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Marine Biology

, Volume 152, Issue 2, pp 405–414 | Cite as

Chlorophyll fluorescence measures of seagrasses Halophila ovalis and Zostera capricorni reveal differences in response to experimental shading

  • Juanita S. Bité
  • Stuart J. Campbell
  • Len. J. McKenzie
  • Robert G. Coles
Research Article

Abstract

In coastal waters and estuaries, seagrass meadows are often subject to light deprivation over short time scales (days to weeks) in response to increased turbidity from anthropogenic disturbances. Seagrasses may exhibit negative physiological responses to light deprivation and suffer stress, or tolerate such stresses through photo-adaptation of physiological processes allowing more efficient use of low light. Pulse Amplitude Modulated (PAM) fluorometery has been used to rapidly assess changes in photosynthetic responses along in situ gradients in light. In this study, however, light is experimentally manipulated in the field to examine the photosynthesis of Halophila ovalis and Zostera capricorni. We aimed to evaluate the tolerance of these seagrasses to short-term light reductions. The seagrasses were subject to four light treatments, 0, 5, 60, and 90% shading, for a period of 14 days. In both species, as shading increased the photosynthetic variables significantly (P < 0.05) decreased by up to 40% for maximum electron transport rates (ETRmax) and 70% for saturating irradiances (Ek). Photosynthetic efficiencies (α) and effective quantum yields (ΔF/Fm′) increased significantly (P < 0.05), in both species, for 90% shaded plants compared with 0% shaded plants. H. ovalis was more sensitive to 90% shading than Z. capricorni, showing greater reductions in ETRmax, indicative of a reduced photosynthetic capacity. An increase in Ek, Fm′ and ΔF/Fm′ for H. ovalis and Z. capricorni under 90% shading suggested an increase in photochemical efficiency and a more efficient use of low-photon flux, consistent with photo-acclimation to shading. Similar responses were found along a depth gradient from 0 to10 m, where depth related changes in ETRmax and Ek in H. ovalis implied a strong difference of irradiance history between depths of 0 and 5–10 m. The results suggest that H. ovalis is more vulnerable to light deprivation than Z. capricorni and that H. ovalis, at depths of 5–10 m, would be more vulnerable to light deprivation than intertidal populations. Both species showed a strong degree of photo-adaptation to light manipulation that may enable them to tolerate and adapt to short-term reductions in light. These consistent responses to changes in light suggest that photosynthetic variables can be used to rapidly assess the status of seagrasses when subjected to sudden and prolonged periods of reduced light.

Keywords

Photosynthetically Active Radiation Photosynthetic Efficiency Electron Transport Rate Shade Treatment Depth Gradient 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgements

This work was conducted as part of a Ph.D. degree in the School of Tropical Environment Studies and Geography, James Cook University. The work was supported by an Australian Postgraduate Award (Industry) from the Australian Research Council and Industry partners, Queensland Department of Primary Industries and Fisheries, Queensland, Parks and Wildlife Service (Environment Protection Authority) and World Wide Fund for Nature (WWF). The appropriate permit, required to remove seagrasses in Queensland, was obtained from the Queensland Department of Industries and Fisheries. The authors would like to acknowledge S. Kerville and D. Foster for their technical and field assistance.

References

  1. Abal EG, Loneragan NR, Bowen P, Perry CJ, Udy JW, Dennison WC (1994) Physiological and morphological responses of the seagrass Zostera capricorni Aschers. to light intensity. J Exp Mar Biol Ecol 178:113–129CrossRefGoogle Scholar
  2. Alcoverro T, Cerbian E, Ballesteros E (2001) The photosynthetic capacity of the seagrass Posidonia oceanica: influence of nitrogen and light. J Exp Mar Biol Ecol 261:107–120CrossRefGoogle Scholar
  3. Beer S, Vilenkin B, Weil A, Veste M, Susel L, Eshel A (1998) Measuring photosynthetic rates in seagrasses by pulse amplitude modulated (PAM) fluorometry. Mar Ecol Prog Ser 174:293–300CrossRefGoogle Scholar
  4. Biber PD, Paerl HW, Gallegos CL, Kenworthy WJ (2005) Evaluating indicators of seagrass stress to light. In: Bortone SA (ed) Estuarine indicators. CRC, Boca Raton, FL, pp 193–210Google Scholar
  5. Campbell SJ, McKenzie LJ (2004) Flood related loss and recovery of intertidal seagrass meadows in southern Queensland, Australia. Estuarine Coast Shelf Sci 60:477–490CrossRefGoogle Scholar
  6. Campbell SJ, Miller C, Steven A, Stephens A (2003) Photosynthetic responses of two temperate seagrasses across a water quality gradient using chlorophyll flourescence. J Exp Mar Biol Ecol 291:57–78CrossRefGoogle Scholar
  7. Czerny AB, Dunton KH (1995) The effects of in situ light reduction on the growth of two subtropical seagrasses, Thalassia testudinum and Halodule wrightii. Estuarties 18:418–427CrossRefGoogle Scholar
  8. Dennison WC (1987) Effects of light on seagrass photosynthesis, growth and depth distribution. Aquat Bot 27:15–26CrossRefGoogle Scholar
  9. Dennison WC, Alberte RS (1986) Photoadaptation and growth of Zostera marina L. (eelgrass) transplants along a depth gradient. J Exp Mar Biol Ecol 98:265–383CrossRefGoogle Scholar
  10. Duarte CM (1991) Seagrass depth limits. Aquat Bot 40:363–377CrossRefGoogle Scholar
  11. Durako MJ, Kunzelman JI, Kenworthy J, Hammerstrom KK (2003) Depth-related variability in the photobiology of two populations of Halophila johnsonii and Halophila decipiens. Mar Biol 142:1219–1228CrossRefGoogle Scholar
  12. Enríquez S, Merino M, Iglesias-Prieto R (2002) Variations in the photosynthetic performance along the leaves of the tropical seagrass Thalassia testudinum. Mar Biol 140:891–900CrossRefGoogle Scholar
  13. Gallegos CL, Kenworthy WJ (1996) Seagrass Depth limits in the Indian River Lagoon (Florida, USA): application of an optical water quality model. Estuarine, Coast Shelf Sci 42:267–288CrossRefGoogle Scholar
  14. Ibarra-Obando SE, Heck KL, Spitzer PM (2004) Effects of simultaneous changes in light, nutrients, and herbivory levels, on the structure and function of a subtropical turtlegrass meadow. J Exp Mar Biol Ecol 301:193–224CrossRefGoogle Scholar
  15. Jassby AT, Platt T (1976) Mathematical formulation of the relationship between photosynthesis and light for phytoplankton. Oceanography 21:540–547Google Scholar
  16. Kraemer GP, Alberte RS (1995) Impact of daily photosynthetic period on protein synthesis and carbohydrate stores in Zostera marina L. (eelgrass) roots: implications for survival in light-limited environments. J Exp Mar Biol Ecol 185:191–202CrossRefGoogle Scholar
  17. Kraemer GP, Hanisak MD (2000) Physiological and growth responses of Thalassia testudinum to environmentally-relevant periods of low irradiance. Aquat Bot 67:287–300CrossRefGoogle Scholar
  18. Lan C-Y, Kao W-Y, Lin H-J, Shao K-T (2005) Measurement of chlorophyll fluorescence reveals mechanisms for habitat niche separation of the intertidal seagrasses Thalassia hemprichii and Halodule uninervis. Mar Biol 148:25–34CrossRefGoogle Scholar
  19. Longstaff BJ, Dennison WC (1999) Seagrass survival during pulsed turbidity events: the effects of light deprivation on the seagrasses Halodule pinifolia and Halophila ovalis. Aquat Bot 65:105–121CrossRefGoogle Scholar
  20. Longstaff BJ, Loneragan NR, O’Donohue MJ, Dennison WC (1999) Effects of light deprivation on the survival and recovery of the seagrass Halophila ovalis (R.Br.) Hook. J Exp Mar Biol Ecol 234:1–27CrossRefGoogle Scholar
  21. Peralta G, Pérez-Lloréns JL, Hernández I, Vergara JJ (2002) Effects of light availability on growth, architecture and nutrient content of the seagrass Zostera noltii Hornem. J Exp Mar Biol Ecol 269:9–26CrossRefGoogle Scholar
  22. Preen AR, Long WJL, Coles RG (1995) Flood and cyclone related loss, and partial recovery, of more than 1000 km2 of seagrass in Hervey Bay, Queensland, Australia. Aquat Bot 52:3–17CrossRefGoogle Scholar
  23. Ralph PJ (1996) Diurnal photosynthetic patterns of Halophila ovalis (R.Br.) Hook f. In: Kuo J, Phillips RC, Walker DI, Kirkman H (eds) Seagrass biology: proceedings of an international workshop, Rottnest Island, Western Australia, pp 197–202Google Scholar
  24. Ralph PJ, Gademann R (2005) Rapid light curves: a powerful tool to assess photosynthetic activity. Aquat Bot 82:222–237CrossRefGoogle Scholar
  25. Ralph PJ, Gademann R, Dennison WC (1998) In situ seagrass photosynthesis measured using a submersible, pulse-amplitude modulated fluorometer. Mar Biol 132:367–373CrossRefGoogle Scholar
  26. Ruiz JM, Romero J (2001) Effects of in situ experimental shading on the Mediterranean seagrass Posidonia oceanica. Mar Ecol Prog Ser 215:107–120CrossRefGoogle Scholar
  27. Schreibers U, Hormann H, Neubauer C, Klughammer C (1995) Assessment of photosystem II photochemical quantum yield by chlorophyll fluoroscence quenching analysis. Aust J Plant Physiol 22:209–220CrossRefGoogle Scholar
  28. Schwarz A-M, Hellblom F (2002) The photosynthetic light response of Halophila stipulacea growing along a depth gradient in the Gulf of Aqaba, the Red Sea. Aquat Bot 74:263–272CrossRefGoogle Scholar
  29. Silva J, Santos R (2003) Daily variation patterns in seagrass photosynthesis along a vertical gradient. Mar Ecol Prog Ser 257:37–44CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Juanita S. Bité
    • 1
  • Stuart J. Campbell
    • 2
    • 3
  • Len. J. McKenzie
    • 2
    • 3
  • Robert G. Coles
    • 2
  1. 1.School of Tropical Environment Studies and GeographyJames Cook UniversityTownsvilleAustralia
  2. 2.Queensland Fisheries Service, Department of Primary Industries and FisheriesNorthern Fisheries CentreCairnsAustralia
  3. 3.CRC Reef Research CentreTownsvilleAustralia

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