SBI PI05 harvey

An Update on Molecular Biomarkers as Tracers of Carbon Cycling in the Western Arctic: 

An Update on Molecular Biomarkers as Tracers of Carbon Cycling in the Western Arctic Rodger Harvey and Laura Belicka Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science Robie Macdonald and Mark Yunker Department of Fisheries and Oceans, Institute of Ocean Sciences, BC

The Goal:: 

The Goal: What is the sources and fate of organic carbon in the western Arctic Ocean Points to consider: Marine versus Terrestrial Carbon Inputs Remineralization verses Preservation Export of Organic Carbon to the Interior East Barrow Transect: Specific Biomarker Profiles, 14C AMS dating, Principal Components Analysis

A Reminder on Structures and SourcesBelicka et al., 2004: 

A Reminder on Structures and Sources Belicka et al., 2004 An organic biomarker approach to the carbon cycle… Source specificity Quality (diagenetic state) and transport of organic carbon >150 individual lipid biomarkers identified in Arctic samples Hydrocarbons Sterols Fatty Acids Terpenoids

Slide4: 

Contribution of individual structures to organic source

PCA Analysis of East Barrow Transect Samples: 

PCA Analysis of East Barrow Transect Samples

Barrow and East Barrow Transects - 2002: 

Barrow and East Barrow Transects - 2002 POM x Sediments

Organic Biomarker Inputs to POM: 

Organic Biomarker Inputs to POM C28Δ5,24(28): “Marine” α-amyrin: “Terrestrial” Kokolik-August Riverine Signal μg/g OC 0 1000 2000 Ikpikpuk-June Mackenzie-August Ikpikpuk Peat

Organic Biomarker Inputs to Sediments: 

Organic Biomarker Inputs to Sediments μg/g OC 0 1000 2000 Kokolik-August Riverine Signal Ikpikpuk-June Mackenzie-August Ikpikpuk Peat C28Δ5,24(28): “Marine” α-amyrin: “Terrestrial”

Carbon Utilization in Particles and Sediments at EB7: 

Carbon Utilization in Particles and Sediments at EB7 14C Age KYR BP 0 2 4 6 Profile of POC at East Barrow Water Depth (m) 0 10 20 30 140 0 500 1000 1500 0 5 10 Total Marine Biomarkers Total Terrestrial Biomarkers mg/g OC Sediment Depth (cm)

Slide11: 

Comparative organic inputs across the Arctic Basin

Findings so far : 

Findings so far Marine carbon dominates POM in the water column, but is quickly remineralized and largely lost in sediments (Belicka et al., 2004) Slope sediments appear an important site for organic matter focusing. Terrestrial carbon accumulates in sediments and accounts for a major fraction of OC preserved, especially in deep basins (Yunker et al., 2005)

Still in the Works: 

Still in the Works Analysis of Deep Basin sediments Samples from Shipboard Incubations to Estimate: Carbon Source lability Bacterial Carbon inputs Age of Organic Carbon Among Compartments