Photosynthetic recovery of transplanted Posidonia sinuosa, Western Australia Lotte E. Horn a, *, Eric I. Paling b , Mike van Keulen c a School of Environmental Science, Murdoch University, Western Australia 6150, Australia b Marine and Freshwater Research Laboratory, School of Environmental Science, Murdoch University, Western Australia 6150, Australia c School of Biological Sciences and Biotechnology, Murdoch University, Western Australia 6150, Australia 1. Introduction A variety of methods have been used to transplant and restore seagrasses (Phillips, 1990; Fonseca et al., 1996; Orth et al., 1999; Paling et al., 2001). All methods result in their handling but little is known about the physiological effects of this manipulation or the recovery process when plants are placed in new environments. Similarly, the use of chlorophyll fluorometry to assess the photosynthetic responses of transplanted seagrasses has been limited. Durako et al. (2003) used reciprocal transplants to evaluate photosynthetic patterns, using PAM fluorometry, in two Halophila species in Florida. They noted that H. johnsonii possessed UV-absorbing pigments (UVPs) which, together with a tolerance to higher irradiances, allowed this species to exploit shallow habitats without competition from H. decipiens, which lacks UVPs and experiences a high mortality. Figueroa et al. (2002) also used fluorometry on transplanted Posidonia oceanica in southern Spain to examine the effects of solar radiation on photosynthesis. They concluded that this species seemed accli- mated to high solar irradiance and that UV radiation triggered the induction of photoprotective mechanisms. This study investigated the variation in photosynthetic performance of Posidonia sinuosa occurring during two methods of transplantation. The specific aims were (a) to examine changes in photosynthetic rates (maximum electron transport rate (ETR max ), effective quantum yield (DF =F 0 m ) and potential quantum yield (F v /F m )) of sprigs and plugs during the process of removal, transport and planting; (b) to determine if sprigs and plugs recovered to the same photosynthetic rate as naturally occurring seagrasses at the same sites; (c) to estimate the time required for full photosynthetic recovery; and (d) finally, to assess the long term survival of the sprigs and plugs. 2. Methods 2.1. Sprig transplantation at Southern Flats This study was part of a large restoration exercise in Western Australia involving the transplantation of 1.5 ha of P. sinuosa sprigs between November 2004 and February 2005 (Paling and van Keulen, 2004). Donor material was collected from 5 to 7 m depth at Parmelia Bank (S 32808.097 0 , E 115842.387 0 ) and transplanted 20 km to the south at a depth of 2–4 m at Southern Flats (S 32815 0 ,E 115843 0 ). Sprigs (rhizomes with attached leaves and roots) were excavated from the edge of the donor meadow, brought onto a boat and stored in seawater-filled containers. During transport to Aquatic Botany 90 (2009) 149–156 ARTICLE INFO Article history: Received 26 November 2007 Received in revised form 25 July 2008 Accepted 18 August 2008 Available online 22 August 2008 Keywords: Electron transport rate Effective quantum yield Potential quantum yield PAM fluorometry Seagrass transplantation Western Australia ABSTRACT Changes in photosynthetic activity during transplantation of Posidonia sinuosa Cambridge et Kuo, from Cockburn Sound, Western Australia, were assessed using a Diving-PAM fluorometer. Two transplantation methods, sprigs and plugs (5, 10 and 15 cm diameter) were examined and photosynthetic activity was compared before, during and after transplantation. Maximum electron transport rate (ETR max ) of transplanted sprigs took 1–2 months to increase to the same level recorded at a control meadow, primarily due to desiccation stress suffered during transport. Effective quantum yield (DF =F 0 m ) of sprigs decreased below 0.2 after transplantation, but fully recovered after 3 months and the ETR max of transplanted plugs took up to 1 week to recover to control meadow values. Once transplanted, the survival of sprigs was reduced due to strong currents and heavy epiphytic fouling, while that of plugs declined due to winter storms and swells. Since the leading human-controlled cause of transplant stress was desiccation, future rehabilitation efforts may be improved by keeping seagrasses submerged at all times during the transplanting process. ß 2008 Elsevier B.V. All rights reserved. * Corresponding author at: Oceanica Consulting Pty Ltd., P.O. Box 3172, Broadway, Nedlands, Western Australia 6009, Australia. Tel.: +61 9389 9669; fax: +61 9389 9660. E-mail address: lotte.horn@oceanica.com.au (L.E. Horn). Contents lists available at ScienceDirect Aquatic Botany journal homepage: www.elsevier.com/locate/aquabot 0304-3770/$ – see front matter ß 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.aquabot.2008.08.002