Benthic Marine Macroalgae Research Articles

First catalogue of benthic marine macroalgae from glacier-influenced environments of the Beagle Channel, deposited in the new Sub-Antarctic Cryptogamic Herbarium (SCH) of the University of Magallanes

The environmental characteristics and geomorphological landscape in the sub-Antarctic Magellanic ecoregion underpin a biological diversity that evolved adapting to the microhabitats produced by these heterogeneous ecological conditions. The high level of endemism found in these biological communities is nowadays protected thanks to the creation of the Cape Horn Biosphere Reserve (CHBR), a natural laboratory at the southern end of the sub-Antarctic Magellanic ecoregion. Studies produced in this region offer a valuable knowledge of its biological, ecological and cultural facets in a state still scarcely impacted by anthropogenic activities. The retreat of glaciers present along the channels and fjords of the CHBR due to global climate change impacts the marine benthic and macroalgae communities hosted in these water bodies. European expeditions in the 18th and 19th centuries pioneered the works which provided our current knowledge about this subantarctic marine flora. Nevertheless, there is still a gap of taxonomic information of macroalgae diversity in the CHBR. To solve this gap, with support of the Cape Horn Internationional Center (CHIC), we created the Sub-Antarctic Cryptogamic Herbarium (SCH) hosted at the Antarctic and Sub-Antarctic Marine Ecosystems Laboratory (LEMAS), University of Magallanes. In 2020, the New York Botanical Garden indexed the SCH in its Index Herbariorum. This indexation granted by this world-renowned institution places the SCH's biological collection as the world's southernmost cryptogamic repository. As such, the SCH's botanical collection is currently the only gateway to the subantarctic ecosystem's biological legacy. The catalogue below provides information about the ecological and morphological characteristics of macroalgae deposited in the SCH, with particular focus on those species present in the CHBR. We identified 54 species. Among them 23 belong to the Rhodophyta division (43%), 19 species to the Chlorophyta division (35%), and 12 species to the Ochrophyta division (22%). In the context of rapid global change, involving increasingly threatened taxa due to human impact, baseline studies and records deposited at the SCH will provide an essential tool for assessing patterns of change and defining conservation practices to protect the rich biodiversity of these sub-Antarctic ecosystems.

Epiphytic macroalgae of maricultured Sargassum and their potential utilizations

Epiphytism commonly occurs in marine benthic macroalgae and seagrass communities under natural conditions and those of mariculture. This can greatly obstruct the cultivation of commercial seaweeds and ultimately impacts the seaweed aquaculture industry negatively. Against a background of climate change and a rapidly increasing market demand, the commercial Sargassum species is experiencing increasing challenges posed by epiphytic macroalgae. Severely reduced growth, lower quality, the emergence of diseases, and the ultimate death of the algae can lead to a commercial loss. Attempts to limit epiphytic macroalgae in aquaculture have so far been inefficient. However, epiphytic macroalgae are also rich in nutritional compounds and their relative biomass could be used as efficiently as the cultivated seaweed. As epiphytes cannot effectively be controlled by the current physical, chemical, and other methods in most cases, the perspective of comprehensive utilization could be an alternative over complete prevention and control by traditional methods. Compared to the existing strategies for controlling the growth and spread of epiphytes in seaweed aquaculture, the integrated and indiscriminate harvest and utilization of epiphytic macroalgae as fertilizer, animal food additive agents, as well as the development of biodegradable materials, might prove to be alternative valorization. However, the implementation of epiphytic macroalgae utilizations still needs to overcome the technical obstacles.

Red algae acclimate to low light by modifying phycobilisome composition to maintain efficient light harvesting

BackgroundDespite a global prevalence of photosynthetic organisms in the ocean’s mesophotic zone (30–200+ m depth), the mechanisms that enable photosynthesis to proceed in this low light environment are poorly defined. Red coralline algae are the deepest known marine benthic macroalgae — here we investigated the light harvesting mechanism and mesophotic acclimatory response of the red coralline alga Lithothamnion glaciale.ResultsFollowing initial absorption by phycourobilin and phycoerythrobilin in phycoerythrin, energy was transferred from the phycobilisome to photosystems I and II within 120 ps. This enabled delivery of 94% of excitations to reaction centres. Low light intensity, and to a lesser extent a mesophotic spectrum, caused significant acclimatory change in chromophores and biliproteins, including a 10% increase in phycoerythrin light harvesting capacity and a 20% reduction in chlorophyll-a concentration and photon requirements for photosystems I and II. The rate of energy transfer remained consistent across experimental treatments, indicating an acclimatory response that maintains energy transfer.ConclusionsOur results demonstrate that responsive light harvesting by phycobilisomes and photosystem functional acclimation are key to red algal success in the mesophotic zone.

Marine macroalgal biodiversity of northern Madagascar: morpho-genetic systematics and implications of anthropic impacts for conservation

A floristic survey of the marine algal biodiversity of Antsiranana Bay, northern Madagascar, was conducted during November 2018. This represents the first inventory encompassing the three major macroalgal classes (Phaeophyceae, Florideophyceae and Ulvophyceae) for the little-known Malagasy marine flora. Combining morphological and DNA-based approaches, we report from our collection a total of 110 species from northern Madagascar, including 30 species of Phaeophyceae, 50 Florideophyceae and 30 Ulvophyceae. Barcoding of the chloroplast-encoded rbcL gene was used for the three algal classes, in addition to tufA for the Ulvophyceae. This study significantly increases our knowledge of the Malagasy marine biodiversity while augmenting the rbcL and tufA algal reference libraries for DNA barcoding. These efforts resulted in a total of 72 new species records for Madagascar. Combining our own data with the literature, we also provide an updated catalogue of 442 taxa of marine benthic macroalgae from Madagascar, comprising 85 Phaeophyceae, 1 Compsopogonophyceae, 240 Florideophyceae and 116 Ulvophyceae. This diversity holds 29 (ca. 6.5%) endemic species to Madagascar. Our results are discussed in the context of increasing threats to biodiversity on Madagascar’s coastal reefs from both anthropic and anthropogenic activities including sewage effluent runoffs and unsustainable agricultural practices such as massive deforestation, leading to ecosystem shifts to algal dominance on reefs, which are recommended to be addressed through integrated land-sea management in a Reef-to-Ridge conservation approach.

Updated Checklist of the Benthic Marine Macroalgae of the Philippines

Records of taxa of benthic marine macroalgae in the Philippines continue to increase as molecularbased biodiversity and systematics research involving seaweed specimens collected from various localities in the country continue to grow. Several molecular systematics studies on seaweeds within the last decade also resulted in taxonomic, nomenclatural, and classification changes, consequently affecting our knowledge and understanding of the biodiversity of the Philippine seaweed flora. Moreover, global efforts to make biodiversity resources that are deposited in various herbaria openly available through online databases provide a good opportunity to reassess our current foundational biodiversity knowledge on these ecologically and economically important marine resources. Herein, we provide an updated checklist of Philippine seaweeds by integrating results of recent biodiversity and systematics studies and by perusing open-access records of seaweeds collected from the Philippines that are deposited in foreign herbaria and/or found in online databases. We report a total of 1,065 seaweed taxa in the Philippines; this is composed primarily of 600 red seaweed taxa (Florideophyceae and Bangiophyceae, Rhodophyta), followed by 272 green seaweed taxa (Ulvophyceae, Chlorophyta), and by 193 brown seaweed taxa (Phaeophyceae, Ochrophyta). We added a total of 104 new records (including recently described species) to the latest checklist on Philippine seaweeds in 2013, more than half of which were derived from records of the collections deposited in foreign herbaria. The latter highlights the need to make herbarium collection records accessible and underscores the important role of herbaria (and museums in general) in documenting and preserving biodiversity resources of biodiversity hotspot areas such as the Philippines. We also reiterate here the call to increase support in building local expertise and funding on marine (seaweed) biodiversity and systematics research as these are crucial not only in documenting and conserving our marine biodiversity resources but also in developing them for their socio-economic values.

Genomics Reveals the Metabolic Potential and Functions in the Redistribution of Dissolved Organic Matter in Marine Environments of the Genus Thalassotalea.

Members of the bacterial genus Thalassotalea have been isolated recently from various marine environments, including marine invertebrates. A metagenomic study of the Deepwater Horizon oil plume has identified genes involved in aromatic hydrocarbon degradation in the Thalassotalea genome, shedding light on its potential role in the degradation of crude oils. However, the genomic traits of the genus are not well-characterized, despite the ability of the species to degrade complex natural compounds, such as agar, gelatin, chitin, or starch. Here, we obtained a complete genome of a new member of the genus, designated PS06, isolated from marine sediments containing dead marine benthic macroalgae. Unexpectedly, strain PS06 was unable to grow using most carbohydrates as sole carbon sources, which is consistent with the finding of few ABC transporters in the PS06 genome. A comparative analysis of 12 Thalassotalea genomes provided insights into their metabolic potential (e.g., microaerobic respiration and carbohydrate utilization) and evolutionary stability [including a low abundance of clustered regularly interspaced short palindromic repeats (CRISPR) loci and prophages]. The diversity and frequency of genes encoding extracellular enzymes for carbohydrate metabolism in the 12 genomes suggest that members of Thalassotalea contribute to nutrient cycling by the redistribution of dissolved organic matter in marine environments. Our study improves our understanding of the ecological and genomic properties of the genus Thalassotalea.

Seaweeds through time: Morphological and ecological analysis of Proterozoic and early Paleozoic benthic macroalgae

Benthic marine macroalgae or seaweeds are key ecological players in oceans today and have been since the Proterozoic. To date, however, morphological and evolutionary patterns for Precambrian macroalgae have been documented only in rather broad terms. To refine our understanding in this critical interval, we updated a dataset of Proterozoic to early Paleozoic noncalcified macroalgal fossils preserved as macroscopic carbonaceous compressions. The data were analyzed using non-parametric multidimensional scaling (NMDS) and functional-form group (FFG) approaches, in order to characterize morphological and ecological evolutionary patterns of these macroalgae. At the broadest scale, the results show progressive increases in thallus size, morphospace range, and aspects of ecological complexity such as canopy heights, surface area/volume ratios, and functional-form groups through time. These trends, however, are not always monotonous. In particular, significant increases in Proterozoic macroalgal morphological diversity and maximum size appear to have occurred in the Neoproterozoic (Tonian and Ediacaran periods, respectively). Analysis of Ediacaran macroalgal assemblages shows that macroalgae broadly follow the Ediacara-like fossil assemblages, with a significant drop in most studied metrics in the terminal Ediacaran stage (~550–539 Ma). The latter event occurs during the Kotlinian crisis experienced by Ediacara-type macro-organisms, highlighting the possibility that this extinction event during the Ediacaran-Cambrian transition affected both macroalgae and Ediacara-type macro-organisms. Our analysis also confirms an Ordovician increase in the morphological and ecological diversity of macroalgae.

An Inventory of Marine Benthic Macroalgae of Hainan Island, China

In this review, the results of the study of marine benthic algal flora of Hainan Island, China, during the period from 1933 to 2015 are considered. It has been found that the local floristic diversity and taxonomic composition are similar to those of macroalgae from other large islands of the Indo-Pacific, where coral reefs are the main ecosystem of the shallow-water zone. An analysis of historical (decadal) changes in the marine benthic flora of Hainan has shown the following pattern of variations in the species diversity of macroalgae since the middle of the 20th century: a decline in low-productive epilithic algae with voluminous forms of thalli and an increase in highly productive opportunistic species with filamentous, fine filamentous, and membranous forms. These historical changes are thought to be caused by human impacts: inappropriate exploitation of coral reefs and eutrophication of coastal waters due to household sewage from large cities and discharge of mariculture wastes.

Marine Benthic Macroalgae Of A Small Uninhabited South Pacific Atoll (Rose Atoll, American Samoa)

Forty-five species of marine benthic macroalgae were identified from the coral reefs of Rose Atoll, American Samoa (Rose Atoll Marine National Monument). The algal collections were made during the February 2002, February 2004, March 2006, and March 2008 Pacific Reef Assessment and Monitoring Program (Pacific RAMP) under the auspices of the U.S. National Oceanic & Atmospheric Administration (NOAA), Pacific Islands Fisheries Science Center (PIFSC), Coral Reef Ecosystem Division (CRED). The collections included 6 species of Cyanobacteria, 14 species of red algae, 4 species of brown algae, and 21 species of green algae. Nine species represented new records for the Samoan Archipelago (American Samoa and Samoa). Based on their occurrences, eight species of green algae were considered most broadly distributed among the stations during all four expedition years. The top three broadly distributed species were Halimeda taenicola, Halimeda micronesica, and Caulerpa cupressoides.

New records of benthic marine macroalgae from the Caribbean coast of Costa Rica

Abstract: Marine macroalgae are highly diverse and play an important role in marine ecosystems, influencing ecological processes. Recording the algae diversity with precise taxonomic identification is required to understand the marine ecosystems. The biodiversity of macroalgae along the southern Caribbean coast of Costa Rica has been studied by several authors, and the updated checklist includes 396 species of benthic marine algae reported for both Pacific and Caribbean coasts of Costa Rica, from which 287 are recorded from the Caribbean. Eighty percent of the total specimens from the Caribbean coast deposited in botanical collections in Costa Rica were collected at Cahuita National Park, an area where most of the studies have been carried out. This study reports on the addition of five new species and one genus of marine benthic macroalgae to the Caribbean Costa Rican flora, found at the poorly studied reefs of Playa Chiquita (Punta Cocles) and Punta Uva. Sampling was directed, searching for benthic macroalgae at Chiquita beach (SCUBA diving and snorkel) and Punta Uva (snorkel only), during October 2014. Specimens were deposited in the Dr. Luis A. Fournier Origgi Herbarium of the University of Costa Rica (USJ). Most of the new records were Chlorophyta, followed by Rhodophyta and Ochrophyta-Phaeophyceae. We recorded four new genera for the Caribbean coast of Costa Rica: Microdictyon Decaisne, 1841, Rhipidosiphon Montagne, 1842, Predaea G. De Toni, 1936, and Augophyllum S.-M. Lin, S. Fredericq & M. H. Hommersand, 2003. In conclusion, is necessary to continue the detailed taxonomic works in the Caribbean coast, focusing on areas poorly studied, in order to improve our knowledge of the marine flora of Costa Rica. Rev. Biol. Trop. 66(Suppl. 1): S328-S339. Epub 2018 April 01.

Erratum to: Metal distributions in seawater, sediment and marine benthic macroalgae from the South Australian coastline

Algal species which are ubiquitous along the coastlines of many countries reflect the environmental conditions of the coastal seawater and may serve as useful biomonitors of anthropogenic pollution. Heavy metal concentrations of ten elements (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) of potential environmental concern were determined in seawater, sediments and twelve species of benthic marine macroalgae from four locations (Glenelg, Port Adelaide, Port Broughton and Port Pirie) along the South Australian coastline. The four sites chosen represented varying degrees of metal contamination, where the capacity for benthic macroalgae to accumulate heavy metals from the environment was evaluated. Spatial differences in heavy metal concentration in both seawaters and sediments were observed at all sites with the highest concentrations of heavy metals including Cd (125 μg g−1), Pb (2,425 μg g−1) and Zn (7,974 μg g−1) found in the finer sediment fractions (<250 μm) of Port Pirie. While all algal species studied (Acrosorium polyneurum, Anotrichium tenue, Cystophora Cephalornithos Cystophora monillifera, Cystophora monilliformis, Dictyopteris australis, Gelidium micropterum, Gracilaria, Hormophysa Cuneiformis, Sargassum cinctum, Scaberia agardhii and Ulva lactuca) accumulated metals to varying degrees, Blindigia marginata was a good biomonitor species for a number of metals including Cd, Co, Cr, Fe, Pb and Zn, exhibiting both relatively high total metal concentrations and significant concentration factors.

Composition and Distribution of Deep Water Macroalgae Species from the Continental Shelf of Sergipe State, Brazil

This study investigates the deep-water flora of the continental shelf in Sergipe State, Brazil located between 10º36’08’’ – 11º21’07’’S and 36º28’10’’ – 37º13’47’’W. The samples were collected by dragging at 18 sampling sites, between 10 to 30 m depth, from May 1999 to March 2000. A total of 91 taxa of marine benthic macroalgae were identified (56 Rhodophyta, 20 Heterokontophyta and 15 Chlorophyta). Forty-seven (47) of these are new occurrences for Sergipe flora. Rhodophyta dominated, accounting for 61% of the total species collected, with the order Ceramiales having the highest number of species present (39.55%), followed by Heterokontophyta (23%), mostly represented by Dictyotales (65%). Finally, 15 Chlorophyta taxa were found (16%), mainly composed of Bryopsidales (53%).

Rhoicosigma parvum n. sp., a benthic marine diatom from The Bahamas and Western Pacific

A new diatom species, Rhoicosigma parvum Hein & Lobban, is described from benthic marine macroalgae and seagrasses northwest of Andros Island, The Bahamas, and from macro- and filamentous seaweeds of Guam and Palau. Specimens observed ranged in length from 30 to 70 µm, and in width from 6 to 9 µm, with 29–32 transverse striae in 10 µm. The frustule is slightly sigmoid in valve view and arched in girdle view. The two valves are dissimilar. The convex valve has an almost-straight raphe and the concave valve has a strongly sigmoid raphe. The chloroplasts are deeply lobed plates, one along each side of the girdle. Scanning electron microscopy revealed that the valves have loculate areolae, with the areolae opening to the valve exterior as apically elongated slits. By contrast, the internal areolar openings are rectangular, elongated apically. Externally, the central raphe endings are deflected in the same direction and terminate in pore-like expansions. The terminal fissures are strongly bent in opposite directions and in the same direction as the sigmoid curvature of the valve end. Internally, the central raphe branch endings are simple and straight, whereas the apical raphe endings terminate in well-developed helictoglossae. There are siliceous thickenings (central bars) on both sides of the central nodule. Specimens are similar to R. compactum (Greville) Grunow but are smaller and have finer striae.

Spatio-temporal, environmental factors, and host identity shape culturable-epibiotic fungi of seaweeds in the Red Sea, Egypt

The study of fungal species diversity from marine algae is in its infancy; as now no studies have been carried out on the distribution and diversity of fungi on the surfaces of marine macroalgae where all fungal–algal interactions tend to begin. The aim of this study was to isolate and describe the culturable part of mycobiota associated with the surface of benthic marine macroalgae (epiphytic or epibiotic fungi). This is an important step in understanding their abundance, diversity and factors influencing their variability and composition. The fungal community was dominated by Ascomycetes (89%) with Eurotiales as the most abundant fungal order followed by Capnodiales, Pleosporales, and Hypocreales, while Zygomycetes was less frequent. The nature of occurrence of fungal genera on different macroalgal hosts suggests that a mix of generalists’ framework applies to fungal epiphytes of seaweeds, but the abundance of fungal taxa varied among ecological functional groups of algae, as well as macroalgal taxonomic groups, which imply host filtering. The fungal assemblages were also characterized by temporal variation with variation in temperature, pH, and salinity as the most important abiotic factors. The structure of fungal assemblages showed high beta diversity and low similarity between hosts.

Metal distributions in seawater, sediment and marine benthic macroalgae from the South Australian coastline

Metal distributions in seawater, sediment and marine benthic macroalgae from the South Australian coastline

Species composition, zonation, and biomass of marine benthic macroalgae in Kongsfjorden, Svalbard

Abstract We surveyed macroalgae at Hansneset, Blomstrand (78°39′N, 11°57′E) in Kongsfjorden, Svalbard, down to 30 m depth between 1996 and 1998. In total, 62 species were identified: 16 Chlorophyta, 25 Phaeophyceae, and 21 Rhodophyta. The majority of species (53.5%) belonged to the Arctic cold-temperate group, followed in frequency by species distributed from the Arctic to the warm-temperate region (25.9%). Four endemic Arctic species (Laminaria solidungula, Acrosiphonia flagellata, A. incurva, and Urospora elongata) were found. Two species (Pogotrichum filiforme and Mikrosyphar polysiphoniae) were new to Svalbard. Chlorophyta, Phaeophyceae, and Rhodophyta extended from the eulittoral zone down to 11, 21, and &gt;30 m depths with maximum biomasses at 1–5 m, 5–10 m, and 5–30 m depths, respectively. Annual and pseudoperennial species had highest biomasses in the upper 5 m, while perennials were distributed deeper. The highest biomass (8600 g m-2 wet weight) at 5 m depth comprised mainly L. digitata, Saccorhiza dermatodea, Alaria esculenta, and Saccharina latissima. The biogeographic composition of macroalgae at Hansneset was rather similar to that of northeastern Greenland, but different from that of northern Norway, which has a higher proportion of temperate species. Climate warming and ship traffic may extend some of the distribution ranges of macroalgae from mainland Norway to Svalbard.

Photosynthetic response of monospecific macroalgal stands to density

Photosynthesis by benthic marine macroalgae makes an important contribution to the productivity of coastal seas. Quantification of photosynthesis and productivity of macroalgal assem- blages is therefore important in understanding ecosystem functioning in coastal seas and providing realistic values for coastal productivity in global models. Estimates of macroalgal productivity are often based on the photosynthetic characteristics of thallus pieces or whole thalli, and not on those of communities. Such methods may overestimate rates of productivity as they do not account for neigh- borhood shading effects that may reduce photosynthetic rates in macroalgal stands that typically have high densities. In order to determine whether productivity estimates based on individuals differ from those based on communities, a controlled laboratory experiment was conducted with 3 domi- nant sub-canopy macroalgal species (Cystophora scalaris, Xiphophora gladiata and Undaria pinnati- fida) from southern New Zealand. Photosynthetic parameters (initial slope of the photosynthesis vs. irradiance (P-E) curve α, saturation irradiance Ek, maximum rate of photosynthesis Pmax and dark- respiration Rd) were obtained via P-E experiments using a custom-built respirometry chamber for a range of densities that corresponded to the minimum, average and maximum densities of these spe- cies in the field. A 5 to 7-fold decrease in Pmax was observed when the density of the algal stand was above 1 ind. m -2 . Rd and α were also lower in communities than for individuals. Results illustrate that estimates based on single specimens substantially overestimate productivity and we recommend that the densities used in experiments reflect those observed in the field.

Macroalgas submareales de la bahía de Todos Santos, Baja California, México

In order to identify and characterize the species composition of the subtidal zone of the Todos Santos Bay, Baja California, Mexico, benthic marine macroalgae were sampled at 7 sites from 1995 to 2000. As a result of 25 scuba at depths between 3 and 33 m we found a total of 150 species of macroalgae for the study area, of which 10 are Chlorophyta, 26 Phaeophyta and 114 Rhodophyta; 47 species represent new records for the study area, of which Faucheocolax attenuata Setchell and R.L Moe Minium parvum are new to the marine flora of Pacific Mexico. We include a research that consider the macroalgae in the Todos Santos Bay and a discussion on the composition of species found, its vertical distribution and reproduction, particularly the species epiphytes and parasites present in the study area.

A survey of the marine macroalgae of Karpathos Island (the Aegean Sea, Greece)

The results of a floristic survey of benthic marine macroalgae from Karpathos Island (the Aegean Sea, Greece) are reported. A total of 202 taxa at specific and infraspecific levels were identified, comprising 136 Rhodophyta, 42 Ochrophyta and 24 Chlorophyta, 19 of which (13 Rhodophyta, 3 Ochrophyta and 3 Chlorophyta) were new to Greece.

Photosynthesis and growth in macroalgae: linking functional-form and power-scaling approaches

Grouping species into functional-form groups and measuring directly their surface area to volume ratio are 2 common approaches to forecast primary production of marine macroalgae. A link between the functional-form model (FFM) and the power-scaling approach (PSA) for a wide vari- ety of marine macroalgae has been attempted for the first time in the present work. To test both approaches, thalli of 44 species of marine benthic macroalgae were collected from intertidal zones adjacent to Cadiz Bay. Metabolic rates, tissue nutrient content, surface area to biomass ratio (SA/B) and specific growth rates were measured for these species. PSA slopes were close to 2/3 power for growth rate, while metabolic rates scaled very close to, or matched, 3/4 power. The FFM descriptive model provided similar results to the PSA when it was transformed to a numerical model through the SA/B ratio. Even though both models appear to be valid, the problems derived from species alloca- tion into morphological groups, and other previous criticisms, make the direct use of SA/B ratios more suitable for representing primary production in macroalgal functional groups in numerical models of coastal ecosystems.