Armando A. de la Cruz

In Situ Decomposition of Roots and Rhizomes of Two Tidal Marsh Plants

In situ decomposition of roots and rhizomes of the marsh plants Juncus roemerianus and Spartina cynosuroides was investigated using litter bags. The decomposition rate was greatest in the top 10 cm (20%o mass loss/yr) of the marsh soil. There was no apparent decomposition below 20 cm depth. Belowground tissues of S. cynosuroides decomposed faster than those of J. roemerianus during the first 4 mo. The rhizome decomposition rate of 27%/yr (mass loss) was faster than the 16%o/ yr of the roots of J. roemerianus. There was no difference between the decomposition rate of mixed root and rhizome materials between experiments initiated in winter and those started in the spring. This indicates a relatively constant decomposition rate during the year in the 0-10 cm soil zone. There was no apparent trend in the hydrogen, carbon, phosphorus, nitrogen, or caloric content changes of the decomposing roots and rhizomes during the study.

Enegry Value, Elemental Composition, and Productivity of Belowground Biomass of A Juncus Tidal Marsh

Belowground standing crop of a Juncus roemerianus marsh in Mississippi ranged from 9.7 to 12.4 kg dry wt/m2 with the peak biomass occurring in April. Annual productivity estimated from expected maximum minus expected minimum biomass fitted into a periodic regression model was 1.36 kg/m2. Ninety—four percent of the productivity was within the top 20 cm indicating that the bulk of the materials found beyond this depth consisted of dead tissues. Energy, carbon, hydrogen, nitrogen, and phosphorus contents of belowground materials did not vary significantly during the year, but patterns of differences in samples taken from different depths were evident. The productivity of belowground materials in Juncus marshes is comparable with aboveground productions reported in the literature with respect to dry biomass. The probability that large portions of the underground production enter the aqueous system and become incorporated in estuarine energetics merits further consideration. See full-text article at JSTOR

Energy Flow and Grazing Behavior of Conocephaline Grasshoppers in a Juncus Roemerianus Marsh

At least three species of conocephaline grasshoppers (Tettigoniidae) form the major grazing herbivores on the leaves of the marsh black needlerush Juncus roemerianus Scheele. They ingested 105 kJ/m2 of the 31.62 MJ/m2 net annual aboveground production of Juncus. Assimilation of ingested Juncus tissue was 60.7 kJ m-2 yr-1 and production of new tissue by the grasshoppers was 9.6 kJ m-2 yr-t, which represents 0.03% of the net annual primary production. A secondary effect of grazing was manifested by the premature death of portions of the Juncus leaf distal to the grazed area. Subsequent mechanical breakage resulted in early deposition of broken-off leaf tips into the detrital mat on the marsh. This represented a maximum input into the decomposer trophic level of 246 kJ im-2 yr-1 prior to the death and deposition of the entire Juncus leaf. The addition of Juncus to the diet of the conocephaline post-nymphal and adult stages is discussed in the light of the hypothesis that C4 plants are nutritionally inferior to C3 plants, based on comparisons of amino acid concentrations within different parts of the Juncus leaf and in comparison with Spartina cynosuroides.

Litterfall, litter decomposition, and flux of particulate organic material in a coastal plain stream

Import of allochthonous material in terms of litterfall in a 3rd order stream in Mississippi coastal plain was 386g dry wt/m2/yr. Litter materials consisting of deciduous leaves, pine needles, and woody twigs collected during different seasons showed some differences in ash-free dry weight, caloric, carbon, hydrogen, nitrogen and phosphorus contents. In situ decomposition to particulate form of deciduous and pine litter enclosed in nylon litter bags showed 15% and 65%, respectively, of the litter remaining after 334 days. Downstream net transport of suspended particulate organic material in the river averaged 688,290 kg dry wt/yr with a range of 456,061 to 920,518 kg dry wt/yr. There was a tendency for the particulate organic matter load of the water to increase during ebbtide and to decrease during floodtide.

Species composition, standing stock, and net primary production of a salt marsh community in Mississippi

Square meter quadrat samples harvested monthly during 1971 to 1972 provided data on the species composition, standing stock, and net primary aerial production of a salt marsh community in St. Louis Bay Estuary, Mississippi. Although a total of 34 species of marsh plants were identified,Juncus roemerianus, Spartina cynosuroides, Scirpus americanus andDistichlis spicata were found to be the most dominant in all the quadrats sampled. Maximum biomass of alive, dead, and partially decayed plants were observed in July, August and January respectively. Community annual net production estimated by harvest method was 1051 g dry wt m−2 or 5012 ash-free Kcal m−2. Total biomass obtained by reharvesting previously clipped quadrats in various ages of regrowth revealed a seasonal pattern of growth rate with a maximum during late summer and a productivity estimation of 1108 g dry wt m−2 or 5541 ash-free Kcal m−2.

Antimicrobial activity of juncusol, a novel 9-10-dihydrophenanthrene from the marsh plant Juncus roemerianus.

Abstract The 9,10-dihydrophenanthrene phenolic compound juncusol, from the marsh plant Juncus roemerianus , has been shown to be inhibitory to four species of naturally occurring Bacillus and to two ATCC species Bacillus subtilis and Staphylococcus aureus . Juncusol may regulate populations of bacillus bacteria in the marsh and has potential as an antimicrobial agent particularly to gram positive microorganisms.

Changes in interstitial water salinity of a Mississippi tidal marsh

The salinity of interstitial water (i.e., the salinity of the free soil water) was examined at 11 equidistant stations along a transect on a Mississippi tidal marsh dominated byJuncus roemerianus andSpartina cynosuroides. Changes in the nearby surface water (e.g., bay water) were reflected in the changes in interstitial water salinity. The salinity of interstitial water was usually higher, varying between 2.5 and 15.8‰ from February 1975 through January 1976, than the salinity of the nearby surface water which ranged from 0.0 to 11.5‰. Following a long period of high salinity in the bay and sound (exceeding 14‰), the salinity of the interstitial water increased to a maximum of 16.8‰ in October. The salinity increased as the distance of the sampling station from the source of the flood water increased. Mean interstitial wate salinity across the marsh studied was within 10‰ which did not seem to influence the marsh plant zonation occurring on the marsh.

Proximate Nutritive Value Changes during Decomposition of Salt Marsh Plants

Recognition of salt marsh plant detritus as a nutritious source of food for estuarine consumers prompted investigation of in situ decomposition and proximate nutritive values of three plants and their detritus namely: Spartina cynosuroides and Distichlis spicata (Gramineae) and Scirpus americanus (Cyperaceae) growing abundantly in Mississippi tidal marshes. During decomposition to particulate detritus, these plants retain 60–70% organic content and the caloric value either remains the same or increases slightly. Crude fiber, carbohydrate, and fat contents decline but protein shows 96–300% increase from dead plants to particulate detritus stage.

The production of pulp from Marsh Grass

With an adequate technology, the Romanian Government mechanically harvests 125,000 tons of dry marsh grass (Phragmites communis Trinius) annually from the vast reedlands of the Danube Delta which, when processed, yield up to 60% in unbleached pulp. The reed pulp is mixed with wood pulp in the production of fabricated paper. At

Solar input and energy storage in a five-year-old American sycamore plantation

85.00 per ton of reed raw material, the reed pulp industry amounts to over