Conference Agenda

The deep sea remains among the least economically documented ecosystems on Earth, yet it is becoming increasingly central to global governance debates, particularly over deep-sea mining. To our knowledge, this study provides the first Bayesian hierarchical meta-analysis of deep-sea ecosystem-service values, drawing on DEEPVAL, a new open database of 119 harmonized estimates from 37 primary studies published between 1990 and 2024. To address the pronounced heterogeneity, limited sample size, and within-study dependence of this sparse literature, we estimate separate hierarchical models for stated-preference and market-based approaches, preserving welfare-theoretic consistency across valuation regimes. Under common reference scenarios, we further derive the first posterior-adjusted value distributions for deep-sea ecosystem services, providing full posterior distributions as structured reference points for cautious benefit transfer rather than collapsing the underlying uncertainty into single point estimates. The results reveal two distinct value structures: Minerals rank first in the market-based model (337 Int.$/ha/yr), whereas Waste treatment dominates the stated-preference model (280 Int.$/ha/yr). Regulating, supporting, and cultural services are, by contrast, structurally compressed or absent in market-based accounts. This asymmetry suggests that a purely market-based accounting systematically understates the welfare costs of deep-sea degradation, with direct consequences for seabed mining appraisal and marine protected area design.