Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 5

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
EN
Eutrophication of the Baltic Sea is considered a major threat to its ecological status. We present and discuss Polish riverine flow normalized loads of total nitrogen (TN) and total phosphorus (TP) discharged into the Baltic Sea in (i)1988–2014, (ii) periods of maximum TN (1992–1994), TP (1988–1991) emission, (iii) the reference period (1997–2003) established by the Helsinki Commission (HELCOM), (iv) 2012–2014, last years of our study. Despite considerable nutrient load reductions prior to the HELCOM reference period, Poland is expected to reduce TN and TP loads by 30% and 66%, respectively. In the light of our historical and up-to-date findings defining ecological status of the Baltic Sea, we suggest that the proposed TP load reduction is overestimated and its realization may lead to (i) undesirable consequences for the Baltic ecosystem, (ii) would require a decline in TP concentrations to 0.067 mg P dm-3 (the Vistula River) and 0.083 mg P dm-3 (the Oder River), values reported for pre-industrial times. The current nutrient concentrations in the Vistula and Oder safely comply with the requirements of the Water Framework Directive. We also comment on the top-down and bottom-up effect resulting in quantitative and qualitative reorganization of the Baltic ecosystem, a phenomenon already observed in the Baltic Sea.
EN
An attempt is made to use long-term (1979-2014) macrobenthos data series to derive insights on changes in abiotic conditions and on potential effects of long-term macrobenthos variability on food availability for fish and wintering waterfowl. The data were collected from a small embayment, protected as a NATURA 2000 area, functioning as a fishing ground important for the local community and as a site of diverse commercial developments. The analysis showed a drastic reduction of the macrobenthos abundance and biomass, which could have been related to oxygen deficiency; on the other hand, recolonisation processes have also been observed.
EN
Information on distribution of the bivalve Rangia cuneata in the Polish part of the Vistula Lagoon is presented. The species, first recorded in the Lagoon in 2010, has since rapidly colonized almost the entire basin. The distribution and population structure of the species have been studied in the Polish part of the Lagoon since 2012. Preliminary results on distribution and size structure of the population highlight extensive fluctuations in 2012–2014. A drastic reduction in the abundance following the relatively long winter of 2012/2013 suggests that the winter oxygen deficiency associated with the ice cover could be critical for the population development. Potential effects of the new invasive bivalve on the structure of benthic habitats and macrozoobenthos communities are discussed.
EN
The new method of a detailed morphodynamic registration of sandy beaches has been presented. The digital oriented photograms have been taken from a stabilised point at least once a day. Occasionally also more often, for example every hour during a storm cycle. The analyses of the photograms are performed in digital mode using special computer software. This digital beach monitoring of the Polish Baltic coast was initiated in summer 2002. The test fields in Polanka Redłowska within Gdynia and Chłapowo near Władysławowo were selected. The beach areas of the length of about 200 m along the shore were registered there. Selected examples of short-term changes of the beach relief were presented. A range of spatiotemporal transformations related to different periods (hours, days, months etc.) was demonstrated.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.