What is the single biggest challenge for living organisms in caves?

The biggest challenge for living organisms in caves is the absence of natural light.

Explanation:

The darkness of the aphotic zone brings some peculiarities to the cave environment, such as the absence of photosynthesizing organisms, absence of visual stimuli and absence of photoperiods (biological cycles governed by the alternation of light and dark periods). If there are no photosynthetic organisms in the aphotic zone, the existence of food is necessary for the life of cave dwelling organisms. A minimal part of the energy required for these organisms is provided by chemosynthetic bacteria, organisms capable of synthesizing organic substances from the energy provided by chemical reactions, even in the absence of light.

However, most of the nutrients are imported from the outside, reaching the cave environment through underground rivers, rainwater that can penetrate the pituitary environment, animals that accidentally enter the caves and eventually die inside and from the roots. of plants located in the external environment. Another source of food is the organic matter present in the feces of frugivorous species that inhabit caves, such as bats. This material is called guano.

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