, like nitrogen.
The Nepenthes genus, also known as “pitcher plants”, are another type of carnivorous plant. The entire leaves of pitcher plants are modified to hold rainwater. These plants use bright colors and nectar to lure insects inside, and once inside, an insect may find it difficult to fly out. This is due to the inside walls which may be slippery or covered with backward-pointing trichomes. When the insect tires, it falls into the water at the base of the pitcher, where digestive enzymes are waiting to extract the nutrients.
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