Negative relationships between the nutrient and carbohydrate content of the seagrass Thalassia testudinum (original) (raw)

Seasonal Variation in Cell Wall Composition and Carbohydrate Metabolism in the Seagrass Posidonia oceanica Growing at Different Depths

Plants

Posidonia oceanica is a common seagrass in the Mediterranean Sea that is able to sequester large amounts of carbon. The carbon assimilated during photosynthesis can be partitioned into non-structural sugars and cell-wall polymers. In this study, we investigated the distribution of carbon in starch, soluble carbohydrates and cell-wall polymers in leaves and rhizomes of P. oceanica. Analyses were performed during summer and winter in meadows located south of the Frioul archipelago near Marseille, France. The leaves and rhizomes were isolated from plants collected in shallow (2 m) and deep water (26 m). Our results showed that P. oceanica stores more carbon as starch, sucrose and cellulose in summer and that this is more pronounced in rhizomes from deep-water plants. In winter, the reduction in photoassimilates was correlated with a lower cellulose content, compensated with a greater lignin content, except in rhizomes from deep-water plants. The syringyl-to-guaiacyl (S/G) ratio in the ...

Carbon storage by seagrass community.pdf

We analyzed stored carbon in the Above Ground Biomass (AGB) and Below Ground Biomass (BGB) of three seagrass species in Koswari, Kariyachalli and Vilanguchalli during March, 2014 at Gulf of Mannar. Soil Organic Carbon (SOC) was also monitored simultaneously to evaluate the amount of stored carbon in the underlying soil of the intertidal mud flat in the study area. In the selected quadrate, the order of abundance of the seagrass species was Cymodocea serrulata > Thalassia hemprichii > Halophila ovalis. Pronounced variation was observed between AGB and BGB in all the three species. The ratio of AGB and BGB ranged from 1:1.25-1:1.30. The Above Ground Carbon (AGC) and Below Ground Carbon (BGC) also exhibited significant variation with highest value in Cymodocea serrulata followed by Thalassia hemprichii and Halophila ovalis.

Nutrient dynamics of seagrass ecosystems: 15N evidence for the importance of particulate organic matter and root systems

Marine Ecology Progress Series

The availability of nitrogen in sediment phytodetritus to seagrass was investigated in 5 tropical species (Thalassia hemprichii, Halodule uninervis, H, pinifolia, Halophila ovalis/ovata and Syringodium isoetifolium) from Indonesia. N-15-labeled phytodetritus was injected into the sediment and the appearance of N-15 in the roots, the rhizomes and the leaves of the plants were measured after 1, 2, 4 and 8 d. The transfer of N-15 from sediment phytodetritus to the plant tissues was very rapid (within 1 d) and continued over the 8 d period, indicating an efficient retention of the phytodetritus and a net mineralization of nitrogen rather than an immobilisation by bacteria. Relative enrichment of roots versus leaves indicated that N-15 was taken up by the roots and then transferred to the leaves. The combined efficiency of seagrass canopy-induced trapping and retention of sestonic particles and root-uptake, results in the acquisition of nutrients released upon mineralization of particula...