Marsh grass

Sulfides and disulfides can be produced by bacterial reactions in the marine environment. 2-Dimeth-ylthiopropionic acid is produced by algae and by the marsh grass Spartina alternifolia, and may then be metabolized in sediment slurries under anoxic conditions to dimethyl sulfide (Kiene and Taylor 1988), and by aerobic bacteria to methyl sulfide (Taylor and Gilchrist 1991). Further details are given in Chapter 11, Part 2. Methyl sulfide can also be produced by biological methylation of sulfide itself (HS ). Carbon radicals are not the initial atmospheric products from organic sulfides and disulfides, and the reactions also provide an example in which the rates of reaction with nitrate... 

Macroalgal Of large marine plants such as seaweed and marsh grasses. 

Marsh grasses, Spartina spp., whole Control areas 2.3-3.1 DW... 

Estuarine samples of the AAS marsh grass Spartina alterniflora and eelgrass... 

DMSP is present in a number of marsh plants, but only in Spartina altemiflora (191 and S. anglica (221 is it particularly abundant. Spartina altemiflom is the dominant species in temperate marshes of North America but not in marshes or wetlands at lower latitudes. To date, most DMS emission measurements have been made in marshes dominated by S. altemiflora. Emission rates in areas having other marsh grasses, with lower DMSP content, are likely to be considerably lower. Estimates of DMS emission from saltmarshes in general which are based on fluxes from S. altemiflora without considering the species of grass are likely to be considerably overestimated. 

Figure 9. Schematic of biogeochemical processes producing and consuming DMS in marine environments. DMSP in certain phytoplankton and marsh grasses may be slowly metabolized and released diretfly. Disruption of DMSP-containing cells, either by herbivory or by microbial decomposition, results in DMSP release into solution and enhanced production of DMS. DMS may be oxidized microbially to DMSO, and perhaps DMSO photochemical decomposition of DMS in surface waters may also occur. Residual DMS may escape into the atmosphere, where it undergoes further photochemical degradation.

Carbon dioxide water-to-air fluxes have been shown to be significant in estuaries. In estuaries with extensive marsh systems, the pathway of CO2 being fixed by marsh grasses and then exported to coastal waters in the form of organic and inorganic carbon can be described as a marsh CO2 pump. ... 

Table 8.2 Estimates of above- and below-ground net primary production (NPP) of some selected species/community types of salt marsh grasses and mangroves.

Marsh grasses Distichlis spicata Pacific coast 750-1500 ... 

Figure 8.18 Percentage of initial weight of marsh grass (Sarcocornia fructicosa) remaining in litter bags in the Ebre River estuary (Spain) after one year. (Modified from Curdo et al., 2002.)...

In addition to alkalinity inputs from rivers, estuaries can also receive inputs from bordering wetlands. For example, Cai et al. (1999) have shown that respiration rates in rivers/estuaries of Georgia (USA) cannot account for O2 consumption and CO2 degassing. It has since been shown that the missing DIC source is from marshes in the Satilla estuary (USA) (Cai et al., 2000). Other studies have also shown that intertidal marshes are important sources of DIC in estuaries (Raymond et al., 1997, 2000 Neubauer and Anderson, 2003). It has been further suggested that CO2 fixation of marsh grasses and the subsequent export of DIC and organic C to the coastal ocean can be described as... 

Haddad, R.I., Newell, S.Y., Martens, C.S., and Fallon, R.D. (1992) Early diagenesis of lignin-associated phenolics in the salt marsh grass Spartina altemiflora. Geochim. Cosmochim. Acta 56, 3751-3764. 

Hodson, R.E, Christian, R.R., and Maccubbin, A.E. (1983) Lignocellulose and lignin in the salt marsh grass Spartina altemiflora initial concentration and short-term, post-depositional changes in detrital matter. Mar. Biol. 81, 1-7. 

Newell, S. Y. Porter, D. (2000). Microbial secondary production from salt marsh-grass... 

Bagwell, C. E., and Lovell, C. R. (2000a). Microdiversity of crdturable diazotrophs from the rhizo-planes of the salt marsh grasses Spartina alternijlora and Juncus roemerianus. Microb. Ecol. 39(2), 128-136. 

Moisander, P. H., Piehler, M. F., andPaerl, H. W. (2005). Diversity and activity of epiphytic nitrogen-fixers on standing dead stems of the salt marsh grass Spartina alternijlora. Aquat. Microb. Ecol. 39, 271— 279. 

Whiting, G., Gandy, E., and Yoch, D. (1986). Tight coupling of root-associated nitrogen fixation and plant photosynthesis in the salt marsh grass Spartina alternijlora and carbon dioxide enhancement of nitrogenase activity. Appl. Environ. Microbiol. 52, 108-113. 

Bagwell, C., Dantzler, M., Berghoz, P., and Lovell, C. (2001). Host-specific ecotype diversity of rhizoplane diazotrophs of the perennial glasswort Salkornia virginica and selected salt marsh grasses. Aquat. Microb. Ecol. 23, 293—300. 

Burdick, D., Mendelssohn, I., and McKee, K. (1989). Live standing crop and metabohsm of the marsh grass Spartina patens as related to edaphic factors in a brackish, mixed marsh community in Louisiana. Estuaries 12, 195—204. 

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