Settlement of marine periphytic algae in a tropical estuary

• Published in: Estuarine, coastal and shelf science Vol. 64; no. 2; pp. 241 - 248
• Main Authors: Nayar, S., Goh, B.P.L., Chou, L.M.
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01-08-2005; Elsevier
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; Brackish; Brackish water ecosystems; chlorophyll a; diatoms; Fundamental and applied biological sciences. Psychology; nutrients; periphytic algae; photosynthetically available radiation; Ponggol estuary; productivity; settlement; Skeletonema costatum; Synechococcus; Synecology; Thalassiosira rotula; ISEW, Singapore; productivity; diatoms; photosynthetically available radiation; Ponggol estuary; chlorophyll a; periphytic algae; settlement; nutrients; Brackish water environment; Algae; Estuaries; Chlorophyll a; settlement: productivity; Marine environment; Heterokontophyta; Bacillariophyta; Population recruitment; Nutrient; Population dynamics; Thallophyta
• ISSN: 0272-7714; 1096-0015
• DOI: 10.1016/j.ecss.2005.01.016

This note describes settlement studies of marine periphytic algae on glass substrata in a tropical estuary in Singapore. The rates of production in terms of
14C radiotracer uptake, biomass in terms of chlorophyll
a, community structure and cell abundance were measured from the settled periphytic algae at various depths in the water column and compared with the prevailing hydrographical conditions. Relatively higher periphytic algal settlement was observed at 1
m depth, even though it was not statistically different from other depths. Diatoms such as
Skeletonema costatum and
Thalassiosira rotula dominated the assemblage, together with the marine cyanobacteria
Synechococcus sp. The three settlement parameters viz., periphytic algal production, chlorophyll
a and cell counts showed significant differences between the days of settlement, with no significant differences observed for different depths. The periphytic algal community in this study comprised 30 microalgal species, dominated by diatoms (78%), followed by cyanobacteria (19% – primarily
Synechococcus sp.), green flagellates (1%), dinoflagellates (1%) and other forms accounting for the remaining 1% of the total cell counts. Correlation studies and principal component analysis (PCA) revealed significant influence of silicate concentrations in the water column with the settlement of periphytic algae in this estuary. Though photoinhibited at the surface, photosynthetically available radiation did not seem to influence the overall settlement of periphytic algae. Diatoms and
Synechococcus in the periphytic algal community were influenced by water temperature, PAR, pH and dissolved oxygen as seen in the PCA plots.