PANGAEA_992561
Photosynthetic responses of seagrass in Changuu Island (Zanzibar Archipelago, Tanzania) during a nutrient enrichment and macrofauna exclusion experiment
Moreira-Saporiti, Agustín; Teichberg, Mirta; O'Sullivan, Aoife
Photosynthetic responses of seagrass in Changuu Island (Zanzibar Archipelago, Tanzania) during a nutrient enrichment and macrofauna exclusion experiment
2026-04-14
PANGAEA
Dataset
https://doi.pangaea.de/10.1594/PANGAEA.992561
Investigator
Agustín
Moreira-Saporiti
am.saporiti@gmail.com
Earth Science
Event label
Sample code/label
Sampling date/time, experiment
Day of experiment
LATITUDE
LONGITUDE
Site
Station label
Experimental treatment
Treatment: nutrients
Species, unique identification
Sample type
Electron transport rate, relative
Electron transfer rate, light-limited
Light saturation
Type of study
geoscientificInformation
Changuu_C1_T1
Changuu_C1_T2
Changuu_C1_T3
Changuu_C10_T1
Changuu_C10_T2
Changuu_C10_T3
Changuu_C11_T1
Changuu_C11_T2
Changuu_C11_T3
Changuu_C12_T1
Changuu_C12_T2
Changuu_C12_T3
Changuu_C13_T1
Changuu_C13_T2
Changuu_C13_T3
Changuu_C14_T1
Changuu_C14_T2
Changuu_C14_T3
Changuu_C15_T1
Changuu_C15_T2
Changuu_C15_T3
Changuu_C16_T1
Changuu_C16_T2
Changuu_C16_T3
Changuu_C17_T1
Changuu_C17_T2
Changuu_C17_T3
Changuu_C18_T1
Changuu_C18_T2
Changuu_C18_T3
Changuu_C19_T1
Changuu_C19_T2
Changuu_C19_T3
Changuu_C2_T1
Changuu_C2_T2
Changuu_C2_T3
Changuu_C20_T1
Changuu_C20_T2
Changuu_C20_T3
Changuu_C21_T1
Changuu_C21_T2
Changuu_C21_T3
Changuu_C22_T1
Changuu_C22_T2
Changuu_C22_T3
Changuu_C23_T1
Changuu_C23_T2
Changuu_C23_T3
Changuu_C24_T1
Changuu_C24_T2
Changuu_C24_T3
Changuu_C3_T1
Changuu_C3_T2
Changuu_C3_T3
Changuu_C4_T1
Changuu_C4_T2
Changuu_C4_T3
Changuu_C5_T1
Changuu_C5_T2
Changuu_C5_T3
Changuu_C6_T1
Changuu_C6_T2
Changuu_C6_T3
Changuu_C7_T1
Changuu_C7_T2
Changuu_C7_T3
Changuu_C8_T1
Changuu_C8_T2
Changuu_C8_T3
Changuu_C9_T1
Changuu_C9_T2
Changuu_C9_T3
PAM fluorometry
Photosynthesis
Sampling by hand
tropical seagrass
Western Indian Ocean
GPS in field
2017-08-09
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
1863 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
Genty, B; Briantais, J M; Baker, N R (1989): The relationship between quantum yield of photosynthetic electron transport and quenching of chlorophyll fluorescence. Biochimica et Biophysica Acta-General Subjects, 990(1), 87-92, https://doi.org/10.1016/S0304-4165(89)80016-9
Jassby, Alan D; Platt, Trevor (1976): Mathematical formulation of the relationship between photosynthesis and light for phytoplankton. Limnology and Oceanography, 21(4), 540-547, https://doi.org/10.4319/lo.1976.21.4.0540
Sakshaug, Egil; Bricaud, Annick; Dandonneau, Yves; Falkowski, Paul G; Kiefer, D A; Legendre, Louis; Morel, André; Parslow, John; Takahashi, Masayuki (1997): Parameters of photosynthesis: definitions, theory and interpretation of results. Journal of Plankton Research, 19(11), 1637-1670, https://doi.org/10.1093/plankt/19.11.1637
Silsbe, Greg; Malkin, Sairah Y (2015): Phytotools: Phytoplankton Production Tools [software]. https://www.researchgate.net/publication/272294040_Phytotools_Phytoplankton_Production_Tools
Seagrass photosynthetic responses (alpha, Ek and ETRmax) were measured during a nutrient enrichment and macrofauna exclusion experiment. A total of 24 plots were set up parallel to the shore, with presence of two seagrass species (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 between July 19th and September 20th of 2017 in three sampling times. Day 20 (09.08.2017), Day 38 (31.08.2017) and 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. Seagrass photosynthetic traits were measured to understand the photosynthetic responses of two seagrass species present in Changuu Island to the nutrient enrichment and macrofauna exclusion treatments. To determine the photosynthetic responses of the seagrass plants, their photosynthetic performance was measured through rapid light response curves (RLCs) generated by a Diving PAM chlorophyll fluorometer (Walz, Germany). RLCs were performed above the meristem of the second leaf of one plant per treatment plot for T. hemprichii and T. ciliatum. The basal portion of the leaf was chosen since it represents similar distances from the surface (and thus from the light source) among plants with different leaf lengths, thus minimizing variability within plants and species. A clip was attached to the leaf and to hold the optical cable of the PAM at 3 mm distance from the tissue and to dark adapt the tissue for 5 min prior to measurement. Leaves were kept in a laboratory tray with ambient seawater during dark adaptation and through the measurements. The first quantum yield measurement was performed in the absence of actinic light (dark-adapted effective quantum yield), after which the RLC consisted of 8 saturating light pulses (separated by 30-s intervals), increasing the photosynthetic active radiation (PAR) between pulses until 819 μmol photons m–2 s–1. The effective quantum yield (ΔF/Fm') was measured in each interval. From the RLC, light saturation coefficient (Ek) and the slope of the light limited part of the curve (Alpha) were calculated using the package "Phytotools" (Silsbe and Malkin, 2015) following the model of Jassby and Platt (1976) under the R software (R Core Team, 2019). The maximum light utilization efficiency or maximum quantum yield of PSII was calculated following equation by Genty et al. (1989) [Fv/Fm = (Fm-Fo)/Fm], where Fm is the maximum dark-adapted fluorescence and Fo is the minimal fluorescence from a dark-adapted sample. The relative electron transport rate (rETR) was calculated for each step of the curve following the equation by Sakshaug et al. (1997), [rETR = (Fm'-F'/Fm')∗(PAR/2)], where Fm' is the light adapted maximum fluorescence and F' the fluorescence yield at a particular light level. From the rETR values, maximum rETR (rETRmax) was estimated as the inflection point of the fitted rETR curve. ** For all details see the full metadata description at "https://doi.pangaea.de/10.1594/PANGAEA.992561"!
http://en.wikipedia.org/wiki/ISO_6709
LATITUDE
http://en.wikipedia.org/wiki/ISO_6709
LONGITUDE
https://doi.org/10.1016/S0304-4165(89)80016-9
The relationship between quantum yield of photosynthetic electron transport and quenching of chlorophyll fluorescence
https://doi.org/10.1093/plankt/19.11.1637
Parameters of photosynthesis: definitions, theory and interpretation of results
https://doi.org/10.4319/lo.1976.21.4.0540
Mathematical formulation of the relationship between photosynthesis and light for phytoplankton
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://www.leibniz-zmt.de/en/research/research-projects/seamac.html
SEAMAC
https://www.leibniz-zmt.de/en/research/research-projects/seatrait.html
SEATRAIT
https://www.researchgate.net/publication/272294040_Phytotools_Phytoplankton_Production_Tools
Phytotools: Phytoplankton Production Tools
DIF
9.4
2026-04-14
2026-04-14