Thesis Abstract and Dissertation Abstracts

The morphometric data of 1009 C. racemosa specimens taken from three sites along the south coast of Malta were recorded. Destructive sampling was adopted during the sampling months of December 2000 and January 2001 where six shore line transects varying in length from 60 to 600m were laid perpendicularly to the shore. Six replicates at each depth along the line transect were taken. The location of the sampling units was determined by the seawater depth and the location of Caulerpa racemosa along that depth by a random number function carried out prior to the dive using Excel.

Data on standing stock of Caulerpa racemosa at various depths in the three different sampling sites was produced. A short-term sea water analysis for two major nutrients nitrates and phosphates was conducted along with transparency measurements. The application of univariate analysis (One-way Anova) was used in analysing morphological variations of groups with different depths, while the Pearson correlation coefficient was used in order to relate the various morphological variations with depth. The morphological variations observed were influenced by the increasing depth (reduced light intensity) along the line transects. Similar morphological variations with reduced light intensities were reported in the controlled conditions of the laboratory (Calvert, 1976), thus confirming the hypothesis that the local variety is the var. occidentalis, since other varieties would give a different type of morphological variation with depth such as trumpet-like with obconical apex to shield-like with flat discoidal apex. A reduction in shoot density was recorded in all the three sites, however, two different contrasting results were obtained for biomass measurements. Few epiphytes were recorded living on Caulerpa racemosa specimens taken from the three sites.

No significant short term changes were recorded from the sea-water analysis in all the six stations taken from the middle of each line transect.

Locally this introduced species is still expanding to occupy the whole of the accessible local biotopes between 0 and 60m depth, thus altering the local biocenosis. The wide range of areas that locally are colonised by this species confirms the high settling capability and growth rate. Thus it is important to keep on monitoring the distribution of C. racemosa both at a local and an international level.

This Thesis Abstract may be cited as follows:
Vella, K. (2001), A Study of the Recently Introduced Chlorophyte Caulerpa racemosa along the South Coasts of Malta, Unpublished B.Sc. (Hons.) Dissertation, May 2001, Department of Biology, University of Malta

Submission Details: Thesis Abstract submitted by Keon Vella from Malta on 31-Oct-2003 23:55.
Abstract has been viewed 3083 times (since 7 Mar 2010).

Keon Vella Contact Details: Email: keon.vella@mma.gov.mt