Interactive comment on “ Subaqueous speleothems ( Hells Bells ) formed by the interplay of pelagic redoxcline biogeochemistry and specific hydraulic conditions in the El Zapote sinkhole , Yucatán Peninsula , Mexico ” by Simon

Line 20: Given that this is a sinkhole, I’m uncomfortable with the author’s description of this chamber as lightless in the absence of measurements of light intensity over annual timescales. While it may appear dark to divers, there may be some “light” that still makes it to the chamber during some portions of the year. Line 32: It would be nice if the authors could include information about why Hell’s Bells are not more widely distributed in coastal aquifers in general (and the Yucatan more specifically) in the abstract. Improved information and word economy in the preceding sections should create space for this insertion. Page 2 Line 1: I’ve been working on karst research problems for almost 20 years and have never heard the term “pending speleothems.” That doesn’t mean the term does not exist, but it probably means it is not common. Page 3 lines 18-19: I don’t understand why a recharge event would elevate the freshwater lens. It should depress it, as recharge would increase the thickness of the lens. . .. The manuscript that was cited wasn’t much help in explaining the process either. Page 10, Line 3: I suggest “oxygenated” or “aerobic” as an alternative to “oxygenized“ Page 11, Figure 3: The symbols change in panel C but there is no corresponding legend. I’m guessing that the circles are still winch collected and the squares are diver collected, but it would be helpful if the symbols remained constant across each panel. Page 17