2000 pollen sam­ples stud­ied

Upper Hutt Leader - - FRONT PAGE -

Fos­silised tree pollen is giv­ing us a bet­ter un­der­stand­ing of cli­mate change over the last 34 mil­lion years.

More than 2000 sam­ples of fos­silised tree pollen held at GNS Sci­ence in Lower Hutt have been stud­ied to get a pic­ture of the cli­mate over the past 34 mil­lion years, cov­er­ing a pe­riod when New Zealand was six to eight de­grees Cel­sius warmer than to­day.

The re­search, pub­lished this month in Earth and Plan­e­tary Sci­ence Let­ters, is based on fos­silised tree pollen that sci­en­tists have ex­tracted from rocks over the last 60 years.

By com­par­ing the pollen found in the rocks to the mod­ern dis­tri­bu­tion of closely-re­lated trees, the sci­en­tists were able to re­con­struct changes in air tem­per­a­ture and rain­fall.

This is the first such study in New Zealand.

The sci­en­tists used pollen from about 75 plant species – mostly trees – and their dis­tri­bu­tion pro­vides data on tem­per­a­ture and rain­fall over the last 34 mil­lion years.

Some of the trees are to­day only found in New Cale­do­nia, New Guinea and Aus­tralia.

The pollen grains are mi­cro­scopic and gen­er­ally need to be mag­ni­fied sev­eral hun­dred times for mean­ing­ful study.

‘‘Other than com­puter cli­mate mod­els, these types of fos­sil cli­mate records are the only way we have to un­der­stand how cli­mate re­sponded to el­e­vated car­bon diox­ide con­cen­tra­tions in the past, and might re­spond in the fu­ture,’’ said pa­ly­nol­o­gist Joe Preb­ble, lead au­thor of the study.

Study­ing pollen had im­pli­ca­tions be­yond look­ing at cli­mate.‘‘It is an es­sen­tial tool for as­sess­ing the age of rocks dur­ing ex­plo­ration for min­er­als and petroleum, and for un­der­stand­ing the evo­lu­tion of our unique plants and an­i­mals.’’

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