After a short break, we stay in the deep sea with another fascinating symbiotic system. For this Microbial Advent Calendar weekend, we have a look at the bathymodiolin mussels! I personally\u00a0worked with those mussels during my Ph.D. and they keep on fascinating me as an organism capable of establishing so\u00a0many different associations with bacteria. They were first\u00a0discovered and described at the same time as hydrothermal vents. If the existence\u00a0of hydrothermal vents, those gigantic bursts of hot water in the depth of the ocean close to tectonic margins, was hypothesized\u00a0before being found, the presence of luxurious megafauna around them was pretty much a surprise.<\/p>\n[\/vc_column_text][vc_row_inner column_margin=”default” text_align=”left” css=”.vc_custom_1545003664708{margin-top: 1% !important;}”][vc_column_inner column_padding=”no-extra-padding” column_padding_position=”all” background_color_opacity=”1″ background_hover_color_opacity=”1″ column_shadow=”none” column_border_radius=”none” column_link_target=”_self” width=”1\/2″ tablet_width_inherit=”default” column_border_width=”none” column_border_style=”solid” bg_image_animation=”none”][vc_column_text]\n
After their initial discovery, the bathymodiolin mussels\u00a0have been found everywhere around the world. Close to hydrothermal vents, but also close to cold seeps, which are pockets of gas or hydrocarbons\u00a0on frictions zone slowly leaking into the water column. The common thing between these two deep-sea geological features is the presence of high quantities of sulfur compounds and methane, which is the source of energy and carbon for microbial primary producers. If the surface world has photosynthesis to fix inorganic carbon and redistribute it to the food chain, in the dark ocean depths, carbon is fixed through sulfur- and methane-oxidizing bacteria.<\/p>\n
And to succeed in those reduced and extreme environments the bathymodiolin mussels established symbiotic associations with such bacteria.\u00a0 The bacteria are housed in the first epithelial layer of the gills. In comparison to a normal mussel, they have overgrown gills taking up most of their body volume, a trick which increases the area of exchange between bacteria and seawater. The tweet on the right, which is a whole mount fluorescence in situ<\/em>\u00a0hybridization\u00a0picture of a Bathymodiolus<\/em> mussel by Miguel \u00c1ngel Gonzalez Porras<\/a> from the Max Planck Institute in Bremen, shows perfectly the bacteria (in red) packed in individual mussel cells!<\/p>\n[\/vc_column_text][\/vc_column_inner][vc_column_inner column_padding=”no-extra-padding” column_padding_position=”all” background_color_opacity=”1″ background_hover_color_opacity=”1″ column_shadow=”none” column_border_radius=”none” column_link_target=”_self” width=”1\/2″ tablet_width_inherit=”default” column_border_width=”none” column_border_style=”solid” bg_image_animation=”none”][vc_column_text]\n There must be something special about the epithelial gill tissue of #bathymodiolus<\/a> mussels that makes it like a magnet for marine symbionts! Mutualistic, parasitic and even new #friends<\/a> to be revealed! All marine microbes want to live in this awesome biorreactor! pic.twitter.com\/sKDifmn2tN<\/a><\/p>\n \u2014 PhD_Fharon (@PhD_Fharon) December 7, 2018<\/a><\/p><\/blockquote>\n\n