Browsing by Author "Bachok, Zainudin"

Now showing 1 - 7 of 7
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    Characterization of Fatty Acid Composition in Healthy and Bleached Corals from Okinawa, Japan. Coral Reefs
    (Springer Link, 2006) Bachok, Zainudin; Mfilinge, Prosper L.; Tsuchiya, Makoto
    Under bleaching conditions, corals lose theirsymbiotic zooxanthellae, and thus, the ability to syn-thesize fatty acids (FAs) from photosynthetically derivedcarbon. This study investigated the lipid content and FAcomposition in healthy and bleached corals from theOdo reef flat in Okinawa, southern Japan, following ableaching event. It was hypothesized that the FA com-position and abundance would change as algae are lostor die, and possibly microbial abundance would increasein corals as a consequence of bleaching. The lipid con-tent and FA composition of three healthy coral species(Pavona frondifera, Acropora pulchra, and Gonia streaaspera) and of partially bleached and completelybleached colonies of P. frondifera were examined. TheFA composition did not differ among healthy corals, butdiffered significantly among healthy, partially bleached,and completely bleached specimens of P. fro ndifera.Completely bleached corals contained significantly lowerlipid and total FA content, as well as lower relativeamounts of polyunsaturated FAs and higher relativeamounts of saturated FAs, than healthy and partiallybleached corals. Furthermore, there was a significantlyhigher relative concentration of monounsaturated FAsand odd-numbered branched FAs in completelybleached corals, indicating an increase in bacterial col-onization in the bleached corals.
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    The Diet of the Mud Clam Geloina Coaxans (Mollusca, Bivalvia) as Indicated by Fatty Acid Markers in a Subtropical Mangrove Forest of Okinawa, Japan
    (Elsevier, 2003) Bachok, Zainudin; Mfilinge, Prosper L.; Tsuchiya, Makoto
    Fatty acid compositions in the tissues of the clam Geloina coaxans collected from Oura mangal, Okinawa, Japan, during the cold and warm seasons (January and July 2001, respectively) were compared with those in suspended materials (SM) in order to assess the clams' diet. In both seasons, the suspended mangrove detritus at the sediment–water interface was high as indicated by the mean percentage of even-numbered long-chain fatty acids in SM (12.8–18.4%). The contribution of this marker in the clam tissues, especially during the cold season (3.9%), indicates the consumption of mangrove detritus in considerable amounts by the clams. The occurrence of the fatty acids 16:1ω7, 18:1ω9, 18:2ω6 and 18:3ω3 in SM was most likely due to the mangrove detritus sources, whereas in the SM they together constituted 12.9% and 23.9% of total fatty acid contents during the cold and warm seasons, respectively. As a result, their contribution in the clam tissues was high in the cold (15.4%) and warm seasons (19.0%). These results indicate that mangrove detritus play a significant role in the clams' diet. The mean percentages of bacterial markers (odd-numbered branched fatty acids and vaccenic acid, 18:1ω7) in the SM and tissues during both seasons ranged from 8.1% to 9.5%. This indicates that the clam diet is also dependent on the attached bacteria on the partially decomposed leaf detritus suspended at the sediment–water interface. The relative contribution by microalgae markers (18:4ω3, 20:5ω3 and 22:6ω3) in clam tissues ranged from 4.3% to 7.6%, suggesting considerable microalgae sources in the diets.
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    Fatty Acid Markers as an Indicator for Temporal Changes in Food Sources of the Bivalve Quidnipagus Palatum
    (Taylor and Francis, 2009) Bachok, Zainudin; Meziane, Tarik; Mfilinge, Prosper L.; Tsuchiya, Makoto
    Changes in the fatty acid composition in the tissues of the bivalve Quidnipagus palatum from the Tomigusuku intertidal flat, Okinawa, Japan, collected in four different seasons (November 2000, the beginning of cold season; January 2001, the cold season; May 2001, the rainy season; and July 2001, the warm season) were examined and compared to the composition of surface sediments and suspended particulate materials. Assessment of fatty acid markers suggested that the food sources of Q. palatum differed between seasons and depended on the sources of organic material present in the sediment and water column. Vascular plants and bacteria were the main dietary components from July to November because of their abundance in the sediment. From November to January, macroalgae and phytoplankton were the major food sources of Q. palatum, corresponding to their predominance in sediments and algal blooms, respectively. During the May rainy season, organic matter in the sediment was dominated by diatoms, whereas the water column contained diatoms and resuspended macroalgal detritus. The transition to the warm season by July significantly increased the contribution of diatoms to the organic matter present in both the sediment and the water column. Consequently, from May to July, diatoms became the main food source for Q. palatum.
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    Fatty Acids in Decomposing Mangrove Leaves: Microbial Activity, Decay and Nutritional Quality. Marine Ecology Progress Series, 265, 97-105
    (2003) Mfilinge, Prosper L.; Meziane, Tarik; Bachok, Zainudin; Tsuchiya, Makoto
    Changes in lipid content and fatty acid (FA) composition in decomposing mangrove leaves of Bruguiera gymnorrhiza (L.) Lamk and Kandelia candel (L.) were investigated in a subtropical mangrove forest on Okinawa Island, Japan (26.5°N, 128°E) by field experiments for 18 wk (July to November 2000), using yellow senescent leaves, and compared with FAs in the green leaves and mangrove sediments. We tested the hypothesis that changes in FA composition during decomposition can indicate the state of leaf decay and periods of high and low microbial activity, and that bacteria may rapidly degrade polyunsaturated fatty acids (PUFAs). During decay, FA composition in the yellow leaves changed in 2 wk from predominantly saturated FAs to monounsaturated FAs, and to the more branched FAs typical of bacteria, and lipid and N increased due to microbial colonization. However, the microbial decomposition of leaves did not alter the concentrations of long-chain fatty acids (LCFAs), suggesting that these vascular plant-markers remain unchanged in mangrove detritus and surface sediments for more than 4 mo. Furthermore, bacteria did not degrade PUFAs as we had hypothesized, indicating that during decomposition of mangrove leaves, bacteria tend to conserve PUFAs (as they do nitrogen), thus enriching the detritus with nutrients. Comparison of ω3 and ω6 PUFAs between the 2 species showed that nutritional quality varies greatly with the state of the leaf material, increasing through time in B. gymnorrhiza and decreasing through time in K. candel.
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    Food Sources of Coexisting Suspension-Feeding Bivalves as Indicated by Fatty Acid Biomarkers, Subjected to the Bivalves Abundance on a Tidal Flat
    (2006) Bachok, Zainudin; Mfilinge, Prosper L.; Tsuchiya, Makoto; Meziane, Tarik
    Resources partitioning among co-existing suspension-feeding bivalves - Cyclina sinensis, Gafrarium tumidum, Katelysia japonica, Psammotaea elongata and Semele carnicolor on Tomigusuku intertidal flat, Okinawa was investigated using fatty acid (FA) biomarkers during the cold (January 2001) and warm seasons (July 2001). P. elongata is the most dominant infaunal species. Other species are semi-infaunal and minority on the tidal flat. The total FA methyl esters (FAMEs) content during both seasons was significantly higher in the tissues of P. elongata and S. carnicolor than in C. sinensis, G. tumidum and K. japonica. P. elongata showed most unique fatty acid characteristics compared to other species during the cold–season: low percentage of w3 and w6 polyunsaturated FAs (PUFA; 11.5% of total FAMEs) compared to others (23.6 to 37.3%), highest percentage of odd-numbered branched FAs (odd-BrFAs; 5.7 %), the revelation of even-numbered long-chain FAs (0.7%), and the lowest value of PUFA/saturated FA (SAFA), PUFA/monounsaturated FA (MUFA), 16:1w7/16:0 and w3/w6 PUFA ratios. Analysis of specific FA markers (irrespective to their mean percentage) showed a significant contribution of diatom (16:1w7 and 20:5w3), dinoflagellates (18:4w3 and 22:6w3), bacterial (odd-BrFAs and 18:1w7) and green macroalgal (18:2w6 and 18:3w3) markers in all bivalves during the cold-warm seasons. These indicate that the coexisting bivalves on Tomigusuku tidal flat utilize the same food sources, originating from phytoplankton, benthic microalgae, macroalgae detritus and bacteria. However, with references to the concentration of total FAMEs in all species, the level of most FAs (SAFA, MUFA, PUFA) and FA markers of food sources was significantly higher in P. elongata and S. carnicolor, suggesting that these bivalve species accumulate food more than other species. Because P. elongata is a deep burrower, this behaviour might have increased its survival rate and therefore its greater abundance on Tomigusuku tidal flat compared to other suspension-feeding bivalves.
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    Litter Dynamics and Particulate Organic Matter Outwelling from a Subtropical Mangrove in Okinawa Island, South Japan
    (Elsevier, 2005) Mfilinge, Prosper L.; Meziane, Tarik; Bachok, Zainudin; Tsuchiya, Makoto
    Litter dynamics and outwelling of particulate organic matter (POM) was investigated in a subtropical mangrove (Okinawa Island, South Japan) in order to quantify the impact of mangrove POM on adjacent intertidal sediments. A distinct seasonal pattern was found with maximum litter fall during the autumn season, and minimum during winter. Total litter production between sites did not differ significantly. Tall mangroves (average 7 m) did not show any higher contribution to the litter production than short mangroves (average 4 m). The mean annual litter production was 12.95 ± 2.95 t ha−1 (dry weight) with leaf fall contributing more than 70% of the total litter production. Analysis of fatty acids (FAs) in the surface sediments of an adjacent mud flat and sand flat during the winter, spring and autumn seasons indicated that outwelling of POM from the mangrove ecosystem occurs. However, it is spatially restricted to within 300 m from the mangrove forest. The magnitude of the outwelling increased during spring and autumn consistent with the increase in the total litter production. Despite the presence of mangrove-derived organic matter in the estuarine surface sediments, autochthonous sources of organic matter, green macroalgae (Ulva pertusa and Enteromorpha intestinalis), diatoms and bacteria are the main contributors of sedimentary organic matter and ω3 and ω6 PUFAs than mangrove-derived (POM) during winter and spring. While the contribution of mangrove-derived POM to sedimentary organic matter is limited to the autumn season.
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    Total Lipid and Fatty Acid Classes in Decomposing Mangrove Leaves of Bruguiera gymnorrhiza and Kandelia candel: Significance with respect to Lipid Input
    (Springer Link, 2005) Mfilinge, Prosper L.; Meziane, Tarik; Bachok, Zainudin; Tsuchiya, Makoto
    Changes in the concentration of total lipid and fatty acids (FAs) during the decomposition of mangrove leaves were investigated by field experiments using yellow leaves of Bruguiera gymnorrhiza (L.) Lamk. and Kandelia candel (L.) Druce, in order to quantify mangrove contribution to lipid and fatty acid inputs to marine sediments. Total lipid and total FA in the fresh (green and yellow) and decomposing leaves of both species were significantly higher during winter than summer. During decomposition, total lipid content and FA concentration, in particular branched chain fatty acids (BrFAs) and bacterial fatty acids (BFAs), increased to a maximum concentration in 45 days during winter and in 17 days during summer. Lipids were lost faster in K. candel leaf detritus than in B. gymnorrhiza leaf detritus in which >90% of the total lipid original weight was lost during the summer experiment and <60% during the winter experiment. The changes in the concentrations of total lipids and FAs in the decomposing leaves also indicate that mangrove leaves are significant sources of fatty acids and probably other lipid compounds to estuarine ecosystems and that tidal waters transport the lipids and FAs adsorbed to particulate matter from mangroves to adjacent estuarine sediments and the ocean.