Sampling event

Marine algal (seaweed) flora of Terceira Island, Azores

Latest version published by Universidade dos Açores on 31 July 2020 Universidade dos Açores
Publication date:
31 July 2020
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Universidade dos Açores
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Background As for many other Azorean islands, the macroalgal flora of Terceira (central group of the archipelago) is poorly known, the published information reflecting occasional collections of sporadic visitors to the island. In order to overcome this, and contribute to improve the knowledge of Azorean macroalgal flora at both local and regional scales, a thorough investigation was conducted and both collections and presence data recordings were undertaken at the littoral and sublittoral levels down to approximately 40 m around the island (total area of approximately 49 km2). This paper lists the taxonomic records and provides information on each species’ ecology and occurrence on the island’s littoral.

New information A total of 418 specimens (including taxa identified only to genus level) belonging to 147 taxa of macroalgae, comprising 95 Rhodophyta, 33 Chlorophyta and 19 Ochrophyta (Phaeophyceae) are registered. Of these, 113 were identified to species level (73 Rhodophyta, 24 Chlorophyta and 16 Ochrophyta), encompassing 35 new records for the island (27 Rhodophyta, 6 Chlorophyta and 2 Ochrophyta). Most species are native including the Macaronesian endemisms (Codium elisabethiae O.C.Schmidt, Millerella tinerfensis (Seoane-Camba) S.M.Boo & J.M.Rico and Phyllophora gelidioides P.Crouan & H.Crouan ex Karsakoff), eight are introduced and 15 have uncertain origin.

Introduction The macroalgal flora of the isolated mid-Atlantic Azores archipelago, as a whole, may be considered relatively rich when compared to that of other remote oceanic islands such as the Shetlands and Faroes in the colder North Atlantic, and Ascension and Tristan da Cunha in the Southern Atlantic (Neto et al. 2005; Tittley & Neto 2005; Wallenstein et al. 2009). With approximately 400 species (Freitas et al. 2019), the Azorean algal flora has been considered cosmopolitan, as it shares species with Macaronesia, North Africa, the Mediterranean Sea, Atlantic Europe and America (Tittley 2003; Tittley & Neto 2006; Wallenstein et al. 2009). The published information, however, reflects data from only a few of the nine islands. Terceira, the second largest island of the central group and the third largest of the archipelago, is among the lesser studied ones. To overcome this and contribute to a better understanding of the seaweed flora of the Azores archipelago, a thorough investigation was conducted in the period between 2000 and 2014, mainly by the Island Aquatic Research Group of the Azorean Biodiversity Centre of the University of the Azores ( In these surveys, special attention was dedicated to the sheet-like and filamentous forms that are difficult to identify in the wild, the seasonal and fast growing annuals, and particularly to the small forms that are often short-lived and fast growing species, very difficult to identify without the aid of a microscope. This paper compiles physical, occurrence and survey data and is intended as a practical resource for biological studies (such as systematics, diversity and conservation, biological monitoring, climate change and ecology), and for academics, students, government, private organizations, and the general public.

Purpose By listing the taxonomic records for Terceira and presenting general information for each taxon’s occurrence on the island’s littoral, this paper addresses several biodiversity shortfalls (see Hortal et al. 2015), namely the need to catalogue the Azorean macroalgae (Linnean shortfall) and improve the current information on their local and regional geographic distribution (Wallacean shortfall), as well as on species’ abundances and dynamics in space (Prestonian shortfall).

Data Records

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This resource has been registered with GBIF, and assigned the following GBIF UUID: b03dce75-cbc2-457b-8725-33885d766a05.  Universidade dos Açores publishes this resource, and is itself registered in GBIF as a data publisher endorsed by GBIF Portugal.


Macroalgae; seaweeds; Rhodophyta; Chlorophyta; Ochrophyta; Azores; Terceira Island; endemism; native; introduced; uncertain; occurrence data.; Samplingevent


Ana Isabel Neto
  • Metadata Provider
  • Author
  • Originator
  • Point Of Contact
Associate professor with aggregation; Macroalgae Curator at the AZB Herbarium Ruy Telles Palhinha
Universidade dos Açores, Faculdade de Ciências e Tecnologia, Departamento de Biologia and Grupo de Investigação Aquática Insular, IBBC-GBA/cE3c
Rua da Mãe de Deus, 13-A
9500-321 Ponta Delgada
São Miguel, Açores
Afonso C. L. Prestes
  • Originator
Universidade dos Açores, Faculdade de Ciências e Tecnologia, Departamento de Biologia and Grupo de Investigação Aquática Insular, IBBC-GBA/cE3c
Rua da Mãe de Deus, 13-A
9500-321 Ponta Delgada
São Miguel, Açores
Nuno V. Álvaro
  • Originator
Universidade dos Açores, Faculdade de Ciências Agrárias, CCMMG (Centro do Clima Meteorologia e Mudanças Globais), IITA-A (Instituto de Investigação e Tecnologias Agrárias e do Ambiente)
Campus de Angra do Heroísmo Rua Capitão João d’Ávlia – Pico da Urze
9700-042 Angra dp Heroísmo
Terceira, Açores
Roberto Resendes
  • Originator
Curator at the AZB-Herbarium Ruy Telles Palhinha
* Universidade dos Açores, Faculdade de Ciências e Tecnologia, Departamento de Biologia
Rua da Mãe de Deus, 13-A
9500-321 Ponta Delgada
São Miguel, Açores
+351296650000, ext. 1731
Raul M. A. Neto
  • Originator
Ignacio Moreu
  • Metadata Provider
  • Author
  • Originator
Rua da Mãe de Deus, 13-A
9500-321 Ponta Delgada
São Miguel, Açores

Geographic Coverage

Terceira Island, Azores, Macaronesia, Portugal (approximately 38°48′50″N, 27°23′25″W).

Bounding Coordinates South West [38.627, -27.389], North East [38.814, -27.033]

Taxonomic Coverage

All macroalgae were identified to genus or species. In total, 147 taxa were identified belonging to 21 orders and 45 families, distributed by the phyla Rhodophyta (9 orders and 25 families), Chlorophyta (5 orders and 8 families) and Ochrophyta (7 orders and 12 families).

Phylum Rhodophyta (Red algae), Chlorophyta (Green algae), Ochrophyta (Brown algae)

Temporal Coverage

Start Date / End Date 2000-01-01 / 2014-01-01

Project Data

In order to improve the knowledge of Terceira Island’s macroalgal flora, extensive observations were made in the period between 2000 and 2014, encompassing both collections and presence data recordings, and covering the littoral and sublittoral levels down to approximately 40 m around the island (total area of approximately 49 km2). This paper lists the resulting taxonomic records and provides information on each species’ ecology and occurrence on the island’s littoral.

Title Marine algal (seaweed) flora of Terceira Island, Azores
Identifier Seaweeds of Terceira Island (Azores)
Funding This study was mainly financed by the following projects/scientific expeditions: • Campaign CAMAG-TER/2008, under the project “CAMAG/TER - Caracterização das massas de água costeira da Ilha Terceira”. 2008 - 2009. The Azores Regional Government; • Project “ACORES-01-0145-FEDER-000072 - AZORES BIOPORTAL – PORBIOTA. Operational Program Azores 2020 (85% ERDF and 15% regional funds); • Portuguese National Funds, through FCT – Fundação para a Ciência e a Tecnologia, within the projects UID/BIA/00329/2013, 2015 - 2018, and UID/BIA/00329/2019 and UID/BIA/00329/2020-2023; • Portuguese Regional Funds, through DRCT – Direção Regional da Ciência e Tecnologia, within several projects, since 2013; • CIRN/DB/UAc (Research Centre for Natural Resources, Universidade dos Açores, Departamento de Biologia); • CIIMAR (Interdisciplinary Centre of Marine and Environmental Research, Porto, Portugal).
Study Area Description Located along a WNW-trending strip and spreading over 500 km in the North Atlantic, roughly at 38°43′49″N 27°19′10″W, the Azores archipelago is composed by nine islands and several islets. The islands are surrounded by deep waters due to the absence of a continental shelf, and therefore have a restricted coastal extension, which is subjected to swell and surge most of the year. The tidal range is small (<2 m, see Instituto Hidrográfico 1981) and the shore geomorphology alternates between high cliffs and rocky cobble/boulder beaches (Borges 2004). The climate is temperate oceanic, with regular and abundant rainfall and high levels of relative humidity and persistent winds mainly during winter and autumn (Morton et al. 1998). Terceira, located in the central group, roughly at 38°48′50″N, 27°23′25″W, 150 km northeast of São Miguel, is the third biggest island of the Azores archipelago. It has an elliptical form, 29 km long and 18 km wide, a maximum altitude of 1021 m at the summit of Serra de Santa Bárbara, and a total area of about 397 km2. The coastline has a total length of 112 km and is characterized by cliffs that vary from small to moderate heights, interrupted by small bays. Sandy beaches are limited to Praia da Vitória, located on the more protected eastern part of the island. The northern coast is more exposed and constantly submitted to the wave action (Gomes & Pinto 2004). The intertidal and shallow subtidal rocky-shore communities of Terceira are dominated by macroalgae, similarly to those of the remaining Azorean islands (Neto et al. 2005). The frondose species Fucus spiralis Linnaeus, Ulva rigida C.Agardh and Gelidium microdon Kützing are often present at mid shore levels, growing interspaced with the small chthamalid barnacles. Slightly below this level, the lack of herbivores, resulting from the overexploitation of limpets (Martins et al. 2008, 2011, Faria et al. 2015), favours an almost homogeneous coverage of the shore by algal turfs. These are growth forms of either diminutive algae or diminutive forms of larger species that create a dense, compact mat 20-30 mm thick, either monospecific (mainly composed by Caulacanthus ustulatus (Mertens ex Turner) Kützing or Gymnogongrus spp.), or multispecific and composed by articulate calcareous algae (e.g. Ellisolandia elongata and Jania spp.) and/or soft algae (e.g. Centroceras clavulatum (C.Agardh) Montagne, Chondracanthus spp. and Laurencia spp.). Lower in the shore the erect, corticated macrophytes Ellisolandia elongata (J.Ellis & Solander) K.R.Hind & G.W.Saunders, Cystoseira spp. and Osmundea pinnatifida (Hudson) Stackhouse are commonly found, frequently epiphyting multispecific algal turfs. The shallow subtidal is mainly characterized by associations of two or three frondose macrophytes, predominantly the brown seaweeds Dictyota spp. and Zonaria tournefortii (J.V. Lamouroux) Montagne.
Design Description The algae referred to in this paper were sampled during field studies at littoral and sublittoral levels down to approximately 40 m on Terceira Island, covering an area of 49 Km2. Presence recordings and physical collections were made by walking over the shores or by scuba diving. The specimens collected were taken to the laboratory for standard procedures and the resulting vouchers were deposited at the AZB Herbarium Ruy Telles Palhinha, at the Faculty of Sciences and Technology of the University of the Azores.

The personnel involved in the project:

Afonso C. L. Prestes
  • Content Provider
Albert Cámara
  • Content Provider
Luís Cabral
  • Content Provider
Mariana Brito
  • Content Provider
Marisa Toste
  • Content Provider
Marlene Terra
  • Content Provider
Nuno Álvaro
  • Content Provider
Rita Patarra
  • Content Provider

Sampling Methods

Intertidal collections were made at low tide by walking over the shores. Subtidal collections were made by scuba diving around the area. Sampling encompassed both physical collections and species presence recordings. For the former, in each sampling location, collections were made manually by scraping one or two specimens of species found into labelled bags. Species recording data was gathered by registering all species present in the visited locations. Complementary data such as shore level (high, mid, low), orientation and type of substrate (bedrock, boulders, cobbles, mixed), habitat (tide pool, open rock, gully, crevice, cave) was also recorded.

Study Extent This study covers a relatively large area, approximately 49 Km2, encompassing littoral and sublittoral levels down to approximately 40 m around the Terceira island.
Quality Control The collected taxa were investigated by trained taxonomists with the help of keys and floras. This involved morphological and anatomical examination by eye or under the dissecting and compound microscopes of an entire specimen or slide preparation. In difficult cases specimens were sent to experts for identification.

Method step description:

  1. In the laboratory the specimens were sorted and studied following standard procedures used in macroalgae identification. Species identification was based on morphological and anatomical characters and reproductive structures. For small and simple thalli, this required the observation of the entire thallus by eye and/or using dissecting and compound microscopes. For larger and more complex algae, the investigation of the thallus anatomy required histological work to obtain longitudinal and transverse sections needed for the observation of cells, reproductive structures and other diagnosing characters. Since the Azorean algal flora is composed of taxa from various geographical regions, floras and keys mainly from the Atlantic and Western Mediterranean were used in species identification (e.g. Schmidt 1931, Taylor 1967, 1978, Levring 1974, Dixon & Irvine 1977, Lawson & John 1982, Irvine 1983, Gayral & Cosson 1986, Fletcher 1987, Afonso-Carrillo & Sansón 1989, Burrows 1991, Boudouresque et al. 1992, Cabioc'h et al. 1992, Maggs & Hommersand 1993, Irvine & Chamberlain 1994, Brodie et al. 2007, Lloréns et al. 2012 and Rodríguez-Prieto et al. 2013). For more critical and taxonomically difficult taxa, specimens were taken to the Natural History Museum (London) for comparison with collections there, or sent to specialists. A reference collection was made for all specimens collected by giving them an herbarium code number and depositing them at the AZB Herbarium Ruy Telles Palhinha, University of Azores. Depending on the species and on planned further research, different types of collections were made, namely (i) liquid collections using 5% buffered formaldehyde seawater and then replacing it by the fixing agent Kew (Bridsen & Forman 1999); (ii) dried collections, either by pressing the algae (most species) as described by Gayral and Cosson (1986), or by letting them air dry (calcareous species); and (iii) silica collections for molecular studies. Nomenclatural and taxonomic status used here follow Algaebase (Guiry & Guiry, 2020). The database was organized on FileMaker Pro.

Collection Data

Collection Name AZB | Marine macroalgae collection of Terceira Island (Azores) – Campaign CAMAG-TER/2008
Collection Identifier 389ac3c6-6c63-4de0-b5fb-bc7cc93d3791
Parent Collection Identifier AZB Herbarium Ruy Telles Palhinha, Faculty of Sciences and Technology of the University of the Azores.
Collection Name AZB | Marine macroalgae collection of Terceira Island (Azores) – Occasional sampling
Collection Identifier 247417a8-f838-405e-b5ac-82940e866a9a
Parent Collection Identifier AZB Herbarium Ruy Telles Palhinha, Faculty of Sciences and Technology of the University of the Azores.
Collection Name Marine macroalgae occurrence on Terceira Island (Azores) – Campaign CAMAG-TER/2008
Collection Identifier 43bb7387-0e2f-47ce-a121-ca66a9abcaab
Parent Collection Identifier Not applicable
Specimen preservation methods Dried and pressed,  Dried,  Formalin,  Other

Bibliographic Citations

  1. Afonso-Carrillo J & Sansón M, 1989. Clave llustrada para la Determinación de los Macrófitos Marinas Bentónicos de las Islas Canarías. Departamento de Biologia Vegetal (Botânica), Universidad de La Laguna, La Laguna. 55 pp.
  2. Borges PJA, 2004. Ambientes litorais nos grupos Central e Oriental do arquipélago dos Açores - conteúdos e dinâmica de microescala. Tese de Doutoramento em Geologia. Universidade dos Açores, Ponta Delgada.
  3. Boudouresque C-F, Meinesz A & Verlaque M, 1992. Médíterranée. In Boudouresque C-F et aL. (Eds.), Guide des Algues des Mers d'Europe, pp: 138-231. Delachaux et Niestlé, Paris.
  4. Bridsen D & Forman L (Eds), 1999. The Herbarium Handbook. Third Edition. Kew: The Board of Trustees of the Royal Botanic Gardens, Kew. xii, 334p., ISBN 1-900347-43-1.
  5. Brodie J, Maggs C, John DM (Eds.), 2007. The green seaweeds of Britain and Ireland. British Phycological Society, XII+242 pp. Dunmurry, Northern Ireland.
  6. Burrows EM, 1991. Seaweeds of the British lsles. Vol. 2. Chlorophyta. Natural History Museum, London. XII + 238 pp.
  7. Cabioc'h J, Floc'h J-Y & Le Toquin A, 1992. Manche et Atlantique. ln C.-F. Boudouresque, et al. (Eds.), Cuide des Algues des Mers d'Europe, pp: 30-136. Delachaux et Niestlé, Paris.
  8. Dixon SP & Irvine ML, 1977. Seaweeds of the British Isles. Vol. I Rhodophyta. Part 1 Introduction, Nemaliales, Gigartinales. XI+252p. British Museum (Natural History) London.
  9. Faria J, Rivas M, Martins GM, Hawkins S, Ribeiro P, Pita A, Neto AI & Presa P, 2015. A new multiplexed microsatellite tool for metapopulation studies in the overexploited endemic limpet Patella aspera (Roding, 1798). Animal Genetics, 46(1): 96-97. http://dx.doi: 10.1111/age.12243
  10. Fletcher RL, 1987. Seaweeds of the British Isles. Vol. III. Fucophyceae (Phaeophyceae). Part 1. X+359p. British Museum (Natural History) London.
  11. Freitas R, Romeiras M, Silva L, Cordeiro R, Madeira P, González JA, Wirtz P, Falcón JM, Brito A, Floeter SR, Afonso P, Porteiro F, Viera-Rodríguez MA, Neto AI, Haroun R, Farminhão JNM, Rebelo AC, Baptista L, Melo CS, Martínez A, Núñez J, Berning B, Johnson ME Ávila SP, 2019. Restructuring of the ‘Macaronesia’ biogeographic unit: A marine multi-taxon biogeographical approach. Scientific Reports, 9, 15792. DOI:10.1038/s41598-019-51786-6
  12. Gayral P & Cosson J, 1986. Connaitre et reconnaitre les algues marines. 220p. Ouest France.
  13. Gomes FV & Pinto FT, sd. Azores Islands (Portugal). EUROSION Case Study. Instituto de Hidráulica e Recursos Hídricos, Lisboa, 28 pp.
  14. Guiry MD & Guiry GM, 2020. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway.; searched on 30 March.
  15. Hortal J, de Bello F, Diniz-Filho JAF, Lewinsohn TM, Lobo JM & Ladle RJ (2015). Seven shortfalls that beset large-scale knowledge of biodiversity. Annual Review of Ecology, Evolution, and Systematics, 46, 523-549.
  16. Instituto Hidrográfico, 1981. Roteiro do Arquipélago dos Açores. PUB. (N) -lli-128-SN, Lisboa.
  17. Irvine ML, 1983. Seaweeds of the British Isles. Vol. I Rhodophyta. Part 2 A Cryptonemiales (sensu stricto), Palmariales, Rhodymeniales. XII+115p. British Museum (Natural History) London.
  18. Irvine ML & Chamberlain YM, 1994. Seaweeds of the British Isles. Vol. 1. Rhodophyta. Part 2B. Corallinales, Hildenbrandiales. Natural History Museum, London. VII + 276 pp.
  19. Lawson Gw & John Dm, 1982. The marine algae and coastal environment of Tropical West Africa. 455p. Beihefte zur Nova Hedwigia, J. CRAMER, Vaduz.
  20. Levring T, 1974. The marine algae of the archipelago of Madeira. Boletim do Museu Municipal do Funchal, 28 (125): 5-111.
  21. Lloréns JLP, Cabrero IH, Lacida RB, González GP, Murillo FGB & Oñate JJV, 2012. Flora marina del litoral gaditano. Biologia, ecologia, usos y guía de identificacíon. 368 p. mCN Monografias de Ciencias de la Naturaleza. Servicio de Publicaciones de la Universidad de Cadiz, Cadiz.
  22. Maggs CA & Hommersand MH, 1993. Seaweeds of tfte British Jsles. Vol1. Rhodophyta. Part 3A. Ceramiales. Natural History Museum, London. xv + 444 pp.
  23. Martins GM, Thompson RC, Hawkins SJ, Neto AI & Jenkins SR, 2008. Rocky intertidal community structure in oceanic islands: scales of spatial variation. Marine Ecology Progress Series, 356: 15-24. DOI 10.3354/meps07247
  24. Martins GM, Jenkins SR, Hawkins SJ, Neto AI, Medeiros AR & Thompson RC, 2011. Illegal harvesting affects the success of fishing closure areas. Journal of the Marine Biological Association UK, 91 (4): 929-937. DOI 10.1017/S0025315410001189
  25. Morton, B, Britton JC, Martins AMF, 1998. Coastal Ecology of the Azores. Sociedade Afonso Chaves, Ponta Delgada. 249pp.
  26. Neto AI, Tittley I & Raposeiro P, 2005. Flora Marinha do Litoral dos Açores [Rocky Shore Marine Flora of the Azores]. 156pp., Secretaria Regional do Ambiente e do Mar, Açores, ISBN 972 99884 0 4.
  27. Rodríguez-Prieto C, Ballesteros E, Boisset F & Afonso-Carrillo J, 2013. Guía de las macroalgas y fanerógamas marinas del Mediterráneo Occidental. 656 p. Ed. Omega, S.A., Barcelona.
  28. Schmidt OC, 1931. Die marine vegetation der Azoren in ihren Grundzügen dargestellt. Bibliotheca Botanica, 24(102): IX+116p., 10 Tafl.
  29. Taylor WR, 1967. Marine algae of the northeastern coasts of North America. VIII+509p. The University of Michigan Press.
  30. Taylor WR, 1978. Marine algae of the eastern tropical and subtropical coasts of the Americas. XXI+870p. The University of Michigan Press.
  31. Tittley I & Neto AI, 2005. The Marine Algal (Seaweed) Flora of the Azores: additions and amendments. Botanica Marina, 48: 248-255. DOI 10.1515/BOT.2005.030
  32. Wallenstein FM, Neto AI, Álvaro NV, Tittley I & Azevedo JMN, 2009. Guia para Definição de Biótopos Costeiros em Ilhas Oceânicas [Coastal Biotope Definition Manual for Oceanic Islands], Secretaria Regional do Ambiente e do Mar, ISBN 978-972-99884-9-3.

Additional Metadata

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Alternative Identifiers b03dce75-cbc2-457b-8725-33885d766a05