Samples Of Aquatic Plants Research Articles

The stable isotopic (C and N) composition of modern plants and lichens from northern Iceland: with ecological and paleoenvironmental implications

The stable carbon and nitrogen isotopic composition (δC and δN) of plants and lichens can indicate a considerable amount of information about the physiology and ecology of an environment. To our knowledge no stable isotope (C and N) data have been generated for plants and lichens from Iceland. These data could subsequently provide a unique perspective of nitrogen and carbon cycling in Iceland and aid in interpretation of data generated from stable isotope analyses of organic matter preserved in lake sediments. We analyzed plants and lichens around four lakes (Litla-Viðarvatn, Torfadalsvatn, Stifluvatn, Arnarvatn stora) in northern and interior Iceland. The δC values for plants from the sites ranged from –30.9‰ to –23.3‰ that are typical of plants using C3 photosynthesis. Aquatic plant samples (e.g. Potamogeton sp.) analyzed from the sites had δC values (mean=–13.0‰) that were considerably less negative than the terrestrial plants and are typical for submerged freshwater aquatic macrophytes. The δN values from the analyses of plants and lichens showed a surprisingly large range (∼ –12.4‰ to +5.5‰), and many of the specimens had δN values lower than –6.0‰. A number of competing and testable causal mechanisms for the low δN values are proposed and discussed, including plant uptake of atmospheric ammonia and phosphorus limitation.

Environmental contamination of chrysotile asbestos and its toxic effects on growth and physiological and biochemical parameters of Lemna gibba.

Asbestos was monitored in water, sediment, and aquatic plant samples around an asbestos cement factory. Based on asbestos concentration found in aquatic plants during monitoring, and the propensity of asbestos to cause oxidative stress in animal models, laboratory experiments were conducted to assess toxicity of chrysotile asbestos on an aquatic macrophyte, duckweed (Lemna gibba). L. gibba plants were exposed to two concentrations of chrysotile asbestos (0.5 microg and 5.0 microg chrysotile in 5.0 microl double distilled water) twice per week during a period of 28 days and cultured in medium containing 0.1 g chrysotile/L. Control plants were cultured in medium without chrysotile asbestos. Effect of chrysotile exposure on certain growth and physiological and biochemical parameters was evaluated. An inhibition effect of chrysotile exposure was found on the number of fronds, root length, and biomass. Similar alterations in contents of chlorophyll, carotenoid, total free sugar, starch, and protein were also found. Contrary to effect on these parameters, a dose- and time-dependent increase in efflux of electrolytes, lipid peroxidation, cellular hydrogen peroxide, catalase, and superoxide dismutase activity was found. The results indicate oxidative stress and phytotoxicity of chrysotile asbestos on duckweed.

Artificial radionuclides in aquatic plants of the Yenisei River in the area affected by effluents of a Russian plutonium complex

The Yenisei River, one of the largest rivers in the world, is contaminated with artificial radionuclides released by one of the Russian nuclear plants, which produces weapons-grade plutonium and has been in operation for many years. The aim of the study that was conducted between 1997 and 2002 was to investigate accumulation of artificial radionuclides by aquatic plants of the Yenisei River. The aquatic plants sampled were: Potamogeton lucens (shining weed) and Fontinalis antipyretica (water moss). The γ-spectrometric analysis of the samples of aquatic plants for artificial radionuclides has revealed a wide spectrum of long-lived and short-lived radionuclides. Artificial radionuclides such as 51Cr, 54Mn, 58Co, 60Co, 65Zn, 137Cs, and 152Eu were found in aquatic plants collected both near the plutonium complex and 194 km downstream in the river. The radiochemical analysis of aquatic plants revealed strontium and isotopes of plutonium. Fontinalis antipyretica had very high concentration factors of the principal radionuclides: 14220, 3110 and 500 of 51Cr, 46Sc and 239Np, respectively.

The Varying Radiocarbon Activity of Some Recent Submerged Estonian Plants Grown in the Early 1990s

Eleven samples of aquatic plants from three Estonian lakes were analyzed for their radiocarbon content in a collaboration between the laboratories in Tallinn and Uppsala. δ13C values for the actual species were compiled to allow normalization of activities measured in Tallinn without δ13C values. The range for well determined species is usually a few per mil and the statistical uncertainty ≥1‰. δ13C values vary considerably for differentPotamogétonspecies andMyriophýllumspp. Lake Äntu Sinijärv and Lake Päidre are hard-water lakes containing 300 and 200 mg HCO3–/L, respectively. One sample consisted of a carbonate crust deposited on aCeratophýllum demersumplant in L. Äntu Sinijärv. Its Δ14C value was −147.3 ± 6.7‰ in 1990, whereas the plant had a value of −74.1 ± 8.0‰ (δ13C = −35.0‰). The same species in L. Päidre had a Δ14C value of +8.0 ± 8.8‰ (δ13C = −25.2‰) in 1992. Other species in L. Päidre contained more14C, from a Δ14C value of about +30‰ to about +155‰, the latter value measured in Tallinn on floating leaves ofNuphar lútea,close to that of the contemporaneous atmospheric CO2. In the third lake, Lake Punso, containing ≤30 mg HCO3–/L, the stems ofNuphar lúteaexhibited in 1990 a memory effect: the activity, Δ14C = 209.6 ± 10.3‰, significantly exceeded that of the contemporaneous atmospheric CO2. However, the floating leaves of the same plant had the Δ14C value 143.1 ± 10.0‰, close to the atmospheric14C level in 1990. The memory is explained by nutrients stored in the root stock, used when the growth starts.

First order speciation of As using flow injection hydride generation atomic absorption spectrometry with in-situ trapping of the arsine in a graphite furnace

A simple method is described to distinguish between As species that react with sodium tetrahydroborate (III) to form AsH 3 and the naturally occurring As species that are unreactive. Results for this rudimentary or “first order” speciation scheme are reported for biological tissue, aquatic plant material, urine and natural water samples. Biological tissue and aquatic plant samples were briefly solubilized in a mixture of 50% nitric acid, no sample preparation was required for the urine or natural water samples. Organoarsenic species which do not react with sodium borohydride under acidic conditions such as arsenobetaine, arsenocholine and tetramethylarsenic, are converted to As(V) by on-line photo-oxidation or microwave heating in a mixture of 0.5 M NaOH and 0.05 M K 2S 2O 8. The sample is subsequently acidified, reduced with sodium borohydride and the generated arsine is trapped in a heated graphite furnace prior to atomization. The superior detection limit (0.14 ng) of the trapping technique permits the dilution of most types of samples, minimizing or eliminating interference effects. Without photolysis or microwave heating a combined result for As(III), As(V), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) is obtained. Results are reported for the first order speciation of As in a suite of certified reference materials (CRMs) including National Research Council (NRC) biological tissues and natural water samples, Community Bureau of Reference (BCR) aquatic plant materials and the National Institute of Standards and Technology (NIST) SRM 267ON urine sample. The determination of a non-hydride forming As fraction in untreated urine and natural water certified reference materials (CRMs) has revealed a species of As previously undetected in NRC seawater CRMs.

Accumulation of Cu, Zn, Cd, and Pb by aquatic macrophytes

The levels of Cu, Zn, Cd, and Pb were determined in water, sediment, and aquatic plant samples taken from the Nile River and its branches at selected sites characterized by heavy industrialization and dense population. The results revealed that concentration factors in the sediments were, in most cases, much higher than in plants. Metals content in the plants collected from downstream wastewater discharge points was usually higher than that in the plants collected from sites upstream of these points. In laboratory scale models of the piston and completely mixed continuous flow hydraulic systems, Cu, Cd, and Pb removal by a test plant ( Eichhornia crassipes) was assessed. The results showed that the root of the test plant acted as a scavenger for the metals up to a certain capacity. The metals were taken up by different rates, the least of them was that of cadmium. In a batch system metals accumulation from waters of different compositions was investigated using the same test plant. The results are summarized in the following: (1) Cu, Zn, Cd, or Pb accumulation was a function of metal: plant root exposure ratio on dry weight basis. (2) The rates of metals accumulation from both the natural medium (Nile water) and the synthetic medium (mM NaHCO 3 solution) were quite close. (3) Metal accumulation was much lower in the presence of EDTA. (4) The presence of Ca 2+ and Mg 2+ in a concentration equivalent to that of EDTA did not eliminate the retarding effect of the latter on metal accumulation. (5) Metal translocation from the root to the shoot occurred at a low rate compared to metal accumulation by the root.

Radioactivity in Some Aquatic Plants

A study was made of total BETA -radioactivity of 196 samples of aquatic plants obtained from fresh water lakes and the sea between July and November 1962. The samples included many kinds of phytoplankton, 20 genera of marine algae, and 14 genera of aquatic flowering plants collected from the New England coast, Bermuda, and Puerto Rico, Results indicate that radionuclides are accumulated by diverse kinds of aquatic plants. (C.H.)