Monospecific meadows of Halophila ovalis (R. Brown) Hooker f. were studied in deep waters (14-16 m) around Langkai island in South Sulawesi, Indonesia, during May-September 1990, The average shoot density of Halophila in biomass samples (n=10) taken from these meadows was 1099 +/- 195 leaf pairs m(-2). Comparison with average leaf pair densities (427 +/- 211 leaf pairs m(-2)) estimated by in situ counts under water (using SCUBA) revealed that more than 50% of the leaf tissue was covered under the sediment. The leaf area index (LAI) was 0.68 +/- 0.32 m(2) m(-2) (including sediment-covered leaves). Total seagrass biomass in the meadows averaged 10.93 +/- 2.65 g ADW m(-2), of which 42% was contributed by above-ground plant parts. Metabolic measurements using m the bell jar-technique and plastochron interval measurements gave comparable results, revealing total plant production to range between 0.83 and 1.38 g C m(-2) day(-1) with a turn-over of total plant biomass of 3.9-6.6 days. Rhizome tagging experiments showed that 34% of this production may be contributed by the below-ground biomass, The light compensation point fur Halophila ovalis at 15 m depth was 33 mu mol photons m(-2) s(-1). The high primary production of these sparsely grown meadows at such considerable depths (14-16m) and under high stress from sedimentation (at the bottom of a reef slope) is attributed to the strongly opportunistic character of this seagrass species, whose meadows can be found to depths of over 30 m in the study area. [KEYWORDS: Halophila ovalis; Indonesia; light limitation; oxygen exchange; production; seagrass; sedimentation South sulawesi; seagrass beds; indonesia; decipiens; biomass; decomposition; queensland; australia; growth]
Original languageEnglish
JournalAquatic Botany
Journal publication date1999

ID: 83537