This is the part of the intertidal zone where debris, algae and other flotsam are left behind by the previous receding tide. Many organisms find shelter here, feeding on the algae and other organic material.
Along sandy shores, Ulva is the most common stranded algae while on rocky shores, Sargassum is predominant.
Along the strand line are also found the skeletal remains of many marine animals. Seashells (gastropods and bivalves) dominate. The gastropod shell shown here has most likely been broken by crabs and later eroded by wave action. In some cases, shell boring barnacles, sponges and worms further perforate the shell.
The globose sea urchin test which belongs to the banded urchin, Salmacis, is actually the animal's exoskeleton and is made up of separate plates. In some specimens, the characteristic mouthparts can still be found on the ventral surfaces.
Cuttlefish bones are actually the internal skeleton of this important food mollusc which is related to the octopus. The bone is frequently collected to serve as a calcium supplement for cage birds.
From A Guide to Seashore Life by Dr Leo W H Tan and Peter K L Ng
Published by the Singapore Science Centre and sponsored by BP
@Raffles Museum of Biodiversity Research and Singapore Science Centre