Real-world Zostera marina geography and a candidate coastal atmospheric chemical signature: analysis-ready data and geographic-placebo results

<p dir="ltr">This dataset supports an open-data geographic-placebo analysis investigating whether the real-world mapped geography of eelgrass (Zostera marina) aligns with a reproducible coastal atmospheric chemical state measured during the 2002 North Atlantic Marine Boundary Layer Experiment (NAMBLEX) at Mace Head, Ireland.</p><p dir="ltr">A wind-direction- and distance-weighted Eelgrass Atmospheric Exposure (EAE) index was constructed from mapped Z. marina geography.

The atmospheric chemical state incorporated dimethyl sulfide (DMS) and oxygenated volatile organic compounds (OVOCs), including methanol, acetaldehyde, and acetone.</p><p dir="ltr">In the canonical analysis (distance scale L = 75 km; angular scale σ = 30°; n = 150), EAE was negatively associated with the atmospheric chemical-state score (β = −0.249, 95% CI −0.399 to −0.100; nominal p = 0.00108). The true eelgrass geography ranked first among 36 geographic rotations, corresponding to an empirical geographic-placebo p value of 1/36 = 0.0278.