Big Island Marine

Photo Assignment

A’a Lava

A’a lava is the sharp or rough variety of lava rock found in Hawaii. It forms from more viscous lavas that have more gasses in them. The gasses form pockets and bubbles that create a sharp, rough texture. This is where the name comes from. Someone walking across it barefoot would say “AH! AH!”

Areal Roots

Areal roots can have many purposes, including support, parasitism and breathing. Many areas in Hawaii have low nutrient or waterlogged soil. Roots can rot in such soils. Some plants also use areal roots to pull nutrients out of the air or other plants that they couldn’t get from the soil.

Black Sand

Most beaches on the big island of Hawaii have black sand that is formed from the steady erosion of lava rock. It indicates a lack of coral reefs in the area because white sand is created by the brake down of coral by wave action and parrot fish. Hawaii has more black sand than the other islands in the chain, because it is the youngest. Coral reefs grow slowly, and younger islands have not had enough time to develop these reefs which are the source of white sand.

Buttress Roots

Buttress roots are common in areas with poor soil. This iron wood tree is growing on a sand dune with very few nutrients. What little nutrition there is lies close to the surface so the roots are shallow but widespread. The broad base created by the large roots also help keep the tree in place in the loose material. This is important because these trees are near the coastline, so they are subjected to strong winds.