Capability or participation? A dimensional analysis of ocean digital twins and its implications for maritime spatial planning governance

Abstract

Ocean digital twins, Digital Twins of the Ocean (DTOs), are increasingly promoted as the decision-support backbone for marine spatial planning (MSP), yet the term denotes at least four incompatible conceptions across communities that rarely cite one another, alongside a critical strand that interrogates the object rather than advancing a conception of it, and most marine decision-support tools are never adopted in practice. This paper asks whether, and how, a DTO can serve participatory marine governance. Using a concept-centric morphological analysis, we assemble a corpus of eleven DTO conceptions, one critical reading of the field, and fifteen deployed systems and decision-support tools, and code each against six dimensions derived from the literature: three graded (scope, capability, coupling) and three categorical (object, purpose, intended users); the full coding matrix is provided as supplementary material. Mapping the corpus reveals a structured capability–participation trade-off rather than a uniform spread: the conceptions richest in analytical capability address the narrowest set of users, while those reaching non-expert stakeholders sit lowest on the capability ladder; no continuously synchronised system combines both, and only an aspirational programme (DITTO) claims to. Because MSP is a stakeholder-driven governance process that demands both, this trade-off diagnoses why capable ocean twins go unused in planning. Setting the framework against the stages of the planning cycle sharpens this into practical guidance: continuous synchronisation, the property that distinguishes a twin from a decision-support tool, is decisive at three of six stages and contributes little at the three where participation matters most, which gives authorities a basis for deciding whether a digital twin is what their planning problem requires. We translate the analysis into governance-relevant guidance: treating stakeholder-usability as an explicit, evaluable requirement when MSP authorities specify, commission and assess DTOs, and decoupling a high-capability predictive backbone from a simple stakeholder-facing interface. A descriptive definition, derived from the dimensions, gives marine managers a shared vocabulary for asking what any Digital Twin of the Ocean is for, and for whom.