Geniculate Coralline Algae Research Articles

Effects of seawater temperature and irradiance on the growth of sporelings of Amphiroa cf. zonata and Corallina berteroi (Corallinales, Rhodophyta) in Japan

ABSTRACTGeniculate coralline algae in temperate waters form dense, carpet-like turfs and are prevalent in intertidal rocky habitats or as understory beneath canopy-forming seaweeds in shallow subtidal zones. Using laboratory cultures, we determined the optimum and vital growth conditions for sporelings of two geniculate species, Amphiroa cf. zonata and Corallina berteroi, which are dominant in temperate waters around Japan. Samples were genetically identified as matching those two species as known from the coasts of Japan and worldwide, respectively. The optimum water temperature range and the upper critical water temperatures for sporeling growth were similar for the two coralline species. The optimum growth temperatures of A. cf. zonata (25–30°C) and C. berteroi (20–25°C) were comparable to those for temperate seaweeds commonly found in the same temperate region of Japan as the study sites. However, the upper critical temperatures for growth (33°C in A. cf. zonata and 32°C in C. berteroi) were higher than what is known for temperate kelps, though similar to those for other macroalgae. Amphiroa cf. zonata in the upper subtidal zone exhibited photoinhibition in conditions of less than 400 µmol photons m–2 s–1, whereas C. berteroi in the intertidal zone did not show such photoinhibition. The difference in irradiance effects upon growth was inferred to be related to the species distributions in their local environments of the coastal zone.

A possible erect coralline alga from the Ediacaran Dengying Formation in the Zhenba area of South China

AbstractStudies of molecular biology suggest a deep origin of coralline red algae in the Neoproterozoic, but unequivocal representatives have not been found in Precambrian rocks. Such scarcity in the fossil record significantly limits our knowledge regarding the origin and early evolution of this group. Phosphatized, fragmented columnar microfossils from the Zhenba microfossil assemblage at the base of the Ediacaran Dengying Formation, South China are presented. Morphologically they represent a novel taxon characterized by: (1) variable and irregularly shaped cross sections, and (2) discontinuous, nonisopachous laminae transversely stacked inside the columns. Integrated morphological comparisons favor their interpretation as probable erect coralline algae. Anatomically, the Zhenba columns resemble present-day geniculate coralline algae in columnar thalli and stromatolithic tissue construction, although they differ from modern geniculate corallines in lacking highly calcified skeletons and tissue-organ differentiation. These anatomical similarities collectively suggest that the Zhenba columns probably represent stem-group coralline algae. The new finding indicates that early coralline algae could be more diverse than previously thought, and their initial morphological diversification and resultant ecological expansion probably occurred in the middle to late Ediacaran.

Identification of ‘articuliths’ in a unique algal bed formation from Brazil and description of Jania cabista sp. nov. (Corallinales, Rhodophyta)

ABSTRACT A unique algal bed formation, composed largely of free-living geniculate coralline algae (articuliths), was recorded within the subtidal zone of Arraial do Cabo Bay, Brazil. The importance of these articuliths was shown by previous ecological surveys, which, using morpho-anatomical analyses, identified these algal specimens as belonging to Amphiroa beauvoisii, Jania adhaerens and J. capillacea. Cryptic diversity was recently found in Brazilian corallines and prompted the reassessment of the species diversity of the Arraial do Cabo Bay algal bed. Here we identified the species of geniculate coralline algae commonly associated with the subtidal beds of Arraial do Cabo Bay using a combination of molecular (psbA) and morpho-anatomical analyses, and compared them to closely related species described for Brazil and elsewhere. Two species belonging to the genera Amphiroa and Jania were identified as the major components of these algal beds. Our analyses suggest that these specimens belong to Amphiroa cf. exilis and to a new species of Jania, Jania cabista sp. nov.

Degradation of a photophilic algal community and its associated fauna from eastern Sicily (Mediterranean Sea)

The status of the “Biocoenosis of the Infralittoral Algae” of the upper infralittoral zone (at 5 m depth) from two selected stations along the eastern coast of Sicily (Ionian Sea, Mediterranean) was studied with a multiproxy approach involving the study of algae and associated protist and animal organisms, including foraminifers, serpulids, molluscs, bryozoans and ostracods. Scraped samples (40x40 cm) were collected at selected seasons during a 2-year period (2015-2016) in order to identify possible seasonal and spatial differences between the two stations, and to compare present data with historical ones. A community made up of the algae Halopteris scoparia, Padina pavonica, Dictyota dichotoma, Ellisolandia elongata and several other geniculate coralline algae was found in sites historically colonised by a Cystoseira brachycarpa community, which was not found during our study. These algae presently structure the community and provide substratum for several associated epibiotic species. Hierarchical cluster analysis and Non-Metric Multi-Dimensional Scaling Ordination significantly differentiate the communities between the two stations but show no clear seasonal trend. Differences largely relate to changes in the algal vegetation and the impact produced by the regression of structuring species on epibiots (especially serpulids and bryozoans). Comparison with historical algal data from the area indicates the disappearance of Cystoseira brachycarpa, which was present at least until the last ’1990s, and a community degradation with a considerable loss in species richness. This parallels observations in other Mediterranean areas, and could be related to the increase in echinoid population density and their heavy grazing activity.

Heterozoan carbonate-enriched beach sand and coastal dunes—with particular reference to rhodoliths, Dirk Hartog Island, Shark Bay, Western Australia

This is a preliminary interdisciplinary study on the enrichment of heterozoan carbonates on Dirk Hartog Island, Shark Bay, Western Australia, with particular reference to rhodolith (free-living non-geniculate) coralline algae. The current study aims to investigate the geological impact of shallow-water rhodoliths in Shark Bay, as well as fill critical information gaps on the biogeographical distribution of rhodoliths in Australia. We analyzed the composition of sand from eight sites (totaling 21 beach and sand dune samples) on the eastern (windward) shore of the island, and investigated the origin of the coralline algal grains. Heterozoan carbonates (shell, geniculate coralline algae grains, and rhodolith grains) together comprised 3–84% of the carbonate-enriched beach and dune sand samples. While shell fragments often comprised the highest percentage (up to 73%), rhodolith grains (up to 27%) were found in 12 of 21 samples, with rhodolith grains also occurring in two dune samples. Geologically, the study has shown that rhodoliths and rhodolith beds are important shallow-marine habitats in Shark Bay, with a proven capacity to enrich beach/dune sands in Shark Bay and potentially other areas along the Australian coast. Biogeographically, the study confirmed the presence of a previously undescribed shallow rhodolith bed in Shark Bay (the first bed documented on the Western shore) with the possibility of a third bed near Sandy Point on Dirk Hartog Island. It also confirmed the presence of rhodolith forming Neogoniolithon brassica-florida and Lithophyllum sp. in Shark Bay, and is the first record of Hydrolithon reinboldii rhodoliths in Australia.

Elevated temperature and changed carbonate chemistry: effects on calcification, photosynthesis, and growth of Corallina officinalis (Corallinales, Rhodophyta)

:Recent ecophysiological studies of coralline algae have highlighted the effects of several environmental concerns, such as acidification and warming of the world's coastal oceans. Among these, elevated temperature might be the most critical environmental factor affecting rocky benthic communities, where coralline algae tend to dominate the habitat. This study was conducted to investigate changes in photosynthesis, calcification, and growth of the geniculate coralline alga Corallina officinalis after 7 d of acclimation to four temperature conditions (13, 18, 23, and 28°C). Calcification rates decreased with increasing temperature in the light, although growth of C. officinalis did not differ considerably under different temperatures. Furthermore, although photosynthesis was largely unaffected by increasing temperature, respiration increased significantly under the highest temperature. These physiological responses are strongly related to the carbonate chemistry of seawater, which is itself affected by elevated temperature. Our results also indicate that C. officinalis exhibits physiological tolerance to a wide range of temperatures, even when increased by more than 10°C above ambient temperature of 18°C. Consequently, if noncalcareous macroalgae are negatively affected by higher temperatures, the ability of C. officinalis to acclimate to these conditions could cause it to become a more dominant species of rocky macroalgal habitats as ocean temperatures continue to rise.

The enigmatic Palaeocene-Eocene coralline Distichoplax: Approaching the structural complexities, ecological affinities and extinction hypotheses

Abstract The alluring but scarcely understood Palaeocene-Eocene coralline alga Distichoplax has been examined in detail from multiple carbonate sections outcropping in Mawmluh near Cherrapunji (East Khasi Hills) in Meghalaya, N-E India. Despite having a wide geographical distribution Distichoplax still remains a mysterious taxon with faint knowledge pertaining to its evolution, ecology and causes of ultimate extinction. The commonly known feather-shaped and zipper-shaped cell arrangements need detailed reassessment considering the morphological intraspecific variability. The threefold objective of this paper is to analyse the complex cell/anatomical variations in Distichoplax, provide some insights into its ecological affinity, and most importantly propose hypotheses on the possible causes of its untimely demise in sharp contrast to other coralline algae distinguished by a long evolutionary record continuing to the present-day. The abundance of Distichoplax varies from monodominant assemblages to their co-dominance with geniculate coralline algae, non-geniculate Sporolithon and larger benthic foraminifera (orthophragminids) before facing sharp decline and ultimate extinction. Rare fairly well-preserved uniporate conceptacles and absence of cell fusions link Distichoplax to the subfamily Lithophylloideae of the family Corallinaceae. Very poor incidence of reproductive features, significant blooms of the species during the Thanetian (Late Palaeocene) and its eventual disappearance in the Eocene indicate Distichoplax may have been excessively dependent on vegetative propagation, and perished due to the climate adversities like the Palaeocene-Eocene Thermal Maximum (PETM) and biotic pressures like the Larger Foraminiferal Turnover (LFT).

Early Eocene Calcareous Algae and Benthic Foraminifera from Meghalaya, NE India: A New Record of Microfacies and Palaeoenvironment

Abstract: Early Eocene carbonate sediments of the Umlatdoh Limestone (Meghalaya, N-E India) represent a shallow marine shelf environment. The major biotic components characterizing these carbonates are calcareous green algae and small to larger benthic foraminifera. Based on the biogenic associations and general sedimentological features, five major facies types (MFTs) are distinguished. They are dominated by poor to moderately sorted grainstones followed by packstones, rudstones and wackestones. Considerable abundance of Halimeda, scarcity of z-corals and poor to moderate occurrence of filter-feeding organisms imply mesotrophic to a slightly oligotrophic nutrient regime. Rare occurrence of geniculate coralline algae is probably due to the lack of suitable substrate and environmental conditions. High incidence of grainstones and packstones, fairly preserved microfossils and few reworked specimens indicate a parautochthonous mode of deposition. Preponderance of Alveolina and Nummulites indicate the possible advent of larger foraminiferal turnover (LFT) in the east Tethys during or even before early Eocene. A conceptual palaeoenvironmental model for the studied succession is provided to showcase various facies gradients, bathymetry levels and shelf zones pertinent to the Umlatdoh Limestone.

Seaweed community response to a massive CO2 input

Changes in the structure of seaweed communities were examined following a massive CO2 input caused by a submarine eruption near the coast of El Hierro island (Canary Islands, Spain). The event lasted almost five months (October 2011–March 2012) and created a significant pH gradient. Specifically, we compared three different zones: highly affected with extreme low pH (6.7–7.3), affected with low pH (7.6–7.8), and unaffected ambient pH zone (∼8.1) according to the pH gradient generated by the predominate currents and waves in the south of the island. Studies were carried out before, during and after the CO2 input event in each zone. We found community-wide effects on seaweed communities during the eruption; these included changes in species abundance and changes in the diversity. However, changes in all these community traits were only evident in the highly affected zone, where there were major shifts in the seaweed community, with a replacement of Lobophora variegata by ephemeral seaweeds. Lobophora variegata dropped in cover from 87–94 to 27% while ephemeral seaweeds increased 6–10 to 29%. When the impact ended Lobophora variegata began to recover reaching a cover higher than 60%. In the moderate affected area the Lobophora variegata canopies maintained their integrity avoiding phase shifts to turfs. Here the only significant changes were the reduction of the cover of the crustose and geniculate coralline algae.

Reef Community Changes Associated with the 2009–2010 El Niño in the Southern Mexican Pacific

Abstract: We surveyed coral reefs communities before (September 2007–March 2009) and during (September 2009) the 2009–2010 El Nino event on the coast of Oaxaca, southern Mexican Pacific to evaluate community changes associated with the warming event. From May 2009 to December 2010, we recorded positive deviations from the historical in situ sea surface temperature values. There were differences among the coral species Pocillopora damicornis, Pavona gigantea, and Porites panamensis with significant reductions in chlorophyll a and Symbiodinium density during El Nino, resulting in bleaching (>13%) and increase in algal coverage (mainly geniculate coralline algae). Concurrently, echinoderm and fish assemblages also experienced significant modifications; abundances of the sea urchins Eucidaris thouarsii and Centrostephanus coronatus increased during the warming event, whereas Diadema mexicanum declined; meanwhile, fish species such as Thalassoma lucasanum declined in favor of Stegastes acapulcoensis and Haemul...

Pleistocene aeolianites at Cape Spencer, South Australia; record of a vanished inner neritic cool‐water carbonate factory

AbstractAeolianites are integral components of many modern and ancient carbonate depositional systems. Southern Australia contains some of the most impressive and extensive late Cenozoic aeolianites in the modern world. Pleistocene aeolianites on Yorke Peninsula are sculpted into imposing seacliffs up to 60 m high and comprise two distinct imposing complexes of the Late Pleistocene Bridgewater Formation. The lower aeolianite complex, which forms the bulk of the cliffs, is a series of stacked palaeodunes and intervening palaeosols. The diagenetic low Mg‐calcite sediment particles are mostly bivalves, echinoids, bryozoans and small benthic foraminifera. This association is similar to sediments forming offshore today on the adjacent shelf in a warm‐temperate ocean. By contrast, the upper aeolianite complex is a series of mineralogically metastable biofragmental carbonates in a succession of stacked lenticular palaeodunes with impressive interbedded calcretes and palaeosols. Bivalves, geniculate coralline algae and benthic foraminifera, together with sparse peloids and ooids, dominate sediment grains. Fragments of large benthic foraminifera including Marginopora vertebralis, a photosymbiont‐bearing protist, are particularly conspicuous. Palaeocean temperatures are interpreted as having been sub‐tropical, somewhat warmer than offshore carbonate factories in the region today. The older aeolianite complex is tentatively correlated with Marine Isotope Stage 11, whereas the upper complex is equivalent to Marine Isotope Stage 5e. Marine Isotope Stage 5e deposits exposed elsewhere in southern Australia (Glanville Formation) are distinctive with a subtropical biota, including Marginopora vertebralis. Thus, in this example, palaeodune sediment faithfully records the nature of the adjacent inner neritic carbonate factory. By inference, aeolianites are potential repositories of information about the nature of long‐vanished marine systems that have been removed due to erosion, tectonic obliteration or are inaccessible in the subsurface. Such information includes not only the nature of marine environments themselves but also palaeoceanography.

Effects of algal turfs and sediment accumulation on replenishment and primary productivity of fucoid assemblages

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 511:59-70 (2014) - DOI: https://doi.org/10.3354/meps10932 Effects of algal turfs and sediment accumulation on replenishment and primary productivity of fucoid assemblages T. Alestra1,*, L. W. Tait2, D. R. Schiel1 1Marine Ecology Research Group, School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8041, New Zealand 2National Institute of Water and Atmospheric Research (NIWA), 10 Kyle Street, PO Box 8062, Riccarton, Christchurch 8011, New Zealand *‑Corresponding author: tommaso.alestra@pg.canterbury.ac.nz ABSTRACT: As a result of anthropogenic habitat degradation worldwide, coastal ecosystems are increasingly dominated by low-lying, turf-forming species, which proliferate at the expense of complex biogenic habitats such as kelp and fucoid canopies. This results in dramatic alterations to the structure of the associated communities and large reductions in primary productivity. The persistence of turf-dominated systems has been attributed to the impacts of the turfs on the recovery of algal canopies and also to the different susceptibility of canopy- and turf-forming algae to altered physical conditions, in particular increased sedimentation. Here we tested the impacts of turfing geniculate coralline algae and sediment on fucoid recovery dynamics and their influence on assemblage net primary productivity (NPP). The recruitment of the habitat-forming fucoid Hormosira banksii on bare substrata was significantly higher than in treatments in which sediments, coralline turfs or turf mimics covered the substratum, indicating that sediment deposition and space pre-emption by algal turfs can synergistically affect the development of fucoid beds. NPP of coralline turfs was much lower than that of fucoid-coralline assemblages, which included a H. banksii canopy, and was reduced further by sediment accumulation. When devoid of sediment, however, coralline algae contributed to enhance fucoid-coralline assemblage NPP, because of synergistic interactions among the components of the multi-layered assemblage in optimizing light use. Our findings amplify extensive research addressing the global loss of macroalgal canopies and highlight key processes involving sediment accumulation in the benthic environment and effects on the replenishment and productivity of fucoid stands. KEY WORDS: Canopy · Coralline algae · Habitat structure · Intertidal · Macroalgae · Photosynthesis · Sediment · Turf-forming Full text in pdf format PreviousNextCite this article as: Alestra T, Tait LW, Schiel DR (2014) Effects of algal turfs and sediment accumulation on replenishment and primary productivity of fucoid assemblages. Mar Ecol Prog Ser 511:59-70. https://doi.org/10.3354/meps10932 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 511. Online publication date: September 24, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.

Phylomineralogy of the Coralline red algae: Correlation of skeletal mineralogy with molecular phylogeny

The coralline algae in the orders Corallinales and Sporolithales (subclass Corallinophycidae), with their high degree of mineralogical variability, pose a challenge to projections regarding mineralogy and response to ocean acidification. Here we relate skeletal carbonate mineralogy to a well-established phylogenetic framework and draw inferences about the effects of future changes in sea-water chemistry on these calcified red algae. A collection of 191 coralline algal specimens from New Zealand, representing 13 genera and 28 species, included members of three families: Corallinaceae, Hapalidiaceae, and Sporolithaceae. While most skeletal specimens were entirely calcitic (range: 73-100 wt.% calcite, mean 97 wt.% calcite, std dev=5, n=172), a considerable number contained at least some aragonite. Mg in calcite ranged from 10.5 to 16.4 wt.% MgCO(3), with a mean of 13.1 wt.% MgCO(3) (std dev=1.1, n=172). The genera Mesophyllum and Lithophyllum were especially variable. Growth habit, too, was related to mineralogy: geniculate coralline algae do not generally contain any aragonite. Mg content varied among coralline families: the Corallinaceae had the highest Mg content, followed by the Sporolithaceae and the Hapalidiaceae. Despite the significant differences among families, variation and overlap prevent the use of carbonate mineralogy as a taxonomic character in the coralline algae. Latitude (as a proxy for water temperature) had only a slight relationship to Mg content in coralline algae, contrary to trends observed in other biomineralising taxa. Temperate magnesium calcites, like those produced by coralline algae, are particularly vulnerable to ocean acidification. Changes in biomineralisation or species distribution may occur over the next few decades, particularly to species producing high-Mg calcite, as pH and CO(2) dynamics change in coastal temperate oceans.

Temporal changes in biotic and abiotic composition of shallow-water carbonates on submerged seamounts in the northwestern Pacific Ocean and their controlling factors

The lithology of Cretaceous to Pleistocene shallow-water carbonates, which were collected from 29 sites on 24 submerged seamounts in the northwestern Pacific Ocean using the Deep-sea Boring Machine System, are described. The shallow-water carbonate deposits examined in the present study can be roughly divided into three types based on their composition: Cretaceous, Eocene (to lowest Oligocene?), and Oligocene to Pleistocene. The Cretaceous type is characterized by an abundance of molluscs (including rudists), smaller foraminifers, microencrusters, non-skeletal grains (e.g., peloids, cortoids, and intraclasts), and microbial sediments. Most components have been micritized and possess thick micrite envelopes. The Eocene type is characterized by the dominance of larger foraminifers, Halimeda spp., nongeniculate and geniculate coralline algae, bryozoans, and dasycladacean algae. Scleractinian corals are very minor components. The Oligocene to Pleistocene type is similar in composition to the Eocene type, but it differs from the latter by the abundant occurrence of scleractinian corals and nongeniculate coralline algae. Corals, nongeniculate coralline algae, and Halimeda spp., which precipitate carbonates within closed to semi-closed spaces in and around their bodies (intra-tissue), are major components of the Eocene and Oligocene to Pleistocene types. In contrast, the Cretaceous-type sediments contain relatively more carbonates of extra-tissue origin (i.e. carbonates deposited in relatively open spaces around the bodies of organisms, such as rudists, as well as microbialite and ooids) than the Eocene and Oligocene to Pleistocene types. The changes in the major constituents of the carbonate factory depend on local environments, such as nutrient availability, as well as a global factor: seawater chemistry in the surface waters. Temporal variations in the abundance of the shallow-water carbonates on the examined seamounts suggest that carbonate accumulation was not necessarily controlled by climatic conditions; instead, it was related to the volcanism and tectonics that served as the foundations for reef/carbonate-platform formation.

Additional coralline algae from the Lower Miocene to Late Holocene sediments of the Porbandar Group, Gujarat

The Neogene-Quaternary sediments well exposed in the Porbandar Basin are characterized by coralline algae. The limestone, calc-arenites and marls are the dominant lithology of this sequence. The present paper documents ten species of coralline algae. Among these, the nongeniculate coralline algae are represented by four species and geniculate coralline algae include six species. The sediments yielding this algal flora range in age from the Lower Miocene to Late Holocene.

Carbonate production and deposition in a warm-temperate macroalgal environment, Investigator Strait, South Australia

The prolific macroalgal forests in shallow (< 20 m), warm-temperate, marine environments off southern Yorke Peninsula, South Australia have two carbonate-producing habitats, 1) upward-facing, exposed rock surfaces beneath large phaeophytes, and 2) concealed rock surfaces under overhangs, on rock walls, in crevasses, and indentations that all lie behind a curtain of brown macroalgae. Exposed surfaces have three growth tiers; 1) a basal, cm-high veneer or turf of crustose corallines, geniculate corallines, and short fleshy red algae that are grazed by herbivorous gastropods, 2) an intermediate, 5–20 cm-high community of fleshy red algae, and 3) a 20–100 cm+-high canopy of large phaeophytes (especially Ecklonia, Cystophora and Xiophora) whose blades are locally encrusted with bryozoans, such as Membranipora membranacea, and spirorbids. Concealed surfaces of subvertical rock walls and cryptic habitats behind the macroalgal curtain have two tiers; 1) a cornucopia of encrusting plants and animals, especially crustose and geniculate corallines in shallow water, that give way in water depths > 4 m to numerous bryozoans (especially fenestrates), serpulid worms, numerous and diverse demosponges, ascidians, small solitary corals, epifaunal echinoids, and gastropods, and 2) a veil of macroalgae (mainly Cystophora and Ecklonia) that drapes down and shades the rock walls. Most carbonate sediment production does not come from calcareous epiphytes on the macroalgae but comes from the coralline algae and calcareous invertebrates living on the rock walls and in concealed depressions. Mollusks (gastropods and bivalves) and geniculate coralline algae with numerous lithoclasts, crustose coralline fragments, barnacle plates, serpulid worms, bryozoans, and large benthic foraminifers (especially Amphistegina) dominate the resultant gravels and sands; but there is little or no mud. This is because carbonate sediment is the result of production not only in the macrophyte factory but also in adjacent seagrass factories. Particles produced in the macroalgal factory are shed onto the adjacent seafloor, where they form the requisite sandy substrates for quick colonization by seagrasses. Thus, over time the sediment in this shallow but hydrodynaically energetic environment becomes a mixture of materials from the two sources with seagrasses contributing gastropods, large benthic foraminifers, spirorbids, bryozoans and articulated corallines to the sediment milieu. If this system is a typical example, then warm-temperate Neogene carbonate facies related to macroalgal factories should be a mixture of materials from the rocky substrates, a calcareous infauna, and marine seagrasses.

&amp;lt;i&amp;gt;Subterraniphyllum thomasii&amp;lt;/i&amp;gt; Elliott, Fossil Calcareous Alga the Evolutionary Link between Geniculate and Nongeniculate Coralline Algae: A Hypothesis

The Neogene sediments exposed in the Saurashtra region along the southwest coast India, consists of well preserved diversified coralline algae [1-5].The Subterraniphyllum thomasii Elliott, a fossil Calcareous alga has been reported from the Dwarka Formation (Lower to Middle Miocene) from Porbandar area, Saurashtara, Indian subcontinent. This is the first report of Subterraniphyllum thomasii Elliott from Lower-Middle Miocene sediments from the Indian subcontinent; however it has been documented earlier from Late Lutetian sediments of Kuchchh Basin, India. There is a controversy regarding the generic placement of the extinct species Subterraniphyllum thomasii Elliott as distinct genus of the geniculate coralline algae or not i.e. nongeniculate coralline algae [6,7]. However, the present specimens of Subterraniphyllum thomasii Elliott exhibit pinpointing features of both geniculate and nongeniculate coralline algae. Finally on the basis of our observations, we hypothesis that Subterraniphyllum thomasii Elliott may be transitional species and evolutionary link between geniculate and nongeniculate coralline algae.

An automated pH‐controlled culture system for laboratory‐based ocean acidification experiments

Using a spectrophotometric pH measurement system, an automated 12‐tank culture system was developed, which is capable of maintaining pH levels between 7.51 and 8.00 (local, in‐situ pH) within 0.02 pH units at 15.1°C. The precise control of pH in the individual culture tanks was achieved through the addition of CO2‐enriched seawater to unamended seawater. A feed‐back system, which automatically adjusted the mixing ratio of unamended and CO2‐enriched seawater, ensured that the pH in each tank was kept within 0.02 pH units of target values. After each tank adjustment, the spectrophotometric pH measurement was combined with a dissolved inorganic carbon measurement to automatically re‐calculate carbonate chemistry in each tank. The system was used to study the growth of the geniculate coralline alga Arthrocardia corymbosa at pH levels of 7.52, 7.76, and 7.98.

Variable effects of a kelp foundation species on rocky intertidal diversity and species interactions in central California

The effect of foundation species on community assemblages in physically stressful environments has received much recent attention because of the importance of foundation species in ameliorating environmental stress. Many studies have described variable effects of foundation species on community diversity at small scales, but net positive effects over large scales. Egregia menziesii (Turner) J.E. Areschoug is a large and robust perennial kelp that creates a structurally complex habitat on rocky shores of the Northeast Pacific. This study investigated the effects of Egregia sporophytes on benthic assemblages of the rocky intertidal along the central California coast. Egregia sporophytes strongly impacted the structure of associated communities, due to wave-driven whiplash of fronds, shading, or habitat provision. A survey of Egregia populations at 10 stations along 200 km of the central California coast found effects of Egregia density on the intertidal to be consistent among sites. Increased Egregia sporophyte density negatively affected algal species richness, total algal cover, and cover of the most conspicuous species of algae. However, there was a positive relationship with algal crusts, geniculate coralline algae, and sessile invertebrates. Egregia removal experiments at two sites within the study area experimentally tested for the effects of Egregia on intertidal communities. Results from Soberanes Pt. were consistent with survey results because of the negative effect of Egregia on algal species diversity, subcanopy layering, and cover of abundant algal species. However, removal experiments at Pigeon Pt. resulted in a positive Egregia effect on algal diversity and cover of abundant algal species possibly due to lower Egregia densities, lower wave exposure than Soberanes Pt., and stress amelioration. In the lower energy environment, Egregia acted as a sand trap, yet sand accumulation did not negatively impact algal diversity. Negative effects of large brown algae on benthic assemblages have been observed in temperate waters around the world for certain intertidal or subtidal kelp in wave-swept environments allowing for scouring and substrate shading. This study shows that Egregia and morphologically similar brown algal species can have both negative and positive effects on community diversity depending on variation in density and local environmental conditions. Egregia has the opposite effect on community diversity than what has been previously reported for foundation species because it negatively affects biodiversity in stressful environments, but has a positive effect in less stressful environments.

Taxonomic biodiversity of geniculate coralline red algae (Corallinales, Rhodophyta) from the Macaronesian region: summary and analysis

A catalog and critical review of species and infraspecific taxa of non-fossil geniculate coralline red algae (Corallinales, Rhodophyta) previously reported from the Macaronesian region are presented along with an assessment of species diversity in the region. Published records of geniculate coralline algae are included along with comments relating to type material. Within the catalog, taxa are organized alphabetically by genus and within this by final epithet. From the 31 taxa recorded, 4 are based on type collections from Macaronesian localities. The types of most species and infraspecific taxa reported from the region have yet to be re-examined in a modern context, and most Macaronesian records require verification. The biodiversity of Macaronesian geniculate coralline algae may be lower than current information indicates.