Scientists use SHRIMP device to learn of cooling temperatures millions of years ago

BEHIND the discovery of the link between a cooling climate and an explosion almost 500 million years ago of marine biological diversity lies the SHRIMP, according to the Australian National University team that led the research.

BEHIND the discovery of the link between a cooling climate and an explosion almost 500 million years ago of marine biological diversity lies the SHRIMP, according to the Australian National University team that led the research.

The scientists used a room-sized instrument invented at ANU, the sensitive high resolution ion microprobe (Mark II) -- SHRIMP II -- to measure isotopes from samples as small as the diameter of a human hair.

SHRIMP enabled them to work with oxygen isotope ratios of the fossils of conodonts, extinct eel-shaped sea creatures. Conodonts were used because they were made of material similar to fish teeth (calcium phosphate), which better preserves oxygen through time than the calcium carbonate from fossil seashells used in earlier studies.

The conodont's oxygen ratios depended on the temperature of the water in which it lived. The study found that after the sea temperature cooled from about 40C to temperatures similar to those in the tropics today, there was a flourishing of marine biodiversity.

"Using the SHRIMP to measure oxygen from phosphate microfossils is a real breakthrough," lead scientist Julie Trotter said.

"The SHRIMP will let us track climate change over hundreds of millions of years more easily and reliably, and therefore help us to understand how life might respond to future climate change."