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A decade of Primary Productivity in Wadden Sea from MERIS: The effects of ancillary climate variables

Golmohammadi, Maryam (2013) A decade of Primary Productivity in Wadden Sea from MERIS: The effects of ancillary climate variables.

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Abstract:Marine primary productivity is a process by which inorganic matters convert to organic materials with the help of CO2 and light through photosynthesis. In current research, we tried to lead two main objectives. The preliminary step is to provide a satellite-based quantification of long-term Primary Production (PP) which has been done as the first attempt for the entire coastal area of Wadden Sea (WS) as well as 4 West Frisian Islands (WFIs). Vertically Generalized Production Model (VGPM) was utilized to determine the spatially and temporally oscillation of Depth Integrated PP from Jan-2003 till Mar-2012 with the help of MERIS and MODIS ocean products. Short-term investigation demonstrates that WS daily PP varies between 0.12 to 13.4gC.m-2d-1 which occurred in Oct-2003 and May-2008 respectively. Between 2003 and 2012, monthly PP was estimated in the range of 9.81 and 0.28gC m-2d-1 which in sequence recorded in Jun-2004 and Nov-2008 for the Wadden Sea region. Long-term oscillation of primary production presents a year to year cyclic seasonally pattern in such a way that the peaks and falls in biomass growth rate respectively occurred in summer (for 2011 it appears in spring) and winter (it happened in autumn for the year 2008). Two strong blooms of spring and summer were detected for Texel and Ameland which happened late in June and in August respectively while similar to WS, Vlieland and Terschelling experienced only one summer bloom between July and August. Decadal weighted average was computed about 122.8gC m-2y-1 for the Wadden Sea whereas for WFIs it is appeared more or less than 70gC m-2y-1. This difference illustrates the cumulative effect of Greman and Danish productivity on total pp. No harmonic trend was detected between productivity variations starting from 2003 to 2012. The year 2008 was highlighted as the highest value of total PP less than 190gC m-2y-1. 10 years tracing of primary production shows lowest amount of productivity in cold seasons as a result of more rainfall, runoff and more sediment loads which flows into the sea through neighbor rivers and streams. These suspended materials then limit the penetrated light and reduce the euphotic zone. According to spatial distribution of PP, WS showed higher amount of productivity than WFIs, since it consists of German and Danish coasts rather than Dutch region. German coasts represented relatively high variability during a decadal observation. Along with this, Texel labelled as the most temporally variable area with the daily coefficient of variation about 68% since it is affected by nutrient loads of Marsdiep inlet and Lake Ijsselmeer. However the direct and indirect effect of North Sea on physical and biological variability of Wadden Sea coastal area should be taken into account. As the second goal of this research, we identified the plausible consequences of two ancillary climate variables (SST & PAR) on marine chlorophyll concentration. Statistical analysis shows an inverse (negative slope) but strong (0.56≤R2≤0.74) relationship between physical parameters and biomass activities in the coasts of WS. As such, whenever Chl_a concentration rises as a reason of tidal mixed-layer growing caused by North Sea severe flows toward the inner parts of WS, SST and PAR decreases by less temperature and light in early winter. Finally, it is concluded that the determined ancillary climatic variables are not perfectly able to reflect the marine biological responses since they might be strongly controlled by other dominant factors which should be investigated by further studies.
Item Type:Essay (Master)
Faculty:ITC: Faculty of Geo-information Science and Earth Observation
Programme:Geoinformation Science and Earth Observation MSc (75014)
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