

FOLLOWUS
1.State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing210008, China
2.University of Chinese Academy of Sciences, Beijing100049, China
3.State Environmental Protection Key Laboratory of Aquatic Ecosystem Health in the Middle and Lower Reaches of Yangtze River, Jiangsu Provincial Academy of Environmental Science, Nanjing210036, China
knchen@niglas.ac.cn
xlshi@niglas.ac.cn
收稿:2023-09-22,
网络首发:2023-12-27,
纸质出版:2024-09-01
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Response of phytoplankton functional group to spring drought in a large subtropical reservoir[J]. 海洋湖沼学报(英文), 2024,42(5):1586-1596.
WU Yue,YE Qi,CHEN Siwen,et al.Response of phytoplankton functional group to spring drought in a large subtropical reservoir[J].Journal of Oceanology and Limnology,2024,42(05):1586-1596.
Response of phytoplankton functional group to spring drought in a large subtropical reservoir[J]. 海洋湖沼学报(英文), 2024,42(5):1586-1596. DOI: 10.1007/s00343-024-3190-1.
WU Yue,YE Qi,CHEN Siwen,et al.Response of phytoplankton functional group to spring drought in a large subtropical reservoir[J].Journal of Oceanology and Limnology,2024,42(05):1586-1596. DOI: 10.1007/s00343-024-3190-1.
Global warming has caused an increase in the frequency and duration of droughts worldwide. Droughts could trigger large changes in physico-chemical conditions and phytoplankton community in waterbodies
resulting in a shift in the phytoplankton community. Spring diatom blooms in reservoirs have been increasingly observed in the past decade in the Taihu Lake basin. The aim of the present study is to elucidate the impacts of droughts on aquatic environment and to determine the driving factors for the succession of the phytoplankton functional groups based on the analysis of data collected during spring from 2009 to 2020 in the Daxi Reservoir. The unimodal relationship between 1-month aggregated precipitation index and phytoplankton species richness indicated the competitive exclusion occurred in extremely drought period. The structural equation modeling indicated that drought-related low water level conditions intensified sediment resuspension
and increased the phosphorus-enriched nonalgal turbidity in the Daxi Reservoir. Concurrently
a steady shift in the Reynolds phytoplankton functional groups from L0
TD
J
X2
and A (phytoplankton taxa preferring low turbidity and nutrient conditions) to TB (pennate diatoms being adapt to turbid and nutrient-rich conditions) was observed. The increased TP and non-algal turbidity in addition to the lowered disturbance contribute to the prevalence of Group TB. Considering the difficulties in nutrient control
timely water replenishment is often a feasible method of controlling the dominance of harmful algae for reservoir management. Finally
alternative water sources are in high demand for ensuring ecological safety and water availability when dealing with drought.
Abirhire O , Davies J M , Guo X L et al . 2020 . Understanding the factors associated with long-term reconstructed turbidity in Lake Diefenbaker from Landsat-imagery . Science of the Total Environment , 724 : 138222 , https://doi.org/10.1016/j.scitotenv.2020.138222 https://doi.org/10.1016/j.scitotenv.2020.138222 .
Abonyi A , Ács É , Hidas A et al . 2018 . Functional diversity of phytoplankton highlights long-term gradual regime shift in the middle section of the Danube River due to global warming, human impacts and oligotrophication . Freshwater Biology , 63 ( 5 ): 456 - 472 , https://doi.org/10.1111/fwb.13084 https://doi.org/10.1111/fwb.13084 .
Arhonditsis G B , Stow C A , Steinberg L J et al . 2006 . Exploring ecological patterns with structural equation modeling and Bayesian analysis . Ecological Modelling , 192 ( 3-4 ): 385 - 409 , https://doi.org/10.1016/j.ecolmodel.2005.07.028 https://doi.org/10.1016/j.ecolmodel.2005.07.028 .
Arthaud F , Vallod D , Robin J et al . 2012 . Eutrophication and drought disturbance shape functional diversity and life-history traits of aquatic plants in shallow lakes . Aquatic Sciences , 74 ( 3 ): 471 - 481 , https://doi.org/10.1007/s00027-011-0241-4 https://doi.org/10.1007/s00027-011-0241-4 . https://do 10.1007/s00027-011-0241-4 http://dx.doi.org/10.1007/s00027-011-0241-4
Bakker E S , Hilt S . 2016 . Impact of water-level fluctuations on cyanobacterial blooms: options for management . Aquatic Ecology , 50 ( 3 ): 485 - 498 , https://doi.org/10.1007/s10452-015-9556-x https://doi.org/10.1007/s10452-015-9556-x . https://do 10.1007/s10452-015-9556-x http://dx.doi.org/10.1007/s10452-015-9556-x
Barone R , Naselli Flores L . 1994 . Phytoplankton dynamics in a shallow, hypertrophic reservoir (Lake Arancio, Sicily) . Hydrobiologia , 289 ( 1-3 ): 199 - 214 , https://doi.org/10.1007/BF00007421 https://doi.org/10.1007/BF00007421 . https://do 10.1007/bf00007421 http://dx.doi.org/10.1007/bf00007421
Barrett P R F , Curnow J C , Littlejohn J W . 1996 . The control of diatom and cyanobacterial blooms in reservoirs using barley straw . Hydrobiologia , 340 ( 1-3 ): 307 - 311 , https://doi.org/10.1007/BF00012773 https://doi.org/10.1007/BF00012773 .
Bellinger B J , Richter A , Porras A et al . 2018 . Drought and management effects on biophysicochemistry in a rapidly-flushed reservoir . Lake and Reservoir Management , 34 ( 2 ): 182 - 198 , https://doi.org/10.1080/10402381.2017.1384770 https://doi.org/10.1080/10402381.2017.1384770 .
Brasil J , Attayde J L , Vasconcelos F R et al . 2016 . Drought-induced water-level reduction favors cyanobacteria blooms in tropical shallow lakes . Hydrobiologia , 770 ( 1 ): 145 - 164 , https://doi.org/10.1007/s10750-015-2578-5 https://doi.org/10.1007/s10750-015-2578-5 .
Cardoso M M L , Sousa W , Brasil J et al . 2022 . Prolonged drought increases environmental heterogeneity and plankton dissimilarity between and within two semiarid shallow lakes over time . Hydrobiologia , 849 ( 17-18 ): 3995 - 4014 , https://doi.org/10.1007/s10750-022-04882-0 https://doi.org/10.1007/s10750-022-04882-0 .
Connell J H , Orias E . 1964 . The ecological regulation of species diversity . The American Naturalist , 98 ( 903 ): 399 - 414 , https://doi.org/10.1086/282335 https://doi.org/10.1086/282335 .
Coops H , Hosper S H . 2002 . Water-level management as a tool for the restoration of shallow lakes in the Netherlands . Lake and Reservoir Management , 18 ( 4 ): 293 - 298 , https://doi.org/10.1080/07438140209353935 https://doi.org/10.1080/07438140209353935 .
Costa M R A , Menezes R F , Sarmento H et al . 2019 . Extreme drought favors potential mixotrophic organisms in tropical semi-arid reservoirs . Hydrobiologia , 831 ( 1 ): 43 - 54 , https://doi.org/10.1007/s10750-018-3583-2 https://doi.org/10.1007/s10750-018-3583-2 .
da Costa M R A , Attayde J L , Becker V . 2016 . Effects of water level reduction on the dynamics of phytoplankton functional groups in tropical semi-arid shallow lakes . Hydrobiologia , 778 ( 1 ): 75 - 89 , https://doi.org/10.1007/s10750-015-2593-6 https://doi.org/10.1007/s10750-015-2593-6 .
Devercelli M . 2006 . Phytoplankton of the middle Paraná River during an anomalous hydrological period: a morphological and functional approach . Hydrobiologia , 563 ( 1 ): 465 - 478 , https://doi.org/10.1007/s10750-006-0036-0 https://doi.org/10.1007/s10750-006-0036-0 .
Di Baldassarre G , Martinez F , Kalantari Z et al . 2017 . Drought and flood in the Anthropocene: feedback mechanisms in reservoir operation . Earth System Dynamics , 8 ( 1 ): 225 - 233 , https://doi.org/10.5194/esd-8-225-2017 https://doi.org/10.5194/esd-8-225-2017 . https://do 10.5194/esd-8-225-2017 http://dx.doi.org/10.5194/esd-8-225-2017
Diniz L P , Petsch D K , Mantovano T et al . 2023 . A prolonged drought period reduced temporal β diversity of zooplankton, phytoplankton, and fish metacommunities in a Neotropical floodplain . Hydrobiologia , 850 ( 5 ): 1073 - 1089 , https://doi.org/10.1007/s10750-023-05140-7 https://doi.org/10.1007/s10750-023-05140-7 .
Edwards K F , Thomas M K , Klausmeier C A et al . 2016 . Phytoplankton growth and the interaction of light and temperature: a synthesis at the species and community level . Limnology and Oceanography , 61 ( 4 ): 1232 - 1244 , https://doi.org/10.1002/lno.10282 https://doi.org/10.1002/lno.10282 .
Eppley R W . 1972 . Temperature and phytoplankton growth in the sea . Fishery Bulletin , 70 ( 4 ): 1063 - 1085 .
E W Rice , APHA . 2012 . Standard Methods for the Examination of Water and Wastewater. 22 nd edn. American Public Health Association, American Water Works Association, Water Environment Federation . Washington, DC .
Ferris J A , Lehman J T . 2007 . Interannual variation in diatom bloom dynamics: roles of hydrology, nutrient limitation, sinking, and whole lake manipulation . Water Research , 41 ( 12 ): 2551 - 2562 , https://doi.org/10.1016/j.watres.2007.03.027 https://doi.org/10.1016/j.watres.2007.03.027 .
Gallouli E , Ali H O , Aamiri A . 2020 . Impact of climate change on the phytoplankton community of the Aglou-Sidi Ifni coastline (Moroccan Atlantic coast) . E3S Web of Conferences , 183 : 01004 , https://doi.org/10.1051/e3sconf/202018301004 https://doi.org/10.1051/e3sconf/202018301004 .
Hall J W , Hannaford J , Hegerl G . 2022 . Drought risk in the anthropocene . Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences , 380 ( 2238 ): 20210297 , https://doi.org/10.1098/rsta.2021.0297 https://doi.org/10.1098/rsta.2021.0297
Halsband-Lenk C , Pierson J J , Leising A W . 2005 . Reproduction of Pseudocalanus newmani (Copepoda: Calanoida) is deleteriously affected by diatom blooms—a field study . Progress in Oceanography , 67 ( 3-4 ): 332 - 348 , https://doi.org/10.1016/j.pocean.2005.09.003 https://doi.org/10.1016/j.pocean.2005.09.003 .
Hardin G . 1960 . The competitive exclusion principle . Science , 131 ( 3409 ): 1292 - 1297 , https://doi.org/10.1126/science.131.3409.1292 https://doi.org/10.1126/science.131.3409.1292 .
Horn H , Paul L , Horn W et al . 2011 . Long-term trends in the diatom composition of the spring bloom of a German reservoir: is Aulacoseira subarctica favoured by warm winters? Freshwater Biology , 56 ( 12 ): 2483 - 2499 , https://doi.org/10.1111/j.1365-2427.2011.02674.x https://doi.org/10.1111/j.1365-2427.2011.02674.x .
Howard K , Noble P . 2018 . Hydrological perturbations drive rapid shifts in phytoplankton biodiversity and population dynamics in Butte Lake (Lassen Volcanic National Park, California) . Lake and Reservoir Management , 34 ( 1 ): 21 - 41 , https://doi.org/10.1080/10402381.2017.1360418 https://doi.org/10.1080/10402381.2017.1360418 .
Huisman J , Codd G A , Paerl H W et al . 2018 . Cyanobacterial blooms . Nature Reviews Microbiology , 16 ( 8 ): 471 - 483 , https://doi.org/10.1038/s41579-018-0040-1 https://doi.org/10.1038/s41579-018-0040-1 .
Huston M A . 2014 . Disturbance, productivity, and species diversity: empiricism vs. logic in ecological theory . Ecology , 95 ( 9 ): 2382 - 2396 , https://doi.org/10.1890/13-1397.1 https://doi.org/10.1890/13-1397.1 .
Hutchinson G E . 1961 . The paradox of the plankton . The American Naturalist , 95 ( 882 ): 137 - 145 , https://doi.org/10.1086/282171 https://doi.org/10.1086/282171 .
Istvánovics V , Somlyódy L , Clement A . 2002 . Cyanobacteria-mediated internal eutrophication in shallow Lake Balaton after load reduction . Water Research , 36 ( 13 ): 3314 - 3322 , https://doi.org/10.1016/S0043-1354(02)00036-2 https://doi.org/10.1016/S0043-1354(02)00036-2 .
Janatian N , Olli K , Cremona F et al . 2020 . Atmospheric stilling offsets the benefits from reduced nutrient loading in a large shallow lake . Limnology and Oceanography , 65 ( 4 ): 717 - 731 , https://doi.org/10.1002/lno.11342 https://doi.org/10.1002/lno.11342 .
Janssen A B G , Droppers B , Kong X Z et al . 2021 . Characterizing 19 thousand Chinese lakes, ponds and reservoirs by morphometric, climate and sediment characteristics . Water Research , 202 : 117427 , https://doi.org/10.1016/j.watres.2021.117427 https://doi.org/10.1016/j.watres.2021.117427 .
Jupp D L B , Kirk J T O , Harris G P . 1994 . Detection, identification and mapping of cyanobacteria-using remote sensing to measure the optical quality of turbid inland waters . Australian Journal of Marine and Freshwater Research , 45 ( 5 ): 801 - 828 , https://doi.org/10.1071/MF9940801 https://doi.org/10.1071/MF9940801 . https://do 10.1071/mf9940801 http://dx.doi.org/10.1071/mf9940801
Kibuye F A , Zamyadi A , Wert E C . 2021 . A critical review on operation and performance of source water control strategies for cyanobacterial blooms: Part I-chemical control methods . Harmful Algae , 109 : 102099 , https://doi.org/10.1016/j.hal.2021.102099 https://doi.org/10.1016/j.hal.2021.102099 .
Kiss K T , Genkal S I . 1993 . Winter blooms of centric diatoms in the River Danube and in its side-arms near Budapest (Hungary) . Hydrobiologia , 269 ( 1 ): 317 - 325 , https://doi.org/10.1007/BF00028030 https://doi.org/10.1007/BF00028030 .
Kong X Z , Seewald M , Dadi T et al . 2021 . Unravelling winter diatom blooms in temperate lakes using high frequency data and ecological modeling . Water Research , 190 : 116681 , https://doi.org/10.1016/j.watres.2020.116681 https://doi.org/10.1016/j.watres.2020.116681 .
Kruk C , Piccini C , Devercelli M et al . 2021 . A trait-based approach predicting community assembly and dominance of microbial invasive species . Oikos , 130 ( 4 ): 571 - 586 , https://doi.org/10.1111/oik.07694 https://doi.org/10.1111/oik.07694 .
Lehman J T , Platte R A , Ferris J A . 2007 . Role of hydrology in development of a vernal clear water phase in an urban impoundment . Freshwater Biology , 52 ( 9 ): 1773 - 1781 , https://doi.org/10.1111/j.1365-2427.2007.01808.x https://doi.org/10.1111/j.1365-2427.2007.01808.x .
Liang Z Y , Soranno P A , Wagner T . 2020 . The role of phosphorus and nitrogen on chlorophyll a : evidence from hundreds of lakes . Water Research , 185 : 116236 , https://doi.org/10.1016/j.watres.2020.116236 https://doi.org/10.1016/j.watres.2020.116236 . https://do 10.1016/j.watres.2020.116236 http://dx.doi.org/10.1016/j.watres.2020.116236
Litchman E , Klausmeier C A . 2008 . Trait-based community ecology of phytoplankton . Annual Review of Ecology, Evolution, and Systematics , 39 : 615 - 639 , https://doi.org/10.1146/annurev.ecolsys.39.110707.173549 https://doi.org/10.1146/annurev.ecolsys.39.110707.173549 . https://do 10.1146/annurev.ecolsys.39.110707.173549 http://dx.doi.org/10.1146/annurev.ecolsys.39.110707.173549
Ma P M , Shi L D , Zhao X F et al . 2013 . A bloom-forming freshwater diatom: Achnanthidium catenatum . Journal of Lake Sciences , 25 ( 1 ): 156 - 162 , https://doi.org/10.18307/2013.0120. https://doi.org/10.18307/2013.0120. (in Chinese with English abstract)
McCarthy J J , Eppley R W . 1972 . A comparison of chemical, isotopic, and enzymatic methods for measuring nitrogen assimilation of marine phytoplankton . Limnology and Oceanography , 17 ( 3 ): 371 - 382 , https://doi.org/10.4319/lo.1972.17.3.0371 https://doi.org/10.4319/lo.1972.17.3.0371 .
Messager M L , Lehner B , Grill G et al . 2016 . Estimating the volume and age of water stored in global lakes using a geo-statistical approach . Nature Communications , 7 : 13603 , https://doi.org/10.1038/ncomms13603 https://doi.org/10.1038/ncomms13603 .
Milly P C D , Dunne K A , Vecchia A V . 2005 . Global pattern of trends in streamflow and water availability in a changing climate . Nature , 438 ( 7066 ): 347 - 350 , https://doi.org/10.1038/nature04312 https://doi.org/10.1038/nature04312 .
Mouchet M A , Villéger S , Mason N W H et al . 2010 . Functional diversity measures: an overview of their redundancy and their ability to discriminate community assembly rules . Functional Ecology , 24 ( 4 ): 867 - 876 , https://doi.org/10.1111/j.1365-2435.2010.01695.x https://doi.org/10.1111/j.1365-2435.2010.01695.x .
Naselli-Flores L , Barone R . 2005 . Water-level fluctuations in mediterranean reservoirs: setting a dewatering threshold as a management tool to improve water quality . Hydrobiologia , 548 ( 1 ): 85 - 99 , https://doi.org/10.1007/s10750-005-1149-6 https://doi.org/10.1007/s10750-005-1149-6 .
Naselli-Flores L , Padisák J , Dokulil M T et al . 2003 . Equilibrium/steady-state concept in phytoplankton ecology . Hydrobiologia , 502 ( 1-3 ): 395 - 403 , https://doi.org/10.1023/B:HYDR.0000004297.52645.59 https://doi.org/10.1023/B:HYDR.0000004297.52645.59 .
Oberski D . 2014 . lavaan. survey: an R package for complex survey analysis of structural equation models . Journal of Statistical Software , 57 ( 1 ): 1 - 27 , https://doi.org/10.18637/jss.v057.i01 https://doi.org/10.18637/jss.v057.i01 . https://do 10.18637/jss.v057.i01 http://dx.doi.org/10.18637/jss.v057.i01
Oliveira C Y B , Oliveira C D L , Almeida A J G et al . 2019 . Phytoplankton responses to an extreme drought season: a case study at two reservoirs from a semiarid region, Northeastern Brazil . Journal of Limnology , 78 ( 2 ): 176 - 184 , https://doi.org/10.4081/jlimnol.2019.1869 https://doi.org/10.4081/jlimnol.2019.1869 .
Portielje R , Van der Molen D T . 1999 . Relationships between eutrophication variables: from nutrient loading to transparency . Hydrobiologia , 408 - 409 : 375 - 387 , https://doi.org/10.1023/A:1017090931476 https://doi.org/10.1023/A:1017090931476 .
Ren J , Zhu G W , Jin Y W et al . 2017 . Combined effects of water exchange rate and nutrient on diatom proliferation in Hengshan Reservoir, Taihu Basin . Journal of Lake Sciences , 29 ( 3 ): 604 - 616 , https://doi.org/10.18307/2017.0309. https://doi.org/10.18307/2017.0309. (in Chinese with English abstract) . https://do 10.18307/2017.0309 http://dx.doi.org/10.18307/2017.0309
Reynolds C S , Huszar V , Kruk C et al . 2002 . Towards a functional classification of the freshwater phytoplankton . Journal of Plankton Research , 24 ( 5 ): 417 - 428 , https://doi.org/10.1093/plankt/24.5.417 https://doi.org/10.1093/plankt/24.5.417 .
Reynolds C S , Padisák J , Sommer U . 1993 . Intermediate disturbance in the ecology of phytoplankton and the maintenance of species diversity: a synthesis . Hydrobiologia , 249 ( 1-3 ): 183 - 188 , https://doi.org/10.1007/BF00008853 https://doi.org/10.1007/BF00008853 .
Salmaso N , Naselli-Flores L , Padisák J . 2015 . Functional classifications and their application in phytoplankton ecology . Freshwater Biology , 60 ( 4 ): 603 - 619 , https://doi.org/10.1111/fwb.12520 https://doi.org/10.1111/fwb.12520 .
Schindler D W . 1974 . Eutrophication and recovery in experimental lakes: implications for lake management . Science , 184 ( 4139 ): 897 - 899 , https://doi.org/10.1126/science.184.4139.897 https://doi.org/10.1126/science.184.4139.897 .
Sommer U , Gliwicz Z M , Lampert W et al . 1986 . The peg-model of seasonal succession of planktonic events in fresh waters . Archiv für Hydrobiologie , 106 ( 4 ): 433 - 471 , https://doi.org/10.1127/archiv-hydrobiol/106/1986/433 https://doi.org/10.1127/archiv-hydrobiol/106/1986/433 .
Strom S . 2002 . Novel interactions between phytoplankton and microzooplankton: their influence on the coupling between growth and grazing rates in the sea . Hydrobiologia , 480 ( 1-3 ): 41 - 54 , https://doi.org/10.1023/A:1021224832646 https://doi.org/10.1023/A:1021224832646 .
Tilahun S , Kifle D . 2022 . Limnological responses of a shallow tropical reservoir to recent incidence of hydro-climatic anomaly suggest potential challenges of future restoration efforts . Environmental Science and Pollution Research , 29 ( 7 ): 10729 - 10739 , https://doi.org/10.1007/s11356-021-16433-6 https://doi.org/10.1007/s11356-021-16433-6 . https://do 10.1007/s11356-021-16433-6 http://dx.doi.org/10.1007/s11356-021-16433-6
Van Loon A F , Gleeson T , Clark J et al . 2016 . Drought in the anthropocene . Nature Geoscience , 9 ( 2 ): 89 - 91 , https://doi.org/10.1038/ngeo2646 https://doi.org/10.1038/ngeo2646 .
Wan W H , Zhao J S , Li H Y et al . 2017 . Hydrological drought in the anthropocene: impacts of local water extraction and reservoir regulation in the U.S. Journal of Geophysical Research : Atmospheres , 122 ( 21 ): 11313 - 11328 , https://doi.org/10.1002/2017JD026899 https://doi.org/10.1002/2017JD026899 .
Xu Y P , Wang L , Tang Q H et al . 2023 . The relationship between phytoplankton diversity and ecosystem functioning changes with disturbance regimes in tropical reservoirs . Ecosystems , 26 ( 4 ): 752 - 767 , https://doi.org/10.1007/s10021-022-00791-4 https://doi.org/10.1007/s10021-022-00791-4 .
Yatigammana S K , Ileperuma O A , Perera M B U . 2011 . Water pollution due to a harmful algal bloom: a preliminary study from two drinking water reservoirs in Kandy, Sri Lanka . Journal of the National Science Foundation of Sri Lanka , 39 ( 1 ): 91 - 94 , https://doi.org/10.4038/jnsfsr.v39i1.2930 https://doi.org/10.4038/jnsfsr.v39i1.2930 . https://do 10.4038/jnsfsr.v39i1.2930 http://dx.doi.org/10.4038/jnsfsr.v39i1.2930
Zhou H , Liu Y B . 2018 . Spatio-temporal pattern of meteorological droughts and its possible linkage with climate variability . International Journal of Climatology , 38 ( 4 ): 2082 - 2096 , https://doi.org/10.1002/joc.5319 https://doi.org/10.1002/joc.5319 .
Zhu G W , Jin Y W , Ren J et al . 2016 . Characteristics of diatom blooms in a reservoir-water supply area and the countermeasures in Taihu Basin, China . Journal of Lake Sciences , 28 ( 1 ): 9 - 21 , https://doi.org/10.18307/2016.0102. https://doi.org/10.18307/2016.0102. (in Chinese with English abstract)
Zohary T , Ostrovsky I . 2011 . Ecological impacts of excessive water level fluctuations in stratified freshwater lakes . Inland Waters , 1 ( 1 ): 47 - 59 , https://doi.org/10.5268/IW-1.1.406 https://doi.org/10.5268/IW-1.1.406 .
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