SEASONALITY IN MARINE ARCHIVES: IMPLICATIONS OF HIGH-RESOLUTION DATA FOR ASSESSING ECOSYSTEM RESILIENCE

To predict the resilience of ecosystems to future environmental change, we often assess their experience with past environmental variability. Seasonal variability, as confirmed by long-term monitoring, is often of equal or greater magnitude than inter-annual or inter-decadal variability. Constraining past seasonal dynamics is therefore critical in predicting the response of organisms and ecosystems to future environmental change. Despite widespread agreement on the importance of seasonal dynamics, centennial and multi-centennial paleoclimate archives are often at annual or lower resolution. To assess bias introduced by annual averaging, we will examine sub-annual d¹¹B and d¹³C archives in annually-banded, long-lived, benthic calcifying red algae from the Canadian Arctic, using LA-MC-ICMPS (laser ablation multi-collector inductively coupled mass spectrometry). We will compare magnitudes of sub-annual and inter-annual variability recorded by the algae, examining the importance of constraining seasonal shut down of proxy organisms, and how this influences climate archives. We will also compare sub-annual laser derived d¹³C records with conventional bulk sampling methods, highlighting the importance of integrating bulk and laser derived data. We will then contrast sub-annual variability recorded in Arctic coralline algae with that of other latitudes, to discuss the relative vulnerabilities of different ecosystems.