Relative impacts of morphological alteration to shorelines and eutrophication on littoral macroinvertebrates in Mediterranean lakes

Development of effective methods for assessing the ecological status of lakes based on littoral benthic fauna has been hampered by the lack of quantitative data on the relative impacts of key pressures on the benthic community. We used variance partitioning at 126 sites belonging to 14 natural Mediterranean lakes to analyze the pure and shared effects of eutrophication, morphological alterations, microhabitat type, lake morphometry and geographic position on the littoral macroinvertebrate community. The spatial arrangement of the sampling sites was responsible for 9.1% of the total variance in littoral benthic community composition, lake morphometry accounted for 4.3% of variation, and microhabitat type accounted for 3.9%. Communities appeared to be affected primarily by morphological alterations to lake shorelines, and their impact was 2.5 times as important as that of eutrophication. The structure of littoral benthic communities was governed by processes acting at several spatial scales from region to lake scale. Thus, several pressures and the various spatial scales at which these act should be taken into account when implementing methods of assessing lake ecological condition based on littoral benthic invertebrates. Region-specific methods for subalpine and volcanic lakes might enhance the validity of assessment of results of morphological alterations and improve management of those water resources

Inventaire bibliographique des algues benthiques du littoral marocain. I. Chlorophyceae et Phaeophyceae

nventaire préliminaire des algues benthiques du littoral marocain. I. Chlorophyceae et Phaeophyceae. L'inventaire bibliographique des Chlorophyceae et Phaeophyceae marines benthiques du littoral marocain a révélé 213 espèces dont 93 Chlorophyceae (6 ordres, 15 familles et 31 genres) et 110 Phaeophyceae (11 ordres, 20 familles et 50 genres

Qualitative and quantitative investigations on the macrobenthic fauna of Central Amazon lakes. 1. Lago Tupé, a black water lake on the lower Rio Negro

Lago Tupé is a black water "ria lake". It is connected with the Rio Negro throughout the year and shows similarly large fluctuations in water level, amounting to nearly 8 m in 1971. The exceptionally high minimum water level of the one-year sampling period implied that there was thermal stratification in the lake throughout the year; because of this the oxygen content of the bottom water layers did not exceed 0,6 mg/l, and H2S formed in the hypolimnion during the period of decreasing water level. These unfavourable external conditions led to the development of a qualitatively and, to a lesser extent, quantitatively poor benthic fauna in the lake centre. Dominant were Chaoboridae larvae (192 individuals/m² over the year) and Ostracoda (457 individuals/m² over the year); the Acari were sub-dominant (70 individuals/m² over the year), and Nematoda were also present 110 individuals/m² over the year). The mean annual biomass was 0.136 g/m². The corresponding patterns of abundance and biomass were also determined for the year. The benthic fauna of the littoral zone was investigated during the phases of low and rising water levels, also at a locally fixed sampling station. The characteristic littoral fauna appears only during the low water phase (November to January) when Chironomidae larvae are dominant with an abundance of 43-74 %. The rest of the fauna consists of many groups with low relative abundances. When the water level begins to rise the qualitative composition alters completely within a few weeks, Chaoboridae larvae and Ostracoda becoming dominant. Apart from the absence of Acari the resulting zoocoenose is qualitatively identical with the profundal zoocoenose. It is conceivable that some of the true littoral species migrate at rising water to the neighbouring inundated forest (igapó), and move back again when the water level falls. The rhythmic faunal movements between profundal, littoral and igapô zones, caused by the large water level fluctuations, are schematically represented. Biomass values were also determined in the littoral zone. The values for both this and abundance were much higher than in the lake centre at any given time. The feeding habits of the individual taxa of profundal and littoral zoocoenoses were examined. The Ostracoda are the detritophages of the profundal zoocoenose; they are fed on by the zoophagous Acari and to a certain extent by the chaoborid larvae. In the true littoral zone the phytophages feed on blue green algae and diatoms growing on firm substrates; these are absent from both igapó and profundal zone. The fungi, which are an important food source in the igapó, play a lesser role in the littoral. The larvae of the Tanypodinae are the zoophages of the true Littoral zone. Finally, comparable studies of the zoobenthos of other black water lakes are discussed; these lend support to the inferences from Lago Tupé i.e. the profundal zone of the black water lakes has qualitatively and quantitatively the poorest benthic fauna of all lacustrine biotopes in the Central Amazon

The Straits of Malacca: Regional powers vis-a-vis littoral states in strategic and security issues and interests

This paper presents an overview of the strategic and security issues surrounding the Straits of Malacca. It begins by introducing the strategic nature of the Straits of Malacca and piracy threat in the busy sea lane. Subsequently this paper discusses the issues and interests of the emerging powers in the Straits of Malacca historically. This covers the Asia’s emerging powers such as India, Japan and China. Then, the position of the three littoral states of Malaysia, Indonesia and Singapore towards the issue of piracy in the Straits of Malacca is touched upon before analyzing the littoral states’ position on external powers’ involvement in the Straits of Malacca. This is paper also briefly discusses the individual littoral states’ interests in the vital sea lane

Megacylops viridis Jurine, abyssal form in Lake Maggiore. [Translation of: Memorie dell'Istituto Italiano di Idrobiologia Dott.Marco de Marchi 17 57-79, 1964]

Megacyclops viridis Jurine, noticed in Lago Maggiore in 1912 by De Marchi from the littoral vegetation of Pallanza, is a normal member of the littoral plankton of the lake. The subgenus Megacyclops, created by Kiefer in his revision of the viridis-vernalis group, contains european and american species some of which are today considered as varieties of the species viridis. This paper examines morphology and of the distribution of the Italian viridis in Lake Maggiore

Zooplankton - fish interaction in the littoral zone of Nyanza Gulf, Lake Victoria

The zooplankton community of the littoral zone of Nyanza Gulf, Lake Victoria, was studied between June 1998 and June 1999 to identify and quantify various zooplankton groups, and investigate the interactions that occur between them and the littoral fish through the food chain. Zooplankton samples were collected from five stations using a 83 micro-m mesh size plankton net hauled vertically through the water column. Fish samples were obtained by beach seine, except at Gingra (May 1999), where trawl samples were used. Gut/stomach analysis was carried out on the three major commercial species, Lates niloticus (L.), Oreochromis niloticus (L.) and Rastrineobola argentea (Pellegrin)

Bilateral Delimitation of the Caspian Sea and the Exclusion of Third Parties

© Koninklijke Brill NV, Leiden, 2011This article discusses the position of the littoral States of the body of water known as the Caspian Sea (hereinafter ‘the Caspian’), particularly on the basis of their numerous bilateral treaties and unilateral statements of action, with respect to the legal status and sui generis regimes of the Caspian. It is argued that these States have excluded the possibility that the Caspian be equated for legal purposes to a sea, but they have, nonetheless, employed legal formulae borrowed from the international law of the sea in order to delimit their respective maritime zones and other entitlements. The ambit of these rights is sketchy and they do not conclusively cover the entirety of inter-State relations in the Caspian. There is an urgent need for the adoption of a multilateral convention in order to remedy these gaps, if for no other reason than for the sake of investor confidence and the avoidance of future disputes

Efficient sampling methodologies for lake littoral invertebrates in compliance with the European Water Framework Directive

Lake shores are characterised by a high natural variability, which is increasingly threatened by a multitude of anthropogenic disturbances including morphological alterations to the littoral zone. The European Water Framework Directive (EU WFD) calls for the assessment of lake ecological status by monitoring biological quality elements including benthic macroinvertebrates. To identify cost- and time-efficient sampling strategies for routine lake monitoring, we sampled littoral invertebrates in 32 lakes located in different geographical regions in Europe. We compared the efficiency of two sampling methodologies, defined as habitat-specific and pooled composite sampling protocols. Benthic samples were collected from unmodified and morphologically altered shorelines. Variability within macroinvertebrate communities did not differ significantly between sampling protocols across alteration types, lake types and geographical regions. Community composition showed no significant differences between field composite samples and artificially generated composite samples, and correlation coefficients between macroinvertebrate metrics calculated with both methods and a predefined morphological stressor index were similar. We conclude that proportional composite sampling represents a time- and cost-efficient method for routine lake monitoring as requested under the EU WFD, and may be applied across various European geographical regions