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1.
This work, carried out within the framework of the PRISMA II project, aims at evaluating the effects of the Po River flow on primary productivity, measured by C with in situ sample incubations. A total of four cruises was carried out in late winter and early summer (1996-1998) along transects from the coast offshore. In both seasons, the highest primary productivity was found in the most oligohaline stations. The effects of the Po River inputs were therefore clearly evident in the westernmost area, both in high productivity values and in the shape of productivity profiles. In late winter, extensive blooms of Skeletonema costatum and Pseudo-nitzschia delicatissima resulted in productivity values that were sometimes higher than in early summer. In early summer 1996, greatly reduced river flow clearly influenced productivity which was much lower than in 1997. 相似文献
2.
区域水环境生物学评价浅析 总被引:1,自引:0,他引:1
本文论述了辽河三角洲区域地面水系浮游植物的种类分布,根据调查获得的生态学资料,探讨了其群落结构特征及其与水体环境质量的关系,运用“Shannon—Weaver多样性指数法”对区域水体质量进行了分类评价,并研究了浮游植物的多样性指数与水质理化污染指标之间的关系. 相似文献
3.
以浮游植物评价金堂水库富营养化 总被引:10,自引:0,他引:10
通过对浮游植物的生物量、优势种、初级生产力、叶绿素a等指的分析,判断金堂水库质已达富营养化水平;网箱养鱼是产生富营养化的主要原因;富营养化对水库功能的不利影响将是很骓消除的。 相似文献
4.
Numerous studies support that biodiversity predict most to ecosystem functioning, but whether other factors display a more significant direct impact on ecosystem functioning than biodiversity remains to be studied. We investigated 398 samples of the phytoplankton phosphorus resource use efficiency (RUEP = chlorophyll-a concentration/dissolved phosphate) across two seasons in nine plateau lakes in Yunnan Province, China. We identified the main contributors to phytoplankton RUEP and analyzed their potential influences on RUEP at different lake trophic states. The results showed that total nitrogen (TN) contributed the most to RUEP among the nine lakes, whereas community turnover (measured as community dissimilarity) explained the most to RUEP variation across the two seasons. Moreover, TN also influenced RUEP by affecting biodiversity. Species richness (SR), functional attribute diversity (FAD2), and dendrogram-based functional diversity (FDc) were positively correlated with RUEP in both seasons, while evenness was negatively correlated with RUEP at the end of the rainy season. We also found that the effects of biodiversity and turnover on RUEP depended on the lake trophic states. SR and FAD2 were positively correlated with RUEP in all three trophic states. Evenness showed a negative correlation with RUEP at the eutrophic and oligotrophic levels, but a positive correlation at the mesotrophic level. Turnover had a negative influence on RUEP at the eutrophic level, but a positive influence at the mesotrophic and oligotrophic levels. Overall, our results suggested that multiple factors and nutrient states need to be considered when the ecosystem functioning predictors and the biodiversity-ecosystem functioning relationships are investigated. 相似文献
5.
a ), and nutrient availability (phosphorus and nitrogen). High variability in these limnological characteristics, particularly
among impoundments, obscured potential differences between impoundments and ponds. No significant differences were found in
chlorophyll or nutrient concentrations, and in only two cases were there differences in invertebrate production: gastropods
were significantly more abundant in impoundments than in ponds in June, and trichopterans were significantly more abundant
in impoundments than in ponds in July. For comparisons within impoundments and ponds, there were significant differences in
invertebrate abundance between habitats and between wetland types. For example, plecopterans, trichopterans, and gastropods
(all taxa combined) were consistently more abundant in shallow–Arctophila impoundments and ponds than in shallow–Carex impoundments and ponds. Thus, ponds and impoundments may differ significantly in invertebrate production, but we lack information
on the amount of different habitat types (i.e., center versus emergent vegetation, Carex versus Arctophila) used by these taxa within each water body type. It is a reasonable speculation, based on results of this study, that impoundments
and ponds may have similar value as feeding habitat for invertebrate-eating waterbirds. Thus the presence of impoundments
may be consistent with waterbird management goals on the Arctic Coastal Plain. 相似文献
6.
Submerged vegetation removal promotes shift of dominant phytoplankton functional groups in a eutrophic lake 总被引:1,自引:0,他引:1
Historical data indicate that the dominance of submerged plants in Dianchi Lake in the 1960 s was characterized by low algal density with dominance of non-toxic group J(Scenedesmus,Pediastrum,etc.). The removal of submerged plants,which began in the 1970 s,resulted in the expansion of bloom-forming Microcystis(group M). Laboratory experiments suggested that Microcystis aeruginosa was inclined to grow and develop at elevated temperatures. The growth of Scenedesmus obliquus was slower than that of co-cultivated M. aeruginosa in the absence of Ceratophyllum demersum,especially at higher temperatures. The existence of submerged plant C. demersum could inhibit the growth of the harmful algae M. aeruginosa and this inhibitory effect by C. demersum was enhanced with an increase in temperature. Instead,with C. demersum,the growth of S. obliquus was not inhibited,but the co-cultivated M. aeruginosa was eliminated in a short time. Combined with the historical data and laboratory experiments,it was indicated that the submerged plants might play important roles in the dominance of the non-toxic group J in the historical succession. Consequently,the introduction of the submerged plant such as C. demersum might alter the dominant phytoplankton functional groups from M to J and benefit the restoration of the eutrophic lake. 相似文献
7.
本文通过2006~2010年五年间对水质生物学评价指标一浮游植物种类和数量的变化来评价红旗水库水质的现状,得出红旗水库水质属于轻污一中污染水体,但仍然符合饮用水源地标准。 相似文献
8.
对2013年夏季南岔湖的浮游植物进行了初步研究,共鉴定初浮游植物6门,8纲,13目,24科,43属,共94个分类单位。其中优势种6种。南岔湖水体属于中污染。 相似文献
9.
Multivariate Analysis of Interactions Between Phytoplankton Biomass and Environmental Variables in Taihu Lake, China 总被引:1,自引:0,他引:1
Phytoplankton variation in large shallow eutrophic lakes is characterized by high spatial and temporal heterogenity. Understanding
the pattern of phytoplankton variation and the relationships between it and environmental variables can contribute to eutrophic
lakes management. In this study Taihu Lake, one of the largest eutrophic fresh water lake in China, was taken as study area.
The water body of Taihu Lake was divided into five regions viz. Wuli bay (WB), Meilian Bay (MB), West Taihu Lake (WTL), Main
Body of Taihu Lake (MBTL) and East Taihu Lake (ETL). Concentrations of chlorophyll-a and the related environmental variables
were determined in each region in the period 2000–2003. Factor analysis and multivariate analysis were applied to evaluate
the interactions between phytoplankton variation and environmental variables. Results showed that the highest average concentrations
of TN, TP and Chl-a were observed in WB, followed in a descending order by MB and WTL, and the lowest concentrations of TN,
TP and Chl-a were observed in MBTL and ETL. Chl-a and TP concentrations in most regions (except ETL) declined during the study
period. It suggested that to some extent the lake was recovering from eutrophication. However, persistent ascending of TN
and NH4–N in all five regions indicated the deteriorating of water quality in the study period. Results of multivariate showed that
the relationships between phytoplankton biomass and environmental variables varied among regions. TP illustrated itself a
controlling role on phytoplankton in WB, MB, WTL and MBTL according to the significant positive relations to phytoplankton
biomass in these regions. Nitrogen could be identified as a limiting factor to phytoplankton biomass in ETL in view of the
positive correlations between TN and phytoplankton and between NH4–N and phytoplankton. Spatial variation of interactions between phytoplankton and environmental parameters suggested proper
eutrophication control measures were needed to restore ecological system in each region of Taihu Lake. 相似文献
10.
Eutrophication conditions and ecological status in typical bays of Lake Taihu in China 总被引:4,自引:0,他引:4
Sampling was conducted at three site groups, group E (in East Taihu Bay), G (in Gonghu Bay) and M (in Meiliang Bay) in Lake
Taihu. TN and TP concentrations among site groups was in the increasing order of E < G < M. TP level at G sites is at the
critical threshold for loss of submersed macrophytes. Mean values of DO and Transparence showed different trend, i.e., E >
G > M. The mean phytoplankton fresh-weight biomass at M sites was 5.81 mg/l, higher than that at E sites (4.96 mg/l) and G
sites (5.18 mg/l). Mean zooplankton fresh-weight biomass was in the decreasing order of M (6.4 mg/l) > G (4.9 mg/l) > E (2.7 mg/l).
However, Rotifera density was in the sequence of E > G > M. Both zooplankton biomass and phytoplankton biomass increased with the rise of TN
and TP concentrations. Relationships between zooplankton biomass and phytoplankton biomass showed that zooplankton played
a limited role in the control of algae in eutrophic lakes. Nutrient availability is much more important than zooplankton grazing
pressure in controlling phytoplankton growth in lakes. For most sites in Lake Taihu, reduction of nutrient loading, as well
as macrophyte conservation, zappears to be especially important in maintaining high water quality and regulating lake biological
structure, but for M sites, it’s urgent to control nutrient inputs rather than to restore macrophyte community. 相似文献