|Several aspects of nutrients dynamics in seagrass plants (Zostera marina L.), and their environment in the south west Netherlands|
Muchtar, M. (1989). Several aspects of nutrients dynamics in seagrass plants (Zostera marina L.), and their environment in the south west Netherlands. MSc Thesis. VUB: Brussel. 67 pp.
|Available in|| Author |
- VLIZ: Archive VLIZ ARCHIVE A.THES18 
- VLIZ: Non-open access 228454
|Document type: Dissertation|
This thesis reports some methodological findings concerning the study of nutrients (silica, phosphate, nitrate and ammonium) in seagrass beds. -Silica concentration measured by two Gavimetric methods: method I use hydrochloric acid (silica + sand) and method II use hydrochloric acid and ammonium fluoride (silica only) were compared in order to find out which method is most accurate.-The main subject of this investigation was the comparison of two sampling methods for determination of nutrient concentrations in pore water: corer and in situ sediment sipper method. The influence of time on nutrient concentrations measured in sipper samples was also studied.-Thirdly, this investigation also studied the phosphorus and nitrogen budget of the seagrass environment in the South West Netherlands. The period of research was January-June, 1989 on location Zandkreek and Grevelingen lagoon. Phosphate, nitrate and ammonium concentration in pore water and in sea water were analyzed by using a Technicon and Skalar auto analyzer. Nitrogen concentration in plant materials were analyzed using a Carlo Ebra 1500 Nitrogen/Carbon analyzer, while the total phosphate in the plant material was analyzed by using a spectrophotometer. Generally, the silica concnetration measured using method I is higher than silicate concentration measured with method II.The percentage recovery of pure silica is lower than 100% in both methods. More research is needed to develop the right method. Considering all results obtained from different sediment layers togehter, no significant differences were measured in concentrations of phosphate, nitrate and ammonium when using the corer or the sipper sampler (ANOVA, p<0,05). Results obtained by using the sity sediment sipper sampler at time intervals during 24 hours are constant. The variation between place to place or between time to time may be due to different factors: analytical technique, sampler used, sampling procedure in the field and spatial heterogenity. A phosphorus and nitrogen budget was made using the June data for Grevelingen lagoon. Concentrations of phosphate and nitrate in the seagrass bed occurred mainly as particulate detritus in the sediments (90% of P and 79% of N). Only 9,5% of P and 20,4% of N was found in the plants while less than 1% of these nutrients was found in water and in pore water