Leaf production and nutrient contents of the seagrass Thalassodendron ciliatum in the proximity of a mangrove forest (Gazi Bay, Kenya)

Hemminga, M.A.; Gwada, P.; Slim, Frederik J.; Koeyer, P. De; Kazungu, Johnson Michael

doi:10.1016/0304-3770(95)00450-e

Cited by 38 publications

(17 citation statements)

References 21 publications

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“…Interestingly, while these nutrient trends were significant, they did not result in greater community NPP rates at sites closer to the mangroves. Seagrass beds adjacent to mangroves in Gazi Bay, Kenya, similarly showed no increase in NPP (plastocrone interval method) compared to beds in a central lagoon or reef site (Hemminga et al 1995). Hemminga et al (1995) further found no significant relationship between proximity to mangroves and nutrient composition (C:N:P) of the dominant seagrass Thalassodendron ciliatum, in contrast to our results and those of Fourqurean et al (1992a).…”

Section: Discussioncontrasting

confidence: 57%

Patterns of primary production and nutrient availability in a Bahamas lagoon with fringing mangroves

Koch

Madden²

2001

Mar. Ecol. Prog. Ser.

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Section: Discussioncontrasting

confidence: 57%

Patterns of primary production and nutrient availability in a Bahamas lagoon with fringing mangroves

Koch

Madden²

2001

Mar. Ecol. Prog. Ser.

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“…Spring tidal range in Gazi bay is reported to be 3.2 m (Kitheka, 1997). T. ciliatum production in the bay has been estimated to range between 710 and 1365 g C m −2 y −1 (Hemminga et al, 1995); litterfall data for C. tagal, R. mucronata, and A. marina correspond to litter production of 164, 412, and 236 g C m −2 y −1 , respectively (Slim et al, 1996b;Ochieng and Erftenmeijer, 2002).…”

Section: Study Site and Sampling Methodsmentioning

confidence: 99%

Carbon sources supporting benthic mineralization in mangrove and adjacent seagrass sediments (Gazi Bay, Kenya)

2004

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Abstract. The origin of carbon substrates used by in situ sedimentary bacterial communities was investigated in an intertidal mangrove ecosystem and in adjacent seagrass beds in Gazi bay (Kenya) by δ 13 C analysis of bacteria-specific PLFA (phospholipid fatty acids) and bulk organic carbon. Export of mangrove-derived organic matter to the adjacent seagrasscovered bay was evident from sedimentary total organic carbon (TOC) and δ 13 C TOC data. PLFA δ 13 C data indicate that the substrate used by bacterial communities varied strongly and that exported mangrove carbon was a significant source for bacteria in the adjacent seagrass beds. Within the intertidal mangrove forest, bacterial PLFA at the surface layer (0-1 cm) typically showed more enriched δ 13 C values than deeper (up to 10 cm) sediment layers, suggesting a contribution from microphytobenthos and/or inwelled seagrass material.Under the simplifying assumption that seagrasses and mangroves are the dominant potential end-members, the estimated contribution of mangrove-derived carbon to benthic mineralization in the seagrass beds (16-74%) corresponds fairly well to the estimated contribution of mangrove C to the sedimentary organic matter pool (21-71%) across different seagrass sites. Based on the results of this study and a compilation of literature data, we suggest that trapping of allochtonous C is a common feature in seagrass beds and often represents a significant source of C for sediment bacteria -both in cases where seagrass C dominates the sediment TOC pool and in cases where external inputs are significant. Hence, it is likely that data on community respiration rates systematically overestimate the role of in situ mineralization as a fate of seagrass production.

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“…Unfortunately, early attempts to compare C:N:P tissue content in seagrasses failed to provide generalizations about seagrass nutritional status because of their seemingly aberrant (high) carbon content, relative to Redfield's stoichiometry (Atkinson and Smith, 1984). Tissue nutrient content was also found to vary with species, tissue type, season, age, and environmentaĺć onditions (Perez-Llorens and Niell, 1993;Hemminga et al, 1995). For example, tissue C:N ratios in intertidal Z. noltii were reported as highest in summer and lowest in winter,ẃ ith higher values in below-than in aboveground tissues (Perez-Llorens and Niell, 1993).…”

Section: Carbon Nitrogen and Phosphorus Ratiosmentioning

confidence: 99%

Review of nitrogen and phosphorus metabolism in seagrasses

Touchette

Burkholder

2000

Journal of Experimental Marine Biology and Ecology

320

232

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Within the past few decades, major losses of seagrass habitats in coastal waters impacted by cultural eutrophication have been documented worldwide. In confronting a pressing need to improve the management and protection of seagrass meadows, surprisingly little is known about the basic nutritional physiology of these critical habitat species, or the physiological mechanisms that control their responses to N and P gradients. The limited available evidence to date already has revealed, for some seagrass species such as the north temperate dominant Zostera marina, unusual responses to nutrient enrichment in comparison to other vascular plants. Seagrasses derive N and P from sediment pore water (especially ammonium) and the water column (most nitrate). The importance of leaves versus roots in nutrient acquisition depends, in part, on the enrichment conditions. For example, a shift from reliance on sediment pore water to increased reliance on the overlying water for N and P supplies has been observed under progressive water-column nutrient enrichment. Seagrasses may be N-limited in nutrient-poor waters with sandy or (less so) organic sediments, and P-limited in carbonate sediments. On the basis of data from few species, seagrasses enrichment (as low as 3.5-7 mM NO , 3-5 weeks), which is actively taken up without apparent 3 product feedback inhibition. Inhibition by elevated nitrate has also been reported, with description of the underlying physiological mechanisms, in certain macroalgae and microalgae. In Z. marina, this effect has been related to the high, sustained energy demands of nitrate uptake, and to inducement of internal carbon limitation by the concomitant 'carbon drain' into amino acid assimilation. In contrast, nitrate enrichment can stimulate growth of Z. marina when the sediment, rather than the water column, is the source. Because seagrass species have shown considerable variation in nutritional response, inferences about one well-studied species, from one geographic location, should not be applied a priori to that species in other regions or to seagrasses in general.Most of the available information has been obtained from study of a few species, and the basic nutritional physiology of many seagrasses remains to be examined and compared across geographic regions. Nonetheless, the relatively recent gains in general understanding about the physiological responses of some seagrass species to nutrient gradients already have proven valuable in both basic and applied research. For example, physiological variables such as tissue C:N:P content have begun to be developed as integrative indicators of nutrient conditions and anthropogenic nutrient enrichment. To strengthen insights for management strategies to optimize seagrass survival in coastal waters adjacent to exponential human population growth and associated nutrient inputs, additional emphasis is critically needed to assess the role of variable interactions-among inorganic as well as organic N, P and C, environmental factors such as temperature, ...

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Leaf production and nutrient contents of the seagrass Thalassodendron ciliatum in the proximity of a mangrove forest (Gazi Bay, Kenya)

Cited by 38 publications

References 21 publications

Patterns of primary production and nutrient availability in a Bahamas lagoon with fringing mangroves

Patterns of primary production and nutrient availability in a Bahamas lagoon with fringing mangroves

Carbon sources supporting benthic mineralization in mangrove and adjacent seagrass sediments (Gazi Bay, Kenya)

Review of nitrogen and phosphorus metabolism in seagrasses

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