The Synergistic Impact of Climate Change and Anthropogenic Management on the Lake Kinneret Ecosystem

Anthropogenic and natural processes caused significant changes in Lake Kinneret and its drainage basin ecosystems. Climate change of warming and dryness induced a decline in the lake water level. Changes in the composition structure of the phytoplankton assemblages were enhanced by the decline of nitrogen availability resulting in reduction of Peridinium and enhancement of Cyanobacteria. Increase of the phosphorus availability enhanced Chlorophyta and diatoms. Nutrient export from the Hula Valley to Lake Kinneret is discharge-dependent. The external input decline of organic nitrogen and total dissolved phosphorus is due to anthropogenic achievements. Nitrogen decline and slight increase of phosphorus in Lake Kinneret were followed by Peridinium decline and increase of non-Peridinium algae. The resulting change of food-web structure and water quality in the Kinneret was a shift from phosphorus to nitrogen limitation, which enhanced cyanobacteria

Water-Mediated Nutrients Export from the Hula Valley to Lake Kinneret: A Review

The Lake Kinneret and its Drainage Basin ecosystems have undergone significant changes Those ecosystem modifications include Anthropogenic and Natural processes A comprehensive overview of data collected during 1970 2018 about relations between Lake Kinneret and its drainage basin is summarized in this paper The data evaluation is aimed at the discovery of the dominant factors which has an impact on nutrient inputs into Lake Kinneret The nutrient sources in the Hula Valley and their water-mediated migration towards Lake Kinneret as runoff and through subterranean preferential channels is discussed It is suggested that the dominant mechanism of nutrient export from the Hula Valley to Lake Kinneret is mostly dischargedependent The long-term decline of Organic Nitrogen and Total Dissolved Phosphorus is due to Fishponds reduction and sewage removal The nitrate migration is therefore precipitation capacity-dependent and significantly reduced during drought period

Uptake and depuration of gold nanoparticles in Daphnia magna

This study presents a series of short-term studies (total duration 48 h) of uptake and depuration of engineered nanoparticles (ENP) in neonate Daphnia magna. Gold nanoparticles (Au NP) were used to study the influence of size, stabilizing agent and feeding on uptake and depuration kinetics and animal body burdens. 10 and 30 nm Au NP with different stabilizing agents [citrate (CIT) and mercaptoundecanoic acid (MUDA)] were tested in concentrations around 0.5 mg Au/L. Fast initial uptake was observed for all studied Au NP, with CIT stabilized Au NP showing similar rates independent of size and MUDA showing increased uptake for the smaller Au NP (MUDA 10 nm > CIT 10 nm, 30 nm > MUDA 30 nm). However, upon transfer to clean media no clear trend on depuration rates was found in terms of stabilizing agent or size. Independent of stabilizing agent, 10 nm Au NP resulted in higher residual whole-animal body burdens after 24 h depuration than 30 nm Au NP with residual body burdens about one order of magnitude higher of animals exposed to 10 nm Au NP. The presence of food (P. subcapitata) did not significantly affect the body burden after 24 h of exposure, but depuration was increased. While food addition is not necessary to ensure D. magna survival in the presented short-term test design, the influence of food on uptake and depuration kinetics is essential to consider in long term studies of ENP where food addition is necessary. This study demonstrates the feasibility of a short-term test design to assess the uptake and depuration of ENP in D. magna. The findings underlines that the assumptions behind the traditional way of quantifying bioconcentration are not fulfilled when ENPs are studied.Peer reviewed: YesNRC publication: Ye

Limnological Changes in the Lake Kinneret (Israel) Ecosystem: The Beginning and Its Significance

Abstract The Lake Kinneret (Israel) ecosystem has undergone limnological changes. The trend of changes started in the mid 1990's. The deviation from the previously known as stable long-term structure of the ecosystem included, among others, phytoplankton community structure, nutrient dynamics, zooplankton densities, water temperature increase, water level decline, and fishery management. This study is aimed at identifying ecosystem stability by focusing on three major compartments of the ecosystem: Total Dissolved Solids (TSS), Plankton (Phyto and Zoo), and Detritus (TSS minus plankton). It is suggested that although significant temporary changes of biotic and abiotic parameters were recorded and despite the existence of the normal seasonal fluctuations, the major compartments' structural relations were not modified. The objective of the study is to analyze the process initiation of the modification trend. Previous studies and reports were focused on descriptive evaluation of the modified parameters. The expected outcome is a comprehensive evaluation of the modification process. Consequently, resulted prediction might be a tool for managers to improve management design

Sustainable Utilization of the Lake Kinneret and Its Watershed Ecosystems: A Review

Lake Kinneret and its watershed have undergone significant structural modifications. Some of them are anthropogenic, and others are natural. Among natural modifications, the climate change is prominent. Among man-made changes, the drainage of the Hula Valley, construction of the National Water Carrier designating Lake Kinneret as a national resource of drinking water, construction of the Dam on the lake south outlet, agricultural developments in the Hula Valley, and others are included. Additional factors that recently have a significant impact on the management of the lake ecosystem are the development of ocean water desalinization capabilities. Nevertheless, these two ecosystems were carefully studied directed by limnological and wetland-agricultural scientific trait. One parameter was not yet accounted intensively, the assurance of long-term sustainability. This paper provides an overviewed insight into the conducted principles of management toward sustainable management after the establishment of the modifications as an attempt of predictive development outline

Plankton ecology: The past two decades of progress

This is a selected account of recent developments in plankton ecology. The examples have been chosen for their degree of innovation during the past two decades and for their general ecological importance. They range from plankton autecology over interactions between populations to community ecology. The autecology of plankton is represented by the hydromechanics of plankton (the problem of life in a viscous environment) and by the nutritional ecology of phyto- and zooplankton. Population level studies are represented by competition, herbivory (grazing), and zooplankton responses to predation. Community ecology is represented by the debate about bottom- up vs. top-down control of community organization, by the PEG model of seasonal plankton succession, and by the recent discovery of the microbial food web

Testate amoeba communities of the drained Hula wetland (Israel): Implications for ecosystem development and conservation management

This study investigates the testate amoeba communities of semi-aquatic environments in two anthropogenic wetland ecosystems within an extensive drained wetland complex in northern Israel. Aims are to add to the species record for the region, test the similarity in amoeba communities and ecology to more studied sites and regions and investigate processes of wetland development and the implications of this for conservation management. The testate amoeba community is predominantly composed of cosmopolitan taxa but the community composition is distinct from that of previous studies. Redundancy analyses show that much the strongest environmental control is hydrology (depth to water table). Surprisingly, strontium (Sr) is an important secondary control, probably representing the trophic gradient. With a few exceptions the autecology of taxa identified here agrees with their preferences indicated by previous studies. There are significant differences in species richness and community structure between the amoeba communities of the two sites. Partly the difference may be due to differences in nutrient state, although some of the difference is independent of all environmental variables tested here. The lower species richness of the more recently created site suggests the testate amoeba community may be at an earlier successional stage