A field-deployable CRISPR-based biosensing platform for monitoring marine ecosystems.

Ocean ecosystems are undergoing accelerating disruption from human impacts such as climate change. Warming ocean temperatures drive pathogenic outbreaks, increase harmful algal blooms, and cause coral stress. These can have serious consequences for marine ecosystems, human health and the aquaculture industry, representing a critical One Health issue. Monitoring key marine species offers valuable insights, but current methods are resource-intensive, low-resolution, and unsuitable for frequent deployment. Here, we introduce a low-cost, field-deployable CRISPR biosensing platform for detecting marine organismal DNA and RNA. Harnessing the programmability of CRISPR diagnostics for environmental biosurveillance, we demonstrate versatility across three climate-linked indicators: Vibrio spp., Pseudo nitzschia spp., and heat-stressed corals. Portable 3D-printed processor and incubator devices enable direct processing of filter-captured samples with temperature control. Field-readiness is reinforced by lyophilized reagents, lateral-flow readouts, dropper-based handling, and a two-step multiplexed workflow, delivering results within one hour without laboratory instruments. Benchmarking with authentic pathogens and environmental seawater confirmed seawater tolerance and robust detection of 108 CFU/filter Vibrio pathogens, equivalent to 102 cp/µL for a 1L filtered sample. This decentralized platform reduces barriers to routine monitoring and can provide early warnings of ecosystem disturbances, whilst supporting One Health initiatives in the marine space.