Table 1.
Excavations into crustal subseafloor hydrothermal vents at Fava Flow Suburbs at 9°50’N EPR region in 2023
| ROV recovery dive # | S0552 | S0554 | S0556 | S0557 | S0558 | S0560 |
|---|---|---|---|---|---|---|
| Fig. 2c | #1 | #2 | #3 | #4 | #5 | #6 |
| Fig. 3 | a,b | c,d | e,f | g,h | i,j | k,l |
| Date | 13.07.23 | 15.07.23 | 17.07.23 | 18.07.23 | 19.07.23 | 21.07.23 |
| Longitude | 9.840237 | 9.840121 | 9.840075 | 9.840133 | 9.840238 | 9.840108 |
| Latitude | −104.291860 | −104.291818 | −104.291812 | −104.291874 | −104.292038 | −104.291805 |
| Depth (m) | 2515 | 2515 | 2515 | 2515 | 2512 | 2515 |
| Ambient T (°C) | 1.9 | 1.9 | 1.9 | 2.0 | 2.0 | 2.1 |
| Ambient salinity | 34.7 | 34.7 | 34.7 | 34.7 | 34.7 | 34.7 |
| Ambient oxygen (∑mol·L−1) | 107 | 106 | 105 | 106 | 105 | N/A |
| Surface max. T (°C) | 19.7 | 10.4 | 22.7 | 2.1 | 9.5 | 9.1 |
| Subseafloor max. T (°C) | 24.9 | 24.0 | 24.9 | 11.6 | 7.0 | 10.0 |
| Subs. salinity | 33.8 | 34.0 | 33.3 | 34.0 | 34.4 | 33.8 |
| Subs. pH | 6.4 | 5.7 | 5.5 | 6.5 | 6.5 | 6.2 |
| Subs. min. H2S (∑mol·L−1)a | N/A | 197 | 401 | 14 | 20 | 25 |
| Subs. max. oxygen (∑mol·L−1) | N/A | N/A | 50 | 91 | 115 | 47 |
| ~ Lava shelf thickness (cm) | 10 | 12 | 11 | 15 | 10 | 12 |
| ~ Lava plate surface (m2) | 0.13 | 0.21 | 0.24 | 0.08 | 0.07 | 0.06 |
| ~ Cavity height (cm) | 10 | 10 | 10 | 10 | 5 | 10 |
| Animals at vent surfaceb | ||||||
| Oasisia alvinae | 5 | 4 | 3 | 1 | 0 | 0 |
| Riftia pachyptila | 6 | 5 | 7 | 6 | 0 | 0 |
| Bathymodiolus thermophilus | 0 | 3 | 5 | 2 | 4 | 22 |
| Animals in lava crackb | ||||||
| Oasisia alvinae | 0 | N/Ad | N/Ad | 1 | 0 | 10 |
| Oasisia tubes | 30 | N/Ad | N/Ad | N/Ad | 0 | 40 |
| Riftia pachyptila | 6 | 5 | N/Ad | N/Ad | 0 | 0 |
| Lepetodrilus spp. | 2 | 1 | 0 | 0 | 0 | 0 |
| Nereis sandersi | 1 | 0 | 0 | 1 | 0 | 1 |
| Paralvinella spp. | 0 | 0 | 1 | 0 | 0 | 0 |
| Animals in subseafloor cavitiesc | ||||||
| Oasisia alvinae | 0 | 0.8 | 0.7 | 2 | 0 | 5.3 |
| Oasisia tubes | 12.3 | 15.2 | 53.3 | 200 | 0 | 16 |
| Riftia pachyptila | 0 | 0 | 3.3 | 2 | 0 | 0 |
| Archinome rosacaea | 0 | 0.8 | 0 | 0 | 0 | 0 |
| Branchinotogluma spp. | 0 | 0.8 | 0.7 | 0 | 0 | 2.7 |
| Lepetodrilus spp. | 0 | 1.5 | 0.7 | 0 | 0 | 0 |
| Lepidonotopodium williamsae | 0 | 0 | 0.7 | 0 | 0 | 2.7 |
| Neomphalus fretterae | 0 | 0 | 0 | 0 | 0 | 10.7 |
| Nereis sandersi | 0 | 2.3 | 0 | 0 | 0 | 2.7 |
| Nicomache arwidssoni | 1.2 | 0 | 0 | 0 | 0 | 5.3 |
| Paralvinella spp. | 0 | 0 | 33.3 | 0 | 0 | 0 |
Abiotic and biotic characteristics of subseafloor (subs.) and surface habitats.
asum of all forms of dissolved sulfide; short sulfide.
b custom-made aluminum frame (0.16 m2) placed on the surface over a crack in the lava shelves, animals on the surface and in the crack were counted.
c total numbers of counted animals in subseafloor cavities beneath lava shelves estimated to 0.16 m−2.
d present but not counted.