In an interesting piece of investigation in which 11 scientists took part sufficient data were obtained to establish the fact that the success of seagrasses represented by two families, Hydrcharitaceae and Potamogetonaceae of the Angiosperms to colonize submerged islands lay in their ability to establish a 3-way symbiosis . The results were published in the 15th June issue of Science 336: 1432-1434.
lucinid bivalves mollusk.
Bacteria in gills of the mollusk
Sea grasses belonging to two angiosperm families, Potamogetonaceae and Hydrocharitaceae are believed to have been derived from terrestrial plants around 100 million years ago. The currently accepted hypothesis of the origins of sea grasses is that they evolved from terrestrial plants into marine base species. It’s still unknown how sea grasses tolerate toxic sediment sulfide levels. A three-way investigation consisting of meta-analysis, field studies, and laboratory experiments has revealed how an ancient three-stage symbiosis between sea grass,
lucinid bivalves, and their sulfide-oxidizing gill bacteria reduces sulfide stress for sea grasses. Their results further show that the bivalve–sulfide-oxidizer symbiosis reduces sulfide levels and enhances seagrass production. In turn, the bivalves and their endosymbionts are benefited from organic matter accumulation and release of oxygen from the seagrass roots. These findings demonstrate why seagrasses have succeeded in thriving in warm waters across the globe and will help devise ways and means for the conservation of seagrass ecosystem.