Ian Tittley

A provisional classification of algal-characterised rocky shore biotopes in the Azores.

Recent studies of the rocky shores of the Azores archipelago have provided information on community structure allowing provisional identification of plant-characterised biotopes (habitats and their associated communities). Although the Azores share some littoral and sublittoral biotopes with the Atlantic coast of mainland Europe, shores in the archipelago mostly lack the functionally important ‘leathery macrophyte’ communities of fucoids and laminarians widespread in the North Atlantic. Intertidal biotopes are mainly turfs typical of warm-temperate and tropical regions, and characterised by articulated Corallinaceae or by non-coralline algae such as Cladophora spp., Gelidium spp., Pterocladiella capillacea, Stypocaulon scoparia, and Valonia utricularis. Subtidal algal biotopes are characterised by Dictyota spp., Halopteris filicina, Sphaerococcus coronopifolius and, most commonly, Zonaria tournefortii.

The marine algal (seaweed) flora of the Azores: additions and amendments 3

Thirteen species of benthic marine algae are reported new for the isolated mid-Atlantic Azores archipelago and five older records are confirmed. Seven (Bangia atropurpurea, Codium fragile spp. tomentosoides, Ectocarpus fasciculatus, E. siliculosus, Porphyrostromium ciliare, Ulothrix flacca and Ulvaria oxysperma) are widespread amphi-Atlantic species some of which extend in distributional range south to the Canary Islands. Cryptonemia seminervis, Ctenosiphonia hypnoides and Phyllophora sicula are known from the northeastern Atlantic Ocean only and also occur in the Canary Islands. The Azores archipelago is the western limit of distribution of Codium fragile ssp. atlanticum, Bostrychia scorpioides, Bryopsis cupressina, Erythroglossum laciniatum, Haliptilon squamatum and Phyllophora sicula, and the southern limit of C. fragile ssp. atlanticum and E. laciniatum. The tropical species Phyllodictyon anastomosans, Valonia macrophysa and Wurdemannia miniata reach their northern limit of distribution there. Asparagopsis taxiformis is now less common possibly due to competition with the non-native A. armata; subspecies of the non-native C. fragile now occur widely in the Azores. The status of Fucus vesiculosus, Ulva (Enteromorpha) clathrata and Rhizoclonium tortuosum is clarified and other species have been removed from the flora. The continuing addition of new species records for the Azores shows the archipelago to be floristically richer than other Atlantic islands except for the Canary Islands.

Additions to the Marine Algal (Seaweed) Flora of the Azores

Abstract Ten species of benthic marine algae, new distribution records for the Azores achipelago, are itemised; two other species records (Heterosiphonia crispella and Laminaria ochroleuca) are confirmed for the islands. Six species (Bryopsis pennata, Cottoniella filamentosa, Dasya baillouviana, Feldmannia paradoxa, Heterosiphonia crispella and Lomentaria clavellosa) show an amphi-Atlantic distribution pattern; four (Bonnemaisonia asparagoides, Laminaria ochroleuca, Pterosphonia ardreana and Stylonema cornu-cervi) show a European-African-Mediterranean distribution pattern. The occurrence of Dudresnaya crassa, a western Atlantic warm-water species, represents an extension of its known distributional range to the east. An Ahnfeltiopsis was found which resembled A. intermedia, a species that occurs in the Atlantic Ocean to the south of the Azores.

Distribution of seaweed floras in the Southern Ocean

An earlier phytogeographical analysis of the marine algal floras of the southern oceans using Detrended Correspondence Analysis enabled the recognition of floristic groupings. In the present analysis attention is focused on the floras of islands or coastlines (21 sites) lying within the Antarctic/sub-Antarctic group. The original database has been amended by the addition of new records from Macquarie Island and South Georgia, addition of records from Terra Nova Bay on Antarctica, and account taken of subsequent taxonomic changes. The main axis of variation in the ordination analysis of 480 species indicates a general north-south trend rather than a sharp discontinuity between the floras of the Antarctic and sub-Antarctic regions

Botryocladia chiajeana and Botryocladia macaronesica sp. nov. (Rhodymeniaceae, Rhodophyta) from the Mediterranean and the eastern Atlantic, with a discussion on the closely related genus Irvinea

J. Afonso-Carrillo, C. Rodríguez-Prieto, F. Boisset, C. Sobrino, I. Tittley and A.I. Neto. 2006. Botryocladia chiajeana and Botryocladia macaronesica sp. nov. (Rhodymeniaceae, Rhodophyta) from the Mediterranean and the eastern Atlantic, with a discussion on the closely related genus Irvinea. Phycologia 45: 277–292. DOI: 10.2216/04-97.1 Specimens from the eastern Atlantic, Mediterranean and Adriatic seas previously reported as Botryocladia chiajeana showed differences in morphology, and re-examination of Meneghinis original collection of Chrysymenia chiajeana (basionym B. chiajeana) revealed that only the Mediterranean and Adriatic specimens are in agreement with the original protologue, whereas plants reported from the eastern Atlantic are recognised here as Botryocladia macaronesica Afonso-Carrillo, Sobrino, Tittley & Neto sp. nov. The vegetative and reproductive morphology of western Mediterranean plants is examined in detail for the first time, and B. chiajeana is characterised by the following combination of features: solid axes bearing frequently dichotomously branched vesicles, vesicle walls three layered, outer cortical cells arranged in rosettes, secretory cells borne on modified medullary cells, spermatangia cut off from scattered spermatangial mother cells, cystocarps strongly protuberant and tetrasporangia cruciately divided and exposed on the outer cortical layer at maturity. From the Meneghini collection, a lectotype specimen of C. chiajeana was selected. Botryocladia macaronesica, known so far only from the islands of Azores, Madeira, Canaries and Cape Verde, differs from other Botryocladia species by a unique combination of significant attributes including elongate saccate vesicles, near-continuous cortication of vesicle walls, secretory cells on unmodified medullary cells and completely immersed cystocarps. An analysis of the morphological characters currently used for separating Botryocladia from related genera (i.e. Chrysymenia, Gloiosaccion and Irvinea), showed that there is considerable overlap between Botryocladia and Irvinea. These genera are presently discriminated mostly by molecular evidence as the supposed morphological characters are shown here to vary considerably within the genus Botryocladia.

Subtidal Rocky Shore Communities of the Azores: Developing a Biotope Survey Method

Abstract At 23 sites selected randomly around the island of São Miguel (Azores), video records were made at the depths of 5, 10, 15, 20, 25, and 30 m where a rocky substratum was present. Semiquantitative abundance data of the most common benthic organisms (algae and fixed/sedentary macroinvertebrates) were recorded in the vicinity of each depth reference point. Qualitative samples of the more conspicuous organisms were taken for confirmation of identification in the laboratory. At each site, substratum type, geographical orientation, and depth level were recorded. Multivariate analysis (nonmetric multidimensional scaling; analysis of similarity [Anosim] tests; similarity percentages [Simper] analysis) on the collected data enabled patterns of community distribution to be identified, as well as their relationship to abiotic factors. Since depth was found to be the sole determining factor for communities, it was the only one considered in the subtidal biotope survey protocol proposed here.

Lower Plant Diversity

The term ‘lower plants’ is a convenient but imprecise label for a disparate group of plants and plant-like organisms which are defined primarily by their lack of vascular tissue (the transport system for water and nutrients within higher plants). Under this heading we here discuss bryophytes, lichens and larger algae. Many authorities would only include the first of these among the ‘true’ plants (defined as those developing from an embryo; see Chapter 8). The lichens are composite organisms, not true plants, discussed here for convenience.

The algae of the Thames estuary: a reappraisal

The benthic marine algal (seaweed) flora of the tidal Thames was first described in detail by (1977a), prior to which there was only scant reference made to it in the literature. That study was undertaken in connection with a wider appraisal of the seaweed flora of Kent (including the Thames estuary), published as an atlas of species distributions (Tittley and Price, 1977b; Tittley et al., 1985). Since the original study, several other works have added to our knowledge of the algal flora. Zonal and seasonal changes were investigated at Woolwich in the middle reaches of the tidal river (Tittley, 1985); this was the first account of seasonal changes in macroalgal populations for any British estuary. Additional observations on the occurrence and distribution of benthic macroalgae have been made by (1982, 1983, unpublished data). The floristic composition, seasonality and distribution of algae in the freshwater reaches of the tidal river were investigated by (1990) as part of a suite of studies on the phytobenthos of the freshwater Thames (John and Moore, 1985a, b; John et al., 1989a b). The algae and macrophytes of the River Wandle, a south bank tributary that enters the tidal river near Wandsworth, were described by (1983).

Life history and morphological studies of Punctaria tenuissima (Chordariaceae, Phaeophyceae), a new record for the Azores

Punctaria tenuissima (Chordariaceae, Phaeophyceae) is reported for the first time from the Azores. Erect thalli were collected on the Island of Sao Miguel; they were up to 3 cm long, flattened and often twisted. The plurilocular sporangia were formed from surface cells that were quadrate or rectan- gular in surface view. Unilocular sporangia were not observed in the field. In culture, the plurispores of P. tenuis- sima developed into Hecatonema-like, tufted, prostrate thalli that formed plurilocular sporangia. The plurispores of the prostrate thalli cultured at 158C with a long day (LD) pho- toperiod developed into new prostrate thalli, which in turn formed plurilocular sporangia. This cycle was repeated 5 times, resulting in several generations of reproductive pros- trate thalli. When these cultures were cooled to 108C with a short day (SD) photoperiod, new erect thalli developed from the prostrate thalli resembling the thalli collected in the field. These erect blades produced unilocular and plurilocular spo- rangia on the same or on different thalli. The plurispores and unispores produced by the erect thalli at 108C under SD con- ditions once again developed into new prostrate thalli. This is the first report of unilocular sporangia formed in cultures of P. tenuissima. Sexual reproduction was not observed. The culture conditions, particularly temperature and daylength, appeared to influence the formation of erect blades. The Punctaria-like thalli were produced in 108C/SD conditions, whilst the Hecatonema-like thalli were produced under 108-158C/LD and SD conditions. These results are similar to those reported for P. tenuissima from other locations and suggest the occurrence of both direct and heteromorphic life histories in the Azorean algae.