Environmental Engineering Reference
In-Depth Information
4
Macrofouling and Bioadhesion of
Organisms on Polymers
Nelamane Vijayakumar Ravi Kumar, Ramasamy Venkatesan and
Mukesh Doble
4.1 Macrofouling
A macrofouling community (consisting of 'soft' or 'hard fouling') develops and grows
above the microfouling community. Soft macrofouling organisms include algae and
invertebrates, including anemones, hydroids, soft corals, sponges, and tunicates.
Hard macrofouling organisms include invertebrates including barnacles, mussels
and tubeworms. The complete set of animals involved in macrofouling consists of
amphipods, barnacles, bryozoans, corals echinoderms, hydroids, isopods, mussels,
nemerteans, platyhelminthes, sea anemones, serpulid worms, sponges, and tunicates.
Not all these organisms are found in all the oceans around the world. Some of them
release a glue which helps them to attach on bare surfaces. Many of these organisms
produce an adhesive which help them to attach to immersed surfaces. In some cases
the attachment is irreversible and in others it is a reversible process [1].
Barnacles and mussels release small free swimming organisms, which settle and grow
to maturity. The protein glue of the blue mussel (
Mytilus edulis
) contains polypeptides
which are rich in dihydroxyphenylalanine, which crosslinks through an oxidative
phenolic tanning type process. Barnacle larvae can attach even in areas where the water
velocities are 2.4−2.7 m/s. The blue mussel prefers stable, low velocity environments.
The barnacle's shell remains attached even after its death whereas the shell of a dead
mussel breaks loose. Bryozoans, also known as moss animals or ectoprocts are tiny
organisms which form a colony. The larvae that are produced attach
via
adhesive sacs
to surfaces and undergo metamorphosis to the adult form. They grow as calciied or
gelatinous encrustant on surfaces [2]. Hydroids are colonies of tiny stinging jellies,
which are colonial in nature. The original polyp anchors itself to a solid substrate
with an adhesive and forms a bud [3].
Tunicates, also called sea squirts, are a group of marine animals which spend most
of their lives attached to rocks, surfaces or the undersides of boats. They are marine
