PANGAEA_992559 Macroalgae biomass, epiphytic biomass on seagrass and phytoplankton biomass in Changuu Island (Zanzibar Archipelago, Tanzania) at end of nutrient enrichment and macrofauna exclusion experiment Moreira-Saporiti, Agustín; Teichberg, Mirta; O'Sullivan, Aoife Macroalgae biomass, epiphytic biomass on seagrass and phytoplankton biomass in Changuu Island (Zanzibar Archipelago, Tanzania) at end of nutrient enrichment and macrofauna exclusion experiment 2026-04-09 PANGAEA Dataset https://doi.pangaea.de/10.1594/PANGAEA.992559 Investigator Agustín Moreira-Saporiti am.saporiti@gmail.com Earth Science Event label Sampling date/time, experiment Day of experiment LATITUDE LONGITUDE Site Station label Experimental treatment Treatment: nutrients Biomass, live, dry weight Chlorophyll a Type of study geoscientificInformation Changuu_C1_T3 Changuu_C10_T3 Changuu_C11_T3 Changuu_C12_T3 Changuu_C13_T3 Changuu_C14_T3 Changuu_C15_T3 Changuu_C16_T3 Changuu_C17_T3 Changuu_C18_T3 Changuu_C19_T3 Changuu_C2_T3 Changuu_C20_T3 Changuu_C21_T3 Changuu_C22_T3 Changuu_C23_T3 Changuu_C24_T3 Changuu_C3_T3 Changuu_C4_T3 Changuu_C5_T3 Changuu_C6_T3 Changuu_C7_T3 Changuu_C8_T3 Changuu_C9_T3 Chlorophyll a epiphytes Macroalgae Phytoplankton Sampling by hand Seagrass tropical seagrass Western Indian Ocean GPS in field 2017-09-19 2017-09-19 Complete -6.118093 -6.117863 39.16728 39.167509 SEAMAC Seagrass and Macroalgal Community Dynamics and Performance under Environmental Change SEATRAIT Seagrass Ecosystem Service Evaluation using a Trait-based Approach unrestricted CC-BY-4.0: Creative Commons Attribution 4.0 International English PANGAEA Data Publisher for Earth & Environmental Science https://www.pangaea.de/ Data Center Contact Michael Diepenbroek info@pangaea.de

Leobener Str.

Bremen Bremen 28359 Germany online 240 data points text/tab-separated-values Moreira-Saporiti, Agustín; Teichberg, Mirta; O'Sullivan, Aoife (2026): Mesofauna density in seagrass meadows of Changuu Island (Zanzibar Archipelago, Tanzania) during nutrient enrichment and macrofauna exclusion experiment [dataset]. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.992558

Macroalgae biomass, epiphytic biomass on seagrass and phytoplankton biomass in the water column was taken at the end of a nutrient enrichment and macrofauna exclusion experiment. A total of 24 plots were set up parallel to the shore, with presence of the three seagrass species (Syringodium isoetifolium, Thalassodendron ciliatum and Thalassia hemprichii) in each plot. The experiment was the factorial combination of two treatments: macrofauna exclusion using cages (three levels: open, closed and uncaged) and nutrient enrichment using garden NPK fertilizer (two levels: ambient and enriched). Each treatment combination was replicated four times. Exclusion treatment simulates the consequences for the food web of losing a top predators and macrograzers. Nutrient enrichment was simulated by issuing nitrogen-phosphorus-potassium (NPK) [15:9:20] fertilizer pellets. NPK fertilizer fast release pellets were packed into cotton tubes and then into a perforated plastic tubes to simulate slow release of nutrients. The tubes were buried half-way into the sediment to ensure enrichment of both the water column and the sediment. Data was collected at the end of the experiment (Day 63, 19.09.2017). Data collection and experiment took place in Changuu Island (Zanzibar Archipelago, Tanzania; 06˚11'S, 39˚16'E). Changuu Island is located 3 km from Stone Town, Zanzibar's busiest town. Changuu remains relatively unaffected by nutrient runoff pollution. The study area is characterised by a fringing reef around a multi-specific seagrass ecosystem. The substrate is primarily carbonate sediment. Average water depth is approximately 30 cm at Spring Low and 5 m at Spring high tide with an average depth of 2 m. Macroalgae biomass, epiphyte biomass on seagrass and phytoplankton biomass was collected in each experimental plot to study the effect of nutrient enrichment and macrofauna exclusion on the primary producers in the ecosystem. To determine the abundance of macroalgae in the different treatments, the macroalgae biomass was collected at the end of the experiment by removing all visible macroalgae present in the experimental plots. Macroalgae was rinsed with freshwater and dried in the oven at 60°C for 48 hours until constant dry weight. The final dry weight was then divided by the treatment plot surface to obtain g DW m-2. To determine phytoplankton biomass under the different treatments, we quantified Chlorophyll-a concentrations in the water column. Water was collected in a 2-litre bottle from each of the 24 plots at the end of the experiment. The water bottles were kept in the dark in a cooler box upon arrival to the lab and water was then filtered under constant pressure onto pre-combusted (5 h, 450◦C) and pre-weighed Whatman GF/F filters (0.45-μm pore size). Chlorophyll-a was then extracted from the filters in 8 ml of 96% ethanol in glass vials heated for 5 min at 80◦C, covered with aluminum foil, and placed in a rotor at room temperature for ∼24 h. Extracts were subsequently centrifuged at 5,000 rpm for 20 min. Chlorophyll-a absorbance of the supernatant was determined in a Shimadzu UV-1700 photometer, and calculated as μg Chl l−1. To determine epiphyte biomass in the treatments, one seagrass shoot per species was collected at each treatment plot at the end of the experiment. Each shoot was collected in a white mesh bag (<1 mm mesh size). In the laboratory, samples were carefully rinsed in freshwater and all epiphytes were scraped off. The scraped epiphytic biomass was dried at 60° C for 48 hours until constant dry weight, and then weighed (mg DW). The epiphytic biomass was then multiplied by the shoot density of each species. This was then summed to obtain the total epiphytic biomass per unit of area (g DW m-2). ** For all details see the full metadata description at "https://doi.pangaea.de/10.1594/PANGAEA.992559"!

http://en.wikipedia.org/wiki/ISO_6709 LATITUDE http://en.wikipedia.org/wiki/ISO_6709 LONGITUDE https://doi.pangaea.de/10.1594/PANGAEA.992558 Mesofauna density in seagrass meadows of Changuu Island (Zanzibar Archipelago, Tanzania) during nutrient enrichment and macrofauna exclusion experiment https://hdl.handle.net/10013/epic.32187.d001 Chlorophyll a https://www.leibniz-zmt.de/en/research/research-projects/seamac.html SEAMAC https://www.leibniz-zmt.de/en/research/research-projects/seatrait.html SEATRAIT DIF 9.4 2026-04-09 2026-04-14