The development of a constructed lagoon system on the east coast of Qatar provided an opportunity to study the colonisation of sediments within an artificial marine waterway and potential for accelerating this process by transplantation of seagrass. Water quality indices such as temperature, salinity, oxygen and nutrients were demonstrated to remain stable within the lagoon, and were not significantly different to those in the open water, although nitrate and silicate were slightly higher than in reference areas. A total of 78 species were reported in the lagoon during the investigation period: 50 species in late winter, 59 in summer, 56 in autumn ( early winter) and 64 species in spring 2003. In the open water sites, 88 species were identified with 47 in late winter and summer, 52 in autumn and 62 in spring 2003. Cluster analysis showed at least 40% similarity between lagoon and open water stations indicating that the extent of species colonization in the lagoon is dependant on the range of species found outside the lagoon. However, based on sediment characterization, ANOS IM test showed that out of ten macro fauna species groupings, between two to six were not significantly different between lagoon and open water at each season (p>0.05). Newly sterilized sediments were colonized with 35 species and maximum abundance of 14896 ind.m-2 indicating that equilibrium community had
been established in the lagoon after three months and the succession phase occured rapidly, within less than one year. Even within a short period of 9 months, benthic macrofaunal species diversity and abundance in the transplanted area was 130% and 214%, respectively higher than the surrounding sand. Seagrass area cover was 4.5 times that of the original transplanted area within 2 years. It is concluded that if adequate circulation of high quality sea water is provided, artificial lagoon habitats IV will be rapidly recolonised by open sea benthic communities leading to the establishment of new areas of marine productivity in the Gulf.