Supplementary Materials: Figure S1

Home , Boergesenia, Caulerpa chemnitzia, Chlorochytrium, Erythrotrichia, Erythrotrichiaceae, Hydroclathrus

1 Supplementary materials: Figure S1. Coral reef in Xiaodong Hai locality: (A) The southern part of the locality; (B) Reef slope; (C) Reef-flat, the upper subtidal zone; (D) Reef-flat, the lower intertidal zone.

Figure S2. Algal communities in Xiaodong Hai at different seasons of 2016–2019: (A) Community of colonial blue-green algae, transect 1, the splash zone, the dry season of 2019; (B) Monodominant community of the red crust alga Hildenbrandia rubra, transect 3, upper intertidal, the rainy season of 2016; (C) Monodominant community of the red alga Gelidiella bornetii, transect 3, upper intertidal, the rainy season of 2018; (D) Bidominant community of the red alga Laurencia decumbens and the green Ulva clathrata, transect 3, middle intertidal, the dry season of 2019; (E) Polydominant community of algal turf with the mosaic dominance of red algae Tolypiocladia glomerulata (inset a), Palisada papillosa (center), and Centroceras clavulatum (inset b), transect 2, middle intertidal, the dry season of 2019; (F) Polydominant community of algal turf with the mosaic dominance of the red alga Hypnea pannosa and green Caulerpa chemnitzia, transect 1, lower intertidal, the dry season of 2016; (G) Polydominant community of algal turf with the mosaic dominance of brown algae Padina australis (inset a) and Hydroclathrus clathratus (inset b), the red alga Acanthophora spicifera (inset c) and the green alga Caulerpa chemnitzia, transect 1, lower intertidal, the dry season of 2019; (H) Sargassum spp. belt, transect 1, upper subtidal, the dry season of 2016. 2

Table S1. List of the seaweeds of Xiaodong Hai in 2016-2019. The abundance of taxa: rare sightings (+); common (++); abundant (+++). Distribution of species in the geographical zones (Dg): T − tropical; S − subtropical; M − temperate; Ar − Arctic; An − Antarctic; T,S,M,Ar,An − from tropics to Arctic and Antarctic; T,S,M,An − from tropics to Antarctic; T,S,M − tropics to (cold) temperate zones; T,S − tropics and subtropics of Atlantic, Indian and Pacific Oceans; T,S,(I-P) − tropical and subtropical Indo- Pacific или только Pacific (P). Tidal zone: (i) − the intertidal zone; (m) − the zone between the intertidal and subtidal zones; (s) − the upper subtidal zone. Life forms (Lf): Ep − epiphytic; En − endophytic; Fl − floating; Ar − artificial substratum. Columns in “Years and seasons of samplings”: 16-d (dry season of 2016); 16-r (rainy season of 2016); 17-d (dry season of 2017); 18-r (rainy season of 2018); 19-d (dry season of 2018).

Species, varieties and forms Lf Dg Tidal Years and seasons of samplings ID zone

i m s 16- 16-r 17-d 18-r 19-d d

DIVISION RHODOPHYTA

CLASS STYLONEMATOPHYCEAE

ORDER STYLONEMATALES

Family Stylonemataceae

Bangiopsis dumontioides (P.Crouan & H. Crouan) Ar T,S * + + + V. Krishnamurthy

Chroodactylon ornatum (C. Agardh) Basson Ep T,S,M * * * + + +

Stylonema alsidii (Zanardini) K.M. Drew Ep T,S,M * * + + + + ++

CLASS COMPSOPOGONOPHYCEAE

ORDER ERYTHROPELTALES

Family Erythrotrichiaceae

Erythrotrichia carnea (Dillwyn) J. Agardh Ep T,S,M * * * ++ + + ++ ++

Ar,An

Erythrocladia irregularis Rosenvinge Ep T,S,MAr,An * * + + + + +

Sahlingia subintegra (Rosenvinge) Kornmann Ep T,S,M * * + + ++ + ++

CLASS FLORIDEOPHYCEAE

ORDER HILDENBRANDIALES

Family Hildenbraniaceae

Hildenbrandia rubra (Sommerfelt) Meneghini HS T,S,M * * ++ ++ ++ ++ ++

Ar,An

ORDER ACROCHAETIALES 4

Species, varieties and forms Lf Dg Tidal Years and seasons of samplings ID zone

i m s 16- 16-r 17-d 18-r 19-d d

Family Acrochaetiaceae

Acrochaetium microscopicum (Nägeli ex Kützing) Ep T,S,M * * + + ++ + ++ Nägeli Ar

Acrochaetium subseriatum Børgesen♣ Ep T,S, * + + + + +

(I-P)

ORDER NEMALIALES

Family Galaxauraceae

Dichotomaria marginata (J. Ellis & Solander) HS T,S * + Lamarck

Tricleocarpa cylindrica (J. Ellis & Solander) HS T,S * * ++ ++ ++ + + Huisman & Borowitzka

Family Liagoraceae

Ganonema farinosum (J.V. Lamouroux) K.C. Fan & HS T,S * * + + + Yung C. Wang

Ganonema pinnatum (Harvey) Huisman HS T,S, * +

(I-P)

Liagora ceranoides J.V. Lamouroux HS T,S * * + + +

ORDER COLACONEMATALES

Family Colaconemataceae

Colaconema daviesii (Dillwyn) Stegenga Ep T,S,M * * ++ + + + +

Ar,An

Colaconema gracile (Børgesen) Ateweberhan & Ep T,S * * + + + ++ Prud'homme van Reine

Colaconema hypneae (Børgesen) A.A. Santos & Ep T,S * * + + C.W.N. Moura

Colaconema robustum (Børgesen) Huisman & Ep T,S * * + + + Woelkerling ORDER CORALLINALES

Family Corallinaceae

Jania adhaerens J.V. Lamouroux HS T,S * * + +++ + + ++

Jania capillacea Harvey HS T,S,(I-P) * * ++ +++ + + +

Jania pumila J.V. Lamouroux HS T,S * +

Ep 5

Species, varieties and forms Lf Dg Tidal Years and seasons of samplings ID zone

i m s 16- 16-r 17-d 18-r 19-d d

Jania ungulata f. brevior (Yendo) Yendo HS T,S,(I-P) * * + + ++ + ++

Pneophyllum fragile Kützing HS T,S,M * * + + +

Family Hydrolithaceae

Hydrolithon boreale (Foslie) Y.M. Chamberlain Ep T,S,M * * + + + + ++

Hydrolithon farinosum (J.V. Lamouroux) Penrose & Ep T,S,M * * * + + + ++ ++ Y.M. Chamberlain

Family Lithophyllaceae

Amphiroa anceps (Lamarck) Decaisne HS T,S, * +

(I-P)

Amphiroa beauvoisii J.V. Lamouroux HS T,S * * ++

Amphiroa foliacea J.V. Lamouroux HS T,S, * * ++ + + + +++

(I-P)

Amphiroa fragilissima (Linnaeus) J.V. Lamouroux HS T,S * * ++ + ++ + +++

Lithophyllum bamleri (Heydrich) Heydrich HS T,S,(I-P) * +

ORDER AHNFELTIALES

Family Ahnfeltiaceae

Ahnfeltia yinggehaiensis B.-M. Xia & Y.-Q. Zhang HS China * +

ORDER BONNEMAISONIALES

Family Bonnemaisoniaceae

Asparagopsis taxiformis (Delile) Trevisan HS T,S * * + +++ + + ++ [Falkenbergia hillebrandii, Sporophytic stage of Asparagopsis taxiformis]

ORDER CERAMIALES

Family Ceramiaceae

Antithamnion antillanum Børgesen Ep T,S * * + + + + +

Centroceras clavulatum (C. Agardh) Montagne HS T,S * * * +++ +++ ++ ++ +++ Ep

Ceramium aduncum Nakamura Ep T,S, * + ++ + + +

(I-P)

Ceramium affine Setchell & N.L. Gardner Ep T,S * + 6

Species, varieties and forms Lf Dg Tidal Years and seasons of samplings ID zone

i m s 16- 16-r 17-d 18-r 19-d d

Ceramium camouii E.Y. Dawson Ep T,S, * * + + HS (I-P)

Ceramium cimbricum H.E. Petersen Ep T,S,M * + +++ + + +

Ceramium cingulatum Weber Bosse Ep T,S * * * + + ++

Ceramium macilentum J. Agardh Ep T,S, * + +

HS (I-P)

Ceramium marshallense E.Y. Dawson Ep T,S, * * * + + + HS (I-P)

Ceramium procumbens Setchell & N.L. Gardner Ep T,S, * * + + +

HS (I-P)

Ceramium tenerrimum (G. Martens) Okamura Ep T,S * * * ++ + + + ++

Ceramium vagans P.C. Silva Ep T,S * * + + +

Corallophila kleiwegii Weber Bosse Ep T,S, * * * + ++ + + + HS (I-P)

Gayliella mazoyerae T.O. Cho, Fredericq & Ep T,S * * * + +++ ++ ++ +++ Hommersand HS

Family Delesseriaceae

Taenioma perpusillum (J. Agardh) J. Agardh Ep, T,S * + +++ HS

Family Rhodomelaceae

Acanthophora muscoides (Linnaeus) Bory HS T,S * + + ++

Acanthophora spicifera (M. Vahl) Børgesen HS T,S * * + +++

Chondria pygmaea Garbary & Vandermeulen Ep T,S * + +

Chondria repens Børgesen Ep T,S, * + + + + +++

(I-P)

Chondrophycus articulatus (C.K. Tseng) K.W. Nam HS T,S, * +

(I-P)

Herposiphonia parca Setchell Ep T,S, * + ++

(I-P)

Herposiphonia secunda (C. Agardh) Ambronn Ep T,S * * * + +

Herposiphonia secunda f. tenella (C. Agardh) M.J. HS T,S * * * + + + +++ + Wynne

Laurencia decumbens Kützing HS T,S * +++ + + +++ 7

Species, varieties and forms Lf Dg Tidal Years and seasons of samplings ID zone

i m s 16- 16-r 17-d 18-r 19-d d

Laurencia pinnata Yamada HS T,S, * * + +

(I-P)

Leveillea jungermannioides (Hering & G. Martens) Ep T,S, * * + + + + ++ Harvey (I-P)

Melanothamnus ferulaceus (Suhr ex J. Agardh) Ep T,S * + + + ++ + Diaz-Tapia & Maggs

Melanothamnus pseudovillum (Hollenberg) Díaz- HS T,S * + Tapia & Maggs

Melanothamnus savatieri (Hariot) Díaz-Tapia & HS T,S * + Maggs

Melanothamnus sphaerocarpus (Børgesen) Díaz- Ep T,S * * * + Tapia & Maggs

Palisada concreta (A.B. Cribb) K.W. Nam HS T,S, * * + +

(I-P)

Palisada parvipapillata (C.K. Tseng) K.W. Nam HS T,S, * + +

(I-P)

Palisada papillosa (C. Agardh) K.W. Nam HS T,S, * * * + + + + +++

(I-P)

Polysiphonia ferulacea Suhr ex J. Agardh f. Ep China * + + implicata C.K. Tseng

Polysiphonia scopulorum Harvey Ep T,S * + +

Polysiphonia subtilissima Montagne Ep T,S * * + + +

Polysiphonia villum J. Agardh Ep T,S * * + + + ++ +

Tolypiocladia glomerulata (C. Agardh) F. Schmitz HS T,S,(I-P) * * + + + + +++ Ep

Family Spyridiaceae

Spyridia filamentosa (Wulfen) Harvey HS T,S * * +++ + ++ + + Ep

Family Wrangeliaceae

Anotrichium tenue (C. Agardh) Nägeli Ep T,S * * ++ + + + ++

Griffithsia metcalfii C.K. Tseng HS T,S, * * + +

(I-P)

Wrangelia argus (Montagne) Montagne HSEp T,S * * + + + + ++

Wrangelia hainanensis C.K. Tseng HS China * + 8

Species, varieties and forms Lf Dg Tidal Years and seasons of samplings ID zone

i m s 16- 16-r 17-d 18-r 19-d d

ORDER GELIDIALES

Family Gelidiaceae

Gelidium crinale (Hare ex Turner) Gaillon HS T,S,M * * + +

Gelidium pusillum (Stackhouse) Le Jolis HS T,S * * ++ + + +++ ++

Gelidium pusillum var. cylindricum W.R. Taylor HS T,S * * ++ + + + +

Gelidium pusillum var. pacificum W.R. Taylor HS T,S * +

Family Gelidiellaceae

Gelidiella acerosa (Forsskål) Feldmann & Hamel HS T,S * ++ + + + +

Gelidiella bornetii (Weber Bosse) Feldmann & HS T,S, * * +++ ++ +++ +++ +++ Hamel (I-P)

Millerella pannosa (Feldmann) G.H. Boo & L. Le HSEp T,S * + + Gall

Family Pterocladiaceae

Pterocladiella caerulescens (Kützing) Santelices & HS T,S * * + + + +++ + Hommersand

Pterocladiella capillacea (S.G. Gmelin) HS T,S,M * * + + +

Santelices & Hommersand

ORDER GIGARTINALES

Family Caulacanthaceae

Caulacanthus ustulatus (Mertens ex Turner) T,S * + Kützing Family Cystocloniaceae

Hypnea cervicornis J. Agardh HS T,S * + +

Hypnea pannosa J. Agardh HS T,S * * +++ + +++ + +++

Hypnea spinella (C. Agardh) Kützing HS T,S * * * + +++ + + +

Hypnea valentiae (Turner) Montagne HS T,S * * * + + ++ + +

Family Gigartinaceae

Chondracanthus intermedius (Suringar) HS T,S, * + + Hommersand (I-P)

Family Phyllophoraceae

Ahnfeltiopsis pygmaea (J. Agardh) P.C. Silva & HS T,S, * + DeCew (I-P) 9

Species, varieties and forms Lf Dg Tidal Years and seasons of samplings ID zone

i m s 16- 16-r 17-d 18-r 19-d d

ORDER PEYSSONNELIALES

Family Peyssonneliaceae

Peyssonnelia boergesenii Weber Bosse HS T,S * + + + +++ +

Peyssonnelia conchicola Piccone & Grunow HS T,S * * * +

Peyssonnelia rubra (Greville) J. Agardh HS T,S * * * + + ++ ++ ++

ORDER GRACILARIALES

Family Gracilariaceae

Gracilaria canaliculata Sonder HS T,S, * * +

(I-P)

Gracilaria salicornia (C. Agardh) E.Y. Dawson HS T,S, * * + +

(I-P)

Hydropuntia edulis (S.G. Gmelin) Gurgel & HS T,S, * * + + Fredericq [Gracilaria edulis (S.G. Gmelin) P.C. Silva] (I-P)

Hydropuntia eucheumatoides (Harvey) Gurgel & HS T,S, * ++ ++ ++ + +++ Fredericq [Gracilaria eucheumatoides Harvey] (I-P)

ORDER HALYMENIALES

Family Halymeniaceae

Grateloupia filicina (J.V. Lamouroux) C. Agardh HS T,S,M * * +

Halymenia maculata J. Agardh HS T,S, * + +

(I-P)

ORDER RHODYMENIALES

Family Champiaceae

Champia parvula (C. Agardh) Harvey HS T,S,M * * + +

Champia vieillardii Kützing HS T,S * +

Coelothrix irregularis (Harvey) Børgesen HS T,S * * + + + ++ +

Family Lomentariaceae

Ceratodictyon intricatum (C. Agardh) R.E. Norris HS T,S * * * + + ++ 10

Species, varieties and forms Lf Dg Tidal Years and seasons of samplings ID zone

i m s 16- 16-r 17-d 18-r 19-d d

Ceratodictyon scoparium (Montagne & Millardet) HS T,S * + + R.E. Norris

Ceratodictyon spongiosum Zanardini HS T,S, * + + + ++ ++

(I-P)

Lomentaria corallicola Børgesen HS T,S * * * + +

PHYLUM OCHROPHYTA

CLASS PHAEOPHYCEAE

ORDER ECTOCARPALES

Family Acinetosporaceae

Feldmannia irregularis (Kützing) G. Hamel HSEp T,S * * + +

Feldmannia mitchelliae (Harvey) H.-S. Kim HS T,S,M * * * + +

Hincksia conifera (Børgesen) I.A. Abbott HS T,S * * * ++ + + +

Family Chordariaceae

Myrionema strangulans Greville Ep T,S,M * +

Family Scytosiphonaceae

Pseudochnoospora implexa (J.Agardh) Santiañez, HS T,S * * + + + + ++ G.Y. Cho & Kogame [Chnoospora implexa J. Agardh]

Colpomenia sinuosa (Mertens ex Roth) Derbès & HS T,S,M * * * ++ + +++ + + Solier Ep An

Hydroclathrus clathratus (C. Agardh) M.A. Howe HS T,S * * +++ + ++ + +++

Hydroclathrus tenuis C.K. Tseng & Lu Baoren HS T,S * * + + + + +

Rosenvingea intricata (J. Agardh) Børgesen HS T,S * +

ORDER RALFSIALES

Family Neoralfsiaceae

Neoralfsia expansa (J. Agardh) P.-E. Lim & H. HS T,S * * + ++ +++ ++ + Kawai ex Cormaci & G. Furnari

ORDER SPHACELARIALES

Family Sphacelariaceae

Sphacelaria fusca (Hudson) S.F. Gray T,S,M * +

An 11

Species, varieties and forms Lf Dg Tidal Years and seasons of samplings ID zone

i m s 16- 16-r 17-d 18-r 19-d d

Sphacelaria novae-hollandiae Sonder Ep T,S * * + + + + +

Sphacelaria rigidula Kützing Ep T,S,M * * * + + ++ +++ +

Sphacelaria tribuloides Meneghini Ep T,S * * * +++ ++ + +++

ORDER DICTYOTALES

Family Dictyotaceae

Canistrocarpus cervicornis (Kützing) De Paula & HS T,S * * + + + + ++ De Clerck

Dictyota bartayresiana J.V. Lamouroux HS T,S * + + + + +

Dictyota friabilis Setchell HS T,S, * * + + +

(I-P)

Dictyota implexa (Desfontaines) J.V. Lamouroux HS T,S * * ++ + + ++

Lobophora variegata (J.V. Lamouroux) Womersley HS T,S * * * ++ +++ ++ + ++ ex E.C. Oliveira

Padina australis Hauck HS T,S, * * +++ ++ ++ + +++

(I-P)

Padina minor Yamada HS T,S, * * * +++ + +++ + ++

(I-P)

Padina ryukyuana Y.P. Lee & Kamura HS T,S Asia * ++

ORDER FUCALES

Family Sargassaceae

Sargassum aquifolium (Turner) C. Agardh HS T,S, * + ++ + ++ [Sargassum crassifolium J. Agardh] (I-P)

Sargassum beihaiense C.K. Tseng & B. Lu HS China * + ++

Sargassum crispifolium Yamada HS T,S, * * + +

(I-P)

Sargassum denticarpum Ajisaka HS T,S, * * ++ +++

(I-P)

Sargassum ilicifolium (Turner) HS T,S, * * + + C.Agardh [Sargassum duplicatum (J. Agardh) J. Agardh] (I-P)

Sargassum feldmannii Pham-Hoàng Hô HS T,S, * * ++ +++ ++

(I-P) 12

Species, varieties and forms Lf Dg Tidal Years and seasons of samplings ID zone

i m s 16- 16-r 17-d 18-r 19-d d

Sargassum hemiphyllum var. chinense J. Agardh HS T,S, * * ++ + +++

( P)

Sargassum huangluense C.K. Tseng & Lu Baroen Fl China + +

Sargassum ilicifolium (Turner) C. Agardh HS T,S, * + + + ++

(I-P)

Sargassum ilicifolium (Turner) C. Agardh HS T,S, * + + [Sargassum sandei Reinbold] ( P)

Sargassum mcclurei Setchell HS T,S, * + +

(I-P)

Sargassum microcystum J. Agardh HS T,S, * * +

(I-P)

Sargassum oligocystum Montagne HS T,S, * * ++ + +++

(I-P)

Sargassum polycystum (C. Agardh) HS T,S, * * +++ ++ ++ + ++

(I-P)

Sargassum sanyaense Tseng & Lu Baoren HS T,S, * * ++ ++ + +

(I-P)

Sargassum tenerrimum J. Agardh HS T,S, * * + +

(I-P)

Turbinaria ornata (Turner) J. Agardh HS T,S, * * ++ ++ ++ + ++

(I-P)

Turbinaria sp. HS T,S, * * ++ + ++

(I-P)

DIVISION CHLOROPHYTA

CLASS CHLOROPHYCEAE

ORDER CHLOROCOCCALES

Family Chlorochytriaceae

Chlorochytrium cohnii E.P. Wright En T,S,M * * + + +

ORDER CHAETOPHORALES

Family Uronemataceae 13

Species, varieties and forms Lf Dg Tidal Years and seasons of samplings ID zone

i m s 16- 16-r 17-d 18-r 19-d d

Uronema marinum Womersley Ep T,S, * + +

(I-P)

CLASS ULVOPHYCEAE

ORDER ULOTRICHALES

Family Ulotrichaceae

Ulothrix flacca (Dillwyn) Thuret Ep T,S,MAr,An * +

Ulothrix implexa (Kützing) Kützing Ep T,S,MAr,An * +

Ulothrix subflaccida Wille Ep T,S,MAr,An * +

ORDER ULVALES

Family Phaeophilaceae

Phaeophila dendroides (P. Crouan & H. Crouan) Ep T,S + + Batters

Family Ulvellaceae

Acrochaete geniculata (N.L. Gardner) O'Kelly En T,S,M * * * + + + + ++

Ulvella lens P. Crouan & H. Crouan Ep T,S,MAr,An * * + + + + ++

Ulvella leptochaete (Huber) R. Nielsen, C.J. O'Kelly Ep T,S,M * + + + + + & B. Wysor Ar

Ulvella scutata (Reinke) R. Nielsen, C.J. O'Kelly & Ep T,S,M * + + B. Wysor Ar,An

Ulvella viridis (Reinke) R. Nielsen, C.J. O'Kelly & Ep T,S,M * * + + + + ++ B. Wysor Ar,An

Family Ulvaceae

Ulva clathrata (Roth) C. Agardh HS T,S,M * * * + ++ ++ + +++

Ar,An

Ulva compressa Linnaeus HS T,S,M * * * +

Ar,An

Ulva flexuosa Wulfen HS T,S,M * * + + ++ + +

Ar,An

Ulva lactuca Linnaeus HS T,S,M * * * + + + + +

Ulva prolifera O.F. Müller HS T,S,M * * + +

Ar 14

Species, varieties and forms Lf Dg Tidal Years and seasons of samplings ID zone

i m s 16- 16-r 17-d 18-r 19-d d

ORDER CLADOPHORALES

Family Anadyomenaceae

Anadyomene wrightii Harvey ex J.E. Gray HS T,S, * * ++ ++ + + ++

(I-P)

Family Boodleaceae

Boodlea composita (Harvey) F. Brand HS T,S * * + ++ + +

Cladophoropsis sundanensis Reinbold HS T,S * * + + + + Ep

Phyllodictyon anastomosans (Harvey) Kraft & M.J. HS T,S * * + ++ + + + Wynne Ep

Family Cladophoraceae

Chaetomorpha antennina (Bory) Kützing HS T,S * +

Chaetomorpha javanica Kützing HS T,S * + Ep

Chaetomorpha linum (O.F. Müller) Kützing HS T,S,M * * ++

Ar,An

Chaetomorpha minima Collins & Hervey HS T,S * + Ep

Cladophora cymopoliae Børgesen Ep T,S * + +

Cladophora gracilis Kützing Ep T,S,M * +

Ar,An

Cladophora laetevirens (Dillwyn) Kützing HS T,S,M * * * + + ++ + +

Cladophora patentiramea (Montagne) Kützing Ep T,S +

Cladophora vagabunda (Linnaeus) Hoek HS T,S,M * * + + + Ep

Lychaete herpestica (Montagne) M.J. HS T,S * + + Wynne [Cladophora herpestica (Montagne) Ep Kützing]

Rhizoclonium grande Børgesen HS T,S, * + + + ++ ++

(I-P)

Rhizoclonium riparium (Roth) Harvey HS T,S,M * * + +

Ar,An

Rhizoclonium sp. Ep T,S,M * + +

Family Siphonocladaceae

Boergesenia forbesii (Harvey) Feldmann HS T,S * * ++ + 15

Species, varieties and forms Lf Dg Tidal Years and seasons of samplings ID zone

i m s 16- 16-r 17-d 18-r 19-d d

Dictyosphaeria cavernosa (Forsskål) Børgesen HS T,S * * + + + + +

Dictyosphaeria versluysii Weber Bosse HS T,S * * + + +

Family Valoniaceae

Valonia utricularis (Roth) C. Agardh HS T,S * * +

ORDER BRYOPSIDALES

Family Bryopsidaceae

Bryopsis australis Sonder Ep T,S,M An * +

Bryopsis pennata J.V. Lamouroux HS T,S * * + + + Ep

Family Caulerpaceae

Caulerpa ambigua Okamura HS T,S * * + ++ ++ +

Caulerpa chemnitzia (Esper) J.V. Lamouroux HS T,S * * +++ + ++ + +++

Caulerpa nummularia Harvey ex J. Agardh HS T,S * + + +

Caulerpa racemosa (Forsskål) J. Agardh HS T,S * * * + + + + +

Caulerpa serrulata (Forsskål) J. Agardh HS T,S * * ++ + + + +

Caulerpa sertularioides (S.G. Gmelin) M. Howe HS T,S * * ++ + + ++ +

Family Udoteaceae

Penicillus sibogae A. Gepp & E.S. Gepp HS T,S, * * * + + + +

(I-P)

Rhipidosiphon javensis Montagne HS T,S * * + + + + ++

ORDER DASYCLADALES

Family Dasycladaceae

Bornetella nitida Munier-Chalmas ex Sonder HS T,S, * * + +

(I-P)

Neomeris annulata Dickie HS T,S * * + + + + +

Family Polyphysaceae

Parvocaulis clavatus (Yamada) S. Berger, U. HS T,S, * * + ++ + + Fettweiss, S. Gleissberg, L.B. Liddle, U. Richter, H. Sawitzky & G.C. Zuccarello (I-P)

Parvocaulis exiguus (Solms-Laubach) S. Berger, HS T,S * * + + + Fettweiss, Gleissberg, Liddle, U. Richter, Sawitzky & Zuccarello (I-P)

Parvocaulis parvulus (Solms-Laubach) S. Berger, HS T,S * * * + + + + Fettweiss, Gleissberg, Liddle, U. Richter, Sawitzky & Zuccarello 16

Table S2. List of benthic blue-green algae (Cyanobacteria) in Xiaodong Hai (2016−2019). The abundance of taxa: rare sightings (+); common (++); abundant (+++). Tidal zones: (i) − the intertidal zone; (m) − the zone between the intertidal and subtidal zones; (s) − the upper subtidal zone. Years and seasons: 16−d (dry season 2016); 16−r (rainy season 2016); 17−d (dry season 2017); 18−r (rainy season 2018); 19−d (dry season 2018). CYANOBACTERIA i m s 16-d 16-r 17-d 18-r 19-d

ORDER CHROOCOCCALES

Family Chroococcaceae

Chroococcus turgidus (Kützing) Nägeli + + + ++

ORDER SYNECHOCOCCALES

Family Merismopediaceae

Aphanocapsa litoralis Hansgirg + + + + + ++

Aphanocapsa reinboldii (Richter) Komárek & + + + + + ++ ++ Anagnostidis

ORDER PLEUROCAPSALES

Family Hyellaceae

Chamaecalyx swirenkoi (Sirsov) Komárek & + + ++ ++ + ++ Anagnostidis [Dermocarpa clavata Geitler]

Hyella caespitosa Bornet & Flahault + + + ++

ORDER NOSTOCALES

Family Rivulariaceae

Calothrix contarenii Bornet & Flahault + + + ++

Kyrtuthrix maculans (Gomont) I. Umezaki + + + + + ++ ++ ++

Scytonematopsis crustacea (Thuret ex Bornet & ++ Flahault) Koválik & Komárek [Calothrix crustacea Thuret ex Bornet & Flahault]

ORDER OSCILLATORIALES

Family Coleofasciculaceae

Coleofasciculus chthonoplastes (Thuret ex + + + ++ + ++ ++ Gomont) M. Siegesmund, J.R. Johansen & T. Friedl [Microcoleus chthonoplastes Thuret ex Gomont]

Family Hapalosiphonaceae 17

Mastigocoleus testarum Lagerheim ex Bornet & + + + ++ Flahault

Family Microcoleaceae

Planktothrix agardhii (Gomont) Anagnostidis & ++ + + Komárek

Symploca muscorum Gomont ex Gomont +++

Family Oscillatoriaceae

Lyngbya majuscula Harvey ex Gomont + + + +++ +

Lyngbya semiplena J. Agardh ex Gomont + + +

Phormidium nigroviride (Thwaites ex Gomont) + + + + Anagnostidis & Komárek [Oscillatoria nigroviridis Thwaites ex Gomont]

Oscillatoria bonnemaisonii P. Crouan & H. + +++ +++ Crouan ex Gomont

Oscillatoria limosa C. Agardh ex Gomont + + + ++ + + ++ +

Oscillatoria simplicissima Gomont + + + ++

ORDER SPIRULINALES

Family Spirulinaceae

Spirulina major Kützing ex Gomont + + +

Spirulina subtilissima Kützing ex Gomont + + + + + + ++