New species of Uroglena and Ochromonas (Chromulinales, Chrysophyceae) from Estonia

During the spring of 2003 ninety-five water bodies in southeastern Estonia were surveyed for chrysophytes. The sampling was carried out as the ice broke up, when, within two weeks, the water temperature rose from 3 degrees C to 13 degrees C. Large lakes to small pools of different water chemistry were investigated. The plankton collected was studied alive within a few hours after sampling. Preparations for scanning electron microscopy (SEM) were made from fresh samples and later also from material preserved in Lugol's solution. About 95% of the water bodies contained chrysophytes. Species belonging to the genera Chrysosphaerella, Dinobryon, Mallonionas, Synura, Ochromonas, Paraphysomonas, Spiniferomonas, Uroglena and Uroglenopsis were recorded. The genus Uroglena was frequent and recorded in 30% of the localities studied. Mass development of different Uroglena species was found in several waterbodies. Many populations had developed stomatocysts (statospores, cysts) of different morphology, and, using LM, smooth stomatocysts and stomatocysts with long spines could be recognised. However, using SEM, it was shown that also the smooth stomatocysts had short spines. Four new species of Uroglena were found and are described here. Uroglena estonica and U. spinosa had long spines while U. kukkii and U. pikamae had very short spines. In addition, mass development of stomatocysts of an Ochromonas was recorded in two lakes. This species had similarities with Ochromonas stellaris, but differed in stomatocyst ornamentation, and is also described as a new species, O. magnifica

Aboriginal men carrying weapons in ceremonial dancing, Wahgunyah Region, Victoria, 1881 /

Title devised by cataloguer based on acquisitions documentation.; Seven men wearing body paint and holding an assortment of boomerangs, shields and axes.; In: Sketchbook of Aboriginal daily life scenes, Wahgunyah Region, Victoria, 1881.; Condition: Spotting, yellowing.; Also available online at: http://nla.gov.au/nla.pic-vn6220709-s5

Analysis of Changes Over 44 Years in the Phytoplankton of Lake Võrtsjärv (Estonia): The effect of Nutrients, Climate and the Investigator on Phytoplankton-Based Water Quality Indices

We analysed long-term changes in phytoplankton composition in relation to hydrological, meteorological and nutrient loading data in the large (270 km2) shallow (mean depth 2.8 m) Lake Vortsjarv. Nutrient loads to the lake were heavy in the 1970s and 1980s and decreased considerably thereafter. The average nutrient concentrations for 1985-2004 (1.6 mg l-1 of total nitrogen and 53 ug l-1 of total phosphorus) characterize the lake as a eutrophic water body. All four calculated taxonomic indices showed a unidirectional deterioration of the lakes ecological status, despite reduced concentrations of nutrients. We focused our analysis on the PTSI index, which revealed a stepwise change between the years 1977 and 1979 that coincided with a large increase in water level, but also with a change of investigator. After correcting input data for possible investigator-induced differences, the step change remained because it was caused by major changes in the whole phytoplankton community. The previous dominant Planktolyngbya limnetica was replaced by two species of seasonally altering Limnothrix. Among phytoplankton functional groups, there was a decrease in all groups comprising smallsized phytoplankton species, such as X1, E, F, J, N and an increase in S1 and H1, both represented by filamentous cyanobacteria. Our results suggest a non-linear response of phytoplankton to changing nutrient loadings, and that the change observed between 1977 and 1979 was a regime shift triggered by water level change. High shade tolerance of the new dominants, and their ability to create shade, obviously stabilized the new status making it resistant to restoration efforts.JRC.H.1-Water Resource

Is the Destabilisation of Lake Peipsi Ecosystem Caused by Increased Phosphorus Loading or Decreased Nitrogen Loading?

Lake Peipsi (3,555 km2, mean depth 7.1 m) located on the border of Estonia and Russia is the largest transboundary lake in Europe. L. Peipsi consists of three parts. The shared largest northern part L, Peipsi s.s. (2,611 km2, 8.3 m) and the southern L. Pihkva (708 km2, 3,8 m) which belongs mainly to Russia al:e connected by the river-shaped L. Liimmijiirv (236 km2, 2.5 m). The catchment area (44,245 km2 without lake area) is shared between Estonia (33,3%), Russia (58.6%) and Latvia (8%). Intensive eutrophication of L. Peipsi started in the 1970s. The biomass of N2-fixing cyanobacteria was low at heavy nutrient loading in the 1980s. After the collapse of soviet-type agriculture in the early 1990s, the loading of nitrogen sharply decreased. A certain improvement of L. Peipsi s.s. was noticed at the beginning of the 1990s together with the temporary reduction of phosphorus loading from Estonian catchment while in recent years a destabilisation of the ecosystem has been observed. This deterioration has been expressed mainly as intensive blue-green blooms and fish-kills in summer. Reappearance of blooms has been explained by the decrease in NIP loading ratio due to reduced N discharge while in some periods increased phosphorus loading could have supported this trend. Keywords Cyanobacterial blooms; nutrient loading; transboundary lakeJRC.H.5-Rural, water and ecosystem resource

Consequences of Catchment Processes and Climatic Changes on the Ecology Status of Large Shallow Temperate Lakes

Riverine transport is the most important pathway for the input of nutrients into two large shallow nonstratified lakes Peipsi (3 555 km2, mean depth 7.1 m) and Võrtsjärv (270 km2, mean depth 2.8m) in Estonia . In the 1980s, the riverine discharge of nutrients increased drastically while in the early 1990s a sharp decrease occurred, first of all in TN loadings caused mainly by the collapse of the extensive type of agriculture. The ecosystem of L. Võrtsjärv is very sensitive to water level fluctuations which are following the pattern of North Atlantic Oscillation index (NAO) refelecting the changes of climate in northern hemisphere. In L. Võrtsjärv high phosphorus concentration and better light availability are the main concequences of low water level bringing about higher phytoplankton density and deteriorated water quality. In deeper L. Peipsi the direct influence of the water level is not so obvious and the effect of climate realizes through nutrient loading, temperature and wind.JRC.H.5-Rural, water and ecosystem resource

Phylogeography of the freshwater raphidophyte Gonyostomum semen confirms a recent expansion in northern Europe by a single haplotype

Gonyostmum semen is a freshwater raphidophyte that has increased in occurrence and abundance in several countries in northern Europe since the 1980s. More recently, the species has expanded rapidly also in north-eastern Europe, and it is frequently referred to as invasive. To better understand the species history, we have explored the phylogeography of G. semen using strains from northern Europe, United States, and Japan. Three regions of the ribosomal RNA gene (small subunit [SSU], internal transcribed spacer [ITS] and large subunit [LSU]) and one mitochondrial DNA marker (cox1) were analyzed. The SSU and partial LSU sequences were identical in all strains, confirming that they belong to the same species. The ITS region differentiated the American from the other strains, but showed high intra-strain variability. In contrast, the mitochondrial marker cox1 showed distinct differences between the European, American, and Japanese strains. Interestingly, only one cox1 haplotype was detected in European strains. The overall low diversity and weak geographic structure within northern European strains supported the hypothesis of a recent invasion of new lakes by G. semen. Our data also show that the invasive northern European lineage is genetically distinct from the lineages from the other continents. Finally, we concluded that the mitochondrial cox1 was the most useful marker in determining large-scale biogeographic patterns in this species