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Nitrogen and phosphorus fertilization of Sparganium eurycarpum Engelm. and Typha glauca Godr. Stands. I. Emergent plant production
Abstract
In 1979 and 1980, NH4NO3 and (NH4)2HPO4 were applied monthly to the surface water of enclosed experimental plots dominated by either Sparganium eurycarpum Engelm. or Typha glauca Godr. in Eagle Lake, Iowa, a natural prairie marsh. The impact of nitrogen and phosphorous loading on concentrations of NH4N, NO3N, and PO4P in 15-cm deep interstitial water was unclear in 1979 because of muskrat damage to many interstitial water-sampling devices. However, in 1980, fertilizer application resulted in significant increases in NH4N (+189%) and PO4P (+60%) in interstitial waters. In 1980, significant increases of 57% and 19% in net annual above-ground production occurred for Sparganium and Typha, respectively, in the fertilized enclosures. Root—rhizome production was not altered by fertilization.
... In very eutrophic environments, the share of total biomass produced is allocated to the aboveground shoots (i.e. ramets in clonal taxa), as compared to the allocation patterns in the same plant species growing at some less fertile habitats (Neely and Davis, 1985). Such an allocation strategy is a logical explanation for the tall and heavy ramets in both Typha angustifolia and T. latifolia, seen in the present study. ...
The growth dynamics of two tall littoral helophytic plants, the narrow-leaved cattail ( Typha angustifolia L.) and broad-leaved cattail ( Typha latifolia L.; Typhaceae) were studied in the rapidly changing estuarine habitats in the Kokemäenjoki River delta, western Finland. The two cattails form uniform, single-species communities (monocultures) throughout the plant-covered estuary. Of the two taxa compared, the shoots were taller in T. angustifolia (mean 166 cm) than in T. latifolia (mean 120 cm ) . But due to the robust leaves, the relation in the average weight of individual ramets was opposite: The mean weight of T. angustifolia was 9.6 g (dry wt), and that of T. latifolia was 16.5 g. In a separate study, the leaf height was compared between the fertile (flowering) and sterile (non-flowering) ramets. In flowering ramets the average leaf length was 35 cm taller in Typha angustifolia than in T. latifolia . The differences were even more pronounced in sterile ramets, where the leaves of Typha angustifolia were 70 cm taller than those of T. latifolia . The differences were statistically highly significant. Interspecific competition between the two T y pha species is negligible, because the microhabitats differ from each other. T. angustifolia grows in considerably deeper (mean depth 42 cm) waters than T. latifolia (mean depth 19 cm). The optimum range in the water depth is markedly stricter in T. angustifolia than in T. latifolia . The differences between the rooting depths of the two cattails were statistically highly significant. The physico-chemical characteristics of the rooting zones (rhizospheres) of the two cattails are similar, with the locally produced (autochthonous) organic matter dominating and determining the fertility of the habitats.
... Litter decomposition is sensitive to nutrient availability in plant litter (Enríquez et al., 1993;Webster & Benfield, 1986) and/or the environment (Rejmánková & Houdková, 2006;Song et al., 2011). The degradation of plant litter can be limited by nitrogen availability, as indicated by negative correlations between litter C:N ratios and rates of decomposition (Keuskamp et al., 2015;Lee & Bukaveckas, 2002;Neely & Davis, 1985;Song et al., 2011). A similar pattern is seen with phosphorus (P), where higher litter phosphorus levels can lead to higher decomposition rates (J. ...
The recognition that wetlands play an important role in regulating global climate has led to management actions intended to maintain and enhance the globally significant amounts of carbon preserved in wetland soils while minimizing greenhouse gas emissions. Our goal in this chapter is to review the biogeochemical processes that are relevant to wetland climate regulation, which we do by discussing: (1) the concepts of radiative balance and radiative forcing; (2) the mechanisms for wetland carbon preservation; (3) factors influencing greenhouse gas emissions and other carbon losses; and (4) opportunities for wetland management actions to influence carbon preservation and flux. Wetland carbon preservation, which reflects the accumulation of undecomposed organic material, is a function of the redox environment, organic matter characteristics, and physicochemical factors that inhibit decomposition. However, the conditions that favor carbon preservation often result in increased emissions of methane and nitrous oxide such that there is a biogeochemical tradeoff between carbon preservation and greenhouse gas emissions. The losses of carbon via gaseous and dissolved pathways are sensitive to environmental disturbances and raise challenges about fully accounting for the climatic impacts of wetlands. Wetland management and disturbance intentionally or unintentionally affect biogeochemical processes, such that wise environmental management offers opportunities to enhance wetland carbon preservation, prevent the destabilization of accumulated soil carbon, and reduce greenhouse gas emissions, thus maintaining the role of wetlands as regulators of global climate.
... In contrast, comparing to forested wetlands, marsh systems are more nutrient sufficient due to faster N immobilization-decomposition cycle which occurs in grass plant, e.g. Spartina alterniflora, whose litter could act as nutrient exporter (Neely and Davis, 1985;Morris, 1991). In our incubation study, the FS soil with sufficient C source, as evident by abundant polysaccharides in DOM (Fig. 2) and reflected by high MBC (Table 1) and total PLFA biomass (Fig. 3a), should positively respond to the addition of NO 3 − , which acts as both an e − acceptor and nutrient to thus facilitate the oxidation of these OC. ...
Recent studies have shown the effect of nitrate (NO3-) on carbon gas emissions from wetland soils that contradict thermodynamic predictions. In this study, CO2 production in three Mississippi River deltaic plain wetland soils (forest swamp, freshwater and saline marshes) with the presence of different NO3- levels (0.2, 2.0, and 3.2 mM) was evaluated in an anaerobic microcosm. Molecular composition of dissolved organic matter (DOM) of these soils was investigated using pyrolysis-GC/MS, and soil microbial community was characterized based on phosphorus lipid fatty acid (PLFA) method to elucidate the underlying mechanisms. Addition of NO3- promoted CO2 production in swamp forest soil, but inhibited CO2 emission from marsh soils. Pyrolysis-GC/MS analysis showed that swamp soil contained more polysaccharides, whereas both marsh soils had high abundance of phenolic compounds. Total PLFAs of forest swamp soil were 34% and 66% higher than freshwater and saline marsh soils, respectively. The PLFA profiles indicated different microbial distribution along a salinity gradient with the forest swamp having a higher proportion of fungi and NO3- reducers but lower sulfate (SO42-) reducers than marsh soils. Overall, the study indicated that the inherent differences in soil DOM and microbial community led to the contrasting response in soil CO2 respiration between forest swamp and marsh ecosystems to NO3- loading. These differences should be considered in determining the fate of nitrate entering Louisiana coastal wetlands from river diversions and other sources and their management.
... Water is one of the primary factors which structures plant communities within wetland ecosystems. Hydrological factors which influence the development and productivity of aquatic plant communities include water depth (Gosselink and Turner, 1978;Lieffers and Shay, 1981;van der Valk, 1981;Grace and Wetzel, 1982;Spence, 1982;Grace, 1989), flow rates (Westlake, 1967;Tilton and Kadlec, 1979;Dolan et al., 1981;Madsen and Sendergaard, 1983;Chambers et al., 1991), water chemistry (Brown, 1981;Ewel, 1984;Pip, 1984;van der Valk, 1987), nutrient availability ( Neely and Davis, 1985;Neill, 1990), and soil and sediment characteris- tics ( Smart, 1983, 1986). The hydrologic regime can be thought of as a master variable with respect to all of these factors since it not only determines the hydroperiod but is also ultimately responsible for carrying nutrients and sediment, thus modifying soil type, into wetland ecosystems. ...
... In very eutrophic environments, the share of total biomass produced is allocated to the aboveground shoots (i.e. ramets in clonal taxa), as compared to the allocation patterns in the same plant species growing at some less fertile habitats (Neely and Davis, 1985). Such an allocation strategy is a logical explanation for the tall and heavy ramets in both Typha angustifolia and T. latifolia, seen in the present study. ...
The growth dynamics of two tall littoral helophytic plants, the narrow-leaved cattail ( Typha angustifolia L.) and broad-leaved cattail ( Typha latifolia L.; Typhaceae) were studied in the rapidly changing estuarine habitats in the Kokemäenjoki River delta, western Finland. The two cattails form uniform, single-species communities (monocultures) throughout the plant-covered estuary. Of the two taxa compared, the shoots were taller in T. angustifolia (mean 166 cm) than in T. latifolia (mean 120 cm ) . But due to the robust leaves, the relation in the average weight of individual ramets was opposite: The mean weight of T. angustifolia was 9.6 g (dry wt), and that of T. latifolia was 16.5 g. In a separate study, the leaf height was compared between the fertile (flowering) and sterile (non-flowering) ramets. In flowering ramets the average leaf length was 35 cm taller in Typha angustifolia than in T. latifolia . The differences were even more pronounced in sterile ramets, where the leaves of Typha angustifolia were 70 cm taller than those of T. latifolia . The differences were statistically highly significant. Interspecific competition between the two T y pha species is negligible, because the microhabitats differ from each other. T. angustifolia grows in considerably deeper (mean depth 42 cm) waters than T. latifolia (mean depth 19 cm). The optimum range in the water depth is markedly stricter in T. angustifolia than in T. latifolia . The differences between the rooting depths of the two cattails were statistically highly significant. The physico-chemical characteristics of the rooting zones (rhizospheres) of the two cattails are similar, with the locally produced (autochthonous) organic matter dominating and determining the fertility of the habitats.
... 3,4). Nutrient enrichment experiments by Neely and Davis (1985) indicate that S. eurycarpum produces greater biomass with increased interstitial nutrients. Water levels appear to favor Sparganium at plot C10, however the lower nutrient concentrations at this site may give a competitive advantage to Leersia. ...
Urban wetlands can provide valuable ecological services through filtration and moderation of non-point source pollutants. They provide habitat for wildlife, green space, and recreational opportunities
for nearby human populations. We investigated an isolated section of an urban wetland in the Cleveland metropolitan area to determine the overall quality of the vegetation and to evaluate the site for possible rehabilitation. We also researched the distribution of plant species in relation to existing hydrologic, soil, and nutrient conditions in order to identify possible impacts of historic or present human activities in the surrounding watershed. Vegetation composition and physical/chemical parameters were measured
in 1.0 × 1.0 m2 plots along three transects. Canonical correspondence analysis (CCA) was used to directly correlate species distributions to nutrient concentrations, soil carbon content, and water depth. Our
sample area was dominated by Typha angustifolia, Leersia oryzoides, and Sparganium eurycarpum. A few high quality species were present, but the overall macrophyte community was indicative of
human disturbance. Historic information revealed a long history of disturbance at the site and continuing anthropogenic impact. Patchiness in nutrient and water depth gradients results from historic and
current human impacts in the study area. Our results indicate any rehabilitation efforts of the site need to take into account past and current anthropogenic stressors. We recommend aggressive removal of invasive species and re-introduction of nutrient-tolerant native taxa to achieve successful rehabilitation at the site.
... Nutrient enrichment. Nutrient loading is well recognized as a major form of water quality degradation and the effect of increased nutrient loading on aquatic plants is documented from lakes and streams throughout the northern hemisphere (Kimbel, 1982;Anderson and Kalff, 1986;Niemeier and Hubert, 1986;Rorslett et al., 1986;Madsen and Adams, 1988;Chambers and Fourqurean, 1991;Scheffer et al., 1992;Craft et al., 1995;Srivastava et al., 1995;Toivonen and Huttunen, 1995;Coops and Doef, 1996), as well as laboratory studies (Gutenspergen, 1984;Neely and Davis, 1985;Jordan et al., 1990). At least two common forms of nutrient enrichment occur along the Great Lakes shoreline, introduction of animal wastes, typically as sewage effluent or untreated agricultural animal wastes, and the introduction of fine-textured mineral soils (siltation) and fertilizers from agricultural activities. ...
... In addition, the sites at Eagle Lake and Griffith share two characteristics that may contribute to their higher productivity. Both are nutrient enriched and both have a previous history of vegetation clearing either by clipping or burning, to which emergent species are known to respond (Neeley and Davis 1985;Thompson and Shay 1985). ...
The annual aboveground production of T. orientalis was estimated from harvest data by three techniques. The first calculated production as the difference between maximum and minimum standing crop and gave a value of 1175 g m⁻². Demographic data showed this was an underestimate. The second estimate by Smalley's method of 3824 g m⁻² was considered an overestimate since no account was taken of stand variability. The third estimate, 2334 g m⁻², used data fitted by splined regression and was considered the most reliable since it accounted for stand variability, continuous growth, shoot mortality and the translocation of carbon substrate.
Annual aboveground production of inland T. orientalis was greater than most estimates from temperate climates, and whole plant production, 4379 g m⁻², greatly exceeded the suggested maximum of 3000 g m⁻² for freshwater emergent macrophytes.
... These stages are characterized by a rapid flow-through of groundwater and surface water. Plant growth is primarily controlled by nutrients carried to the system by water flow and precipitation, and N is probably the limiting factor (see also Bowden 1987;Barko & Smart 1978;Neely & Davis 1985). In the 'mid'-successional stage, the vegetation has formed a continuous thick floating mat of rhizome material and loose peat, in which large amounts of organic C, N and P have accumulated (Vermeer & Verhoeven 1987;Verhoeven 1986). ...
A fertilization experiment was carried out in 3 mesotrophic fens to investigate whether plant growth in these systems is controlled by the availability of N, P or K. The fens are located in an area with high N inputs from precipitation. They are annually mown in the summer to prevent succession to woodland. Above-ground plant biomass increased significantly upon N fertilization in the two mid-succession fens studied. In the late-succession fen that had been mown for at least 60 years, however, plant biomass increased significantly upon P fertilization. The mowing regime depletes the P pool in the soil, while it keeps N inputs and outputs in balance. A long-term shift occurs from limitation of plant production by N toward limitation by P. Hence, mowing is a suitable management tool to conserve the mesothrophic character of the fens.
... Both Typha and Sparganium spp. are highly competitive taxa and respond vigorously to increased nutrients (Neely and Davis 1985;Woo and Zedler 2002). Nutrient concentrations, particularly phosphorus, in the Great Lakes and St. Lawrence River water began to increase slowly with deforestation and increased rapidly between 1940s and the 1970s (Schelske and Hodell 1995). ...
Cattails (Typha latifolia L., Typha angustifolia L., and Typha x glauca Godr.) are the predominant emergent vegetation of upper St. Lawrence River coastal wetlands. We sought to describe Holocene
vegetation in a St. Lawrence River wetland to assess patterns of succession and examine the timing and potential causes of
a historic cattail invasion. Paleoecological analysis indicated presence of four distinct wetland vegetation stages, including
a shallow water marsh (8240 YBP to 5160 YBP), a variable-depth aquatic plant community with adjacent alder (5160 YBP to 1610
YBP), a shallow sedge community (1610 YBP to 100 YBP), and a robust emergent marsh (100 YBP to present). The record of pollen
tetrads demonstrated cattail presence throughout the history of the marsh, but a rapid increase in relative abundance of Typha cf. angustifolia/Sparganium monads indicated major expansion of robust emergent plants beginning near the peak of agricultural activity (ca. 1880 AD)
and reaching modern levels around 1940 AD. Increase in the abundance of robust emergents in this wetland occurred decades
before regulation of St. Lawrence River water levels and were contemporary with increased sedimentation and changes associated
with the early agricultural period.
KeywordsCoastal wetlands-Palynology-Wetland succession
... Under oxic peat conditions, the converse holds true. Barko and Smart (1978) (1986) and Neely and Davis (1985) suggested that production in freshwater marshes is limited by N and high water levels, and subsequent anoxic peat condition could lead to a release of dissolved P but not N into the water column. The nutrient loading rates in our study were too low to cause a significant increase in plant production in the fens and marshes. ...
In order to determine whether nitrogen (N) or phosphorus (P) limits aboveground plant growth in peatlands in Alberta, we fertilized
one bog, two fens, and two marshes with N and P at a ratio of 7∶1 (Redfield ratio of these two elemental nutrients in aquatic
plants) as well as with water without either fertilizer in 1994. The response of aboveground plant production to N or P was
species-specific and varied among the sites. In the bog,Smilacina trifolia, a herb, showed significant increases in net primary production (NPP) after fertilization with N plus water and the addition
of water, whileAndromeda polifolia only showed significant increases in NPP after fertilization with N plus water.Ledum groenlandicum, an ericaceous shrub, showed significant decreases in NPP after additions of N plus water, P plus water, and water, whileOxycoccus quadripetalus, another ericaceous shrub, also showed significant decreases of NPP after additions of N plus water and water.Sphagnum fuscum (moss) NPP increased significantly after the additions of water and decreased significantly after the additions of N plus
water and P plus water. In the fens and marshes, onlyCarex spp. in the lacustrine sedge fen showed a significant increase in NPP after the addition of N. Vascular NPP (shrubs and herbs
combined) did not increase significantly in any of the five peatlands. Total NPP (moss, herb, and shrub strata combined) increased
significantly only in the bog after the addition of water due to the dominance of the moss stratum in that site. In the bog,
moss growth was limited by water, and herb and shrub growth responses to N and P fertilization were species-specific. Neither
N nor P limited aboveground plant production in the fens and marshes.
... Water is one of the primary factors which structures plant communities within wetland ecosystems. Hydrological factors which influence the development and productivity of aquatic plant communities include water depth (Gosselink and Turner, 1978;Lieffers and Shay, 1981;van der Valk, 1981;Grace and Wetzel, 1982;Spence, 1982;Grace, 1989), flow rates (Westlake, 1967;Tilton and Kadlec, 1979;Dolan et al., 1981;Madsen and Sendergaard, 1983;Chambers et al., 1991), water chemistry (Brown, 1981;Ewel, 1984;Pip, 1984;van der Valk, 1987), nutrient availability (Neely and Davis, 1985;Neill, 1990), and soil and sediment characteristics Smart, 1983, 1986). The hydrologic regime can be thought of as a master variable with respect to all of these factors since it not only determines the hydroperiod but is also ultimately responsible for carrying nutrients and sediment, thus modifying soil type, into wetland ecosystems. ...
Macrophyte biomass production and species richness were monitored from 1988 through 1991 in four freshwater wetlands constructed on the floodpain of the Des Plaines River, Lake County, Illinois, USA. The wetlands were constructed in 1988 and pumping of river water began in 1989 under two differentd hydrologic regimes: two wetlands received high water inflow (equivalent to 40 cm wk−1 of water depth) and two received low flow (11 cm wk−1). Biomass production showed no relationship to the hydrologic inflows after two years of experimentation, with both the highest and lowest production occuring in low flow wetlands. Rates of primary production increased between 1990 and 1991 under low flow conditions and decreased under high flow conditions, primarily as a result of the initial composition of the plant community. The change from dry conditions in 1988 to flooded conditions in 1989 altered the species composition in each wetland to include almost 100% wetland-adapted species. Similarity in species composition among the four wetlands diverged from 1988 to 1989 as the plant community adjusted to flooded conditions and then converged in both 1990 and 1991 as the wetlands developed.
Alaska’s waterfowl are receiving more attention as they become an increasingly important component of North American continental populations. Continental populations of ducks are at record low levels (Bortner et al., 1991), largely because of loss of habitat in midcontinent breeding areas (Tiner, 1984) and drought conditions through much of the 1980s (Bortner et al., 1991). Because breeding populations in Alaska have remained stable, or even increased, a larger proportion of continental duck populations are currently recorded in Alaska during breeding pair surveys than ever before (Conant and Dau, 1991). For example, >50% of breeding Northern Pintails (Anas acuta) in North America have been recorded in Alaska each year since 1987 (Conant and Dau, 1991). Alaska also contains >90% of the world’s Trumpeter Swans (Cygnus buccinator), which are classified as endangered in the contiguous 48 states. Many other breeding populations of waterfowl achieve their highest concentrations in Alaska.
Biweekly elevation of available nitrogen and phosphorus concentrations in marsh surface waters did not alter the rate of Sparganium eurycarpum Engelm. or Typha glauca Godr. shoot decomposition. After 505 days, losses of shoot material totaled 39% for both species under fertilized and unfertilized conditions. However, Sparganium shoot litter with an initial nitrogen concentration of 1.41% lost 27% more dry weight over a 505-day period than did Sparganium with an initial concentration of 0.59%. Typha shoot litter with an initial concentration of 0.55% lost 2% more dry weight during 505 days than Typha tissues with an initial nitrogen concentration of 0.48%.
During the 505-day sampling interval, quantities of nitrogen in shoot litter increased 31% for Sparganium and decreased 10% for Typha under unfertilized conditions. Unfertilized Sparganium shoot litter lost 2% and unfertilized Typha litter gained 25% of original phosphorus quantities. Under fertilized conditions, nitrogen quantities increased 35% for the 2 species. The quantity of phosphorus in Sparganium and Typha shoot litter increased 7 and 121%, respectively, with fertilization. Sparganium shoot litter with a high initial nitrogen concentration lost 50% of its original quantity of nitrogen over 505 days, but high-nitrogen Typha shoot litter gained an additional 19% nitrogen.
Data Sets for Figures 1 and 2 in Main Text and Figure S1.
(0.49 MB PDF)
The biodegration of 5 aquatic angiosperms in Lower Manair Dam and Kakatiya Canal waters Karimnagar, Andhra Pradesh, was undertaken in 10 to 40 day of incubation time. The pH, alkalinity, chlorides, biomass and organic matter contents were determined during the biodegradation. Among these 5 plants Ceratophyllum desmarium showed maximum degradation (97%) both in canal and dam waters. The pH range during biodegradation was in between 7 to 9, while the mean increase of alkalinity was 400 to 714 mg/L. The maximum accumulation of chlorides was with Typha angustifolia (295 mg/L). The average values of organic matter ranged from 0.14 to 0.44% in dam waters and 0.11 to 0.40% in canal waters.
Plants, besides their key importance in energy flow, also play a major role in the circulation of the chemical elements. Primary production, i.e. conversion of radiant energy into chemical energy in photosynthesis, necessarily involves a large number of chemical elements. Primary production, i.e. conversion of radiant energy into chemical elements. The elements essentially required for the life processes are known as nutrients. Energy and the chemical elements flow together through the community and are indeed inseparable and interdependent. However, unlike energy, chemical elements return to their respective pools after death and decay of the organisms and are available for reuse.
To investigate the function of floating mats in seedling establishment and growth of Cicuta virosa, a vulnerable hydrophyte, we surveyed the seedling distribution in the field and examined the growth increment in mesocosms formed by planting C. virosa on both artificial plant mats and base soil. Seedling density and coverage on floating mats and their edges, with high levels of solar radiation and sufficient water level, were significantly higher than those on soil. In the mesocosm experiment, shoot and root dry weight in soil was twice that for artificial mats, and these significant differences reflected nitrogen availability in the substrates. However, there was no significant difference in the number of flowering stalks, tiller or stem width, despite the difference in the level of nutrients between the substrates. These results show that floating mats provide sufficient water level and light-mitigated competition with nutrient limitation under continuous disturbance. This was advantageous to the establishment of seedlings and to the population sustenance of C. virosa. Also, high reproduction allocation of C. virosa sustained coexistence with prolific macrophytes on floating mats even though the overall growth on floating mats was worse than that on soil. Use of such floating mats could be a method for conservation of vulnerable hydrophytes.
The relative contribution of different decay processes were determined for Eichhornia crassipes (Mart.) solms. The dry weight loss in the initial 4 days of decay was solely due to non-microbial processes and thereafter, the contribution of microbial processes increased and that of non-microbial processes decreased exponentially. The green litter recorded significantly higher raye constants of non-microbial and microbial decay than the brown litter. In 30 days of decay, the dry mass loss due to physical, autolytic and microbial leachings was 27%, 5% and 20%, respectively, in the green litter, and 18%, 2% and 7% respectively, in the brown litter. The non-microbial decomposition solely caused 31–33% dry mass loss in the E. crassipes litter.
Dry mass, nitrogen and phosphorus content in belowground litter of four emergent macrophytes (Typha glauca Godr., Phragmites australis (Cav.) Trin., Scolochloa festucacea (Willd.) Link and Scirpus lacustris L.) were followed for 1.2 years in a series of experimental marshes, Delta Marsh, Manitoba. Litter bags containing roots and rhizome materials of each species were buried in unflooded soil, or soil flooded at three water depths (1–30, 31–60, > 60 cm). There were few differences in dry mass loss in unflooded or flooded soils, and depth of flooding also had little effect on decomposition rates. In the flooded sites, Scolochloa and Phragmites roots lost more mass (48.9–63.8% and 59.2–85.5%, respectively) after 112 days than Typha and Scirpus (36.3–43.6 and 37.0–47.2%, respectively). These differences continued through to the end of the study, except in the shallow sites where Scirpus roots lost more mass and had comparable mass remaining as Scolochloa and Phragmites. In the unflooded sites, there was little difference between species. All litters lost nitrogen (22.9–90.0%) and phosphorus (46.3–92.7%) during the first 112 days, then levels tended to remain constant. Decay rates for our belowground root and rhizome litters were comparable to published literature values for aboveground shoot litter of the same species, except for Phragmites roots and rhizomes which decomposed at a faster rate (−k = 0.0014−0.0032) than shoots (−k = 0.0003−0.0007, [van der Valk, A.G., Rhymer, J.M., Murkin, H.R., 1991. Flooding and the decomposition of litter of four emergent plant species in a prairie wetland. Wetlands 11, 1–16]).
Field 15N balance studies were conducted to determine the fate of K 15NO3 added during summer to surface water in 0.27 m2 plots within a North Dakota cattail (a mixture of Typha glauca Godr. and Typha angustifolia L.) marsh. In a 1989 study, 50.4 mmol 15NO3−-N (approximately 1.1 mmol NO3− 1−1) disappeared within 8 days after a temporary build-up of NO2−-N. Approximately 42% of the applied 15N remained in the marsh. This residual N was found in cattail roots and rhizomes (9.5%), floating plants (Lemna minor L. and Spirodela polyrhiza (L.) Schleiden) (8.9%), soil (8.3%), litter (6.9%), surface water (4.6%) and cattail shoots (4.1%). The missing 15N (58%) was presumably lost as a result of denitrification. In a 1991 experiment, 50.4 mmol of K 15NO3 was added to plots which had previously received additions of deionized water or 153 mmol of unlabeled KNO3. All the labeled NO3− again disappeared within 8 days. The unaccounted-for 15N was approximately 56% and 82% of the added K 15NO3-N in plots without and with the antecedent unlabeled KNO3 treatment, respectively. The difference in recovery (26%) was highly significant. Stimulation of dissimilatory NO3− and NO2− reductases and/or suppression of dissimilatory reduction of 15NO3− to 15NH4+ are postulated as likely factors for the higher apparent denitrification loss associated with the antecedent KNO3 treatment.
The objective of this study was to examine the combined effect of acidity and nitrogen (N) concentration on decomposition of Sparganium eurycarpum Engelm. litter. Decomposition was examined in the laboratory for 200 days with a factorial arrangement of three pH levels (pH 4, 6 and 8) and two N regimes (high and low) in water surrounding Sparganium litter. Increasing acidity inhibited decomposition (47.5%, 27.9% and 7.3% dry weight remaining after 200 days at pH 4, 6 and 8, respectively), but N fertilization had no overall effect on weight loss. Under all treatments, both N and phosphorus (P) were exported from decaying litter. After 200 days, maximum export of N and P from decaying tissues occurred at pH 8 (maximum losses of 13.07 mg N g−1 and 1.22 mg P g−1 of initial litter mass). Conversely, the least export occurred at pH 4 (minimum losses of 4.79 mg N g−1 and 0.68 mg P g−1). The effects of N fertilization on nutrient export varied with pH. After 200 days, nitrogen export was virtually the same between high and low N treatments at pH 4; however, at the two higher pH regimes, less N was exported in the high N treatment (as much as −2.12 mg N g−1 less at pH 8). For P, losses were actually higher (+0.14 mg P g−1) under the high N treatment at pH 4, but lower under high N conditions at pH 6 (−0.02 mg P g−1) and 8 (−0.26 mg P g−1) after 200 days. In each case the effects of acidification and N fertilization were greater after 100 days of decomposition. In summary, low pH slowed N and P export from decaying litter and N fertization seemed to retard N and P export at high pH.
We measured the amount of N, P, K, Ca, Mg, Fe, B, Mn, Na, Sr, Cu and Zn in above- and belowground parts of cattails (Typha latifolia L.) every 2 weeks during the growing season (April–October) in plants growing in a marsh on the shore of Lake Mendota, Wisconsin. Elements differed considerably in their distribution between above- and belowground parts and the amount of apparent exchange between parts. The ratio of the amount of an element in aboveground plant parts to that belowground (A:B) was between 1:1 and 2:1 for most elements, as compared with the 2.2:1 ratio of biomass. The maximum amounts of Fe and Zn belowground exceeded their aboveground maxima, while K, Ca and Mn had A:B ratios greater than 2:1. N, P and K in belowground plant parts decreased considerably during the spring, and belowground decreases were large enough to be potentially important sources of these elements for shoot growth. Belowground stores of Ca, Mg, Mn, Na and Sr decreased little in the spring and do not function as reserves.
Contributions of abiotic and biotic processes to the decomposition of floating leaves ofNymphaea elegans were separately evaluated by comparing the rate obtained from anin situ experiment of submerging dry leaf material in a lake, and that from a laboratory experiment of submerging dry leaf material
in lake water with a bio-fixing reagent. It took 8 days to decompose 79.4% of the initial dry weight of the floating leaf
ofN. elegans in a tropical lake. Of the dry weight loss, 32.9% and 67.1% were atributed to abiotic and biotic decomposition, respectively.
The relationship between decomposition rate and the mesh size of the leaf litter bags was examined by the application of a
mathematical model. A reasonable value of decomposition loss at an early stage could be obtained using a bag with a mesh opening
of 9.9 mm2. The decomposition rate of floating leaves is faster than that of other aquatic plants. Rapid decomposition ofN. elegans leaves may be attributed to the fact that the plant has a low carbon to nitrogen ratio.
The effects of altering litter and nutrient loading on above-ground production, nutrient content and borer infestation of Typha angustifolia L. were studied with a 3-year field experiment. In replicated plots, litter was either removed, replaced with plastic strips (pseudolitter), increased 3-fold or left unaltered. One set of plots received fortnightly surface applications of ammonium phosphate solution at a rate totaling 65 g N m−2 and 72 g P m−2 annually. Peak above-ground biomass was increased by nutrient addition, except in the third year of the experiment when peak biomass in all plots was low, possibly due to high salinity that year. The nutrient additions also decreased the rate of flowering, increased concentrations of N and P in plant tissues, and increased the frequency of shoot infestation by boring noctuid larvae. The effects of the litter manipulations seem to be attributable to the physical structure of the litter layer rather than the decomposition process. Plots with neither litter nor pseudolitter showed enhanced incorporation of added N and P in fruits, and were colonized by the herbaceous dicotyledons Lilaeopsis chinensis (L.) Kuntze and Pluchea purpurascens (Swartz) DC. Plots receiving extra litter developed a litter layer thick enough to suppress the growth of Typha in the third year.
Flooding ten 5- to 7-ha diked marshes in the Delta Marsh, Manitoba, to about 1 m above natural marsh levels did not increase dissolved or suspended nutrient concentrations in the surface water. Dissolved forms of N and P increased in interstitial water, possibly as a direct or indirect effect of death of emergent macrophytes (e.g. cattail, Typha spp.) and associated changes such as wave action and detritus deposition. Concentrations of suspended N, P and C decreased in surface water as a result of flooding, both in absolute terms and relative to concurrent increases shown by natural marsh controls. Concentrations of major ions (Ca2+, Mg2+, Na+, K+ and Cl−) did not change in response to flooding, but did vary in time and space. A predicted decrease in the concentrations of major ions in interstitial water due to seepage of dilute surface water into the sediment was not detected.
ABSTRACT. The effect of phosphorous enrichment on decomposition rate, exoenzymatic activities (β-glucosidase, cellobiohydrolase and alkaline phosphatase), and macroinvertebrate abundance in Typha latifolia leaves were assessed in a 2nd order Pampean stream (Central Argentina). Phosphorous was added to a downstream reach while another reach located upstream was kept intact and, once significant differences in phosphorus concentration in water were attained, leaf bags were attached to each reach bottom. T. latifolia leaves lost 77% of their initial weight along 154 days and decomposition rates were not significantly different between reaches. Besides, neither exoenzymatic activities nor macroinvertebrate abundances differed between reaches. However, an increment in leaf phosphorus content, attributed to immobilization by decomposer microorganisms, was detected in the enriched reach.
摘要 在潘帕草原（阿根廷中部）的一条二级溪流中，研究了磷富集对宽叶香蒲叶片分解速率、外源酶活性（β-葡糖苷酶、纤维二糖水解酶和碱性磷酸酶）以及无脊椎动物丰度的影响。磷被添加到下游的一段溪流，而上游的一段溪流保持原样，并在水中磷浓度出现显著差异后，将装有香蒲叶片的袋子固定在每段溪流的底部。宽叶香蒲叶片在154天内失去了77%的初始重量，两段溪流之间的分解速率没有显著差异。此外，外源酶活性和无脊椎动物丰度在两段溪流之间也没有差异。然而，在富集段中检测到叶片磷含量的增加，这被归因于分解微生物的固定作用。
‘Green tides’ Ulva is often harvested for environmental reasons, and put in a dump. Observations on degradation of Ulva in
such dumps led us to consider recovery of hydrolysis juice in order to methanize this rather than the entire alga. The hydrolysis
step was then studied in the laboratory and under real conditions. The decomposition of Ulva was rapid (7.1% C d−1), but its degradation incomplete (38% C remaining after 52 days). After 9 months in a dump, VFA contents in the flows were
insignificant and N and C contents in the remaining material were due to the non-degradable fraction. Modifications of the
physical or chemical conditions of hydrolysis didn't improve suffisently significantly the results to be used on a large scale.
On the other hand, the techniques which could allow a rapid recovery of the juice improved together the recovery of the COD.
The hydrolysis juice is a very good substrate for methanisation: the methane yield reached 330 L kg−1 VS, and the epuration rate 93%. The process combining the two steps, hydrolysis and juice methanisation, is one which offers
a reasonable compromise between methane output, productivity of the system and treatment cost. However, there are still two
problems, dependence on climatic conditions, and too low a recovery rate of the initial organic material.
The strength and generality of the relationship between decomposition rates and detritus carbon, nitrogen, and phosphorus
concentrations was assessed by comparing published reports of decomposition rates of detritus of photosynthetic organisms,
from unicellular algae to trees. The results obtained demonstrated the existence of a general positive, linear relationship
between plant decomposition rates and nitrogen and phosphorus concentrations. Differences in the carbon, nitrogen, and phosphorus
concentrations of plant detritus accounted for 89% of the variance in plant decomposition rates of detritus orginating from
photosynthetic organisms ranging from unicellular microalgae to trees. The results also demonstrate that moist plant material
decomposes substantially faster than dry material with similar nutrient concentrations. Consideration of lignin, instead of
carbon, concentrations did not improve the relationships obtained. These results reflect the coupling of phosphorus and nitrogen
in the basic biochemical processes of both plants and their microbial decomposers, and stress the importance of this coupling
for carbon and nutrient flow in ecosystems.
Rates of weight loss and release of nutrients during different phases of decomposition in young water hyacinth leaves were
determined under laboratory conditions. The leaves decomposed solely by physical leaching during the initial 4-day phase and
later by microbial processes. The largest part of weight loss and nutrient release by physical leaching took place within
the first 4 h of incubation and thereafter the decomposition rate declined. Microbial processes decayed leaves at a significantly
higher rate than that by physical leaching. The overall decay rate constants were related inversely and the release of nutrients
directly to the levels of leaf additions in the lake water. The dissolved inorganic and organic nutrients were released chiefly
by abiotic processes during the initial as well as later phases of decay. The release was significantly higher during the
initial phase in comparison with that during the later phase. Microbes utilized only a small amount of nutrients that were
released during decomposition of water hyacinth leaves. The % release of various elements from the decaying leaves was in
the order of K > P > C > Na > N.
Fiberglass mesh enclosures (1 1 m2) in a Typha angustifoliaL. marsh were employed to examine the effects of clay additions on theresident macroinvertebrate communities. Total invertebrate density, insectdensity, and number of insect families decreased significantly by 33%,37%, and 17%, respectively, in enclosures receiving sediment. Morespecifically, incoming clay adversely affected densities of Coleoptera larvae,Diptera larvae, Megaloptera larvae, Odonata larvae, Pelecypoda, andGastropoda. Densities of specific families within the Diptera (larvae) andColeoptera were also affected; Dolichopodidae, Stratiomyidae,Hydrophilidae, Tabanidae, Dytiscidae adults, and Scirtidae larvae decreasedsignificantly in numbers in sedimented enclosures. In contrast, the effectof sedimentation on Carabidae (adults and larvae) and Dytiscidae larvaldensities varied significantly with time, whereby densities were higher in thesedimented treatment only for the initial two months of the study. Densities of predator-engulfer, collector-filterer, and scraper feeding groupswere reduced in sedimented plots by 28%, 44%, and 27%,respectively. Significant short- and long-term increases in turbidity andsuspended solids in enclosures treated with clay, as well as sedimentdeposition, were probably responsible for changes in the invertebratecommunities.
Ryegrass was grown under conditions of low N, low P, or high N and P nutrient supply in an atmosphere containing 14CO2 and then incubated in soil supplemented with or without N or P fertilizer. Determined in fresh plant tissue, the persistency of residual labelled C after 6 months was in the order low-N plants>low-P plants>high-N and-P plants. The addition of N conserved C, particularly when there was additional P present. Hydrolysable labelled C (12M/0.5M H2SO4) showed similar trends. In analyses of freeze-dried plant tissue, the main effect was also the increased persistency of C from low-N plants compared to high-N plants. The addition of N fertilizer increased the persistence of plant residue C, but only with grass containing low P. The addition of P fertilizer had no effect. In freeze-dried low-P plant tissue, sampled after 1.5, 6, and 12 months, the conserving effect of adding fertilizer N was confirmed. The addition of P, in contrast, enhanced the rate of decomposition. After 6 months, about a third of the C remained, and after 12 months, about one-quarter. It is concluded that P, whether intrinsic or added, can increase the rate of decomposition of organic residues in soil, but there is a strong interaction with N, which has a predominant influence. The effects of N depend on the form it is in. Increased intrinsic tissue N can increase the rate of C loss, whereas added inorganic N can decrease the rate of C loss during decomposition.
The biogeochemistry of N in freshwater wetlands is complicated by vegetation characteristics that range from annual herbs to perennial woodlands; by hydrologic characteristics that range from closed, precipitation-driven to tidal, riverine wetlands; and by the diversity of the nitrogen cycle itself. It is clear that sediments are the single largest pool of nitrogen in wetland ecosystems (100's to 1000's g N m-2) followed in rough order-of-magnitude decreases by plants and available inorganic nitrogen. Precipitation inputs (< 1–2 g N m-2 yr-1) are well known but other atmospheric inputs, e.g. dry deposition, are essentially unknown and could be as large or larger than wet deposition. Nitrogen fixation (acetylene reduction) is an important supplementary input in some wetlands (< < 1–3 g N m-2 yr-1) but is probably limited by the excess of fixed nitrogen usually present in wetland sediments.Plant uptake normally ranges from a few g N m-2 yr-1 to 35 g N m-2 yr-1 with extreme values of up to 100g N m-2 yr-1 Results of translocation experiments done to date may be misleading and may call for a reassessment of the magnitude of both plant uptake and leaching rates. Interactions between plant litter and decomposer microorganisms tend, over the short-term, to conserve nitrogen within the system in immobile forms. Later, decomposers release this nitrogen in forms and at rates that plants can efficiently reassimilate.The NO3 formed by nitrification (< 0.1 to 10 g N m-2 yr-1 has several fates which may tend to either conserve nitrogen (uptake and dissimilatory reduction to ammonium) or lead to its loss (denitrification). Both nitrification and denitrification operate at rates far below their potential and under proper conditions (e.g. draining or fluctuating water levels) may accelerate. However, virtually all estimates of denitrification rates in freshwater wetlands are based on measurements of potential denitrification, not actual denitrification and, as a consequence, the importance of denitrification in these ecosystems may have been greatly over estimated.In general, larger amounts of nitrogen cycle within freshwater wetlands than flow in or out. Except for closed, ombrotrophic systems this might seem an unusual characteristic for ecosystems that are dominated by the flux of water, however, two factors limit the opportunity for N loss. At any given time the fraction of nitrogen in wetlands that could be lost by hydrologic export is probably a small fraction of the potentially mineralizable nitrogen and is certainly a negligible fraction of the total nitrogen in the system. Second, in some cases freshwater wetlands may be hydrologically isolated so that the bulk of upland water flow may pass under (in the case of floating mats) or by (in the case of riparian systems) the biotically active components of the wetland. This may explain the rather limited range of N loading rates real wetlands can accept in comparison to, for example, percolation columns or engineered marshes.
A sampler for collection of interstitial water from wetland sediments is described. It differs from other sampling devices because it does not have to be filled with solution to facilitate diffusion, it does not have to be removed from the wetland to collect samples, and it can be used to draw repeated samples over time from identical locations. The device facilitates in situ measurement of a wide range of abiotic parameters such as electrical conductivity, redox potential, and pH in wetland sediments. The device has application in ecological investigations of sediment-borne wildlife diseases, studies of benthic invertebrates, measurement of nutrient exchange, and other aspects of wetland ecology.
Rates of abiotic and microbial decomposition in pre- and post-bloom leaves of water hyacinth are determined under laboratory conditions. Decomposition in all types of hyacinth leaves is dominated by physical leaching in an initial phase of 4 days duration, and later by microbial processes. The largest part of physical leaching takes place within the first 4 h. Thereafter, the weight loss due to physical leaching declines exponentially. The weight loss by microbial decomposition is minimal in the initial phase but increases exponentially in the later phase. Pre-bloom leaves decompose significantly faster than post-bloom leaves, and post-bloom green leaves decompose faster than post-bloom brown leaves. The rate constants of abiotic decomposition are significantly higher in post-bloom leaves as compared with pre-bloom leaves, while microbial decomposition is significantly higher in pre-bloom leaves. After 30 days, the dry mass loss by abiotic and microbial decomposition is 15% and 55%, respectively, in pre-bloom leaves, 33% and 19% in post-bloom green leaves, and 24% and 6% in post-bloom brown leaves.
Flooding can be an important control of nitrogen (N) biogeochemistry in wetland ecosystems. In North American prairie marshes, spring flooding is a dominant feature of the physical environment that increases emergent plant production and could influence N cycling. I investigated how spring flooding affects N availability and plant N utilization in whitetop (Scolochloa festucacea) marshes in Manitoba, Canada by comparing experimentally spring-flooded marsh inside an impoundment with adjacent nonflooded marsh. The spring-flooded marsh had net N mineralization rates up to 4 times greater than nonflooded marsh. Total growing season net N mineralization was 124 kg N ha–1 in the spring-flooded marsh compared with 62 kg N ha–1 in the nonflooded marsh. Summer water level drawdown in the spring-flooded marsh decreased net N mineralization rates. Net nitrification rates increased in the nonflooded marsh following a lowering of the water table during mid summer. Growing season net nitrification was 33 kg N ha–1 in the nonflooded marsh but < 1 kg N ha–1 in the spring-flooded marsh. Added NO3
–1 induced nitrate reductase (NRA) activity in whitetop grown in pot culture. Field-collected plants showed higher NRA in the nonflooded marsh. Nitrate comprised 40% of total plant N uptake in the nonflooded marsh but <1% of total N uptake in the spring-flooded marsh. Higher plant N demand caused by higher whitetop production in the spring-flooded marsh approximately balanced greater net N mineralization. A close association between the presence of spring flooding and net N mineralization and net nitrification rates indicated that modifications to prairie marshes that change the pattern of spring inundation will lead to rapid and significant changes in marsh N cycling patterns.
The impact of sedimentation on the decay of Typha latifolia, Typha angustifolia and Sparganium eurycarpum litter was evaluated in two Michigan wetlands. In one wetland, T. latifolia decay was studied among replicates of three treatments (unsedimented treatment, one-time sediment application (sandy loam) and multiple sediment applications). In the second wetland, decomposition of T. angustifolia and S. eurycarpum, exposed to phosphorus-enriched clay and unenriched clay applications, was assessed in contrast to an unsedimented control treatment. A one-time application of coarse sediment was sufficient to inhibit decay of T. latifolia by about 10% over 470 days. Application of unenriched and phosphorus-enriched clay suppressed S. eurycarpum decay by about 6–8% over 117 days; however, T. angustifolia decomposition was diminished by only 2% during the same time period. Neither the net flux of nitrogen nor phosphorus mass from decaying tissues was influenced by sediment application. Averages of %N concentration in T. latifolia tissues, however, were higher under unsedimented regimes than sedimented regimes. Among measures of water quality (dissolved oxygen, NH4-N, NO3-N, total P and suspended solids concentrations), only NH4-N demonstrated a significant difference among treatments at the T. latifolia field site (0.13 mg NH4-N l−1 higher in the unsedimented treatment than the sedimented treatments).
The South Florida Water Management District has constructed large treatment wetlands (stormwater treatment areas (STAs)) to reduce total phosphorus concentrations in agricultural runoff before this water enters the Everglades. An important component of nutrient removal and storage in these systems is incorporation of nutrients into aquatic macrophytes and burial of this biomass in the sediments. However, decomposition of plant biomass before burial returns nutrients to the water column and may reduce STA treatment efficiency. As part of research on biogeochemical control of STA performance, we conducted a summer (July–September) and a long-term (12-month) experiment (February–February) that measured decomposition rates and release of chemical constituents from dominant aquatic macrophytes in a constructed wetland located in south Florida. The rank order of mean decomposition rates was Najas/Ceratophyllum (0.0568 d−1) > Pistia (0.0508 d−1) > Eichhornia (0.0191 d−1) > submerged Typha (0.0059 d−1) > aerial Typha (0.0008 d−1). Summer decomposition rates were generally higher than rates from the long-term experiment, which suggested a temperature effect. Decomposition rates were negatively correlated with litter C:N and C:P molar ratios and cellulose and lignin content and positively correlated with N and P content. There was no significant difference in decomposition rates among sampling stations despite the fact that there was a decreasing gradient in water column inorganic phosphorus and nitrogen concentrations at these sites. Relatively little of the initial P mass remained in the litter of all species, except Typha, by the end of both experiments. First-order decomposition models derived using nonlinear regression generally had explanatory power, i.e. accounted for variance, comparable to more complex decreasing-coefficient models. Decomposition rates for the species examined in this study were within the range of published values when comparisons were made either by species or by plant group.
Shoot production of five populations of Typha latifolia on infertile sites ranged from 530 to 1,132 g dry wt/m2. Daily productivity rates based on the entire period of shoot growth for the stands varied from 4.4 to 10.3 g dry wt/m2/day (average = 7.4 g/m2/day). Variation in production was attributed primarily to factors other than environmental nutrient levels. Patterns of nitrogen, phosphorus, and potassium uptake and synthesis of chlorophyll a and b followed similar trends of change in all stands. Nutrient uptake and pigment synthesis were proportionally more rapid than dry matter production in early spring. As the growing season progressed, uptake and synthesis declined to rates proportionally equal to those for dry matter production. Fertilizer experiments revealed that production increases with increasing levels of nitrogen, phosphorus and potassium when these nutrients collectively constitute the only variable.
Shoot productivity was measured for Typha latifolia and Scirpus americanus. Samples were also subjected to chemical analyses. Tissue concentrations of chlorophylls a and b, carotenoids and most macronutrients declined as the plants aged. Net accumulation of these constituents per square meter usually continued during periods of dry matter increase, even though tissue concentrations were diminishing. Dry matter standing crop was the decisive factor determining quantities of chemical constituents per square meter. Uptake rates for macronutrients were generally not proportional to productivity rates. The most rapid uptake of several nutrients occurred earlier than maximum growth rates.
Concurrent with a limnological investigation of the Holland River, Ontario, an attempt was made to determine relative contributions to the river of nutrients (NO 3 ⁻ ‐N, NO 2 ⁻ ‐N, total and soluble reactive phosphorus) and total electrolyte (specific conductance) in surface runoff water pumped from both cultivated and uncultivated plots of muck soil within the Holland Marsh. In addition, subsurface water from piezometers installed in both cultivated and uncultivated marsh soil was analyzed throughout the growing season to determine fundamental differences in water chemistry and the extent of leaching of N and P under both cultivated and uncultivated conditions.
The present study has shown that the time and amount of rainfall was important in determining nitrate‐N and to a lesser extent, soluble reactive P concentrations in subsurface water beneath the cultivated plot but not beneath the uncultivated plot. The mean concentration (0.75 mg/liter) of inorganic N (NO 3 ⁻ ‐N + NO 2 ⁻ ‐N + NH 3 ‐N) in subsurface water under the cultivated plot was about 10 times higher than under uncultivated marsh during the growing season.
The combined effects of fertilization, drainage and hence oxidizing and nitrifying conditions yielded 4 to 5 times more P (1.56 kg P/ha) and 40 to 50 times more nitrate‐N (4.1 kg N/ha) runoff water from the cultivated over the uncultivated plot. The significance of the loading from the cultivated plot is that the nutrients are lost to the river during a 5 to 6 week pumping period during the spring and that more than 90% of the total P in runoff is in the soluble reactive form (as opposed to only 45% from the uncultivated marsh) and is, therefore, readily available for algae and aquatic plant growth in the lower Holland River and Cook Bay of Lake Simcoe.
Fertilization of a low marsh area inhabited by the cord grass,Spartina alterniflora, with inorganic nitrogen and phosphorus compounds was conducted on a monthly basis during the 1972 growing season. Yield
of the cord grass, as measured by an increase in fresh weight after its harvest, was significantly higher in the nitrogen
fertilized area when compared to the phosphorus fertilized site and a control area. No effect of phosphorus could be demonstrated.
It was concluded that nitrogen supplies are limiting production of dwarf formS. alterniflora in the salt marsh under study, and further suggested that introduction of additional sources of inorganic nitrogen into a
marsh deficient in nitrogen would tend to increase its productivity.
Biweekly elevation of available nitrogen and phosphorus concentrations in marsh surface waters did not alter the rate of Sparganium eurycarpum Engelm. or Typha glauca Godr. shoot decomposition. After 505 days, losses of shoot material totaled 39% for both species under fertilized and unfertilized conditions. However, Sparganium shoot litter with an initial nitrogen concentration of 1.41% lost 27% more dry weight over a 505-day period than did Sparganium with an initial concentration of 0.59%. Typha shoot litter with an initial concentration of 0.55% lost 2% more dry weight during 505 days than Typha tissues with an initial nitrogen concentration of 0.48%.
During the 505-day sampling interval, quantities of nitrogen in shoot litter increased 31% for Sparganium and decreased 10% for Typha under unfertilized conditions. Unfertilized Sparganium shoot litter lost 2% and unfertilized Typha litter gained 25% of original phosphorus quantities. Under fertilized conditions, nitrogen quantities increased 35% for the 2 species. The quantity of phosphorus in Sparganium and Typha shoot litter increased 7 and 121%, respectively, with fertilization. Sparganium shoot litter with a high initial nitrogen concentration lost 50% of its original quantity of nitrogen over 505 days, but high-nitrogen Typha shoot litter gained an additional 19% nitrogen.
Experiments were conducted in situ on isolated plots in a marsh to assess the capability of the system for renovating wastewater. Artificial enrichment of sawgrass did not produce increased growth, even though nutrients were assimilated. Thus, growth was not nutrient limited. Weekly application of 2.2 kg/ha of phosphorus increased tissue levels fivefold after 22 wk. However, this increase represented only 12% of the amount applied. The marsh system seems to have a limited capacity for assimilating nutrients. This capacity was stressed after 3 wk and overloaded by 8 wk at a continuous rate of enrichment. Because of this capacity for nutrient absorption, it was unlikely that sawgrass could be used to renovate wastewater efficiently with high nutrient concentrations.
In situ decomposition rate of Juncus roemerianus (Juncaceae) leaves determined by litterbag method was 40% per year. Caloric, elemental, and proximate nutritive analyses of leaves at various stages of life and decay--classified as young, mature, standing dead, partially decayed, decomposed fragments, and particulate detritus--showed the following: (a) an increase in caloric content (4630-4911 g cal/ash-free g); (b) a decrease in carbon (49.75%-6.38%), nitrogen (1.09%-0.57%), and phosphorus (0.22%-0.17%); and (c) a decrease in crude fiber (37%-9%), carbohydrate (52%-11%), protein (9%-4%) and fats (2.0%-0.85%). Particulate detritus retrieved from litterbags decomposed in incubation flasks at the rate of 50% in 36 days. At intervals of 0, 5, 13, 25, and 36 days, analyses of detritus showed the following: (a) a decrease in organic content (67%-32%) and carbon (5.6%-3.2%); and (b) an increase in nitrogen (0.44%-1.21%) and respiration rates (0.11%-1.10 mg O"2 hr^-^1 ash-free g^-^1). The increase in nitrogen of detritus and consequently protein is attributed to conversion of plant tissue to microbial protoplasm as evidenced by increased respiration rates.
Shoot samples of 21 species of aquatic macrophytes were separated into cell-wall and noncell-wall fractions by digestion in a neutral-detergent solution. This method is useful for estimating the digestibility of plant production by native herbivores. Nitrogen content was also used as an indication of nutritive quality. Amounts of noncell-wall material and nitrogen in the dry matter decreased as shoot standing crops of the different species increased.
Shoot standing crops for Typha latifolia ranged from 428 to 2,252 g dry wt/m^2. Standing crops were positively correlated with concentrations of dilute acid soluble phosphorus in hydrosoils and dissolved phosphorus in the waters. Except for a weak0 correlation for dissolved calcium, additional site fertility parameters were not correlated with standing crop. Tissue nutrient levels varied considerably, maximum values for most minerals being three or four times as great as the smallest values. Correlations between environmental levels of several nutrients and tissue concentrations were significant, but not very strong. Tissue concentrations of most nutrients were positively correlated with nitrogen content. Despite variations in tissue levels of nutrients, standing crop was the decisive factor determining quantities of nutrients per unit area of stand.
All vegetation change can be reduced to one of three basic phenomena, succession, maturation, and fluctuation, or some combination of these. Each of these phenomena is a result of a change in some attribute of one or more of the plant populations comprising the vegetation of an area. Succession ocurs when different populations are present from time to time. Maturation is an increase in the biomass of an area which is the result of a change in the age/size structure of the populations with time. Fluctuations result from changes in the number of individuals or ramets in the populations of an area from year to year.
The contribution of succession, maturation, and fluctuation to the vegetation dynamics of Eagle Lake, a prairie glacial marsh in Iowa, is examined. In those areas where changing water levels and extensive musk-rat damage occur, succession is the most important phenomenon. A knowledge of the life-history characteristics of each species, particularly its establishment requirements, the presence or absence of its seeds in the seed bank, and its life-span, enables successional sequences to be predicted in this marsh. There are short periods where maturation is the major phenomenon causing vegetation change. Fluctuations also occur both in the emergent vegetation and the submerged vegetation.
(1) The growth, production, decomposition and nutrient content of shoots of Phragmites communis and Typha angustifolia were studied at Alderfen Broad, Norfolk, with subsidiary work on decomposition at Upton Broad. (2) Shoots of Phragmites and Typha emerged in April. The peak shoot density of Phragmites, occurring in July, was 127/m2 in 1972 and 72/m2 in 1973, the decrease being caused largely by the grazing of coypus in April 1973. Loss of dead standing shoots occurred mainly in the spring and summer, some dead shoots surviving for over two years. Typha shoots reached a maximum density of 100/m2 in May 1973, thereafter declining steadily through a self-thinning process. (3) The mean peak weight of Phragmites shoots was the same in 1972 and 1973, there being no compensation for a decreased shoot density. The mean peak weight of Typha shoots was greater. The peak standing crop of Phragmites was 942 g dry wt/m2 in 1972 and 524 g/m2 in 1973 and that of Typha 1118 g/m2 in 1973. The net productivity was estimated as 1080 g/m2 and 551 g/m2 for Phragmites in 1972 and 1973 and 1445 g/m2 for Typha in 1973. (4) Growing shoots of Phragmites and Typha showed marked, and different, seasonal changes in nutrient content and seasonal changes in rhizomes were also detected. No autumnal increase in the nutrient content of rhizomes occurred, whereas nitrogen and phosphate in the interstitial waters of the swamp showed a large increase in autumn. A large proportion of nutrients appeared to be leached out of the shoots at senescence. (5) The large-mesh litter bags held high numbers of animals, including decomposers; animals were excluded from the small-mesh bags. No significant differences were recorded in the decomposition rates of Typha in Alderfen and Upton Broads. Phragmites broke down at a faster rate than Typha. There was no statistically significant difference in breakdown rate of Typha and Phragmites in large- and small-mesh bags but the time for 50% decomposition of both species was 10% shorter in large- than in small-mesh bags, probably owing to the presence of animals. The respiration rates of decomposing tissue from large- and small-mesh bags showed no significant differences. (6) Sodium, potassium, magnesium and phosphorus leached out of material in the litter bags in the first month, after which there was a constant residual level. The calcium level showed less change owing largely to precipitation out of the water, and the nitrogen level increased due largely to microbial activity. (7) Bacteria present on the surface of decomposing Typha leaves in the water had a density of 4.5 × 106/cm2, the majority of which were pectolytic. Yellow Cytophaga, Erwinia sp. and Pseudomonas spp. were identified. (8) In laboratory experiments, Lymnaea peregra, allowed to graze over Typha litter, increased the oxygen uptake of the litter, presumably by stimulating microbial activity. In contrast, Asellus aquaticus and Gammarus pulex had no effect on the oxygen consumption of Phragmites litter and the differences are explained in terms of the feeding methods of the animals. The metabolic activity of the animals' faeces and of material comminuted, but not ingested, was markedly higher than the initial litter. Some of this enhanced microbial respiration could be suppressed by the addition of streptomycin. When decomposer animals, at approximately natural densities, were fed coarse (diameter >0.5 mm) litter in the laboratory the weight of small (
The vertical distribution of NH 4 ⁺ ‐N following subsurface placement of different forms of urea was studied in incubated, undisturbed wetland soil cores. For prilled urea, supergranule urea, and prilled urea in mudballs placed at the 10‐cm depth, peak concentration of NH 4 ⁺ ‐N was near the placement site and decreased with time, whereas after placement of sulfurcoated urea (SCU‐21) at the same depth, peak concentration of NH 4 ⁺ ‐N increased over a period of 4 weeks. With time, the NH 4 ⁺ ‐N tended to move downward more than upward from the placement sites, probably because of the mass flow of percolating water.
In another experiment, the movement and spatial distribution of NH 4 ⁺ ‐N were studied following application of 2‐g supergranules of urea (SGU) and sulfur‐coated supergranules of urea (SC‐SGU) at a depth of 10 cm in transplanted and cultivated wetland fallow plots. After 2 weeks, NH 4 ⁺ ‐N concentration gradient for SGU was 1,850 to 32 µg N/cm ³ wet soil, over a distance of 10–12 cm from the placement site. The corresponding gradient for SC‐SGU was 287 to 32 µg N/cm ³ wet soil, over a distance of 5–7 cm from its placement site. For SGU in transplanted plots, the concentration gradient decreased steadily through 8 weeks, whereas for SC‐SGU it increased during the first 4 weeks and then decreased. The disappearance of NH 4 ⁺ ‐N with time and distance from the site of application is attributed to diffusive transport or convective transport, or both, and root‐sink effect. The general movement of NH 4 ⁺ ‐N was downward > lateral > upward. The apparent benefits of deep placement of urea in a wetland rice soil are discussed.
Substrate samples were collected at four depths (0–5, 10–15, 20–25, and 30–35 cm) from six vegetation types at Eagle Lake, Iowa. The number of viable seeds in a sample was estimated by placing samples in environments appropriate for seed germination and counting the number of seedlings. Quantitative and qualitative differences in the composition of the seed bank at different depths and locations revealed that the marsh has two distinct vegetation areas. In the northern area, the vegetation changes cyclically. These cycles involve a rotation of three vegetation types: submerged, mudflat, and emergent (Scirpus validus Vahl./ Typha glauca Godr.). In the southern (shallower) area, the composition of the seed bank indicated that there have been no cyclical changes in vegetation. The presence, however, of Typha seed in 0–5 cm samples and in some 10–15 cm samples (in numbers exceeding those normally found in contemporary Typha communities) in vegetation types presently dominated by Sparganium eurycarpum Engelm., Scirpus fluviatilis (Torr.) Gray, and Carex atherodes Spreng. suggest that, in recent years, Typha has declined significantly in the southern area. Because of the failure of their seeds to germinate under assay conditions or because the dominant species annually produces very little seed, most shallow-water emergent community types could not be detected in the seed bank.
In a greenhouse investigation, Cyperus esculentus L. was grown from tubers on sediments obtained from different shoreline regions of the Great Lakes, U.S.A. The sediments were predominantly fine textures, but differed greatly in organic and nutrient contents. A wide range of biomass was obtained after 3 months of growth. Concurrent sand culture experiments with Cyperus under nitrogen- and phosphorus-limiting conditions provided critical concentrations of nitrogen and phosphorus, which were used to evaluate the supply of these elements to Cyperus grown on the different sediments. Differences in plant growth and biomass distribution were related to sediment fertility. Nitrogen was demonstrated to limit the growth of Cyperus on 10 of the 11 sediments examined. Ratios of belowground to aboveground biomass were negatively correlated with plant growth. The allocation of biomass to both aboveground and belowground portions of Cyperus is discussed in relation to the degree of nutrient limitation and other metabolic stresses.
In this paper, data are presented on the productivity of four hay crops, five prairie plots, one floodplain community, one cultivated aquatic crop, two emergent plant populations, and two floating mat communities. The productivity (production rate) of the communities investigated varied with the amount of light, water, and nutrients available. The average productivity, in grams of carbon per square meter per day, based on the terminal crop, was moderate (1.5) in hay crops, tall grass prairie and rice, relatively high (3.6) in giant ragweed and presumably still higher in certain aquatic plants. The terminal standing crop was found to be less than the sum of periodic measurements of the developing crop. It was noted also that the magnitude of productivity values depended upon the time of harvest. The productivity of vascular aquatic plants was usually highest in spring and autumn and lowest during the summer. Low summer productivity was due primarily to the relatively low rate of photosynthesis, compared with that of respiration, during hot summer weather. On the basis of present data it appears that productivity in the terrestrial habitat was greatest along shorelines of water bodies and did not increase continuously in the hydrarch succession toward the regional climax.
Changes in total, vegetative and flowering shoot densities, weights, heights and standing crops of four emergent species before, during, and after a drought indicate that the growth of three of these species (Typha glauca Godr., Scirpus fluviatilis (Torr.) Gray and Sparganium eurycarpum Engelm.) was adversely affected by the drought. The drought, however, temporarily reversed the decline in vigor, which had started before the drought, in the fourth species, Scirpus validus Vahl, and enabled this species to persist for two more years in the marsh. The data suggest that periodic drawdowns enable several emergent species to coexist in a community because of their diverse responses to disturbance.
Oxygen consumption rates by microbial organisms during decomposition of Typha latifolia L., Eichhornia crassipes (Mart.) Solms, Najas guadalupensis (Spreng.) Morong, Pithophora kewensis Wittrock, Chara braunii Gmelin, Spirogyra sp., Euglena proxima Dangeard, and Anabaena circinalis (Kütz.) Rabenhorst were measured by a modified biochemical oxygen demand (BOD) technique. Rates of oxygen consumption were in the following order: Anabaena > (Pithophora, Chara, Najas, Spirogyra, and Euglena) >Typha and Eichhornia. Oxygen consumption was positively correlated with nitrogen concentrations in the plants. Additions of inorganic nitrogen to the medium in BOD bottles increased the rate of oxygen consumption by microbial organisms decomposing plants of low nitrogen content.
Changes in dry weight and N, P, K, Na, Ca, Mg, Al, and Fe content were studied over a 525-day period in decomposing Typha glauca and Scirpus fluviatilis shoots. Submerged Typha litter decomposed more rapidly than submerged Scirpus litter, losing 50% of its original dry weight in 325 days while Scirpus litter still retained 62% of its original dry weight after 525 days. Major pathways of mineral flow from standing litter were (1) leaching during the first few weeks after shoot death and (2) fragmentation and litter fall during the rest of the study. Mineral losses from fallen litter were mainly due to leaching or to excretion by microbial populations associated with the litter. Microbial uptake (N, P) and adsorption (Ca, Al, Fe) were important processes in the fallen litter. After 525 days, as a result of the combined action of mineral uptake and release, Typha litter had net releases of N (71 kg/ha), P(10 kg/ha), K (123 kg/ha), Na (94 kg/ha), Ca (41 kg/ha), and Mg (25 kg/ha) and net accumulations of Al (21 kg/ha) and Fe (20 kg/ha). Scirpus litter, during this same period, had net releases of N (10 kg/ha), K (9 kg/ha), and Na (11 kg/ha). All other minerals increased in decomposing Scirpus litter: P (8 kg/ha), Ca (55 kg/ha), Mg (5 kg/ha), Al (13 kg/ha), and Fe (11 kg/ha). At the end of the study, the calculated combined dry weight of undecomposed standing and fallen litter had decreased by only 20% in Typha litter and 14% in Scirpus litter. Most of the biomass and minerals were in the fallen litter.
1. This article discusses the principles of comparative productivity and the net primary productivity of different types of plant community.
2. Primary production is denned as the weight of new organic matter created by photosynthesis over a period; expressed as a rate it becomes productivity. Biomass is defined as the total weight of plant present at a particular time. Crop, yield and standing crop are comparable with production, productivity and biomass respectively, but refer to the parts of the plant normally harvested or sampled.
3. Net production is that part of the gross photosynthetic production which is not respired by the plant, and hence becomes available for utilization.
4. Ways of adjusting source data to a common form are examined at length, for meaningful comparisons are impossible if this is not done. Source data are published according to a great variety of criteria such as fresh weight, dry weight, oxygen production and carbon fixation. Standing crop or yield data need correction for omitted parts of the plant. The determination of productivity from changes in biomass may involve corrections for material accumulated from earlier periods and for losses due to death or grazing. Conversions from gross production to net production are usually required when photosynthetic determinations are made.
5. Problems raised by the use of different units are discussed and selected factors for conversions to the recommended units are listed.
6. The basis adopted for comparisons is the maximum average annual net productivity of organic (ash‐free) matter that can be attained over a large area. This facilitates the comparison of the productivity of different types of community by minimizing differences due to local site conditions and weather, and is the most useful measure for general ecological purposes. For some selected examples the productivity and biomass are expressed in a variety of other ways to facilitate direct comparisons with source data.
7. Methods for determining productivity are only discussed in so far as the details affect the comparability of the results.
8. The most productive temperate communities appear to be fertile reedswamps which may produce 30–45 metric tons per hectare in a year. Coniferous forests, and perennial plants under intensive cultivation, may produce 25–40 m.t./ha. Deciduous forests, uncultivated herbs and cultivated annual plants are less productive (10–25 m.t./ha.).
9. The most productive communities of all appear to be found in the tropics. Rain forests and perennial plants under intensive cultivation may produce 50–80 m.t./ha. in a year and it is probable that swamps are similar. Cultivated annual plants only attain 25–35 m.t./ha.
10. The phytoplankton of lakes and oceans are relatively poorly productive even on fertile sites, with an annual production of only 1–9 m.t./ha. Values greater than 3 m.t./ha. are only achieved in waters enriched by man's activities, or in the tropics. Submerged freshwater macrophytes are no more productive in the temperate region but may attain 13–21 m.t./ha. in warmer climates. Benthic marine plants in shallow waters may produce more; from 25–33 m.t./ha. in the temperate zone, rising to nearly 40 m.t./ha. by tropical coral reefs. Algae cultivated in sewage can produce up to 45 m.t./ha. and algae cultivated in mineral media, with carbon dioxide supplied artificially, may produce even more.
11. If it were possible to devise cultivation techniques which would enable plants to grow all the year at the rate normally attained for only short periods in their seasonal cycle, much greater annual productivities, up to 150 m.t./ha. year, might be attained. Eichhornia crassipes might be a suitable plant for such cultivation.
12. Assuming that the soil structure is good and that ample nutrients are available there appear to be three main ways of increasing yields; irrigating, using plants which maintain an active cover throughout the year, and developing techniques to obtain valuable products from plants, or parts of plants, not directly useable.
The decomposition of Typha domingensis Pers. was investigated in Lake Chilwa, a shallow endorheic tropical lake. The decomposition curve showed a typical rapid initial weight loss, followed by a slowing down of this process. The amounts of various elements released by the physical leaching process during the first rapid weight loss period were investigated experimentally. A significant proportion of the ions were released from the dead Typha shoots on the first day of contact with water. During this short period loss by leaching amounted to Na 26%, K 7.5%, Ca 9.2%, Mg 11.5%, P 1.5% and N 0.3%. The significance of this rapid leaching process is discussed in relation to the field conditions prevailing in the Lake Chilwa swamps, and to the general applicability of using swamps to remove nutrients from polluted waters.
Until the introduction of fertilizers in the 19th century nutrient-poor conditions prevailed in the larger part of The Netherlands.
Freshwater wetlands consequently were of nutrient-poor nature. During the first half of the 20th century many surface waters
gradually eutrophied, but most waters in the Pleistocene area and even some polders in the Holocene area kept their nutrient-poor
conditions. Only during the last decades virtually all waters became eutrophied or polluted. The main sources of nutrients
are agriculture, precipitation and water from the large rivers.
Uptake and release of nitrogen, phosphorus, potassium, calcium, and sodium from living above-ground and below-ground tissues and from decomposing litter of Typha glauca Godr. were studied at Eagle Lake, IA, during 1976. All nutrients were accumulated rapidly by shoots in the spring. Some of the nitrogen and phosphorus came from belowground storage; but potassium, calcium, and sodium were extracted entirely from the soil. Nutrients were immobilized in shoot tissues for different periods of time. Potassium content declined as rapidly as it had accumulated, and there was no evidence of belowground storage. Nitrogen and phosphorus content also declined, though not as rapidly. Approximately 45% of the nitrogen and phosphorus lost from the shoots was translocated to the rhizomes and stored. Calcium and sodium were conserved in shoot tissues until the shoots died. In the decomposing litter, potassium and sodium content declined, phosphorus and calcium content remained relatively constant, but nitrogen content increased. Over the full year of production and decomposition, this Typha glauca stand accumulated calcium and nitrogen, maintained phosphorus levels, and lost potassium and sodium.
A single solution reagent is described for the determination of phosphorus in sea water. It consists of an acidified solution of ammonium molybdate containing ascorbic acid and a small amount of antimony. This reagent reacts rapidly with phosphate ion yielding a blue-purple compound which contains antimony and phosphorus in a 1:1 atomic ratio. The complex is very stable and obeys Beer's law up to a phosphate concentration of at least 2 μg/ml.The sensitivity of the procedure is comparable with that of the stannous chloride method. The salt error is less than 1 %.RésuméUne méthode spectrophotométrique est décrite pour le dosage du phosphate dans l'eau de mer, an moyen de molybdate d'ammonium, en présence d'acide ascorbique et d'antimoinc. Il se forme rapidement un composé violet bleu, renfermant antimoine et phosphore dans un rapport atomique de 1:1.ZusammenfassungBeschreibung einer Methode zur Bestimmung von Phosphat in Mecrwasser mit Hilfe von Ammoniummolybdat in Gegenwart von Ascorbinsäure und Antimon. Der gebildete blau-violette Komplex wird spektrophotometrisch gemessen.
The growth of two emergent freshwater plants, Cyperus esculentus L. and Scirpus validus Vahl., was investigated under greenhouse control in a simulated freshwater marsh environment. Plants were grown on one coarse and two fine-textured sediments differing significantly in phosphorus and nitrogen contents. Growth of both species, measured as total biomass accrual during a two-month period, was greatest on silty clay, intermediate on clay, and least on sand. Both shoot density (number of shoots per area) and the specific mass of individual shoots with regard to sediment type demonstrated patterns identical to that of total biomass. Below- to aboveground biomass ratios were inversely related to plant growth. The fine-textured sediments provided proportionately greater aboveground growth than the sand. Analysis of plant shoots indicated possible growth limitation by nitrogen on clay. Growth on silty clay was limited by neither nitrogen nor phosphorus, which were both present in the highest concentrations in this sediment. The biomass of both species on silty clay was within the range of most published estimates of the biomass of emergent freshwater plants in temperate regions of the world.
Root growth increased during the early growing season in Spartina alterniflora salt marsh plots. While fertilization with nitrogenous fertilizer did not affect initial growth, a marked decrease in root biomass followed the spring peak particularly where nutrient doses were highest. A sharp reduction in roots occurred in enriched areas covered by Spartina patens , although, as with S. alterniflora , aboveground biomass increased. Roots disappeared during autumn leaving rhizomes as the only part of the plants to overwinter. The maximum standing crop for roots was 0–2 cm deep, for rhizomes 2–5 cm. Net annual underground production was calculated from annual increments in dead matter belowground. Total production, underground and aboveground, exceeds that of any marine vegetation, ranging from 3,900 to 6,600 g m ‒2 yr ‒1 in S. alterniflora areas and 3,200 to 6,200 g m ‒2 yr ‒1 in S. patens areas. Fertilization increased production particularly aboveground where dead plant parts are subject to export.
Thesis (Ph. D.)--Iowa State University, 1972. Includes bibliographical references (leaves 112-122). Photocopy.
Yearly utilization of total solar radiation by a Typha marsh shows approximately equal allotment to reflection (albedo), evapotranspiration, and conduction-convection. Reflection
during the growing season is proportionally lower because of greater light absorption by the vegetation. Photosynthesis is
a negligible quantity, although in relation to visible radiation during the growing season it nearly equals reflection.
A User's Guide to SAS'76 Production, mineral accumulation and pigment concentrations in Typha latifolia and Scirpus amerieanus
- J A Barr
- J H Goodnight
- J P Sail
- J T Helwig
Barr, J.A., Goodnight, J.H., Sail, J.P. and Helwig, J.T., 1976. A User's Guide to SAS'76. SAS Institute Inc., Raleigh, NC. Boyd, C.E., 1970. Production, mineral accumulation and pigment concentrations in Typha latifolia and Scirpus amerieanus. Ecology, 51 : 285--290.
Floristic composition and primary production of the postdrawdown vegetation of Eagle Lake marsh
- P J Currier
Currier, P.J., 1979. Floristic composition and primary production of the postdrawdown vegetation of Eagle Lake marsh, Hancock County, Iowa. M.S. Thesis. Iowa State University. 149 pp.