Effects of salinity and possible interactions with temperature and pH on growth and photosynthesis of Halophila johnsonii Eiseman

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Title: Effects of salinity and possible interactions with temperature and pH on growth and photosynthesis of Halophila johnsonii Eiseman
Authors: Fernández-Torquemada, Yolanda | Durako, Michael J. | Sánchez-Lizaso, José Luis
Research Group/s: Biología Marina
Center, Department or Service: Universidad de Alicante. Departamento de Ciencias del Mar y Biología Aplicada | University of North Carolina at Wilmington. Department of Biological Sciences
Keywords: Salinity | Temperature | PH | Halophila johnsonii | Growth | Photosynthesis
Knowledge Area: Botánica Marina
Date Created: 2005
Issue Date: 28-Jul-2005
Publisher: Springer Berlin / Heidelberg
Citation: FERNÁNDEZ TORQUEMADA, Yolanda; DURAKO, Michael J.; SÁNCHEZ LIZASO, José Luis. “Effects of salinity and possible interactions with temperature and pH on growth and photosynthesis of Halophila johnsonii Eiseman”. Marine Biology. Vol. 148, No. 2 (Dec. 2005). ISSN 0025-3162, pp. 251-260
Abstract: The effects of salinity, temperature, and pH variations on growth, survival, and photosynthetic rates of the seagrass Halophila johnsonii Eiseman were examined. Growth and survival responses to salinity were characterized by aquarium experiments in which plants were exposed to seven different salinity treatments (0, 10, 20, 30, 40, 50, and 60 psu) during 15 days. Photosynthetic behavior was assessed for short-term salinity exposures (1 or 20 h) by incubation experiments in biological oxygen demand (BOD) bottles and by measuring photosynthesis versus irradiance (PI) responses in an oxygen electrode chamber. In the bottle experiments the possible effects of interactions between salinity and temperature (15, 25, and 35°C) or pH (5, 6, 7, and 8.2) were also examined. Growth and survival of H. johnsonii were significantly affected by salinity, with maximum rates obtained at 30 psu. Salinity also altered the parameters of the PI curves. Light saturated photosynthesis (Pmax) and the photosynthetic efficiency at subsaturating light (α) increased significantly up to an optimum of 40 psu, decreasing again at the highest salinities. Dark respiration rates and compensating irradiance (Ic) showed minimum values at 40 and 50 psu, while light-saturation point (Ik) was maximum at 30–50 psu. An interaction between salinity and temperature was not found although an increase of temperature alone produced an increase in α, Pmax, respiration rates, and Ik. An interaction between salinity and pH was only found in the Pmax response: Pmax increased with pH=5 at 30 psu. In addition, reducing the pH increased α significantly. In the BOD bottles experiment a significant reduction in the dark respiration with decreasing pH was observed, but the opposite trend was observed in the photosynthetic rate. These results suggest that the endemic seagrass H. johnsonii could be negatively affected by hypo- or hypersalinity conditions, although salinity changes did not seem to alter the tolerance of this species to other environmental factors, such as temperature or pH.
Sponsor: This research was supported by a grant of the Generalitat Valenciana (CTESPR/2002/59).
URI: http://hdl.handle.net/10045/7326
ISSN: 0025-3162 (Print) | 1432-1793 (Online)
DOI: 10.1007/s00227-005-0075-5
Language: eng
Type: info:eu-repo/semantics/article
Rights: The original publication is available at www.springerlink.com
Peer Review: si
Publisher version: http://dx.doi.org/10.1007/s00227-005-0075-5
Appears in Collections:INV - BM - Artículos Científicos / Scientific Papers
INV - Recursos Hídricos y Desarrollo Sostenible - Artículos de Revistas

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