Tek (Trimix) speleologist diver in a karstic underwater cave over 70 meters deep, Photogrammetry, twiglight zone, Mayotte

scientific instrument diver man measure (to) swim profile shot overview underwater shot blue mayotte tropical sea cave limestone speleology scuba diving january exploration karst mozambique channel scientific instruments scientific material scientific materials scientific study material scientific studies materials scientific measuring instrument scientific measuring instruments laboratory instrument divers men measured measuring swimming (action) swimming profile sights profile sight profile shots profile view profile views side view overviews global sight global sights full length subaquatic photos subaquatic sights seen under the water photos under the water underwater shots subaquatic image underwater view submarine images submarine sights submarine sight submarine photos submarine photo underwater views submarine photographies submarine photography underwater underwaterphoto underwaterpicture underwaterphotography underwaterphotographies underwaterphotos underwaterpictures tropical seas tropical oceans tropical ocean caves caving scuba divings explorations exploration travel exploration travels exploration journeys exploration journey explorer explorers karsts karst topography karst landscape karst landscapes karst landforms karst landform scientific research science diving sport leisure person individual locomotion motion shot colour comoro islands africa sea marine area area geological formation earth's crust mineral matter matter (substance) geography landform indian ocean world sea and ocean