Inorganic Carbon Source for Photosynthesis in the Seagrass <i>Thalassia hemprichii</i> (Ehrenb.) Aschers

Abel, Kay M.

doi:10.1104/pp.76.3.776

Cited by 33 publications

(13 citation statements)

References 17 publications

(15 reference statements)

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“…The high growth rate at pH > 8-5 shows the ability of U. reticulata and Thalassia sp. to utilise both available CO2 and HCO3 in the seawater, as already has been reported for other Ulva species (Beer & Israel, 1990;Drechsler & Beer, I991;Maberly, I992;Bj6rk et aI., 1993) and Thalassia species (Beer et al, 1977;Andrews & Abel, 1979;Abel, 1984).…”

Section: Discussionsupporting

confidence: 52%

“…all the following have been reported: external CA (Beer & Israel, 1990;Bj6rk et a]., 1993), direct uptake of HCO3 at elevated pH (Drechsler & Beer, 1991, Maberly, 1992 and inorganic carbon (Ci) storage (Beer & Israel, 1986;Beer et al, 1990). Seagrasses utilise either CO 2 and HCO3- (Raven, 1970;Beer et aI., 1977;Beer & Waisel, I979) or CO z only (Abel, 1984). Thalassia testudinum has been shown to have a C 4-type photosynthetic carbon metabolism (Benedict & Scott, 1976).…”

Section: Introductionmentioning

confidence: 99%

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Destructive hydrogen peroxide production inEucheuma denticulatum(Rhodophyta) during stress caused by elevated pH, high light intensities and competition with other species

Mtolera

Collén

Pedersén

et al. 1995

European Journal of Phycology

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Growth of Eucheuma denticulatum was studied in the field and in laboratory experiments. Field co-cultivation of E, denticulatum with the green alga Ulva reticulata or the seagrass Thalassia sp. reduced daily growth rate (DGR) of a Tanzanian and a Philippine strain of E. denticulatum by I0-100% and 10-55%, respectively, depending upon the type of water current: a unidirectional water current produced the best growth. Laboratory co-cultivation of a Tanzanian strain of E. denticulatum with U. reticulata also reduced DGR (to 8% of the control) and nitrate-nitrogen uptake rate (to < 30% of the control) of E. denticu]atum and, moreover, it increased epiphytism of a red filamentous alga on E. denticulatum. E. denticulatum monoculture at pH 8"6 4-0"5 or at photosynthetic photon flux densities (PPFDs) higher than its growth optimum (350 4-50 #tool photons m -2 s -I) also increased epiphytism. The lack of a competitive mechanism for inorganic carbon uptake in Eucheuma may have contributed to its reduced growth during co-cultivation. During co-cultivation, elevated pH regimes (pH ~ 8"5) were created around the Eucheuma thalli as a result of photosynthesis, thus decreasing the concentration of CO 2 in the seawater to values around 1 #raM. As Eucheuma depends mainly on the CO 2 in the seawater for its growth, a higher pH can cause CO 2 limitation by decreasing CO2 concentration. Hydrogen peroxide (H202) production from the Tanzanian strain was also determined by luminol-dependent chemiluminescence. H202 production was found to increase with increased pH and PPFD (probably as a result of oxidative stress). Preincubation of plants with catalase for 5 min before addition of luminol prevented chemiluminescence, confirming H20 z as the substrate of the luminol reaction. We suggest that the inefficiency of E. denticulatum in HCO 3 utilisation contributes to its poor growth during field coexistence with seagrasses or Ulva sp. and that carbon deficiency induces H202 production in E. denticulatum.

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Section: Discussionsupporting

confidence: 52%

Section: Introductionmentioning

confidence: 99%

Destructive hydrogen peroxide production inEucheuma denticulatum(Rhodophyta) during stress caused by elevated pH, high light intensities and competition with other species

Mtolera

Collén

Pedersén

et al. 1995

European Journal of Phycology

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“…Differences in the quality of C. taxifolia and seagrass detritus could affect the release of dissolved inorganic and organic carbon (DIC and DOC), influencing trophic transfer of carbon among heterotrophs and uptake by plants. Many seagrass species demonstrate increased growth following CO 2 enrichment, suggesting that carbon may limit their productivity (Abel 1984;Durako 1993;Invers et al 2001). Altered carbon cycling following C. taxifolia invasion, therefore, has the potential to affect seagrass health and, concomitantly, associated biota.…”

mentioning

confidence: 99%

Carbon self‐utilization may assist Caulerpa taxifolia invasion

Oakes¹,

Bautista²,

Maher³

et al. 2011

Limnology & Oceanography

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Additions of 13 C-labeled macroalgal detritus (Caulerpa taxifolia) and seagrass detritus (Zostera capricorni) to a vegetated intertidal mudflat in subtropical Australia provided insight into the mechanisms and ecosystem effects of C. taxifolia invasions in seagrass beds. Despite the high lability typical of macroalgae, carbon from seagrass detritus was removed from sediments and transferred to benthic compartments (microphytobenthos, bacteria, mud whelks, and live C. taxifolia and Z. capricorni) at a faster rate than carbon from macroalgal detritus. This preference was more pronounced for live Z. capricorni than live C. taxifolia. Whereas rates of dissolved inorganic carbon production and utilization were similar for seagrass and macroalgal detritus, higher fluxes of dissolved organic carbon (DOC) from macroalgal detritus early in the experiment reflected the lower utilization of this carbon pool. Although both seagrass and algae can use DOC as a source of carbon, caulerpenyne may comprise part of the DOC pool leached from C. taxifolia detritus during early degradation. This compound can have allelopathic effects on seagrass and may, therefore, be inaccessible to Z. capricorni. The availability of an additional carbon source for C. taxifolia, generated from its own detritus, represents a competitive advantage for this invasive macroalga over existing seagrass, particularly because seagrass productivity can be carbon-limited. A similar mechanism may exist for other species of invasive macroalga, particularly those that produce toxic secondary metabolites.

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“…In addition, since T. testudinum (Benedict et al 1980) and Thalassia hemprichii (Abel 1984) have been reported to use CO2 exclusively in photosynthesis, it is not clear that tropical seagrasses follow the same trends as temperate species. To what extent bicarbonate utilization is inducible when plants are abruptly exposed to low CO* environments is also not clear (Weaver and Wetzel 1980;Sand-Jensen and Gordon 1984).…”

Section: Ecological Adaptationsmentioning

confidence: 99%

Comparative ecology of submersed grass beds in freshwater, estuarine, and marine environments1

Stevenson

1988

Limnology & Oceanography

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Worldwide, there are 500–700 species of submersed angiosperms adapted to freshwater and estuarine environments compared with 50 species adapted to marine waters. In their evolution from freshwater ancestors, seagrasses have undergone extensive anatomical changes (e.g. reduction in floral and leaf structures, reduction of xylem tissue with a lacunal gas transport system), as well as physiological adaptations (bicarbonate utilization in photosynthesis). Seagrasses appear to have more annual production than do their freshwater counterparts because they develop greater standing crops and have the capacity to store photosynthetic products in extensive rhizome systems in the sediments. For example, maximum productivity of >10 g C m−2 d−1 has been reported for tropical seagrass species (Cymodocea nodosa and Thalassia testudinum), but the maximum productivity of temperate freshwater species such as Myriophyllum or tropical freshwater species such as Hydrilla is usually <5 g C m−2 d−1. In addition, the marine environment provides ample supplies of inorganic carbon (C) and increased mixing energies, making CO2 limitation less likely. One calculation suggests that marine macrophytes impact the global C budget by sequestering as much as 109 t of C per year. Secondary productivities of seagrass communities can also be high. For example, stable isotopic ratios suggest that macrophytic C is important in sustaining several species of commercial fish species in Australia, accounting for >50% of their diets. Also, sea urchins (Diadema antilarum) consume plant material, creating bare halos around tropical patch reefs in the Caribbean Sea. It is difficult to generalize regarding brackish submersed aquatics in estuaries because their coverage is variable due to light limitation and algal overgrowth from eutrophication. Freshwater macrophytes seem rarely grazed by fish (except via exotic introductions of Tilapia or carp), but waterfowl use is often significant at the end of the growing season. Thus, trophic relations in freshwater macrophyte beds may be qualitatively different and much more pulsed than in seagrass systems, with more re‐selection in lakes and more K‐selection in marine environments.

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Inorganic Carbon Source for Photosynthesis in the Seagrass Thalassia hemprichii (Ehrenb.) Aschers

Cited by 33 publications

References 17 publications

Destructive hydrogen peroxide production inEucheuma denticulatum(Rhodophyta) during stress caused by elevated pH, high light intensities and competition with other species

Destructive hydrogen peroxide production inEucheuma denticulatum(Rhodophyta) during stress caused by elevated pH, high light intensities and competition with other species

Carbon self‐utilization may assist Caulerpa taxifolia invasion

Comparative ecology of submersed grass beds in freshwater, estuarine, and marine environments1

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