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Physiological response of temperate microphytobenthos to freezing temperatures

journal contribution
posted on 2023-05-17, 20:45 authored by Lee, SH, Andrew McMinnAndrew McMinn
Microphytobenthos (MPB) contributes up to half the primary production of estuaries. These microorganisms are sensitive to changes in sediment temperatures, particularly the extreme temperatures during exposure periods. This study investigates the physiological responses of MPB to freezing temperatures at two locations near Hobart, Tasmania during winter. Photosynthetic parameters were measured at 2 mm intervals to a depth of 10 mm. FV/FM values at three different distances from the shoreline at Kings Beach and Browns River in winter were between 0.584 and 0.617. rETRmax values were between 24.696 and 20.773. Maximum a values peaked in the subsurface rather than at the sediment surface. In vitro laboratory experiments (down to 258C) showed little difference in response between the control and treatment groups, indicating no apparent effects of short term freezing on the MPB. Little change in photosynthetic parameters in response to freezing was probably associated with the resistance of light-harvesting reactions to freezing temperatures, recovery of the plasmalemma integrity or cryoprotection. Sediment composition and species composition were similar at both sampling sites. Therefore, responses of MPB were not due to species and grain size composition.

History

Publication title

Journal of the Marine Biological Association of The United Kingdom

Volume

93

Issue

8

Pagination

2039-2047

ISSN

0025-3154

Department/School

Institute for Marine and Antarctic Studies

Publisher

Cambridge Univ Press

Place of publication

40 West 20Th St, New York, USA, Ny, 10011-4211

Rights statement

Copyright 2013 Marine Biological Association of the United Kingdom

Repository Status

  • Restricted

Socio-economic Objectives

Marine biodiversity

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