Journal of Limnology 

About: Journal of Limnology is an academic journal published by PAGEPress (Italy). The journal publishes majorly in the area(s): Population & Zooplankton. It has an ISSN identifier of 1129-5767. It is also open access. Over the lifetime, 1046 publications have been published receiving 20441 citations.

Climate change impacts on lakes: an integrated ecological perspective based on a multi-faceted approach, with special focus on shallow lakes

Abstract: Freshwater ecosystems and their biodiversity are presently seriously threatened by global development and population growth, leading to increases in nutrient inputs and intensification of eutrophication-induced problems in receiving fresh waters, particularly in lakes. Climate change constitutes another threat exacerbating the symptoms of eutrophication and species migration and loss. Unequivocal evidence of climate change impacts is still highly fragmented despite the intensive research, in part due to the variety and uncertainty of climate models and underlying emission scenarios but also due to the different approaches applied to study its effects. We first describe the strengths and weaknesses of the multi-faceted approaches that are presently available for elucidating the effects of climate change in lakes, including space-for-time substitution, time series, experiments, palaeoecology and modelling. Reviewing combined results from studies based on the various approaches, we describe the likely effects of climate changes on biological communities, trophic dynamics and the ecological state of lakes. We further discuss potential mitigation and adaptation measures to counteract the effects of climate change on lakes and, finally, we highlight some of the future challenges that we face to improve our capacity for successful prediction.

Freshwater autotrophic picoplankton: a review

Abstract: Autotrophic picoplankton (APP) are distributed worldwide and are ubiquitous in all types of lakes of varying trophic state. APP are major players in carbon production in all aquatic ecosystems, including extreme environments such as cold ice-covered and/or warm tropical lakes and thermal springs. They often form the base of complex microbial food webs, becoming prey for a multitude of protozoan and micro-invertebrate grazers, that effectively channel APP carbon to higher trophic levels including fish. In this review we examine the existing literature on freshwater autotrophic picoplankton, setting recent findings and current ecological issues within an historic framework, and include a description of the occurrence and distribution of both single-cell and colonial APP (picocyanobacteria) in different types of lakes. In this review we place considerable emphasis on methodology and ecology, including sampling, counting, preservation, molecular techniques, measurement of photosynthesis, and include extensive comment on their important role in microbial food webs. The model outlined by Stockner of an increase of APP abundance and biomass and a decrease of its relative importance with the increase of phosphorus concentration in lakes has been widely accepted, and only recently confirmed in marine and freshwater ecosystems. Nevertheless the relationship which drives the APP presence and importance in lakes of differing trophic status appears with considerable variation so we must conclude that the success of APP in oligotrophic lakes worldwide is not a certainty but highly probable.

The palaeogeography of Sundaland and Wallacea since the Late Jurassic

Abstract: The continental core of Southeast (SE) Asia, Sundaland, was assembled from Gondwana fragments by the Early Mesozoic. Continental blocks rifted from Australia in the Jurassic [South West (SW) Borneo, East Java-West Sulawesi-Sumba], and the Woyla intraoceanic arc of Sumatra, were added to Sundaland in the Cretaceous. These fragments probably included emergent areas and could have carried a terrestrial flora and fauna. Sarawak, the offshore Luconia-Dangerous Grounds areas, and Palawan include Asian continental material. These probably represent a wide accretionary zone at the Asia-Pacific boundary, which was an active continental margin until the mid Cretaceous. Subduction ceased around Sundaland in the Late Cretaceous, and from about 80 Ma most of Sundaland was emergent, physically connected to Asia, but separated by deep oceans from India and Australia. India moved rapidly north during the Late Cretaceous and Early Cenozoic but there is no evidence that it made contact with SE Asia prior to collision with Asia. One or more arc-India collisions during the Eocene may have preceded India-Asia collision. The arcs could have provided dispersal pathways from India into SE Asia before final suturing of the two continents. During the Late Cretaceous and Early Cenozoic there was no significant subduction beneath Sumatra, Java and Borneo. At about 45 Ma Australia began to move north, subduction resumed and there was widespread rifting within Sundaland. During the Paleogene east and north Borneo were largely submerged, the Makassar Straits became a wide marine barrier within Sundaland, and West Sulawesi was separated from Sundaland but included land. By the Early Miocene the proto-South China Sea had been eliminated by subduction leading to emergence of land in central Borneo, Sabah and Palawan. Australia-SE Asia collision began, eliminating the former deep ocean separating the two continents, and forming the region now known as Wallacea. The microplate or terrane concept of slicing fragments from New Guinea followed by multiple collisions in Wallacea is implausible. Neogene subduction drove extension and fragmentation of Wallacea that caused both subsidence of deep marine basins and elevation of land; bathymetry changed very rapidly, especially during the Pliocene, but the detailed palaeogeography of this region remains uncertain.

Mediterranean limnology: current status, gaps and the future

Abstract: The current ecosystem paradigm in limnology is represented by the cold temperate, stratifying lake and the single-channelled river. However, the variety of inland water ecosystems is much higher, and so is the ecological complexity of many of them. Most Mediterranean limnosystems are quite distinct from the contemporary limnological paradigm. This overview will deal with the striking and exciting differences between Mediterranean and other temperate limnosystems. For example, most are very small, their catchment area is much larger than their size, and they experience both a longer vegetation period and a strong seasonality in water supply which occurs outside the hot season, often from groundwater sources. In addition, we encourage research on the often poorly known limnological processes taking place in Mediterranean regions by pointing at insufficiently covered research fields. Furthermore, competition for water among different users, arising from population increase in fertile and/or tourist areas, is certainly limiting the ability of many Mediterranean limnosystems to survive at present and in the near future, particularly in the face of the harsher environmental conditions that climatic change is triggering. A new paradigm on Mediterranean limnology is thus necessary. This will enable us to predict and mitigate more accurately the unstoppable effects of man-made change in these beautiful and still largely ignored ecosystems.

Survival strategies of freshwater insects in cold environments

Abstract: At high latitudes and altitudes, ice formation is a major variable affecting survival of freshwater fauna and hence the abundance and composition of invertebrate communities. Freezing, but also desiccation and anoxia, are lethal threats to all life stages of aquatic insects, from the eggs to the adults. During cold periods, the aquatic stages commonly remain in or move to a portion of the water body that will not freeze or dry (e.g., deep waters of lakes, springs and hyporheic zone) where they can remain active. Less frequently they migrate to habitats that will freeze at the onset of winter. Insects have developed a complex of strategies to survive at their physiological temperature minimum, comprising (a) morphological (melanism, reduction in size, hairiness/pubescence, brachyptery and aptery), (b) behavioural (basking in the sun, changes in feeding and mating habit, parthenogenesis, polyploidy, ovoviviparity, habitat selection and cocoon building), (c) ecological (extension of development to several years by quiescence or diapause and reduction of the number of generations per year), (d) physiological and biochemical (freezing tolerance and freezing avoidance) adaptations. Most species develop a combination of these survival strategies that can be different in the aquatic and terrestrial phase. Freezing avoidance and freezing tolerance may be accompanied by diapause. Both cold hardiness and diapause manifest during the unfavourable season and: (i) involve storage of food resources (commonly glycogen and lipids); (ii) are under hormonal control (ecdysone and juvenile hormone); (iii) involve a depression or suppression of the oxidative metabolism with mitochondrial degradation. However, where the growing season is reduced to a few weeks, insects may develop cold hardiness without entering diapause, maintaining in the haemolymph a high concentration of Thermal Hysteris Proteins (THPs) for the entire year and a slow but continuous growth. A synthesis of literature regarding adaptation strategies in aquatic insects is presented, highlighting the scarcity of information on freshwater insects from Alpine regions. Most references are on Diptera Chironomidae from North America and North Europe. Some recent findings on aquatic insects from Italian Alpine streams are also presented.