Effects of the Invasive Freshwater Mussel Limnoperna fortunei on Sediment Properties and Accumulation Rates

Since its introduction into South America around 1990, the freshwater bivalve Limnoperna fortunei (the golden mussel) has spread rapidly and is now a dominant component of the benthic and periphytic fauna in many rivers, lakes, and reservoirs. Sizable impacts of this nonindigenous species on nutrient recycling, plankton abundance and composition, and trophic relationships with fishes have been reported, but its effects on the sediments have received little attention. In this work, we use eighteen 20-L flow-through experimental units with and without mussels where changes in the mass and characteristics of the sediments accumulated throughout a yearly cycle in monthly, biannual, and annual intervals are analyzed. Experimental units with mussels yielded almost 2 times more sediments than units without mussels and contained significantly higher loads of organic matter and total N. Total P was not affected by the presence of mussels. Sediments accumulated in the biannual and annual experimental units agreed well with the yields of the monthly units, but the vertical stratification of organic matter, N, and P was unpatterned. Seasonal changes in the volume of total sediments, biodeposits, and their organic matter and N contents were positively associated with ambient water temperature and with intermediate (~150–250 NTU, nephelometric turbidity units) turbidity. Our results suggest that ecosystem-wide modifications in the living conditions of the benthic epifaunal and infaunal organisms in waterbodies invaded by the mussel are likely significant, although variable locally, regionally, and across taxa.Fil: Tokumon, Romina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Boltovskoy, Demetrio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Cataldo, Daniel Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin

Identification of ChIP-seq mapped targets of HP1β due to bombesin/GRP receptor activation

Epithelial cells lining the adult colon do not normally express gastrin-releasing peptide (GRP) or its receptor (GRPR). In contrast, GRP/GRPR can be aberrantly expressed in human colorectal cancer (CRC) including Caco-2 cells. We have previously shown that GRPR activation results in the up-regulation of HP1β, an epigenetic modifier of gene transcription. The aim of this study was to identify the genes whose expression is altered by HP1β subsequent to GRPR activation. We determined HP1β binding positions throughout the genome using chromatin immunoprecipitation followed by massively parallel DNA sequencing (ChIP-seq). After exposure to GRP, we identified 9,625 genomic positions occupied by HP1β. We performed gene microarray analysis on Caco-2 cells in the absence and presence of a GRPR specific antagonist as well as siRNA to HP1β. The expression of 97 genes was altered subsequent to GRPR antagonism, while the expression of 473 genes was altered by HP1β siRNA exposure. When these data were evaluated in concert with our ChIP-seq findings, 9 genes showed evidence of possible altered expression as a function of GRPR signaling via HP1β. Of these, genomic PCR of immunoprecipitated chromatin demonstrated that GRPR signaling affected the expression of IL1RAPL2, FAM13A, GBE1, PLK3, and SLCO1B3. These findings provide the first evidence by which GRPR aberrantly expressed in CRC might affect tumor progression

Drivers of Cyanobacterial Blooms in a Hypertrophic Lagoon

The Curonian Lagoon is Europe's largest lagoon and one of the most seriously impacted by harmful blooms of cyanobacteria. Intensive studies over the past 20 years have allowed us to identify the major drivers determining the composition and spatial extent of hyperblooms in this system. We summarize and discuss the main outcomes of these studies and provide an updated, conceptual scheme of the multiple interactions between climatic and hydrologic factors, and their influence on internal and external processes that promote cyanobacterial blooms. Retrospective analysis of remote sensed images demonstrated the variability of blooms in terms of timing, extension and intensity, suggesting that they occur only under specific circumstances. Monthly analysis of nutrient loads and stoichiometry from the principal tributary (Nemunas River) revealed large interannual differences in the delivery of key elements, but summer months were always characterized by a strong dissolved inorganic N (and Si) limitation, that depresses diatoms and favors the dominance of cyanobacteria. Cyanobacteria blooms occurred during high water temperatures, long water residence time and low-wind conditions. The blooms induce transient (night-time) hypoxia, which stimulates the release of iron-bound P, producing a positive feedback for blooms of N-fixing cyanobacteria. Consumer-mediated nutrient recycling by dreissenid mussels, chironomid larvae, cyprinids and large bird colonies, may also affect P availability, but their role as drivers of cyanobacteria blooms is understudied

The termination of employment contracts due to gross breach of labour duties whereas encroaching on the labour treatment (pursuant to item 8, 9, 10, part 2, art. 235 of labour code of the republic of lithuania)

Summary The Termination of Employment Contracts Due to Gross Breach of Labour Duties whereas Encroaching on the Labour Treatment (Pursuant to Item 8, 9, 10, part 2, art. 235 of Labour Code of the Republic of Lithuania) The Paper presents review of the grounds for termination of an employment contract without notice in case of gross breach by an employee of work duties as provided for in Paragraphs 2(8), (9), and (10) of Article 235 of the Labor Code. The indicated paragraphs have been reviewed from the legal as well as historical point of view, and compared with other labor relations-regulating national legal acts as well as legal acts of neighboring countries. The Paper also contains analysis of the gross breach associated civil cases which were subject to hearing at the Supreme Court of Lithuania, and indicates the problems and drawbacks associated with termination based on the indicated grounds. In addition, the Paper considers correlation of the cases of collective redundancies and individual termination under the 20th July 1988 EU Directive No. 98/59, as well as the specifics of termination of employees of certain categories for gross breaches of labor discipline in comparison with norms regulated by the Labor Code. The Paper underlines the main criteria based on which an employee may be terminated without notice in case of gross breach of labor discipline as provided for in Paragraphs 2 (8), (9), and (10) of Article 235 of the Labor Code: 1. Paragraph 2(8) of Article 235 of the Labor Code - where, during the working time, the employee is under the influence of alcohol, narcotic or toxic substances, with the exception of cases where intoxication was caused by the industrial processes at the enterprise: - fact of alcohol influence determined; - an employee is under the influence of alcohol during work hours; - an employee is under the influence of alcohol in his/her work place (i.e. in his/her workplace or other place where he/she is obliged to stay for performance of the job functions or employer’s assignments). 2. Paragraph 2(9) of Article 235 of the Labor Code - absence from work throughout the day/shift without any substantial cause: - an employee is absent from work throughout the day (shift); - absence is not due to any substantial cause. 3. Paragraph 2(10) of Article 235 of the Labor Code - refusal to undergo a medical examination where such examinations are obligatory: - an employee is assigned to a category where medical examinations are obligatory; - an employee was included in the employer-approved list of employees with obligatory health examinations; - an employee was acquainted by signing with medical examinations schedule coordinated by an employer with a health care institution; - an employee refuses to timely (as established) undergo a medical examination. If one of the above facts having legal significance is not determined, the termination of an employment contract on the indicated grounds shall be considered as illegal. Legal relations applicable to the public service are the legal relations between public servants and the state being an employer with respect to such persons. Therefore, public service associated legal relations are not identical to the labor relations between an employee, not a public servant, and an employer. It should be noted that today the legal practice of termination on the described grounds is not well-established. The problem has not been completely analyzed and considered. Nearly all norms analyzed in the Paper are new in the labor law, and therefore the subject of this paper is relevant

Household savings and uncertainty in baltic countries.

The aim of this thesis is to assess the relationship between household saving rates and uncertainty in the Baltic countries. For this purpose, theoretical and empirical analysis is undertaken. Appropriately, in the literature review, the major consumption theories, precautionary saving motives and saving in Baltic countries have been revised. An examination of a theoretical model, proving the necessity of precautionary savings was undertaken. Later, an uncertainty variable for GDP volatility is constructed using GARCH methodology. Based on the literature and theoretical results, an econometric model estimating the household saving rates for Baltic countries for the period of 2000-2019 was employed. The results, based on country fixed and random effect models indicate, that precautionary savings exist for the Baltic countries, in addition with housing prices, which have high explanatory power for saving rates. However, further analysis including time fixed effects provides results that cast doubt on the significance of uncertainty on saving. This outcome suggests that saving rates might be time-related and time fixed effects should be included for precautionary saving regressions. For future research it is recommended to use different variables of uncertainty and to reiterate the thesis work later with more time periods

The distribution of carbon stable isotopes as an indicator of temporal and spatial dynamic and distribution of autochtonic and allochtonic organic matter in a shallow estuarine lagoon

Physical and chemical parameters were measured in a mostly freshwater estuarine lagoon in the SE Baltic. Present paper demonstrates an attempt to trace the sources and analyse the seasonal and spatial patterns of distribution of   POC, DIC and DOC in the Curonian lagoon mostly by the isotopic content in different forms of carbon. Samples were collected in 2012-2014 in 9 stations in the Curonian lagoon including riverine and marine input/output stations. Riverine inputs and summarizing outflow to the Baltic sea locations (Nemunas river delta and Klaipeda channel stations were sampled monthly, while  POC, DIC and DOC samples in other stations were collected on a seasonal basis.  The observed results allow easily differentiate between estuarine and riverine POM samples, while the differences in DOC δ13C content between sampling stations were found to be not statistically reliable.  The high biological productivity of the Nemunas river along with the minor contribution of the Baltic Sea inflows to the overall hydrodynamics of the lagoon explain similarity of content between riverine and estuarine material in the spring and autumn.  However, the δ13C content of DIC and DOC could serve as indicator of external inputs only in connection with seasonal water residence variations.DOI: 10.15181/csat.v3i1.1132</p

Phosphorus Cycling in a Freshwater Estuary Impacted by Cyanobacterial Blooms

The availability of reactive phosphorus (P) may promote cyanobacterial blooms, a worldwide increasing phenomenon. Cyanobacteria may also regulate benthic P cycling through labile organic input to sediments, favouring reduced conditions and P release, ultimately acting as self-sustainment mechanism for the phytoplankton blooms. To analyse P–cyanobacteria feedbacks and compare external versus internal loads, we investigated P cycling in the Curonian Lagoon, a freshwater estuary with recurrent summer blooms. At two sites representing the dominant sediment types, we characterised P pools and mobility, via combined pore water analysis, calculation of diffusive exchanges and flux measurements via sediment core incubations. Annual P budgets were also calculated, to analyse the whole lagoon role as net sink or source. Muddy sediments, representing nearly 50 % of the lagoon surface, displayed higher P content if compared with sandy sediments, and most of this pool was reactive. The muddy site had consequently higher pore water dissolved inorganic phosphorus (DIP) concentrations maintaining high diffusive gradients. However, measured fluxes suggested that both sediment types were mostly P sinks except for a large DIP regeneration (nearly 30 μmol m−2 h−1) recorded at the muddy site during an intense cyanobacteria bloom. Such internal regeneration had the same order of magnitude as the annual external P load and may offset the net annual DIP sink role of the estuary. It may also prolong the duration of the bloom. Our results suggest that positive feedbacks can regulate N-fixing cyanobacteria blooms and internal P recycling, through either diffusive fluxes or sediment settling and resuspension