| Title |
Long - term dynamics of zooplankton abundance in relation to environmental conditions and phytoplankton biomass / |
| Translation of Title |
Ilgalaikiai zooplanktono kiekio pokyčiai ir jų sąryšis su aplinkos sąlygomis bei fitoplanktono biomasės pokyčiais. |
| Authors |
Grublytė, Živilė |
| Full Text |
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| Pages |
73 |
| Keywords [eng] |
Planktonas, fitoplanktonas, laiko eilutės, Baltijos jūra, Vakarų Baltijos jūra Plankton, phytoplankton, time series, Baltic Sea, Western Baltic Sea. |
| Abstract [eng] |
Plankton organisms are useful bioindicators which can provide information whether changing environmental conditions have an influence on marine ecosystems. Previous phytoplankton trends studies from the Mecklenburg Bight covered only the period from 1979 until 2005. Moreover, there are no comprehensive studies of zooplankton trends in the Western Baltic Sea yet available. Therefore, this study focuses on plankton abundance trends during 1998-2016 in the Mecklenburg Bight (Western Baltic Sea). Decreasing and increasing trends were detected using Mann-Kendall test and associated with changing environmental conditions based on Spearman correlation coefficient values. In addition, non-metric multidimensional scaling was used to detect unusual years in order to identify anomalies of plankton abundance that are associated with environmental variability. The results of this study indicate that shifts in plankton communities in 2013 can be associated with an exceptionally cold March this year. It is likely that environmental conditions during the bloom season might have the highest influence on plankton abundance. Comparison of phytoplankton biomass trends in 1998-2016 with those detected until 2005 in the Mecklenburg Bight revealed some changes which occurred due to increasing surface water temperature. Due to the salinity gradient in the Baltic Sea, decreasing zooplankton trends of species susceptible to water freshening in the Southern and Southeastern Baltic Sea (e.g. Evadne nordmanni and Pseudocalanus) were not identified in the Western Baltic Sea. However, long-term trend analysis revealed that similar zooplankton abundance trends as in other Baltic Sea areas are detected when they are associated with increasing water temperature (e.g. T. longicornis, C. hamatus, and Acartia species). Overall observed trends during the last two decades indicate significant shifts in the Mecklenburg Bight ecosystem which are related to changes in environmental conditions there. |
| Dissertation Institution |
Vilniaus universitetas. |
| Type |
Master thesis |
| Language |
English |
| Publication date |
2021 |
