Nitrogen acquisition and resource allocation strategies in temperate seagrass Zostera nigricaulis: Uptake, assimilation and translocation processes
S Nayar, MGK Loo, JE Tanner, AR Longmore, GP Jenkins
SCIENTIFIC REPORTS | NATURE PUBLISHING GROUP | Published : 2018
The dominant seagrass in Port Phillip Bay (PPB), Australia, Zostera nigricaulis, declined between 2000 and 2011, coinciding with the 'Millennium drought' that ended in 2009. These seagrasses are nitrogen-limited, underpinning the need to develop nitrogen budgets for better ecosystem management. Environmentally realistic measurements of specific uptake rates and resource allocation were undertaken to develop nitrogen budgets and test the hypothesis that the above-ground and below-ground compartments are able to re-mobilise ammonium and nitrate through uptake, translocation and assimilation to adapt to varying levels of nitrogen in the ecosystem. Uptake of 15N labelled ammonium and nitrate by ..View full abstract
The authors acknowledge funding from the Department of Sustainability and Environment, now called the Department of Environment, Land, Water and Planning, State Government of Victoria. The authors acknowledge the contribution of Dr Alastair Hirst, Environment Protection Authority Victoria for background data and assistance with field work and logistics. Assistance in the field from Dr John Runcie, Aquation Pty Ltd and Mr. Alex Dobrovolskis of SARDI Aquatic Sciences is also gratefully acknowledged. Mr. Ian Garland, skipper of MV Reel Easy is thanked for field assistance and providing us a research platform. Mrs. Michelle Braley and Mr. Kriston Bott, SARDI Aquatic Sciences are thanked for processing samples in the laboratory. Critical but constructive feedback from the anonymous reviewers on the draft version of this manuscript is gratefully acknowledged.