RESUMO
In order to understand the aquatic community structure in the Laoyingyan section of the Dadu River, we collected samples from 9 aquatic sampling points along that section, and studied the phycophyta, zooplankton, benthic invertebrate and fish in them; we also used expert scoring method based on the actual situation of the river to weigh different biome. The water quality was evaluated using comprehensive evaluation of water quality index ( CEWI). The results showed that: (1) there were a total of 105 phycophyta species, belonging to 6 phyla,31 families, and 56 genera in the Laoyingyan section of the Dadu River, among which, diatom species had a higher richness than the others. The mean cell density of the phycophyta was 17.997 8 x 10(4) ind x L(-1), the mean biomass was 0.4463 mg x L(-1), and the highest population density sites were LTS, LYH and XSH. (2) there were a total of 26 zooplankton species, belonging to 3 phyla, 11 families, and 12 genera, among which, Protozoa had a higher richness than the others, accounting for 80.77% of all the zooplankton species; The mean density of the phycophyta was 40.89 ind x L(-1), and the mean biomass was 13.26 x 10(-3) mg x L(-1). The whole community composition was simple, characterized by few species and small population size. (3) there were a total of 14 benthic invertebrate species, belonging to 6 phyla,14 families, and 14 genera, among which, insecta had a higher richness than the others, accounting for 57.16% of the benthic invertebrate species. Benthic invertebrate had higher population densities in LYH and XSH. (4) The mean CEWI of the whole river water was 2. 698 28, characterized by slightly polluted water quality. The CEWI value between every collection point and the individual water quality evaluation index showed a significant positive correlation, manifesting a high consistency. In addition, the water quality of SLH and NYH was mesosaprobic (1 < CEWI < or = 2), and the water quality of LYH and LYY1 was clean (CEWI > 3), among which the worst was SLH with a lowest CEWI of 1.6207, and the best was LYH with a highest CEWI of 3.9545, all the other samples were subjected to different degrees of light pollution.
Assuntos
Biota , Rios , Qualidade da Água , Animais , Biomassa , China , Diatomáceas , Peixes , Água Doce , Insetos , Invertebrados , Densidade Demográfica , Poluição da Água , ZooplânctonRESUMO
To estimate the potential effects of climate change on the growth and leaf quality of Morus alba, one-year-old M. alba seedlings were exposed 60 d under four treatments, i.e., elevated temperature (ET, +2 â), elevated CO2 concentration (EC, +300 ppm CO2), elevated temperature and CO2 concentration (ETC, +2 â & +300 ppm CO2), and control treatment (CK). The results showed that basal diameter, leaf number, total leaf area, leaf dry mass, leaf dry mass fraction and soluble protein were 9.9%, 17.4%, 23.0%, 9.2%, 10.1% and 23.1% higher under ET than those under CK, respectively. EC significantly increased the stem, root and total dry biomass by 10.7%, 15.9% and 9.2% compared with CK, respectively, whereas leaf quality was similar between EC and CK. Compared with CK, leaf number, height, diameter, total leaf area, the leaf, root and total dry biomass, leaf soluble sugar content and crude protein content increased significantly by 28.8%, 9.1%, 19.4%, 32.6%, 12.4%, 17.2%, 10.1%, 45.8% and 11.9% in ETC while the leaf crude fibre content decreased by 16.8%. Our results indicated that climate change had a positive effect on the growth and leaf quality of M. alba in a short period.
