THE OCCURRENCE OF MARINE ORGANISMS - IN BALLAST WATER OF SHIP VISITING COLOMBO HARBOUR
DOI:
https://doi.org/10.31357/fesympo.v15i0.161Keywords:
ballast water, Colombo harbor, plankton species, staining technique, physico-chemical parametersAbstract
Ballast water is a major source of biological invasions around the globe. More than 4500 bulk carriers, cargo
vessels and oil tankers arrive to Colombo harbor annually and they discharge a large amount of ballast water
in Sri Lankan marine environment. Present research was to study the occurrence of marine organisms in the
ballast water of ships visiting Colombo harbour. Ballast water samples were taken from ships visited to
Colombo harbor from different ports in Indian Ocean. The species densities were recorded. In addition
biological oxygen demand, chlorophyll-a, conductivity, dissolved oxygen, nitrate, pH, orthophosphate,
salinity, and temperature were measured in the sample. The vital status (live and dead) of the zooplankton
species studied was ascertained using neutral red staining techniques. Thirty-three plankton species were
recorded in ballast water samples which included fourteen copepods, eight dinoflagllates, eight diatoms, one
protozoan, one rotifer, and one mollusc. Highest density was recorded for Thalassionema sp. and lowest
density was recorded for unidentified species belong to family Tintinnidae and gastropod veliger larvae.
Ceratium furca, Ceratium fusus, Peridinium sp., Protoperidinium grande, Protoperidinium obtusum,and
Protoperidinium robustum were the six species of potentially harmful red tide forming dinoflagllates which
were recorded during the study. Neutral red staining technique revealed that there were no live zooplankton
species in the ballast water samples. According to the Pearson Correlation there were strong positive linear
relationships between species density with nitrate (r2= 0.845) and orthophosphate (r2= 0.800) levels and also
pH (r2=0.694) had slightly positive linear relationships with species density. The temperature (r2=-0.758)
had negative linear relationship with species density.
Keywords: ballast water, Colombo harbor, plankton species, staining technique, physico-chemical
parameters
