Overview of the physiological ecology of carbon metabolism in seagrasses

Touchette, Brant W.; Burkholder, JoAnn M.

doi:10.1016/s0022-0981(00)00196-9

Cited by 209 publications

(134 citation statements)

References 129 publications

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“…This is consistent with previous studies on H. johnsonii, Zostera marina, Z. muelleri, and H. ovalis, which have suggested that photosynthetic rates are more sensitive to salinity than are respiration rates (Biebl and McRoy 1971;Kerr and Strother 1985;Dawes et al 1989;Ralph 1998;Hellblom and Bjo¨rk 1999). In general, H. johnsonii exhibited low compensation (I c ) and saturation points (I k ) with elevated photosynthetic efficiencies (a), compared to those observed for other seagrasses (Hemminga and Duarte 2000;Touchette and Burkholder 2000). This could be due not only to a speciesspecific response but also to the fact that these plants were acclimated to low-irradiance greenhouse conditions for over 1 year prior to the experimentation (Major and Dunton 2000).…”

Section: Discussionsupporting

confidence: 91%

“…P max increased significantly with the lowest pH treatment (pH=5) at 30 psu. Apart from minor direct effects of pH on photosynthesis by affecting the electrochemical gradients and proton flow across plasma membranes (Touchette and Burkholder 2000;Beer et al 2001), the main effect of pH variation is that it alters the concentrations of the different dissolved inorganic carbon (DIC) forms (Beer et al 1977). A decrease in pH in a closed system is expected to cause an increase in CO 2 concentration and subsequently an increase in the photosynthetic rates of seagrasses (Beer and Waisel 1979;Invers et al 1997).…”

Section: Discussionmentioning

confidence: 99%

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

2005

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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 (P max ) and the photosynthetic efficiency at subsaturating light (a) increased significantly up to an optimum of 40 psu, decreasing again at the highest salinities. Dark respiration rates and compensating irradiance (I c ) showed minimum values at 40 and 50 psu, while light-saturation point (I k ) 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 a, P max , respiration rates, and I k . An interaction between salinity and pH was only found in the P max response: P max increased with pH=5 at 30 psu. In addition, reducing the pH increased a 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.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 99%

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

2005

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“…The decline in rhizome starch concentrations lagged behind that of sugars, possibly reflecting a reallocation of rhizome sugars and, later, starch to the leaves, a reallocation of resources similar to that found in other seagrasses (e.g. Touchette & Burkholder 2000, Peralta et al 2005. It is unclear how much stored carbohydrate is lost with the shed leaves.…”

Section: Responses To Shadingmentioning

confidence: 84%

“…These species have shown both morphological and physiological responses to reduced light availability. Typical responses include the loss of above-ground biomass and shifts in leaf morphology and pigment concentrations (Czerny & Dunton 1995, Lee & Dunton 1997) that may allow the plant to maintain a neutral or positive carbon budget (Touchette & Burkholder 2000) by reducing the draw on storage reserves (Peralta et al 2002) or decreasing selfshading in the canopy (Carruthers & Walker 1997).…”

Section: Introductionmentioning

confidence: 99%

Effects of experimental reduction of light availability on the seagrass Amphibolis griffithii

Mackey¹,

Collier²,

Lavery³

2007

Mar. Ecol. Prog. Ser.

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The response of the meadow-forming seagrass Amphibolis griffithii (Black) den Hartog to light reduction was examined over a 3 mo period and a subsequent 1 mo recovery period. Morphological and physiological variables were measured in meadows subjected to an average reduction in photosynthetic photon flux density (PPFD) of 88% relative to unshaded controls. Leaf biomass, leaf cluster density and the number of leaves per cluster all declined in shaded plots, and after 3 mo were about 30, 50 and 60% of the controls, respectively. Leaf extension was one-third that of the control plots. Epiphyte biomass in shaded plots was 44% of the controls after 6 wk of shading and 18% after 3 mo of shading. Leaf chlorophyll concentration was affected by shading, but only in the upper canopy: shaded leaves had 55% more chlorophyll than control leaves. Shading reduced the carbohydrate stored in the rhizomes of shaded plants: sugars declined rapidly and continuously and, after 3 mo, were < 20% of the control values; a decline in starch concentrations lagged behind that of sugars. All variables showed a significant shift towards the values in control plots 42 d after removal of shading, indicating a capacity for recovery, though in many cases these variables remained significantly lower than those in the controls. A. griffithii and its epiphytes respond rapidly to severe, shortterm reductions in light availability, but responses at the scale of shoots and whole meadows also allow the plants to respond rapidly to improved light conditions.

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“…Thalassia tesudinum) (Campbell et al, 2012). Respiration rates of seagrasses may enhance with increasing nutrient enrichment in the sediment (Touchette, 1999), which could help rhizomes and roots of seagrasses to supply the energy and carbon needed to assimilate and reduce nitrate, consequently decrease the toxicity of higher concentration nutrients, facilitate seagrass growth (Touchette, 1999;Touchette and Burkholder, 2000).…”

Section: Positive Effects Of Sediment-nutrient Enrichment On Individumentioning

confidence: 99%

Individual and population indicators of Zostera japonica respond quickly to experimental addition of sediment-nutrient and organic matter

Han

Soissons

Chen

et al. 2017

Marine Pollution Bulletin

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Overview of the physiological ecology of carbon metabolism in seagrasses

Cited by 209 publications

References 129 publications

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

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

Effects of experimental reduction of light availability on the seagrass Amphibolis griffithii

Individual and population indicators of Zostera japonica respond quickly to experimental addition of sediment-nutrient and organic matter

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