Environmental Engineering Reference
In-Depth Information
ilter feeders and once born, they immediately ind a suitable place to live and become
adults. They secrete an adhesive which helps them to attach head irst to a suitable
spot. Sea tulips, sea squirts, sea liver and sea pork are also from the same family [3].
Serpula are also known as calcareous tubeworms, serpulid tubeworms, fan worms,
or plume worms. They are very common in the Paciic, Atlantic, and Indian oceans.
They have a pair of calcium secreting glands. Like most tube building polychaetes,
worms of the Serpula genus are benthic, sedentary and suspension feeders. They secrete
and build a permanent calcareous tube attached to a hard submerged substratum [3].
Sea anemones are a group of water dwelling and predatory animals. A sea anemone
is a sessile polyp. It is attached at the bottom to a bare surface by an adhesive foot,
called a basal disc. It has a column shaped body ending in an oral disc. Anemones
tend to stay in the same spot until the environment becomes unsuitable for it to stay.
This may happen because of dry conditions, insuficient food or a predator attack.
In such a situation anemones can release themselves from the substrate and use lexing
motions to swim to a new location [3]. Most sea anemones attach temporarily to
submerged objects, so their adhesive could be different to that of a barnacle.
The green alga, Enteromorpha , is the slippery grass-like plant that covers rocks in the
intertidal zone and it is a major macrofouling alga. The cement produced by mature
adult barnacles, consists of a complex of hydrophobic proteins which are unrelated
to the blue mussel proteins and it is crosslinked via cysteine residues [3]. More details
about the barnacle cement are given later in this chapter.
4.2 Effect of Macrofouling Organisms on Material
Macrofouling organisms form dense colonies. This means large quantities of nutrients
and other material are removed from the water and deposited on or in the benthos.
This deposition increases further fouling and silt. Macrofouling organisms can
tolerate wide luctuations in the environment and can adhere to submersed surfaces.
They develop hard shells or exoskeletons, form dense colonies and produce planktonic
larvae. Macrofoulers can attach to concrete, metals, wood, plastics and other synthetic
polymers and also to other organisms [4].
Dense layers of macrofouling organisms can cause blockage or reduction in water low
in pipes, mechanical damage, corrosion, and failure of equipment. So macrofouling
increases operational and maintenance costs. Macrofouling also changes the
physical and chemical characteristics of submersed substrates. When an individual
macrofoulant or colonies detach from surfaces their shells and exoskeletons cause
 
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