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Comparison of the cross-shelf phytoplankton distribution of two oceanographically distinct regions off Australia

Citation

Armbrecht, LH and Thompson, PA and Wright, SW and Schaeffer, A and Roughan, M and Henderiks, J and Armand, LK, Comparison of the cross-shelf phytoplankton distribution of two oceanographically distinct regions off Australia, Journal of Marine Systems, 148 pp. 26-38. ISSN 0924-7963 (2015) [Refereed Article]

Copyright Statement

Copyright 2015 Elsevier B.V.

DOI: doi:10.1016/j.jmarsys.2015.02.002

Abstract

The coastline of Australia spans tropical to temperate latitudes and encompasses a highly diverse phytoplankton community. Yet little is known about environmental driving forces of compositional and distributional patterns in natural phytoplankton communities of Australia. We investigate the relationships of phytoplankton (pico-, nano-, microphytoplankton, determined by microscopy and CHEMTAX) with a variety of environmental variables along cross-shelf gradients. Case studies were conducted in two highly distinct oceanographic regions of Australia (2010/2012): the tropical-temperate Coffs Harbour region (~30S, 153E), where the shelf is narrow (~30km), and the tropical Kimberley region (~16S, 122E), where the shelf is wide (~200km). We distinguished three water masses in both study regions: relatively cold, nutrient-rich inshore waters; oligotrophic, stratified offshore waters; and cold, nutrient-rich deep waters. Most phytoplankton taxa (cyanobacteria, cryptophytes, dinoflagellates, haptophytes and prasinophytes) showed group-specific relationships with similar environmental variables in both regions. Diatoms occurred in nutrient-rich inshore waters in the Kimberley, whereas they were widely spread across the narrow continental shelf at Coffs Harbour. Off Coffs Harbour, a senescent bloom of the diatom Leptocylindrus danicus probably caused shelf-scale surface nutrient depletion. While microphytoplankton clearly increased, pico- and nanophytoplankton decreased with distance from the coast over the wide shelf in the Kimberley region. In contrast, the abundance of individual phytoplankton size-classes remained relatively constant across the narrow Coffs Harbour shelf. We conclude that general similarities exist between the relationship of phytoplankton and cross-shelf environmental variables in the two sites and assign differences primarily to the varying spatial resolution of our case studies.

Item Details

Item Type:Refereed Article
Keywords:continental shelf, microscopy, CHEMTAX, phytoplankton size-classes, diatoms, Synechococcus
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Biological Oceanography
Objective Division:Environment
Objective Group:Flora, Fauna and Biodiversity
Objective Field:Marine Flora, Fauna and Biodiversity
Author:Wright, SW (Dr Simon Wright)
ID Code:109774
Year Published:2015
Web of Science® Times Cited:4
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2016-06-30
Last Modified:2017-11-01
Downloads:0

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