The shallow sublittoral marine ecology of Aldabra

The paper represents a preliminary treatment of the marine ecology of certain areas of the shallow sublittoral, mostly on West Island, on Aldabra. Seaward reefs on West Island are, for this island group, calm water localities. Detailed examinations of profiles, and additional observations, indicate that ‘ zones ’ can be recognized in the shallow sublittoral, but these ‘zones’ are more a function of the nature and physiography of the substrate and of the presence and density of marine Angiosperm vegetation than of the marine algae. Luxuriant marine algal flora is, on the reef-flat, found only in deep pools or channels landward of the ‘reef-ridge’, most commonly in the inner ridge/pool area. These circumstances seem to provide protection from direct wave action, together with adequate depth of water at all times. Similar conditions apparently apply in the area immediately lagoon ward of Western Channels, where a most luxuriant ‘turf’ of marine algae and marine angiosperms was located. The biomass of marine vegetation there was quite outstanding for Aldabra, representing a cover of virtually 100%, with much additional growth of one species over another throughout most of the `turf’ area.

2021 ◽  
Vol 9 ◽  
Author(s):  
Ana I Neto ◽  
Ignacio Moreu ◽  
Edgar Rosas Alquicira ◽  
Karla León-Cisneros ◽  
Eva Cacabelos ◽  
...  

The macroalgal flora of the Island of São Miguel (eastern group of the Azores Archipelago) has attracted the interest of many researchers in the past, the first publications going back to the nineteenth century. Initial studies were mainly taxonomic, resulting in the publication of a checklist of the Azorean benthic marine algae. Later, the establishment of the University of the Azores on the Island permitted the logistic conditions to develop both temporal studies and long-term research and this resulted in a significant increase on research directed at the benthic marine algae and littoral communities of the Island and consequent publications. Prior to the present paper, the known macroalgal flora of São Miguel Island comprised around 260 species. Despite this richness, a significant amount of the research was never made public, notably Masters and PhD theses encompassing information regarding presence data recorded at littoral and sublittoral levels down to a depth of approximately 40 m around the Island and the many collections made, which resulted in vouchers deposited in the AZB Herbarium Ruy Telles Palhinha and the LSM- Molecular Systematics Laboratory at the Faculty of Sciences and Technology of the University of the Azores. The present publication lists the macroalgal taxonomic records, together with information on their ecology and occurrence around São Miguel Island, improving the knowledge of the Azorean macroalgal flora at local and regional scales. A total of 12,781 specimens (including some identified only to genus) belonging to 431 taxa of macroalgae are registered, comprising 284 Rhodophyta, 59 Chlorophyta and 88 Ochrophyta (Phaeophyceae). Of these, 323 were identified to species level (212 Rhodophyta, 48 Chlorophyta and 63 Ochrophyta), of which 61 are new records for the Island (42 Rhodophyta, 9 Chlorophyta and 10 Ochrophyta), one an Azorean endemic (Predaea feldmannii subsp. azorica Gabriel), five are Macaronesian endemisms (the red algae Botryocladia macaronesica Afonso-Carrillo, Sobrino, Tittley & Neto, Laurencia viridis Gil-Rodríguez & Haroun, Millerella tinerfensis (Seoane-Camba) S.M.Boo & J.M.Rico, Phyllophora gelidioides P.Crouan & H.Crouan ex Karsakoff and the green alga Codium elisabethiae O.C.Schmidt), 19 are introduced species (15 Rhodophyta, two Chlorophyta and two Ochrophyta) and 32 are of uncertain status (21 Rhodophyta, five Chlorophyta and six Ochrophyta).


The Royal Society Expedition to the Solomon Islands aimed at examining the biogeographical relationships between these islands and other island systems of the western tropical Pacific. The marine party also studied intertidal and reef ecology. Comprehensive collections of benthic marine algae were made at the main localities visited (Florida Islands, north-west and south-east Guadalcanal, Matiu Island off the north coast and Batuona and Ulukoro Islands off the south coast of New Georgia, Banika Island in the Russell Islands, and south-east Gizo Island). Additional small collections were obtained from Kolombangara and the north coast of San Cristobal. Habitat notes accompanied each collection and preliminary determinations were made in the field where possible. General ecological observations on the reefs included profiles selected after a preliminary survey of an area. Such profiles (see below) indicate the general situation but are not based on detailed transect work; restricted time and the great variation in distribution of organisms over the reef surface (especially in the moat) rendered isolated detailed transects of limited value. The marine algal flora of the Solomon Islands has been one of the least known in tropical regions. Setchell (1935) recorded nine species from Malaita Island and also several taxa from Sikaiana Island (in the Stewart Islands, north-east of Malaita Island) and from Bellona Island, south of the Solomon Islands. Levring (i960) recorded a number of species from Rennell Island, near Bellona Island. Otherwise there are only a few scattered records in taxonomic monographs.


1989 ◽  
Vol 67 (11) ◽  
pp. 3295-3314 ◽  
Author(s):  
Dawn E. Renfrew ◽  
Paul W. Gabrielson ◽  
Robert F. Scagel

The red algal order Gelidiales is represented in the benthic marine algal flora of British Columbia, northern Washington, and southeast Alaska by two genera, Gelidium Lamouroux and Pterocladia J. Agardh. Three species of Gelidium are present, G. coulteri Harvey, G. purpurascens Gardner, and G. vagum Okamura, and one species of Pterocladia, P. caloglossoides (Howe) Dawson. For each species we provide a description of its habit and life history, vegetative and reproductive morphology, and habitat and seasonality. Distributions and representative specimens examined are given. Keys are provided to genera and species where appropriate. Habits, and salient vegetative and reproductive features useful in identifying each species, are illustrated. Gelidium vagum is reported for the first time in the northeast Pacific and appears to have been introduced to the flora from Japan in recent historical time. Its distribution is limited to two islands in the Strait of Georgia. Gelidium purpurascens and Pterocladia caloglossoides are distributed throughout British Columbia and northern Washington, and their ranges are extended north to southeast Alaska. Earlier reports of G. amansii (Lamouroux) Lamouroux, G. crinale (Turner) Lamouroux, G. pusillum (Stackhouse) Le Jolis, G. robustum (Gardner) Hollenberg et Abbott, and G. sinicola Gardner from British Columbia and northern Washington are shown to have been based upon misidentifications of other taxa, and these species are excluded from the flora.


2021 ◽  
Author(s):  
REDHA H. AL-HASAN ◽  
◽  
FATEMAH M. AL-KHERAINEJ ◽  

During 2014-2016 a project was launched to update and examine the current status of five phyla of benthic marine algae, in addition to epiphytic diatoms and marine Tracheophyta thriving along the coastal area of Kuwait. 173 species of algae were collected and identified. Fourteen new records of algal species for Kuwait including 2 species as new records from the Arabian Gulf are here reported for the first time. These species are assigned to the Chlorophyta (4), Ochrophyta (1), Rhodophyta (5) and Cyanobacteria (4). From Kuwait coastal line one species of marine angiosperm is also found for the first time. Five algal species collected from Kuwait coastal line remain unidentified.


2020 ◽  
Vol 20 (3) ◽  
pp. 267-276
Author(s):  
Dam Duc Tien ◽  
Nguyen Thi Mai Anh ◽  
Linh Manh Nguyen ◽  
Pham Thu Hue ◽  
Lawrence Liao

This paper exhibites species composition and distribution of marine seaweed at 10 sites of Co To and Thanh Lan islands in May 2019. The studies record 76 species of marine algae in the area, belonging to four divisions: Cyanophytes, Rhodophytes, Ochrophytes and Chlorophytes. Among them, five species are classified into Cyanophytes (comprising 6.6% of total species); thirty-four species into Rhodophytes (44.7%); twenty-one species into Ochrophytes/Phaeophytes (27.6%) and sixteen species into Chlorophytes (21.1%). The species composition of marine seaweeds in Co To and Thanh Lan shows significant differences as follows: 22 species (sites number 4 and 10) to 58 species (site number 2) and the average value is 38.7 species per site. Sørensen similarity coefficient fluctuates from 0.33 (sites number 5 and 10) to 0.84 (sites number 1 and 3) and the average value is 0.53. The current investigations show that four species of twenty-one species are collected in the littoral zone and forty-two species in the sub-littoral zone (in which there are thirteen species distributed in both littoral zone and sub-littoral zone). The algal flora in Co To and Thanh Lan is characterized by subtropics.


2010 ◽  
Vol 5 (4) ◽  
pp. 1934578X1000500 ◽  
Author(s):  
Gerald Blunden ◽  
Peter F. Morse ◽  
Imre Mathe ◽  
Judit Hohmann ◽  
Alan T. Critchley ◽  
...  

Ascophyllum nodosum, and to a lesser extent, Laminaria digitata, L. hyperborea and Fucus serratus, are marine algal species utilized in the commercial production of seaweed extracts used in agriculture. Betaines have been shown to be important constituents of these extracts, but there appears to have been no study made on whether there are variations in the betaine contents of these species based on either the place or date of collection. Samples of each of the four species were collected from widely separated areas at different times of the year. Also, in the case of A. nodosum, approximately monthly collections were made from one location. The betaines detected in the various collections of the same species showed little variation, although in the case of A. nodosum, glycinebetaine was found as a minor constituent in some samples, but was not detected in others. Trigonelline was found in all the tested samples of the two Laminaria species; this is, to our knowledge, the first record of this betaine in marine algae. With the exception of trigonelline in the Laminaria species, the betaine yields from the various samples of L. digitata, L. hyperborea and F. serratus showed little variation, regardless of either the place or date of collection. The trigonelline contents of the Laminaria species collected at one location (Finavarra, Ireland), in particular of L. hyperborea, was substantially greater than those from the other places of collection. In the case of A. nodosum, the betaine yields from samples collected at one site (Dale, Pembrokeshire, UK) were significantly higher than those from the other places of collection, which were very similar to each other. There was no clear indication of seasonal variation in betaine yields from A. nodosum.


1977 ◽  
Vol 20 (2) ◽  
Author(s):  
D. M. John ◽  
G. W. Lawson

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