Site 2
Exploration Project
Into the Subterranean
Cenote Site 2 sits in the karst heartland south of Mérida, near the community of Pixyah, roughly 45 minutes from the city. With a halocline positioned at approximately 60m and a maximum depth that remains unknown — exceeding 70m on current evidence — it is a genuinely deep, unfinished exploration target. This project deploys a four-person multidisciplinary team across eight weekends. Push dives beyond 60m are conducted exclusively on CCR (closed-circuit rebreather) to maximize bottom time and eliminate narcosis and gas logistics constraints at depth. The programme blends systematic cartography, biological sampling, photographic documentation, and technical CCR diving to produce the most complete survey of the system to date.
What We're Here to Do
Cartographic Survey
Produce a full 2D survey map of all known passages using the MNemo or Ariadne survey system. Tie into any existing guideline network. Document passage dimensions, morphology, and bearing data.
Depth & Vertical Profile
Establish a verified depth profile through the full water column. Halocline confirmed at ~60m. CCR push dives target the unknown bottom, currently believed to exceed 70m. Deploy loggers for continuous depth/temp/salinity data through the halocline transition.
Biological Inventory
Catalog stygobitic fauna (cave-adapted fish, crustaceans, microbial mats). Collect non-destructive samples from the halocline layer (~60m) for geochemical and microbiological analysis. The deep saltwater lens below 60m is a priority for undiscovered stygobite diversity.
Visual Documentation
Build a photographic and video archive of speleothem formations, passage character, water stratification, and biological features. Deliverable: high-resolution media package.
New Passage Discovery
Systematically penetrate all known leads and chokes with fresh line. Identify unexplored continuations, squeeze passages, and potential connections to adjacent systems.
Community Report
Compile findings into a formal exploration report for submission to the Quintana Roo Speleological Survey (QRSS) / equivalent Yucatan registry and local community stakeholders.
The Four
- Full Cave · CCR certified
- Primary line layer — deep push lead
- Team lead & safety officer
- CCR gas planning & bailout logistics
- Full Cave · CCR certified
- MNemo / Ariadne operator
- 2D/3D map production
- Deep survey specialist (60m+)
- Full Cave · scientific diver
- Sample collection protocol
- Halocline water chemistry
- Fauna ID & stygobite survey
- Full Cave certified
- Underwater photo / video
- Lighting & strobe rigging
- Post-production & archive
Eight Weekends,
One System
Establish relationship with landowner / local community. Assess access road condition (4.5 km terracería from Pixyah). First water entry — surface assessment and shallow cavern zone only.
- Drive to Pixyah; landowner meeting
- Establish base camp / staging area
- Gear deployment and rigging check
- Entry point survey (dry)
- Cavern zone entry (≤60m penetration)
- Surface conditions + ambient light log
- GPS anchor point, access GPS track
- Debrief + photo site documentation
Penetrate beyond cavern zone on OC. Deploy primary guideline along the main conduit. Log passage azimuth, bearing, and key junction points. Descend toward the halocline (expected ~60m) — confirm exact transition depth. OC bailout bottles staged at mid-depth.
- Primary reel — cave zone penetration
- Line tie-off at entrance and key jumps
- Passage bearing log (compass + MNemo)
- Depth profile Day 1
- Extend line — secondary passages ID'd
- Halocline depth + exact position logged (~60m)
- Photo documentation: formations
- Gas turns respected — strict 1/3 rule
Two-diver survey teams. Systematic measurement of all surveyed line: azimuth, inclination, passage width/height at regular stations. Begin building the CAD/digital map base.
- Pair 1 (Alpha + Beta): survey main trunk
- Pair 2 (Gamma + Delta): photo/video suite
- Station markers placed every 10m
- Ceiling & floor profiles logged
- Continue survey — reach known terminus
- All four divers debrief on junction leads
- Data entry into survey software
- Provisional map draft reviewed
First dedicated CCR push dives. Alpha + Beta on CCR, targeting the halocline at ~60m and probing below. Gamma + Delta on OC with staged bailout bottles at 30m and 50m. Goal: confirm bottom morphology, get first depth reading below 60m. Full deco plan mandatory.
- CCR pre-dive checks: cells, loop, bailout
- Bailout stages placed at 30m + 50m (OC)
- Alpha + Beta: CCR push to halocline
- Gamma + Delta: OC, max 45m — survey support
- CCR push #2: penetrate below halocline
- First sub-60m depth readings recorded
- Full deco stops executed — no rushing
- Retrieve all bailout stages, full debrief
Two-track weekend. Alpha + Beta on CCR push the deepest known point — targeting true bottom or maximum safe depth beyond 70m. Simultaneously, Gamma + Delta on OC work all lateral leads identified in WK2–3 at shallower depths (<50m).
- CCR max depth attempt: Alpha + Beta
- Setpoint discipline: 0.7 PO₂ descent, 1.3 bottom
- Gamma + Delta: OC lateral lead exploration
- Lead A (NW arm) + Lead B (eastern passage)
- CCR push #2 or vertical survey pass
- Lateral leads continued / new line laid
- All jump leads marked with cookies
- Map update: leads resolved vs. open
Dedicated science dives. Logger array covers full water column. Halocline water sampling at ~60m requires CCR divers (Alpha + Beta) to hold position precisely in the transition layer. OC support at shallower depths. Gamma leads sample collection protocol.
- Logger deployment: -10m, -40m, -60m, -70m+
- CCR divers: halocline sample collection at ~60m (×3 vials)
- Saltwater lens fauna observation (CCR only)
- Sediment trap placed at -50m shelf
- Retrieve 24hr logger data — spot check
- Microbial mat sampling (swab + photo)
- Speleothem condition survey + documentation
- Sample labeling, chain-of-custody log
Dedicated filming and photography weekend. Delta leads with full lighting rig. Clean high-resolution sweeps of all major formations, passages, and the halocline layer. Survey gaps filled.
- Light rig deployment (video lights + strobes)
- Formation gallery: stalactites, columns, curtains
- Halocline layer: brackish lens B-roll
- Survey gap fills — any unclosed loops
- Entrance / cavern zone hero shots
- Diver silhouette photography
- Final survey data quality check
- All guide lines checked + repaired
Project closure weekend. Retrieve data loggers and any remaining equipment. Final map quality control. Community handover. Leave no trace — remove all temporary line except permanent survey markers.
- Logger retrieval from all depths
- Temporary line removal (all reels)
- Permanent survey arrows/markers left
- Final underwater site condition check
- Community meeting: preliminary findings
- Map and media handover to landowner
- Team debrief + lessons learned log
- Report writing kickoff
The Stratified System
Site 2, like most Yucatan interior cenotes, hosts a freshwater–saltwater stratification. The halocline position, speleothem distribution, and available passage all shift with depth.
Non-Negotiable Rules
Gear, Gas & Getting There
- Primary: AL80 doubles or backmount
- Sidemount option for restrictions
- Stage bottles for WK4 deep push
- EAN32 for deco obligations
- O₂ surface unit at base camp
- Primary: canister or video light ×4
- 2× backup lights per diver (minimum)
- Delta: video lights + strobes rig
- Surface: headlamps + dive torches
- MNemo or Ariadne survey device
- Backup: compass + depth gauge + slate
- Survey reels (50m + 100m)
- Directional arrows (×40 minimum)
- Permanent markers for stations
- Niskin-style water sample syringes
- Sealed vials — halocline samples
- iButton / HOBO data loggers ×3
- Swab collection for microbiology
- Slate + pencil for field notes
- 4×4 vehicle required (terracería)
- 45 min Mérida to Pixyah + 4.5 km
- Shade structure + water supply
- First aid kit + O₂ unit on-site
- Local community contact (required)
- Mirrorless in underwater housing
- Wide-angle + macro ports
- Dual strobes (Inon / Sea&Sea)
- Video: 4K camera + lights
- Extra batteries + memory cards
What the Project
Produces
Survey Map v1.0
Full plan-view and profile-view cave map. Georeferenced. Suitable for QRSS submission and community use. Digital + printed formats.
Exploration Report
Written report: site description, methodology, findings, biological notes, depth profile, new discoveries, and recommendations for future work.
Media Archive
High-resolution photo archive + edited video reel. Organized by passage section, formation type, and biological subject. Deliverable to community stakeholders.
Science Data Package
Water sample data, logger files, biological inventory, and chain-of-custody documentation. Ready for lab submission or academic collaboration.