Moderate turbidity did not show a common heat-response reduction in repeated coral surveys from three oceans, 2001-2019

We tested the proposed moderate turbidity band from 0.080 to 0.127 per metre against clearer water in repeated Reef Check surveys. The panel has 3,688 site-date records at 672 sites in three oceans, with realized dates in 2001-2019. A model with site, year and month effects gave a band difference in the heat slope of -3.56 bleaching percentage points per four degree-heating weeks. Its nominal ecoregion-cluster 95% interval was -7.74 to +0.61. Both pooled period intervals included zero. Indian Ocean estimates were positive but used only seven moderate-band sites; the early Indian interaction was not identified. All 38 pooled region-omission intervals included zero. The tested band did not show a common clear reduction. This extends a prior continuous-interaction audit using the same archive; it is not independent data. Selected visits and outcomes, few region groups, static optical exposure, unequal heat support and unknown coral composition limit inference. The package includes code, survey records, source hashes, numerical checks and a figure. It does not measure species loss or air pollution.

coral bleaching · heat stress · turbidity · observation bias · repeated surveys