The Centre For Water Research

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Past CWR Seminars

CWR Seminar: Nutrient recycling between the ocean and river basins using stable isotope analysis
Date 26/08/2014 at 16:00:00
Venue CWR Conference Room, Mathematics Link Building 223- UWA
Speaker Professor Keisuke Nakayama, Professor of Civil Engineering, Kitami Institute of Technology, Kitami Institute of Technology, JAPAN
Abstract

Marine derived nutrients (MDN) play a large role in the sustainability of river ecosystems. In particular, salmon and trout runs have been demonstrated to be a dominant mechanism for the transport of nutrients from the ocean to watersheds in cold regions.

Since MDN are recycled not only via river channels but also across the entire river basin, including via ground water and migratory animals, it is necessary to investigate the contribution of MDN to the forest floor (soils) in order to clarify the role of MDN across the whole river ecosystem.

This study investigated the contribution of salmon and trout to total oceanic nitrogen (TN) recycling across a river basin using stable isotope analysis of nitrogen (δ15N). The contribution of nitrogen from the ocean to the river basin was between 23.8 % and 46.9 %.  The contribution of TN from salmon and trout was 23.8 % (SD 3.1 %) relative to the export of TN from the river basin (i.e. 100 %), providing the first estimate of MDN recycling rates for a river basin. Furthermore, SIA showed that TN transported by sea eagles was more dependent on the ocean than in bears, which suggests a need to better clarify the role of sea eagles in the transport of TN from the ocean to river basins.

PS* This seminar is free and open to the public & no RSVP required.

****All Welcome****

Facilitator Clelia Marti
Organiser Askale Abebe
Student Host Bronwyn Woodward


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