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Abstract. Deep (>1 km depth) scientific boreholes are unique assetsthat can be used to address a variety of microbiological, hydrologic, andbiogeochemical hypotheses. Few of these deep boreholes exist in oceaniccrust. One of them, Deep Sea Drilling Project Hole 504B, reaches∼190 ∘C at its base. We designed, fabricated, andlaboratory-tested the Multi-Temperature Fluid Sampler (MTFS), a non-gas-tight, titanium syringe-style fluid sampler for borehole applicationsthat is tolerant of such high temperatures. Each of the 12 MTFS unitscollects a single 1 L sample at a predetermined temperature, which isdefined by the trigger design and a shape memory alloy (SMA). SMAs have theinnate ability to be deformed and only return to their initial shapes whentheir activation temperatures are reached, thereby triggering a sampler at apredetermined temperature. Three SMA-based trigger mechanisms, which do notrely on electronics, were tested. Triggers were released at temperaturesspanning from 80 to 181 ∘C. The MTFS was set fordeployment on International Ocean Discovery Program Expedition 385T, buthole conditions precluded its use. The sampler is ready for use in deepoceanic or continental scientific boreholes with minimal training foroperational success.
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