Food web of benthic macro invertebrates in a large Yangtze River-connected lake: the role of flood disturbance

This Study was conducted in Lake Dongtinghu, a large river-connected lake on the Yangtze River flood-plain, China. Our goal was to determine trophic relationships among benthic macroinvertebrates, as well as the effects of flood disturbance on the benthic food web of a river-connected lake. Macroinvertebrates in the lake fed mainly on detritus and plankton (both zooplankton and phytoplankton). Food web Structure in Lake Dongtinghu was characterized by molluscs as the dominant group, low connectance, high level of omnivory. based oil detritus and primary production, and most ingestion concentrating on a few links. Our analyses showed that flood disturbance is an important factor affecting the benthic food web in Lake Dongtinghu. The numbers of species and functional feeding groups (FFGs), and the density and biomass of macroinvertebrates decreased significantly during flooding. Connectance was higher during the flood season than in other seasons, indicating that floods have a strong effect on connectance in this Yangtze River-connected lake. Flood effects on the benthic web were also evident in the decrease of niche overlaps within and anion, FFGs. Our results provide useful information regarding biodiversity conservation on the Yangtze floodplain. Reconstructing and maintaining natural and regular flow regimes between Yangtze lakes and the river is essential for restoration of macroinvertebrates on the floodplain.

A baseline report of water quality and invertebrate assessment in River Hohwa, Lake Albert: final report

Tullow Oil plc is to launch an onshore Early Production System (EPS) of oil drilling rated at 4,000 barrels of oil per day by 2009. The location of the EPS is in the Kaiso-Tonya area of Block 2 Oil Exploration Zone along Lake Albert within the Albertine graben. Tullow Oil plc contracted Environmental Resources Management (ERM) Southern Africa (Pty) Ltd in conjunction with Environmental Assessment Consult Limited (EACL) to undertake an Environmental Impact Assessment (EIA) for pre-construction and operation of the proposed EPS. ERM in association with EACL requested National Fisheries Resources Research Institute (NaFIRRI) to conduct a baseline survey of water quality and invertebrates in River Hohwa. This study was requested as part of an earlier baseline survey conducted at the Kaiso-Ngassa spit oil exploration area in Block 2. It was conducted at five selected sites (Fig. 1 & Table 1) within the Hohwa River basin in the Kaiso-Tonya Exploration Area 2. The study was pertinent because the targeted oil wells for EPS are upstream this river which drains the Kaiso-Ngassa valley into Ngassa lagoon.

The role of macrophytes in the economy of the lower Sondu-Miriu river of Lake Victoria

This paper highlights the results of a 12 month's ecological study of macrophytes and their role in the economy of the lower Sondu-Miriu river of Lake Victoria. A total of 34 species of aquatic macrophytes were identified. These were grouped as emergent, floating leaved, free floating and submersed. The major community type identified were dominated by Cladium jamaicanse (Crantz) Kurk., Cyperus paprus (L.) and Cyperus latifolius (Poir). The study observed an over dependence on macrophytes by the local community for the supply of bedding, grazing fields, fuel, roofing and other building materials. The white (heart) of Typha shoot, Nile cabbage (Pistia stratiotes and a legume solanum nigrum traditionally known as "osuga" are used as vegetables by local community. The only source of protein in this arid region is the fish caught in the swamps and birds which inhabit the swamp. The swamp provides the only source of green pasture in the dry season for the animals. An export oriented economy has developed involving mat making and basket weaving with exports reaching as far as Japan. The study proposes a rational and sustainable exploitation of the littoral zone to support the adjacent rural community.

Macrozoobenthic community of Poyang Lake, the largest freshwater lake of China, in the Yangtze floodplain

Poyang Lake (Poyang Hu) is located at the junction of the middle and lower reaches of the Yangtze (Changjiang) River, covering an area of 3283 km(2). As one of the few lakes that are still freely connected with the river, it plays an important role in the maintenance of the unique biota of the Yangtze floodplain ecosystem. To promote the conservation of Poyang Lake, an investigation of the macrobenthos in the lake itself and adjoining Yangtze mainstream was conducted in 1997-1999. Altogether 58 benthic taxa, including, 22 annelids, 8 mollusks, 26 arthropods, and 2 miscellaneous animals, were identified from quantitative samples. The benthic fauna shows a high diversity and a marine affinity. The standing crops of benthos in the lake were much higher than those in the river, being 659 individuals/m(2) and 187.3g/m(2) (wet mass) in the main lake, and 549 individuals/m(2) and 116.6 g/m(2) in the lake outlet, but only 129 individuals/m(2) and 0.4g/m(2) in the river. The dominant roup in the lake was Mollusca, comprising 63.4% of the total in density and 99.5% in biomass. An analysis of the functional feeding structure indicated that collector-filterers and scrapers were predominant in the lake, up to 42.2% and 24.7% in density and 70.2% and 29.2% in biomass, respectively, while shredders and collector-gatherers were relatively common in the river. The present study was restricted to the northern outlet and the northeast part of Poyang Lake. A scrutiny is required for the remaining areas.

Mobilization potential of heavy metals: A comparison between river and lake sediments

Toxic metals introduced into aquatic environments by human activities accumulation in sediments. A common notion is that the association of metals with acid volatile sulfides (AVS) affords a mechanism for partitioning metals from water to solid phase, thereby reducing biological availability. However, variation in environmental conditions can mobilize the sediment-bound metal and result in adverse environmental impacts. The AVS levels and the effect of AVS on the fate of Cu, Cd, Zn, Ni in sediments in the the Changjiang River, a suboxic river with sandy bottom sediment and the Donghu Lake, a anoxic lake with muddy sediment in China, were compared through aeration, static adsorption and release experiments in laboratory. Sips isotherm equation, kinetic equation and grade ion exchange theory were used to describe the heavy metal adsorb and release process. The results showed that AVS level in the lake sediment are higher than that of the river. Heavy metals in the overlying water can transfer to sediments incessantly as long as the sediment remains undisturbed. The metal release process is mainly related to AVS oxidation in lake sediment while also related to Org-C and Fe-Mn oxyhydroxide oxidation in river sediment. The effect of sulfides on Zn and Ni is high, followed by Cd, and Cu is easy bound to Org-C. AVS plays a major role in controlling metals activity in lake sediment and its presence increase the adsorption capacity both of the lake and river sediments.

Conference: Pollution of the Interstate Waters of the Grand Calumet River, Little Calumet River, Calumet River, Wolf Lake, Lake Michigan, and Their Tributaries, Illinois--Indiana. Second session, Dec. 11-12, 1968, Jan. 29, 1969, Chicago, Ill.

"Supplement. 2d session, Reconvened, Aug. 26, 1969."

Conference in the matter of: Progress meeting in the matter of pollution of the interstate waters of the Grand Calumet River, Little Calumet River, Calumet River, Wolf Lake, Lake Michigan and their tributaries, Wednesday, March 15, 1967, Chicago, Illinois.

Cover title: Progress evaluation meeting in the matter of pollution of the interstate waters of the Grand Calumet River...

Water-quality assessment of White River between Lake Sequoyah and Beaver Reservoir, Washington County, Arkansas /

Mode of access: Internet.

Report on the location and expense of a ship canal around Niagara Falls : also, from the Illinois River to Lake Michigan : with a report of a select committee to the Assembly, April 14, 1834, relating to the connection from Oswego to the Hudson.

"Published in pursuance of a resolution of the Chamber of Commerce of New York, passed September, 1834."

Dissolved-oxygen regime of the Jordan River, Salt Lake County, Utah /

"WRI 84-4056"--P. [4] of cover.

Study and comparison on freshwater snail fauna in the paddy fields and related river and lake (Babolroad & Parishan) water supply in Mazandaran & Frace provinces of Iran

As a result of this investigation, for the first time from Babolroud river in Iran is 15 species identified, which they belong to 8 genera, from 7 families. The most and least distribution, 13 and 5 species, belong to Miandasht and Rostaye Anarestane Babol stations respectively, which they are 50 kilometers away from each other. Also 20 species belong to 10 genera from 6 families were identified in Parishan lake. The most the distribution belong to stations 1 and 5 with 6 and 18 species respectively. The most commonly distributed family is Lymnaeidae with 6 species: Lyamnaea truncatula, L. auricularia, L. palustris, L. pereger, L. stagnalis and L. gedrosiana, which L. trancatula is identified as the most frequent and has medical importance. L. stagnalis is identified to be the most important to agriculture. Planorbis planorhis, Physa acuta, Lymnaea pereger, Bithynia tenculata and Vavata piscinalis are reported for the first time from this region.

Communities of gastrointestinal helminths of fish in historically connected habitats: habitat fragmentation effect in a carnivorous catfish Pelteobagrus fulvidraco from seven lakes in flood plain of the Yangtze River, China

Background: Habitat fragmentation may result in the reduction of diversity of parasite communities by affecting population size and dispersal pattern of species. In the flood plain of the Yangtze River in China, many lakes, which were once connected with the river, have become isolated since the 1950s from the river by the construction of dams and sluices, with many larger lakes subdivided into smaller ones by road embankments. These artificial barriers have inevitably obstructed the migration of fish between the river and lakes and also among lakes. In this study, the gastrointestinal helminth communities were investigated in a carnivorous fish, the yellowhead catfish Pelteobagrus fulvidraco, from two connected and five isolated lakes in the flood plain in order to detect the effect of lake fragmentation on the parasite communities. Results: A total of 11 species of helminths were recorded in the stomach and intestine of P. fulvidraco from seven lakes, including two lakes connected with the Yangtze River, i.e. Poyang and Dongting lakes, and five isolated lakes, i.e. Honghu, Liangzi, Tangxun, Niushan and Baoan lakes. Mean helminth individuals and diversity of helminth communities in Honghu and Dongting lakes was lower than in the other five lakes. The nematode Procamallanus fulvidraconis was the dominant species of communities in all the seven lakes. No significant difference in the Shannon-Wiener index was detected between connected lakes (0.48) and isolated lakes (0.50). The similarity of helminth communities between Niushan and Baoan lakes was the highest (0.6708), and the lowest was between Tangxun and Dongting lakes (0.1807). The similarity was low between Dongting and the other lakes, and the similarity decreased with the geographic distance among these lakes. The helminth community in one connected lake, Poyang Lake was clustered with isolated lakes, but the community in Dongting Lake was separated in the tree. Conclusion: The similarity in the helminth communities of this fish in the flood-plain lakes may be attributed to the historical connection of these habitats and to the completion of the life-cycles of this fish as well as the helminth species within the investigated habitats. The diversity and the digenean majority in the helminth communities can be related to the diet of this fish, and to the lacustrine and macrophytic characters of the habitats. The lake isolation from the river had little detectable effect on the helminth communities of the catfish in flood-plain lakes of the Yangtze River. The low similarities in helminth communities between the Dongting Lake and others may just be a reflection of its unique water environment and anthropogenic alterations or fragmentation in this lake.

Growth and survival of sockeye salmon (Oncorhynchus nerka) from Karluk Lake and River, Alaska, in relation to climatic and oceanic regimes and indices, 1922–2000

We examined whether the relationship between climate and salmon production was linked through the effect of climate on the growth of sockeye salmon (Oncorhynchus nerka) at sea. Smolt length and juvenile, immature, and maturing growth rates were estimated from increments on scales of adult sockeye salmon that returned to the Karluk River and Lake system on Kodiak Island, Alaska, over 77 years, 1924–2000. Survival was higher during the warm climate regimes and lower during the cool regime. Growth was not correlated with survival, as estimated from the residuals of the Ricker stock-recruitment model. Juvenile growth was correlated with an atmospheric forcing index and immature growth was correlated with the amount of coastal precipitation, but the magnitude of winter and spring coastal downwelling in the Gulf of Alaska and the Pacific Northwest atmospheric patterns that influence the directional bifurcation of the Pacific Current were not related to the growth of Karluk sockeye salmon. However, indices of sea surface temperature, coastal precipitation, and atmospheric circulation in the eastern North Pacific were correlated with the survival of Karluk sockeye salmon. Winter and spring precipitation and atmospheric circulation are possible processes linking survival to climate variation in Karluk sockeye salmon.

FACTORS INFLUENCING CHLOROPHYLL A CONCENTRATION IN THE YANGTZE-CONNECTED LAKES

To determine the environmental factors influencing C, phytoplankton chlorophyll a (Ch1 a), field investigations 4 were conducted in three river-connected lakes (Dongting Lake, Poyang Lake and Shijiu Lake) of the Yangtze floodplain in 2004. Results showed that the average Chi a concentration in these lakes ranged from 2.98 to 3.65 mg m(-3). The major factors influencing Chl a in lentic and lotic regions were total phosphorus (TP) and water velocity (U), respectively. Multiple relationships including total nitrogen (log(10)TN) and water depth (log(10)Z) were established. Further analyses found that the absolute Chi a and slope of log(10)Chl a=f (log(10)TP) in the river-connected lakes were obviously lower than those in the river-isolated lakes. This suggests the river-lake connectivity can significantly modify relationship between TP and chlorophyll a concentration.

Relationships between microcystins and environmental parameters in 30 subtropical shallow lakes along the Yangtze River, China

1. A survey of 30 subtropical shallow lakes in the middle and lower reaches of the Yangtze River area in China was conducted during July-September in 2003-2004 to study how environmental and biological variables were associated with the concentration of the cyanobacterial toxin microcystin (MC). 2. Mean MC concentration in seasonally river-connected lakes (SL) was nearly 33 times that in permanently river-connected lakes (RL), and more than six times that in city lakes (NC) and non-urban lakes (NE) which were not connected to the Yangtze River. The highest MC (8.574 mu g L-1) was detected in Dianshan Lake. 3. MC-RR and MC-LR were the primary toxin variants in our data. MC-RR, MC-YR and MC-LR were significantly correlated with Ch1 a, biomass of cyanobacteria, Microcystis and Anabaena, indicating that microcystins were mainly produced by Microcystis and Anabaena sp. in these lakes. 4. Nonlinear interval maxima regression indicated that the relationships of Secchi depth, total nitrogen (TN) : total phosphorus UP) and NH4+ with MC were characterised by negative exponential curves. The relationships between MC and TN, TP, NO3- + NO2- were fitted well with a unimodal curve. 5. Multivariate analyses by principal component and classifying analysis indicated that MC was mainly affected by Microcystis among the biological factors, and was closely related with temperature among physicochernical factors.