Changes in biomass, chemical composition and nutritive value of Spartina alterniflora due to organic pollution in the Itanhaém River Basin (SP, Brazil)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Dinâmica populacional das macrófitas aquáticas emersas Spartina alterniflora Loiseleur, Crinum procerum Carey e Scirpus californicus Steud, na bacia do rio Itanhaém, SP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Propagation and use of Spartina alterniflora for shoreline erosion abatement /

Experimental plantings to stabilize eroding shorelines in Bogue Sound in 1974 were successful. Better stands were produced on sites subject to severe wave stress by reducing transplant spacing to 1.5 to 2 feet apart. Rhizomes without well-developed culms attached were worthless as propagules within the intertidal zone. Seeding was unsuccessful due to exposure to excessive wave energy.

Propagation of Spartina alterniflora for substrate stabilization and salt marsh development /

"August 1974."

Changes in biomass, chemical composition and nutritive value of Spartina alterniflora due to organic pollution in the Itanhaém River Basin (SP, Brazil)

Foram comparados a biomassa, a composição química e o valor nutritivo da macrófita aquática emersa S. alterniflora em um rio impactado por descargas de efluentes domésticos (Rio Guaú) e em um rio bem conservado (Rio Itanhaém). Amostras de S. alterniflora, água e sedimento foram coletadas nos dois rios, em novembro de 2001. O rio Guaú apresentou as maiores concentrações de N-Total e P-Total na água (415 e 674 µg.L-1, respectivamente) e sedimento (0,25 e 0,20% de Massa Seca, respectivamente), em relação a água (NT = 105 µg.L-1; PT= 20 µg.L-1) e sedimento (NT = 0,12% MS; PT = 0,05% MS) do rio Itanhaém. A biomassa aérea (316 g MS.m-2) e subterrânea (425 g MS.m-2) de S. alterniflora no rio Guaú foram significativamente maiores do que no rio Itanhaém (146 e 115 g MS.m-2). Além disto, os valores de NT, proteínas, PT, lipídios e carboidratos solúveis foram significativamente maiores na biomassa de S. alterniflora no rio Guaú. Por outro lado, a fração de parede celular e os teores de polifenóis foram maiores na biomassa de S. alterniflora no rio Itanhaém. Concluiu-se que o lançamento de efluentes domésticos em corpos d'água pode aumentar a biomassa e alterar a composição química de S. alterniflora. A maior disponibilidade de N e P no rio Guaú, provavelmente, é a causa dos maiores valores de biomassa, NT, PT, lipídeos e carboidratos solúveis em S. alterniflora neste rio.

Non-target Impacts to Eelgrass from Treatments to Control Spartina in Willapa Bay, Washington

Four methods to control the smooth cordgrass Spartina (Spartina alterniflora) and the footwear worn by treatment personnelat several sites in Willapa Bay, Washington were evaluatedto determine the non-target impacts to eelgrass (Zostera japonica). Clone-sized infestations of Spartina were treated bymowing or a single hand-spray application of Rodeo® formulatedat 480 g L-1acid equivalence (ae) of the isopropylaminesalt of glyphosate (Monsanto Agricultural Co., St. Louis, MO;currently Dow AgroSciences, Indianapolis, IN) with the nonionic surfactant LI 700® (2% v/v) or a combination of mowing and hand spraying. An aerial application of Rodeo® with X-77 Spreader® (0.13% v/v) to a 2-ha meadow was also investigated. Monitoring consisted of measuring eelgrass shoot densities and percent cover pre-treatment and 1-yr post-treatment. Impacts to eelgrass adjacent to treated clones were determined 1 m from the clones and compared to a control 5-m away. Impacts from footwear were assessed at 5 equidistant intervals along a 10-m transect on mudflat and an untreated control transect at each of the three clone treatment sites. Impacts from the aerial application were determined by comparing shoot densities and percent cover 1, 3 and 10 m from the edge of the treated Spartina meadow to that at comparable distances from an untreated meadow. Methods utilized to control Spartina clones did not impact surrounding eelgrass at two of three sites. Decreases in shoot densities observed at the third site were consistent across treatments. Most impacts to eelgrass from the footwear worn by treatment personnel were negligible and those that were significant were limited to soft mud substrate. The aerial application of the herbicide was associated with reductions in eelgrass (shoot density and percent cover) at two of the three sampling distances, but reductions on the control plot were greater. We conclude that the unchecked spread of Spartina is a far greater threat to the survival and health of eelgrass than that from any of the control measures we studied. The basis for evaluating control measures for Spartina should be efficacy and logistical constraints and not impacts to eelgrass. PDF is 7 pages.

Dimethylsulfoniopropionate Biosynthesis in Spartina alterniflora1 : Evidence That S-Methylmethionine and Dimethylsulfoniopropylamine Are Intermediates

The osmoprotectant 3-dimethylsulfoniopropionate (DMSP) occurs in Gramineae and Compositae, but its synthesis has been studied only in the latter. The DMSP synthesis pathway was therefore investigated in the salt marsh grass Spartina alterniflora Loisel. Leaf tissue metabolized supplied [35S]methionine (Met) to S-methyl-l-Met (SMM), 3-dimethylsulfoniopropylamine (DMSP-amine), and DMSP. The 35S-labeling kinetics of SMM and DMSP-amine indicated that they were intermediates and, consistent with this, the dimethylsulfonium moiety of SMM was shown by stable isotope labeling to be incorporated as a unit into DMSP. The identity of DMSP-amine, a novel natural product, was confirmed by both chemical and mass-spectral methods. S. alterniflora readily converted supplied [35S]SMM to DMSP-amine and DMSP, and also readily converted supplied [35S]DMSP-amine to DMSP; grasses that lack DMSP did neither. A small amount of label was detected in 3-dimethylsulfoniopropionaldehyde (DMSP-ald) when [35S]SMM or [35S]DMSP-amine was given. These results are consistent with the operation of the pathway Met → SMM → DMSP-amine → DMSP-ald → DMSP, which differs from that found in Compositae by the presence of a free DMSP-amine intermediate. This dissimilarity suggests that DMSP synthesis evolved independently in Gramineae and Compositae.

Persistence and Non-target Impact of Imazapyr Associated with Smooth Cordgrass Control in an Estuary

The herbicide (±-2-[4,5-dihydro-4-methyl-4-(1-methylethyl)- 5-oxo-1 H -imidazol-2-yl]-3-pyridinecarboxylic acid (imazapyr) has shown potential to control smooth cordgrass (Spartina alterniflora Loisel), a noxious weed in many estuaries throughout the world. Research was conducted under tidal estuary conditions in Willapa Bay, Washington, to determine imazapyr’s persistence and aquatic risk and impact to non-target estuary species. Persistence of imazapyr in water and sediment followed an exponential decay.(PDF has 6 pages.)

Mechanical and Chemical Control of Smooth Cordgrass in Waillapa Bay, Washington

We evaluated four methods to control smooth cordgrass (Spartina alterniflora Loisel), hereafter spartina, in Willapa Bay, Washington: mowing, mowing plus herbicide combination, herbicide only for clones, and aerial application of herbicide for meadows. (PDF has 7 pages.)