/* DATA DESCRIPTION: Citation: Moreira-Saporiti, Agustín; Teichberg, Mirta; O'Sullivan, Aoife (2026): Photosynthetically active radiation (PAR) in Changuu Island, Zanzibar Archipelago, Tanzania [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.986944 Abstract: Photosynthetic active radiation (PAR) was measured during a nutrient enrichment and exclusion field experiment on seagrass. 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). Data was collected between July 19th and September 20th of 2017 in four sampling times (Day 0 (19.07.2017), Day 20 (09.08.2017), Day 38 (31.08.2017) and Day 63 (19.09.2017)). Data collection took place in Changuu Island (Zanzibar Archipelago, Tanzania) in the area that the experiment took place, and not per experimental plot. Changuu Island is located 3 km from Stone Town, Zanzibar's busiest town. The study area is characterised by a fringing reef around a multi-specific seagrass ecosystem. The substrate is primarily carbonate sediment. PAR and the calculation of the attenuation coefficient were collected at each sampling time to account for potential confounding variables during the experiment. Photosynthetically active radiation (PAR) was measured every 2 hours at each sampling time using a LiCor-1500 with a PAR sensor. The PAR sensor (μmol photons m−2 s−1) was placed at the water surface and approximately half a meter underwater. The light attenuation coefficient was calculated using the Bouguer-Lambert's law, which follows the equation: I(z)=I0 e -µz, where z is the depth in meters, I(z) is the PAR intensity at a depth z, I0 is the PAR intensity at the water surface and µ is the light attenuation coefficient. Keyword(s): attenuation coefficient; Indian Ocean; PAR; photosynthetically active radiation; Seagrass; seawater; Tropical References: Casini, Michele; Lövgren, Johan; Hjelm, Joakim; Cardinale, Massimiliano; Molinero, Juan-Carlos; Kornilovs, Georgs (2008): Multi-level trophic cascades in a heavily exploited open marine ecosystem. Proceedings of the Royal Society B-Biological Sciences, 275(1644), 1793-1801, https://doi.org/10.1098/rspb.2007.1752 Heck, Kenneth L; Pennock, Jonathan R; Valentine, John F; Coen, Loren D; Sklenar, Susan A (2000): Effects of nutrient enrichment and small predator density on seagrass ecosystems: An experimental assessment. Limnology and Oceanography, 45(5), 1041-1057, https://doi.org/10.4319/lo.2000.45.5.1041 Lotze, Heike K; Worm, Boris (2000): Variable and complementary effects of herbivores on different life stages of bloom-forming macroalgae. Marine Ecology Progress Series, 200, 167-175, https://doi.org/10.3354/meps200167 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/project/278616556) Coverage: LATITUDE: -6.117880 * LONGITUDE: 39.167290 DATE/TIME START: 2017-07-19T11:49:00 * DATE/TIME END: 2017-09-19T13:30:00 MINIMUM DEPTH, water: 0.3 m * MAXIMUM DEPTH, water: 0.6 m Event(s): Changuu_C1_T0_1 (T0_1) * LATITUDE: -6.117880 * LONGITUDE: 39.167290 * DATE/TIME: 2017-07-19T11:49:00 * LOCATION: Changuu Island, Zanzibar Archipelago, Tanzania * METHOD/DEVICE: Field experiment Changuu_C1_T0_2 (T0_2) * LATITUDE: -6.117880 * LONGITUDE: 39.167290 * DATE/TIME: 2017-07-19T13:57:00 * LOCATION: Changuu Island, Zanzibar Archipelago, Tanzania * METHOD/DEVICE: Field experiment Changuu_C1_T0_3 (T0_3) * LATITUDE: -6.117880 * LONGITUDE: 39.167290 * DATE/TIME: 2017-07-19T14:30:00 * LOCATION: Changuu Island, Zanzibar Archipelago, Tanzania * METHOD/DEVICE: Field experiment Changuu_C1_T1_1 (T1_1) * LATITUDE: -6.117880 * LONGITUDE: 39.167290 * DATE/TIME: 2017-08-09T08:16:00 * LOCATION: Changuu Island, Zanzibar Archipelago, Tanzania * METHOD/DEVICE: Field experiment Changuu_C1_T1_2 (T1_2) * LATITUDE: -6.117880 * LONGITUDE: 39.167290 * DATE/TIME: 2017-08-09T09:16:00 * LOCATION: Changuu Island, Zanzibar Archipelago, Tanzania * METHOD/DEVICE: Field experiment Changuu_C1_T1_3 (T1_3) * LATITUDE: -6.117880 * LONGITUDE: 39.167290 * DATE/TIME: 2017-08-09T11:16:00 * LOCATION: Changuu Island, Zanzibar Archipelago, Tanzania * METHOD/DEVICE: Field experiment Changuu_C1_T1_4 (T1_4) * LATITUDE: -6.117880 * LONGITUDE: 39.167290 * DATE/TIME: 2017-08-09T12:56:00 * LOCATION: Changuu Island, Zanzibar Archipelago, Tanzania * METHOD/DEVICE: Field experiment Changuu_C1_T1_5 (T1_5) * LATITUDE: -6.117880 * LONGITUDE: 39.167290 * DATE/TIME: 2017-08-09T13:56:00 * LOCATION: Changuu Island, Zanzibar Archipelago, Tanzania * METHOD/DEVICE: Field experiment Changuu_C1_T2_1 (T2_1) * LATITUDE: -6.117880 * LONGITUDE: 39.167290 * DATE/TIME: 2017-08-31T09:22:00 * LOCATION: Changuu Island, Zanzibar Archipelago, Tanzania * METHOD/DEVICE: Field experiment Changuu_C1_T2_2 (T2_2) * LATITUDE: -6.117880 * LONGITUDE: 39.167290 * DATE/TIME: 2017-08-31T09:05:00 * LOCATION: Changuu Island, Zanzibar Archipelago, Tanzania * METHOD/DEVICE: Field experiment Changuu_C1_T2_3 (T2_3) * LATITUDE: -6.117880 * LONGITUDE: 39.167290 * DATE/TIME: 2017-08-31T10:40:00 * LOCATION: Changuu Island, Zanzibar Archipelago, Tanzania * METHOD/DEVICE: Field experiment Changuu_C1_T2_4 (T2_4) * LATITUDE: -6.117880 * LONGITUDE: 39.167290 * DATE/TIME: 2017-08-31T11:32:00 * LOCATION: Changuu Island, Zanzibar Archipelago, Tanzania * METHOD/DEVICE: Field experiment Changuu_C1_T2_5 (T2_5) * LATITUDE: -6.117880 * LONGITUDE: 39.167290 * DATE/TIME: 2017-08-31T12:25:00 * LOCATION: Changuu Island, Zanzibar Archipelago, Tanzania * METHOD/DEVICE: Field experiment Changuu_C1_T3_1 (T3_1) * LATITUDE: -6.117880 * LONGITUDE: 39.167290 * DATE/TIME: 2017-09-19T07:45:00 * LOCATION: Changuu Island, Zanzibar Archipelago, Tanzania * METHOD/DEVICE: Field experiment Changuu_C1_T3_2 (T3_2) * LATITUDE: -6.117880 * LONGITUDE: 39.167290 * DATE/TIME: 2017-09-19T09:07:00 * LOCATION: Changuu Island, Zanzibar Archipelago, Tanzania * METHOD/DEVICE: Field experiment Changuu_C1_T3_3 (T3_3) * LATITUDE: -6.117880 * LONGITUDE: 39.167290 * DATE/TIME: 2017-09-19T10:20:00 * LOCATION: Changuu Island, Zanzibar Archipelago, Tanzania * METHOD/DEVICE: Field experiment Changuu_C1_T3_4 (T3_4) * LATITUDE: -6.117880 * LONGITUDE: 39.167290 * DATE/TIME: 2017-09-19T12:28:00 * LOCATION: Changuu Island, Zanzibar Archipelago, Tanzania * METHOD/DEVICE: Field experiment Changuu_C1_T3_5 (T3_5) * LATITUDE: -6.117880 * LONGITUDE: 39.167290 * DATE/TIME: 2017-09-19T13:30:00 * LOCATION: Changuu Island, Zanzibar Archipelago, Tanzania * METHOD/DEVICE: Field experiment Parameter(s): Event label (Event) * 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) Sampling date (Sampling date) * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com) Time in days [days] (Time d) * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com) * COMMENT: Days since start of experiment LATITUDE (Latitude) * GEOCODE * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com) LONGITUDE (Longitude) * GEOCODE * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com) Site (Site) * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com) Radiation, photosynthetically active [µmol/m**2/s] (PAR) * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com) * METHOD/DEVICE: PAR sensor LI-1500, Li-COR Inc. * COMMENT: Surface Radiation, photosynthetically active [µmol/m**2/s] (PAR) * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com) * METHOD/DEVICE: PAR sensor LI-1500, Li-COR Inc. * COMMENT: Botttom DEPTH, water [m] (Depth water) * GEOCODE * PI: Moreira-Saporiti, Agustín (https://orcid.org/0000-0002-4798-3775, am.saporiti@gmail.com) * METHOD/DEVICE: Ruler tape Attenuation coefficient [1/m] (AC) * 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: 126 data points */ Event Study type Sampling date Time d [days] (Days since start of experiment) Latitude Longitude Site PAR [µmol/m**2/s] (Surface, PAR sensor LI-1500, ...) PAR [µmol/m**2/s] (Botttom, PAR sensor LI-1500, ...) Depth water [m] (Ruler tape) AC [1/m] Changuu_C1_T0_1 Field experiment 2017-07-19 0 -6.11788 39.16729 Changuu Island, Zanzibar Archipelago, Tanzania 1660.0 1526.0 0.6 0.140279449 Changuu_C1_T0_2 Field experiment 2017-07-19 0 -6.11788 39.16729 Changuu Island, Zanzibar Archipelago, Tanzania 1760.0 1354.0 0.6 0.437084391 Changuu_C1_T0_3 Field experiment 2017-07-19 0 -6.11788 39.16729 Changuu Island, Zanzibar Archipelago, Tanzania 1694.0 1314.0 0.5 0.508033352 Changuu_C1_T1_1 Field experiment 2017-08-09 20 -6.11788 39.16729 Changuu Island, Zanzibar Archipelago, Tanzania 444.1 408.7 0.5 0.166136743 Changuu_C1_T1_2 Field experiment 2017-08-09 20 -6.11788 39.16729 Changuu Island, Zanzibar Archipelago, Tanzania 739.8 734.2 0.3 0.025328028 Changuu_C1_T1_3 Field experiment 2017-08-09 20 -6.11788 39.16729 Changuu Island, Zanzibar Archipelago, Tanzania 1502.0 1209.0 0.5 0.434007963 Changuu_C1_T1_4 Field experiment 2017-08-09 20 -6.11788 39.16729 Changuu Island, Zanzibar Archipelago, Tanzania 1410.0 1220.0 0.5 0.289477691 Changuu_C1_T1_5 Field experiment 2017-08-09 20 -6.11788 39.16729 Changuu Island, Zanzibar Archipelago, Tanzania 1242.0 1014.0 0.5 0.405640157 Changuu_C1_T2_1 Field experiment 2017-08-31 38 -6.11788 39.16729 Changuu Island, Zanzibar Archipelago, Tanzania 1142.0 1053.0 0.6 0.135229797 Changuu_C1_T2_2 Field experiment 2017-08-31 38 -6.11788 39.16729 Changuu Island, Zanzibar Archipelago, Tanzania 954.0 846.0 0.5 0.240288624 Changuu_C1_T2_3 Field experiment 2017-08-31 38 -6.11788 39.16729 Changuu Island, Zanzibar Archipelago, Tanzania 1414.0 1340.0 0.5 0.107505907 Changuu_C1_T2_4 Field experiment 2017-08-31 38 -6.11788 39.16729 Changuu Island, Zanzibar Archipelago, Tanzania 1672.0 1349.0 0.6 0.357761562 Changuu_C1_T2_5 Field experiment 2017-08-31 38 -6.11788 39.16729 Changuu Island, Zanzibar Archipelago, Tanzania 1820.0 1519.0 0.6 0.301307129 Changuu_C1_T3_1 Field experiment 2017-09-19 63 -6.11788 39.16729 Changuu Island, Zanzibar Archipelago, Tanzania 518.8 496.0 0.5 0.089885051 Changuu_C1_T3_2 Field experiment 2017-09-19 63 -6.11788 39.16729 Changuu Island, Zanzibar Archipelago, Tanzania 1066.0 952.0 0.5 0.226207140 Changuu_C1_T3_3 Field experiment 2017-09-19 63 -6.11788 39.16729 Changuu Island, Zanzibar Archipelago, Tanzania 1520.0 1384.0 0.4 0.234331194 Changuu_C1_T3_4 Field experiment 2017-09-19 63 -6.11788 39.16729 Changuu Island, Zanzibar Archipelago, Tanzania 1802.0 1491.0 0.5 0.378900247 Changuu_C1_T3_5 Field experiment 2017-09-19 63 -6.11788 39.16729 Changuu Island, Zanzibar Archipelago, Tanzania 1975.0 1730.0 0.4 0.331117475