/* DATA DESCRIPTION:
Citation:	Moreira-Saporiti, Agustín; Teichberg, Mirta; O'Sullivan, Aoife (2026): Macroalgae biomass, epiphytic biomass on seagrass and phytoplankton biomass in Changuu Island (Zanzibar Archipelago, Tanzania) at end of nutrient enrichment and macrofauna exclusion experiment [dataset]. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.992559 (DOI registration in progress)
Abstract:	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).
Keyword(s):	Chlorophyll a; epiphytes; Macroalgae; Phytoplankton; Seagrass; tropical seagrass; Western Indian Ocean
Related to:	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
Project(s):	Seagrass and Macroalgal Community Dynamics and Performance under Environmental Change (SEAMAC) (URI: https://www.leibniz-zmt.de/en/research/research-projects/seamac.html)
	Seagrass Ecosystem Service Evaluation using a Trait-based Approach (SEATRAIT) (URI: https://www.leibniz-zmt.de/en/research/research-projects/seatrait.html)
Funding:	German Research Foundation (DFG) (URI: http://www.dfg.de/en/), grant/award no. 278616556: SEAMAC - Seagrass and Macroalgal Community Dynamics and Performance under Environmental Change (URI: https://gepris.dfg.de/gepris/projekt/278616556)
Coverage:	MEDIAN LATITUDE: -6.117971 * MEDIAN LONGITUDE: 39.167399 * SOUTH-BOUND LATITUDE: -6.118093 * WEST-BOUND LONGITUDE: 39.167280 * NORTH-BOUND LATITUDE: -6.117863 * EAST-BOUND LONGITUDE: 39.167509
	DATE/TIME START: 2017-09-19T00:00:00 * DATE/TIME END: 2017-09-19T00:00:00
Event(s):	Changuu_C1_T3 * LATITUDE: -6.117880 * LONGITUDE: 39.167290 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C2_T3 * LATITUDE: -6.117863 * LONGITUDE: 39.167333 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C3_T3 * LATITUDE: -6.117881 * LONGITUDE: 39.167354 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C4_T3 * LATITUDE: -6.117920 * LONGITUDE: 39.167354 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C5_T3 * LATITUDE: -6.117941 * LONGITUDE: 39.167335 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C6_T3 * LATITUDE: -6.117963 * LONGITUDE: 39.167361 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C7_T3 * LATITUDE: -6.117962 * LONGITUDE: 39.167392 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C8_T3 * LATITUDE: -6.117930 * LONGITUDE: 39.167413 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C9_T3 * LATITUDE: -6.117969 * LONGITUDE: 39.167436 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C10_T3 * LATITUDE: -6.117956 * LONGITUDE: 39.167464 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C11_T3 * LATITUDE: -6.117994 * LONGITUDE: 39.167486 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C12_T3 * LATITUDE: -6.117968 * LONGITUDE: 39.167502 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C13_T3 * LATITUDE: -6.117928 * LONGITUDE: 39.167509 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C14_T3 * LATITUDE: -6.117896 * LONGITUDE: 39.167498 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C15_T3 * LATITUDE: -6.117910 * LONGITUDE: 39.167280 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C16_T3 * LATITUDE: -6.117983 * LONGITUDE: 39.167312 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C17_T3 * LATITUDE: -6.117999 * LONGITUDE: 39.167331 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C18_T3 * LATITUDE: -6.118008 * LONGITUDE: 39.167374 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C19_T3 * LATITUDE: -6.118007 * LONGITUDE: 39.167401 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C20_T3 * LATITUDE: -6.118043 * LONGITUDE: 39.167417 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C21_T3 * LATITUDE: -6.118067 * LONGITUDE: 39.167403 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C22_T3 * LATITUDE: -6.118093 * LONGITUDE: 39.167405 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C23_T3 * LATITUDE: -6.118093 * LONGITUDE: 39.167447 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
	Changuu_C24_T3 * LATITUDE: -6.118047 * LONGITUDE: 39.167473 * DATE/TIME: 2017-09-19T00:00:00 * METHOD/DEVICE: Sampling by hand (HAND)
Parameter(s):	Event label (Event) * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com)
	Sampling date/time, experiment (Date/time sampling exp) * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com)
	Day of experiment [day] (DOE) * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com)
	LATITUDE (Latitude) * GEOCODE * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com) * METHOD/DEVICE: GPS in field
	LONGITUDE (Longitude) * GEOCODE * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com) * METHOD/DEVICE: GPS in field
	Site (Site) * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com)
	Station label (Station) * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com)
	Experimental treatment (Exp treat) * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com) * COMMENT: Level of macrofauna exclusion. Uncaged= no exclusion; Open=no exclusion, control for cage effects; Closed=total exclusion
	Treatment: nutrients (T:nutrients) * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com) * COMMENT: Level of nutrient enrichment. Ambient=no enrichment; Enriched=nutrient enriched
	Biomass, live, dry weight [g/m**2] (Biom live dw) * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com) * COMMENT: Epiphytes
	Biomass, live, dry weight [g/m**2] (Biom live dw) * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com) * COMMENT: Macroalgae
	Chlorophyll a [µg/l] (Chl a) * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com)
	Type of study (Study type) * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com)
License:	Creative Commons Attribution 4.0 International (CC-BY-4.0) (URI: https://creativecommons.org/licenses/by/4.0/)
Status:	Curation Level: Enhanced curation (URI: https://wiki.pangaea.de/wiki/Curation_levels)
Size:	240 data points
*/
Event	Date/time sampling exp	DOE [day]	Latitude	Longitude	Site	Station	Exp treat (Level of macrofauna exclusion...)	T:nutrients (Level of nutrient enrichment....)	Biom live dw [g/m**2] (Epiphytes)	Biom live dw [g/m**2] (Macroalgae)	Chl a [µg/l]	Study type
Changuu_C1_T3	2017-09-19	63	-6.117880	39.167290	Changuu Island, Zanzibar Archipelago, Tanzania	C1	Closed	Ambient	10.517	5.320	2.921	Field experiment
Changuu_C2_T3	2017-09-19	63	-6.117863	39.167333	Changuu Island, Zanzibar Archipelago, Tanzania	C2	Open	Enriched	48.206	0.200	0.581	Field experiment
Changuu_C3_T3	2017-09-19	63	-6.117881	39.167354	Changuu Island, Zanzibar Archipelago, Tanzania	C3	Closed	Enriched	14.135	30.960	0.946	Field experiment
Changuu_C4_T3	2017-09-19	63	-6.117920	39.167354	Changuu Island, Zanzibar Archipelago, Tanzania	C4	Closed	Ambient	20.377	0.520	1.421	Field experiment
Changuu_C5_T3	2017-09-19	63	-6.117941	39.167335	Changuu Island, Zanzibar Archipelago, Tanzania	C5	Uncaged	Ambient	3.655	0.000	0.786	Field experiment
Changuu_C6_T3	2017-09-19	63	-6.117963	39.167361	Changuu Island, Zanzibar Archipelago, Tanzania	C6	Uncaged	Ambient	19.052	2.680	0.426	Field experiment
Changuu_C7_T3	2017-09-19	63	-6.117962	39.167392	Changuu Island, Zanzibar Archipelago, Tanzania	C7	Closed	Enriched	20.395	8.560	0.561	Field experiment
Changuu_C8_T3	2017-09-19	63	-6.117930	39.167413	Changuu Island, Zanzibar Archipelago, Tanzania	C8	Uncaged	Ambient	8.061	0.000	0.617	Field experiment
Changuu_C9_T3	2017-09-19	63	-6.117969	39.167436	Changuu Island, Zanzibar Archipelago, Tanzania	C9	Open	Ambient	20.357	0.000	0.695	Field experiment
Changuu_C10_T3	2017-09-19	63	-6.117956	39.167464	Changuu Island, Zanzibar Archipelago, Tanzania	C10	Closed	Ambient	21.384	7.040	0.484	Field experiment
Changuu_C11_T3	2017-09-19	63	-6.117994	39.167486	Changuu Island, Zanzibar Archipelago, Tanzania	C11	Closed	Enriched	17.132	8.480	0.566	Field experiment
Changuu_C12_T3	2017-09-19	63	-6.117968	39.167502	Changuu Island, Zanzibar Archipelago, Tanzania	C12	Open	Ambient	10.484	0.000	0.487	Field experiment
Changuu_C13_T3	2017-09-19	63	-6.117928	39.167509	Changuu Island, Zanzibar Archipelago, Tanzania	C13	Open	Enriched	19.294	1.320	0.801	Field experiment
Changuu_C14_T3	2017-09-19	63	-6.117896	39.167498	Changuu Island, Zanzibar Archipelago, Tanzania	C14	Open	Ambient	6.682	1.520	0.536	Field experiment
Changuu_C15_T3	2017-09-19	63	-6.117910	39.167280	Changuu Island, Zanzibar Archipelago, Tanzania	C15	Open	Enriched	6.048	0.520	0.566	Field experiment
Changuu_C16_T3	2017-09-19	63	-6.117983	39.167312	Changuu Island, Zanzibar Archipelago, Tanzania	C16	Open	Ambient	11.368	8.840	0.882	Field experiment
Changuu_C17_T3	2017-09-19	63	-6.117999	39.167331	Changuu Island, Zanzibar Archipelago, Tanzania	C17	Uncaged	Enriched	9.251	1.240	0.528	Field experiment
Changuu_C18_T3	2017-09-19	63	-6.118008	39.167374	Changuu Island, Zanzibar Archipelago, Tanzania	C18	Uncaged	Enriched	8.774	1.600	0.598	Field experiment
Changuu_C19_T3	2017-09-19	63	-6.118007	39.167401	Changuu Island, Zanzibar Archipelago, Tanzania	C19	Open	Enriched	19.265	6.840	0.599	Field experiment
Changuu_C20_T3	2017-09-19	63	-6.118043	39.167417	Changuu Island, Zanzibar Archipelago, Tanzania	C20	Closed	Enriched	25.271	6.720	0.648	Field experiment
Changuu_C21_T3	2017-09-19	63	-6.118067	39.167403	Changuu Island, Zanzibar Archipelago, Tanzania	C21	Closed	Ambient	23.413	35.680	0.556	Field experiment
Changuu_C22_T3	2017-09-19	63	-6.118093	39.167405	Changuu Island, Zanzibar Archipelago, Tanzania	C22	Uncaged	Enriched	18.263	2.640	0.565	Field experiment
Changuu_C23_T3	2017-09-19	63	-6.118093	39.167447	Changuu Island, Zanzibar Archipelago, Tanzania	C23	Uncaged	Ambient	16.986	3.000	1.467	Field experiment
Changuu_C24_T3	2017-09-19	63	-6.118047	39.167473	Changuu Island, Zanzibar Archipelago, Tanzania	C24	Uncaged	Enriched	22.500	23.800	0.455	Field experiment