Managing Eutrophication in the Szczecin (Oder) Lagoon-Development, Present State and Future Perspectives

High riverine nutrient loads caused poor water quality, low water transparency and an unsatisfactory ecological status in the Szczecin (Oder) Lagoon, a trans-boundary water at the southern shore of the Baltic Sea. Total annual riverine N (P) loads into the lagoon raised at the 20th century from approximately 14,000 t TN (1,000 t TP) to 115,000 t TN (10,500 t TP) in the 1980ties and declined to about 56,750 t TN (2,800 t TP) after 2010. Nutrient concentrations, water transparency (Secchi depth) and chlorophyll-a showed a positive response to the reduced nutrient loads in the Polish eastern lagoon. This was not the case in the German western lagoon, where summer Secchi depth is 0.6 m and mean chlorophyll-a concentration is four times above the threshold for the Good Ecological Status. Measures to improve the water quality focused until now purely on nutrient load reductions, but the nutrient load targets and Maximal Allowable Inputs are contradicting between EU Water Framework Directive and EU Marine Strategy Framework Directive. According to the HELCOM Baltic Sea Action Plan, the thresholds of the annual riverine nutrient inputs to the lagoon would be about 48,850 t N (1,570 t P). Actions in the river basins that would allow meeting these targets are hardly achievable. Even if the load targets would be fully implemented, they are not sufficient to transfer the lagoon into a non-eutrophic state. The implementation of EU Water Framework Directive is further hampered, as consistent water quality thresholds for the two parts of Szczecin Lagoon are missing. An approach to harmonize them is presented, which incorporates the spatial differences. By implementing consistent water quality targets, Szczecin Lagoon could serve as blueprint for other trans-boundary waters. In the western lagoon, nutrient load reductions in the past decades had no effect on the water quality. High water residence times, frequent sediment resuspension and the missing submerged vegetation inhibit the load reduction effects on the water quality. Internal measures in the western lagoon are necessary, which aim at removing nutrients and increasing water transparency to overcome the hysteresis effect and to initiate a recovery of macrophytes. Cultivation of zebra mussels seems the most promising approach

Managing Eutrophication in the Szczecin (Oder) Lagoon-Development, Present State and Future Perspectives

publishedVersio

Managing Eutrophication in the Szczecin (Oder) Lagoon-Development, Present State and Future Perspectives

publishedVersio

Effect of an intronic variant within Zinc finger protein 384 gene on pre-mRNA splicing in a Maltese family with osteoporosis

INTRODUCTION: Osteoporosis is a skeletal disease with a strong genetic basis. A study on an extended Maltese family with a highly penetrant form of osteoporosis, revealed the presence of the rs146089604 variant (c.686+32G>A) in intron 7 of the Zinc finger protein 384 (ZNF384) gene, predicted to affect pre-messenger RNA (mRNA) splicing. The aim of this study was to assess the functional effect of the variant using an exon-trapping vector transfected in three human cell types.METHODS: The target DNA region harbouring G or A allele was inserted in the p.SPL3 vector, creating mini-gene constructs that were transfected in human kidney-derived cells (HEK-293) and two human osteoblasts-derived cells (SaOS-2 and h-FOB). Extracted mRNA was converted into complementary DNA (cDNA), amplified by PCR and sequenced to determine the transcript size and identify any splicing variants.RESULTS: Mini-gene construct with the alternative A allele lead to exon 8 and part of intron 8 to be retained, both of which were spliced off in the presence of the G allele. These results were observed for constructs transfected in the osteoblasts-derived cell lines. In HEK-293 cells, no difference in transcript size was seen for the G or A allele, suggesting different splicing mechanisms.CONCLUSION: Observations may indicate that the ZNF384 rs146089604 could be a causal variant contributing to osteoporosis. ZNF384 transactivates type I collagen and matrix metalloproteinases, and suppresses bone morphogenic protein (BMP) and Wnt signalling resulting in reduced bone volume and strength. Thus, impaired ZNF384 splicing could alter the protein’s function affecting bone homeostasis.peer-reviewe