Natural photosynthetic microboring communities produce alkalinity in seawater whereas aragonite saturation state rises up to five

Bioerosion, resulting from microbioerosion or biogenic dissolution, macrobioerosion and grazing, is one the main processes involved in reef carbonate budget functioning. On healthy reefs, most of produced carbonates are preserved accumulate. But context global change, reefs increasingly degraded as environmental factors such ocean warming acidification affect negatively accretion positively bioerosion processes. The recent 2019 SROCC report suggests that if CO 2 emissions atmosphere not drastically reduced rapidly, 70%–99% coral will disappear by 2,100. However, to improve projections evolution, it important better understand dynamics Among those processes, was shown recently bioeroding microflora which actively colonize dissolve experimental blocks, release significant amount alkalinity seawater both day at night under controlled conditions. It also this production enhanced conditions (saturation state aragonite comprised between 3.5) suggesting accumulation be even more limited future. To boring its possible consequences on resilience, we conducted a series experiments with natural rubble maintained artificial light, various saturation states aragonite. We show here dissolution colonized microboring communities dominated chlorophyte Ostreobium sp., thus seawater, can occur large range aragonite, 6.4 daylight directly correlated photosynthetic activity communities. then discuss implications paradoxical activities resilience.