Influence Of Aquatic Plants Research Articles

Spatial Distribution of Aerobic Bacteria, Sources and Risks of Nitrogen and Phosphorus in Taihu Lake Sediments

The release of nitrogen and phosphorus from sediments into lake water will exacerbate the eutrophication of lakes and endanger ecological safety and human health. Microorganisms are indispensable in nitrogen and phosphorus conversion, and accurate analysis of the distribution characteristics and sources of nitrogen and phosphorus in sediments as well as their relationship with microorganisms is an important prerequisite for lake eutrophication control. Taking Taihu Lake as the study area, 30 surface sediment samples were collected, and the grain size, pH, organic matter (OM), dissolved organic carbon (DOC), total phosphorus (TP), total nitrogen (TN), nitrate nitrogen (NO3--N), and dissolved organic nitrogen (DON) along with some other index contents were measured and analyzed; accordingly, spatial distribution characteristics were analyzed. While using nutrient agar (NA), the number of aerobic bacteria (AB) was determined by plate counting in the medium. Combined with principal component analysis (PCA) and Pearson correlation analysis, the spatial distribution characteristics and sources of sediments and AB in Taihu Lake were explored. The characteristics of sediment pollution in Taihu Lake were studied using the comprehensive pollution index and the organic pollution index methods. The results revealed that the average sediment indicators of the surface layer of Taihu Lake were as follows:AB was 9.25×104 CFU·g-1, average particle size (MZ) was 17.59 μm, pH was 7.62, ω(OM) was 15.05 g·kg-1, ω(DOC) was 71.60 mg·kg-1, ω(TP) was 598.13 mg·kg-1, ω(TN) was 1113.92 mg·kg-1, ω(NO3--N) was 3.22 mg·kg-1, and ω(DON) was 22.60 mg·kg-1. The comprehensive pollution index (FF) showed that 13% of the Taihu Lake was moderately polluted, while 87% was heavily polluted. Excluding the area in the center of the lake, the southern lake area, and some lakes in the western part of the East Taihu Lake, TN in the rest of the area was moderately and severely polluted. In addition to the heavy pollution of Zhushan Bay, the TP in Taihu Lake was generally at light and moderate pollution. The organic pollution index (OI) showed that the organic pollution of the sediments of Taihu Lake was relatively light, majorly caused by organic nitrogen (ON) pollution. DOC, DON, TN, and OM in Taihu Lake were primarily derived from the influence of aquatic plants, and TP And AB were primarily derived from the influence of the external input of rivers. This research will provide theoretical support for lake eutrophication treatment and also provide new ideas for further analysis of AB to remove nitrogen and phosphorus pollution from sediments.

Evaluation of the Influence of Aquatic Plants and Lake Bottom on the Remote-Sensing Reflectance of Optically Shallow Waters

Aquatic plants and lake bottoms in optically shallow waters (OSWs) wield great influence on reflectance spectra, resulting in the inapplicability of most existing bio-optical models for water colour remote sensing in lakes. Based on radiative transfer theory and measured spectra from a campaign for Lake Taihu in October 2008, absorption and backscattering coefficients were used to simulate the remote-sensing reflectance, which are considered to be reliable if matched to their measured counterparts. Several cases of measured spectra at different depths, Secchi disk depth transparency, and aquatic plant height and coverage were analyzed thoroughly for spectral properties. The contribution of aquatic plants was evaluated and compared with the measured and simulated remote-sensing reflectance values. This is helpful for removing the influence of aquatic plants and lake bottoms from the spectra and for constructing an improved chlorophyll a retrieval model for OSWs, such as that for Lake Taihu, China.

Influence of Aquatic Plants from Different Ecological Groups on Distribution and Abundance of Zooplankton

Influence of Aquatic Plants from Different Ecological Groups on Distribution and Abundance of Zooplankton

Influence of aquatic plants on the hydrogen isotope composition of sedimentary long-chain n-alkanes in the Lake Qinghai region, Qinghai-Tibet Plateau

The hydrogen isotopic composition (δD) of leaf wax long-chain n-alkanes (C27, C29, and C31) from lacustrine sediments has been widely applied to reconstruct terrestrial paleoclimatic and paleohydrological changes. However, few studies have addressed whether the aquatic-derived n-alkanes can affect the δD values of lake sedimentary long-chain n-alkanes, which are usually regarded as a recorder of the terrestrial hydrological signals. Here we systematically investigated δD values of long-chain n-alkanes from modern aquatic plants, both near-shore and off-shore surface sediments, surrounding terrestrial plant litters, as well as river water and lake water in Lake Qinghai and its satellite lakes on the northeastern Qinghai-Tibet Plateau. Our data showed that (i) δD values of long-chain n-alkanes from aquatic plants varied from -184‰ to -132‰ for n-C27, from -183‰ to -138‰ for n-C29, and from -189‰ to -130‰ for n-C31, respectively, with no significant differences among the three n-alkanes homologues; (ii) δD values of long-chain n-alkanes from aquatic plants were generally more positive than those from surrounding terrestrial plants, possibly because that they recorded the D-enrichment of lake water in this semi-arid region; (iii) δD values of long-chain n-alkanes from surface sediments showed significant differences among the three n-alkanes homologues, due to the larger aquatic input of n-C27 to the sedimentary lipid pool than that of n-C31, and (iv) n-C27δD values of near-shore aquatic plants and near-shore sediments are more negative than those from off-shore as a result of lower δD values of near-shore lake water. Our findings indicate that in this region (i) the offset between sedimentary n-C27 and n-C31δD values (ΔδDC27-C31) could potentially be used to evaluate if sedimentary long-chain n-alkanes are derived from a single source; (ii) while δD values of n-C27 may be influenced by lake water hydrological changes, sedimentary n-C31 is derived predominantly from terrestrial plants and thus its δD can serve as a relatively reliable indicator for terrestrial paleoclimatic and paleohydrological reconstructions.

Influence of aquatic plants on the predation of Piaractus mesopotamicus larvae by Pantala flavescens

The experiment aimed to study the influence of the aquatic plants E. najas, P. stratiotes and S. auriculata on the predation of P. mesopotamicus larvae by P. flavescens. One hundred and twenty larvae of P. mesopotamicus and 24 larvae of P. flavescens were placed in 24 aquariums with capacity of 12 L, with one Odonate per aquarium. Treatments were different regarding the species of aquatic plants E. najas, S. auriculata and P. stratiotes, with one control treatment without aquatic plants. One aquarium (12 L) containing one Odonate and 30 P. mesopotamicus larvae was considered one experimental unit. After 18 hours, the Odonates were removed from the aquariums and fish larvae left (alive) were counted in each experimental unit. The survival rate of P. mesopotamicus larvae in the treatment without aquatic plants (control) was significantly lower than in the treatment with E. najas. However, the survival rates in the aquariums with floating aquatic plants did not differ from the control. The morphological characteristics of E. najas promoted higher structural complexity in the environment, offering more protection to the fish larvae, and increasing their survival. We concluded that the presence of the submerged aquatic plant E. najas promoted the reduction of predation of P. mesopotamicus larvae by Pantala flavescens.

Impact of luxuriant aquatic plants on thermal convection in a closed water body

The attenuation of heat flux at the water surface with aquatic plants was examined by hydraulic experiments to consider the influence of aquatic plants on the magnitude of thermal disturbance in the closed water body. First of all, the experiment measuring temperatures on surface of leaf revealed the thermal conductivity of the leaf which is peculiar physicality of each aquatic plant. Then, the hydraulic experiment examined attenuation of the underwater illuminance and the heat flux in the covered part which depending on the kind and the luxuriant density of the aquatic plants. As the result, it is clarified that the attenuation rate of the illuminance is large in the plant with a thick leaf, and that the heat flux at the water surface and the developmental velocity of the mixed layer decreased when the luxuriant density of the aquatic plants increased.

Case Study: Design and Operation of Sustainable Urban Infiltration Ponds Treating Storm Runoff

Combined wetlands and infiltration ponds are cost-effective ‘end of pipe’ drainage solutions that can be applied for local source control as part of urban development and regeneration. The aims of this case study were to assess constraints associated with the planning, design, and operation of these ponds, the influence of aquatic plants on infiltration rates, and the water treatment potential. Storm runoff was first stored and treated in a constructed wetland before it overflowed into parallel infiltration ponds of which one was planted and the other one was unplanted. Three international best management practice design guidelines failed in practice. The presence of macrophytes in one infiltration pond had no significant influence on the drainage properties. The water quality of both ponds was not acceptable for water reuse directly after the system setup. Filamentous green algae within the unplanted pond were blooming in spring and summer creating an aesthetically unpleasing pond surface area. After 1 year of operation, barley straw and Carassius auratus (common goldfish) were introduced successfully to control the growth of algae.

INFLUENCES OF AQUATIC PLANTS ON THE FATE OF THE PYRETHROID INSECTICIDE LAMBDA-CYHALOTHRIN IN AQUATIC ENVIRONMENTS

Aquatic exposure assessments for pesticides are generally based on laboratory studies performed in water alone or water sediment systems. Although aquatic macrophytes, which include a variety of bryophytes, macroalgae, and angiosperms, can be a significant component of many aquatic ecosystems, their impact on pesticide fate is generally not included in exposure assessments. To investigate the influence of aquatic plants on the fate and behavior of the pyrethroid insecticide lambda (lambda)-cyhalothrin, two laboratory experiments (to assess adsorption and degradation) and an indoor microcosm study (to assess fate under semirealistic conditions) were conducted. In the laboratory studies, adsorption to macrophytes was extensive and essentially irreversible, and degradation occurred rapidly by cleavage of the ester bond. In the indoor microcosm, which contained water, sediment, and macrophytes from a pond, degradation was also rapid, with DT50 and DT90 values of less than 3 and 19 h, respectively, for dissipation from the water column and of less than 3 and 56 h, respectively, for the whole system. For adsorptive and readily degraded pesticides like lambda-cyhalothrin, we conclude that macrophytes have considerable influence on fate and behavior in surface waters.

The Influence of Aquatic Plants on the Conservation of Water

The Influence of Aquatic Plants on the Conservation of Water