Laminarian Algae Research Articles

Seasonal dynamics of subtidal macrophyte assemblages in Sobol Bay (Peter the Great Bay, Sea of Japan) in relation to depth

This paper describes the species composition, vertical distribution, and the seasonal changes in the biomass of subtidal macrophytes in Sobol Bay (Peter the Great Bay, Sea of Japan). The samples were collected in the depth-range from 0.5 to 4 m. A total of 65 macrophyte species were identified, among which were 10 species of Chlorophyta, 17 of Phaeophyceae, 37 of Rhodophyta and 1 of Magnoliophyta. Multivariate analyses were performed to detect spatial and temporal variations. Maximum species richness was registered in June, with a particularly dramatic biomass increase of brown algae. Both the number of species and the biomass of macrophytes decreased with increasing depth. Depth clearly affected the patterns of seasonal fluctuations of the species composition and biomass. In the study area, the species composition of the shallow-water algal assemblages was more stable throughout the year compared to that of the algal assemblages found in deeper waters. In total, four macrophyte assemblages were identified in the bay. A Phyllospadix iwatensis and Coccophora langsdorfii dominated assemblage occupied muddy-gravel bottoms in depths from 0.5 to 2 m throughout the year. An assemblage, co-dominated by annual brown algae Desmarestia viridis and Costaria costata, occurred at depths more than 3 m at late spring. Two other assemblages occurred on the rock and boulder bottom at 0.5–2 m depths, but they were temporally separated. An assemblage co-dominated by annual laminarian algae (Undaria pinnatifida and Costaria costata) developed at late spring and was succeeded in the autumn and winter by a Tichocarpus crinitus, Ulva lactuca, Sargassum pallidum and Codium fragile co-dominated assemblage. A comparison between the data obtained in the present study and the results of a previous study conducted in 1927 shows that the macrophytes assemblages in Sobol Bay underwent little change.

Physical forcing of distributions of bryozoan cyphonautes larvae in a coastal embayment

In shallow rocky subtidal ecosystems in the western North Atlantic, outbreaks of the nonindigenous encrusting epiphytic bryozoan Membranipora membranacea cause defoliation of laminarian algae, facilitating a phase transition from native kelp beds to meadows of invasive algae. We quantified spatial (m [depth] to km [sites]) and temporal (hourly to monthly) patterns in the abundance of larvae of M. membranacea, and a morphologically similar native species, Electra pilosa, in relation to physical structure (temperature, salinity, density) of the water column in St. Margarets Bay, Nova Scotia, Canada, on 8 dates from September to November 2007. During the study period, the water column ranged from strongly stratified to well mixed, and cross-shore movements of water masses (wind-driven upwelling and downwelling) were indicated by shoaling of the isoclines. When a strong pycnocline was located between the 2 sampled depths (4 and 12 m), larvae of both species were more abundant in the shallower, warmer, fresher layer. The linear relationship between strength of stratification and the relative abundance of larvae between depths was significant over 2 temporal (hourly, weekly) and 1 spatial (km) scale examined for M. membranacea, but not for E. pilosa. Highest abundance of larvae of both species in the warm fresh surface layer suggests onshore transport during wind-driven downwelling events. Dissimilar patterns in size-frequency distributions between the indigenous and nonindigenous bryozoan larvae suggest that species-specific characteristics of larvae of M. membranacea may be a contributing factor to its success as an invader in the western North Atlantic.

Loss and gain of the juvenile rudiment and metamorphic competence during starvation and feeding of bryozoan larvae

In many animals, larval structures and juvenile rudiments develop independently. One advantage of this independence is that juvenile rudiments can be expended as a nutrient reserve or for energy conservation. When bryozoan cyphonautes larvae were starved, structures required for settlement and metamorphosis shrank. When the larvae were again fed, these structures grew back. Starvation reduced the size of both the internal sac, a rudiment of postlarval juvenile structures, and the pyriform organ, which functions in sensing and crawling on the substratum at settlement. In contrast, starvation affected neither the size of the larval shell nor the lengths of the ciliary bands used in swimming and feeding. Starved larvae that had reduced the pyriform organ and internal sac did not metamorphose in response to stimuli from a laminarian alga. The laminarian alga did stimulate metamorphosis of the same larvae after renewed feeding, when the larvae had regrown these structures. Thus starved larvae expended body parts needed for settlement and metamorphosis when food was scarce while retaining structures for feeding, swimming, and defense. Starved larvae thereby retained the capacity to regrow structures needed for settlement and metamorphosis when they again encountered food. Advantages from expendable juvenile rudiments may enhance selection for their being developmentally distinct from structures for larval swimming and feeding.

Comparative chemical composition of the Barents Sea brown algae

Comparative study of phytochemical compositions of the most widespread brown algae species (one laminarian and four fucoid algae) from Barents Sea has been performed. A modified technique for mannitol determination in brown algae is proposed. It was revealed that fucus algae (fam. Fucaceae) contain 3% (of total dry weight) less mannitol than laminaria (Laminaria saccharina). The contents of alginic acid and laminaran in the Barents Sea fucoids are more than 10% less compared to laminaria. The alga L. saccharina contains almost two times more iodine than the species of fam. Fucaceae. The amounts of fucoidan and sum lipids in the Barents Sea fucoid algae is higher than in Laminaria saccharina (4-7% and 1-3%, respectively). In terms of contents of main biologically active compounds, fucus and laminarian algae from Barents Sea are inferior to none of the Far-Eastern species. The Barents Sea algae may become an important source of biologically active compounds.

Pliocene Atlanto-Mediterranean biogeography of Patella pellucida (Gastropoda, Patellidae): Palaeoceanographic implications

Patella pellucida is a north-western Atlantic shallow water grazing gastropod typically living and feeding on laminarian algae. It is an Upper Cenozoic species, known from the Icelandic and Iberian Pliocene to Recent. Today the species is usually considered to be primarily a northern cooler water species, inhabiting the Atlantic coasts of Europe, but rarely found off the Atlantic NW African coast and westernmost Mediterranean. Its presence in the warm, subtropical to tropical, Pliocene Atlantic and Mediterranean Iberian waters is thus unexpected. P. pellucida lives on laminarian algae, which occur in cold or temperate nutrient-rich ocean waters. At higher sea surface temperatures laminarian algae become physiologically stressed and are found only where seasonal upwelling of cooler nutrient-rich waters occurs. Such oceanographic conditions exist today, e.g., off the western coast of Iberia. It is suggested that similar upwelling conditions were already in place in western Iberia and in the Alboran Sea during Pliocene times and that the distribution of P. pellucida was dictated by upwelling of nutrient-rich, cooler waters, and high productivity conditions rather than sea surface temperature alone. Thus, the unexpected Pliocene geographic distribution of P. pellucida demonstrates that high productivity associated with upwelling may, at least in the Atlanto-Mediterranean area, override the dominant biogeographic pattern resulting from the latitudinal sea surface temperature gradient of water masses.

Effect of the Meristem on Sporification of Laminaria cichorioides

Isolated disks from vegetative thalli of Laminaria cichorioides Miyabe collected in April in Amursky Bay, Sea of Japan, cultivated separately from meristematic sites, developed sporangial sori after 4–6 weeks of cultivation, i.e., 4 months earlier than in natural conditions. The development of reproductive organs in intact plants, on meristematic sites, and also on vegetative disks, cultivated together with meristematic sites, was not observed. The effect of the meristem on L. cichorioides reproduction is supposed to be conditioned by “inhibitors of sporification” produced by this tissue. We offer a mechanism of sporification regulation for laminarian algae in natural conditions.

The role of grazing by the lysianassid amphipod Orchomenella aahu in dieback of the kelp Ecklonia radiata in north-eastern New Zealand

The lysianassid amphipod Orchomenella aahu was associated with small-scale mass mortality of Ecklonia radiata, the dominant laminarian alga in north-eastern New Zealand. O. aahu burrowed into and hollowed out stipes with severe bleaching, accelerating mortality by 12–14 months. Meristoderm tissue of bleached plants contained approximately one-third of the phlorotannin content (~4% dry mass) present in unbleached, apparently healthier, sporophytes (~12% dry mass). Unbleached stages consistently lacked amphipod damage. O. aahu also colonised plants when non-lethal storm damage afforded entry into the cortical layers of the primary lamina, and ultimately the stipe. O. aahu typically consumed both medullary and cortical tissue of the stipes, forming networked brood-chambers within them, with increasing populations often reducing the plant to the holdfast. There was synchronised mortality across sites and between depths over spatial scales of metres. Following loss of the mature canopy, recruitment of E. radiata was generally within 2 months at most study sites where mortality had occurred.

Structure and distribution of some fouling communities off bering island (commander Islands)

Barnacles and mussels are known to predominate in the majority of estuarine fouling communities on artificial substrata in the upper layers of temperate and subarctic waters. Will they predominate in insular fouling communities far from mainland estuarine regions? Investigations carried out in the summer of 1991 at Nikolskoye Harbour, Bering Island (Commander Islands) have shown that fouling communities on the pier at Bering Island were composed mainly of barnacles and laminarian algae at different depths, and an ecotone of red algae was found. Fouling communities defined on the basis of quantitative and qualitative analyses of samples did not correspond exactly with those based on visual observations. In contrast to some of the Aleutian and Kuril Isles, neither mussel fouling nor natural mussel beds were found on the open coasts off Bering Island. The absence of mussels is probably due to sea otter predation, with the result that a kelp fouling community develops instead of mussel fouling.

Diet in odacid and aplodactylid fishes from Australia and New Zealand

Diets of a number of temperate-water reef fishes considered to be herbivores were examined by stomach content analysis. Two species of the genus Odax (family Odacidae), O. pullus and O. acroptilus, were investigated. Stomach contents of samples of O. pullus from two times and two localities on the New Zealand coast were dominated by fucoid and laminarian algae. There was evidence of selection of reproductive structures of fucoid algae as an important food source. O. acroptilus collected from the central NSW coast of Australia proved to be a carnivore on small benthic invertebrates. In addition, the stomach contents of a taxon unique to Southern Hemisphere waters, Aplodactylus arctidens (family Aplodactylidae), and of one member of a widespread taxon, Girella tricuspidata (family Girellidae), were examined as a comparison with Odax. Collections of each species were made in northern New Zealand. A. arctidens and G. tricuspidata were facultative herbivores with diets dominated by under storey and epiphytic red algae. These results emphasize the unusual feeding patterns of herbivorous odacids and their importance in the development of general models of piscine herbivory.

Patterns in shallow subtidal marine assemblages along the coast of New South Wales

AbstractShallow subtidal areas of rocky reefs in central and southern New South Wales may best be described as a mosaic of habitats, the distributions of which are seemingly related to depth, wave exposure and a number of biological processes, particularly herbivory. The Fringe habitat is generally found only in the most shallow waters. Forests of the laminarian alga Ecklonia radiata are often found at intermediate depths. In deeper, or more sheltered water, sponges, ascidians and red algae are more abundant and the abundances of sea urchins and other invertebrate grazers decline. Overlying this broad‐brush pattern are patches of crustose coralline algae (the Barrens habitat), the distributions of which are not clearly related to depth. Invertebrate herbivores, and sea urchins in particular, are abundant in the Barrens habitat. The Barrens habitat was most represented at the more southern locations. At the two most northern locations, reefs were shorter in length and dominated by ascidians (Pyura species).

Patch formation by herbivorous fish in a temperate Australian kelp forest

The odacid fish Odax cyanomelas feeds on the kelp Ecklonia radiata, an important component of subtidal reef habitats on the central coast of New South Wales, Australia. Herbivory by Odax has a major impact on the structure and dynamics of discrete patches within larger stands of kelp at Cape Banks. This three-year study showed that each year, between August and October, approximately the same patches of kelp were denuded by preferential feeding on the meristem and primary laminae. This coincided with a variable pulse of Ecklonia recruits to the cleared patches, thereby generating patches of a single age-class of plants. Neighbouring areas of Ecklonia forest, non cleared by Odax, consisted of larger, perennial plants, which exhibited more gradual changes in abundance. The seasonal impact of Odax appeared to be due to a change in the behaviour of female Odax during their spawning period. Observations suggested that females aggregate at traditional sites prior to spawning with territorial males in adjacent areas of kelp forest. An alternative hypothesis, that Odax preferentially attacked stands of one-year old Ecklonia plants, was rejected by a field experiment; the establishment of experimental stands of one-year old plants did not lead to increased damage due to Odax or any change in the use of space by the fish. The generality of this effect of fish herbivory is unknown, but this and other Odax species are widely distributed throughout temperate Australia, where Ecklonia is the dominant laminarian alga. The effects of pulsed herbivory by Odax is contrasted to the more continuous grazing by sea urchins in the same system. The latter herbivore has been shown to maintain areas free of Ecklonia, the long-term effects of herbivory by Odax remain unclear.

Depth distribution and abundance of benthic organisms and fishes at the subtropical Kermadec Islands

Abstract Subtidal areas of the Kermadec Islands have not previously been described; samples from a bay at Raoul Island are discussed here. Abundances and percentage cover of benthic organisms were assessed from the high intertidal to 20 m depth using quadrat sampling. Fish abundances were assessed subtidally by random transects in shallow (3–6 m deep) and deep (14–20 m) areas of the reef. Hard corals occurred at 2–18 m depths at densities of 5 colonies per m2, but colonies were generally small. Soft coral colonies occurred at similar densities, but were confined to depths of 5–13 m. The mean percentage cover of corals did not exceed 20% at any one depth, and coral reefs did not occur. Fucalean and laminarian algae were not seen. The most abundant algae were foliose and filamentous species, and encrusting red algae. These covered over 80% of the reef at some depths. Grazing invertebrates were not abundant. Echinoids were found primarily in shallow water, reaching a density of 5 per m2 at 5 m depth. The mos...

Dispersion and phagokinesis in the echinoid Evechinuschloroticus (Val.)

Movement in the echinometrid sea urchin Evechinus chloroticus (Val.) was investigated in relation to the availability of a preferred food species, the laminarian alga Ecklonia radiata (C. Ag.). Patterns of microhabitat occupancy, dispersion, and movement were described in two habitats: Coralline Flats, dominated by encrusting coralline algae; and Sediment Flats, occupied by turfing corallines, Ecklonia and the mussel Modiolus areolatus (Gould). In both habitats, sea urchins were positively associated with encrusting coralline algae, despite the fact that encrusting corallines occupied a minor proportion of the substratum in the Sediment Flat habitat. Sea urchins were significantly clumped in both habitat types, and more so in sites within the Sediment Flats habitat. Movement was not directional in either habitat, but the magnitude of movement was almost twice as high in sites from the Coralline Flats habitat, where kelp was absent, as in the Sediment Flats sites, where kelp was present. Behaviour in response to the presence of Ecklonia in both habitats was investigated experimentally. In both habitats, urchins exposed to a “drift” kelp plant at a distance of 1–2 m exhibited net movement approximately twice as great as that shown by control urchins, not exposed to a kelp plant. Despite the relatively small distances the urchins were from the kelp, there was no evidence of directionality in movement. We conclude from the present study that further understanding of the feeding behaviour of urchins requires that a distinction be made between attached and drift algae, and between directionality and magnitude of movement, and that the interaction of these and other factors are best investigated under field conditions.

The ecological impact of the sea urchin Paracentrotus lividus (Lamarck) in Lough Ine, Ireland

An ecological account is given of the rocky shallow sublittoral of Lough Ine, County Cork, Republic of Ireland, from low water level to about 1 m below this level. With increasing distance from the Rapids mouth a forest of laminarian algae gives way to low algal bush, and still further into the lough the sea urchin Paracentrotus lividus destroys all soft upstanding algae. Much of the grazed area becomes overgrown by crustose coralline algae. Patches of the green algae Codium fragile ssp. tomentosoides and Enteromorpha clathrata fringe the Paracentrotus graze patches. An account is given of the effects of Paracentrotus on the shallow sublittoral community. Algae in the ungrazed areas accommodate large numbers of individuals and many species of invertebrates, especially amphipods, small gastropods and small polychaetes. In grazing, Paracentrotus destroys this population and its habitat. However, the removal of these algae, and of the sediment that they trap, provides a new habitat, suitable for plant and animal species that can resist Paracentrotus . Crustose coralline algae cover much of the rock, and are burrowed into or enclose the tubes of a characteristic and entirely different polychaete fauna. On the surface of the rocks are found saddle oysters ( Anomia ephippium ), limpets ( Patella aspera ) and other hard- shelled animal species. The relations between Codium and Paracentrotus have been investigated by transfer experiments in the ‘field’ and by observations with an aquarium tank. Paracentrotus readily eats Codium , especially when the urchins are at a high population density; but Codium benefits from the clearance of other algae, and is a quick recolonist, so that on balance it benefits from the presence of the urchin. Paracentrotus feeds mainly by day, and on a steep shore some wander up into the littoral region as the tide rises and destroy Fucus serratus . This accounts for the almost complete absence of F. serratus from the North Basin. Paracentrotus does not move upwards by night. The hard-shelled animal species Anomia, Patella, Chlamys varia , adult Gibbula cineraria and Pomatoceros , found plentifully on graze patches in the North Basin, diminish in abundance southwards even within grazed areas, while the numbers of the starfish Marthasterias glacialis under the rocks increase. Experiments show that Marthasterias readily eats Anomia . These Marthasterias are quite small. As they grow bigger they move away onto muddy areas and extend their diet to include large buried lamellibranchs. Small Paracentrotus are usually found in larger numbers underneath boulders than above, while larger ones tend to come up by day onto the tops, where they form graze patches. From a study of growth lines in the interambulacral plates and from growth in cages we conclude that a horizontal diameter of 30-40 mm (with considerable variation) is reached in 3-4 years from settlement. The peak in numbers of Paracentrotus visible in the South Basin in 1979 might perhaps be ascribed to a good settlement in the warm summers of 1975 and 1976. Temperature of the shallow marginal water of the lough is subject to diurnal fluctuation, as in a tide pool, and can reach high levels in summer. This might favour Paracentrotus . However, numbers of Paracentrotus are probably severely reduced by predators in the South Basin. Crabs have already been implicated. It is possible that the small or half grown Marthasterias under shallow sublittoral rocks might destroy newly settled Paracentrotus , although this still has to be demonstrated.

Patterns of distribution and abundance of large brown algae and invertebrate herbivores in subtidal regions of northern New Zealand

The distribution and abundance of subtidal laminarian and fucoid algae, echinoids, and four species of herbivorous gastropods were assessed. Line transects and stratified random quadrats were used, encompassing different depths and seven localities ranging over 1000km in northern New Zealand. This sampling was carried out to form a quantitative basis on which to pose hypotheses for later experimental work. Several patterns were apparent, both within and between localities. Fucoid algae were characteristic of depths between 0–6 m, while laminarian algae had peaks of abundance at 3–6 m and from 10–17 m. Intermediate depths were characterized by areas bare of large brown algae, with high densities of echinoids and gastropods. This pattern of a bimodal depth distribution of algae and abundant grazers at intermediate depth was a consistent feature of the northern coastal sites and the semi-exposed offshore islands. Size—frequency distributions for algae at these sites showed that the largest fucoids generally occurred in very shallow water, while the dominant laminarian alga tended to have larger individuals at depths of 10–14 m. In all cases, the biomass distribution with depth of the algal species mirrored their numerical abundance. Differences between localities were associated both with environmental factors and the unique algal floras of some offshore islands. Echinoids and gastropods were rare at the two most exposed localities, which were also at the extremes of the geographic range. At these sites, depths between 6–10 m were occupied by large brown algae. Deep-water fucoid algae occurred at two offshore localities but the predominant species at one of them was peculiar to that island group. Because of the general consistency between localities, and the few exceptions to these patterns, hypotheses are considered which could be tested on a local scale to account for echinoid and algal abundances and depth distributions. Our results indicate that the chief questions concerning the structuring of subtidal algal communities are demographic in nature and that an assessment of the status of individual organisms, rather than biomass or productivity, is the appropriate approach to resolve these questions.

The Factors Influencing the Distribution of Saccorhiza Polyschides in the Region of Lough Ine

Saccorhiza polyschides (Lightf.) Batt. is a laminarian alga found in the sublittoral region. It is widely distributed around the shores of the British Isles and is particularly common on the south west coast of Ireland. A puzzling aspect of the distribution of the species in Southern Ireland is its absence from Lough Ine, in County Cork.

Shell form, behaviour, and tolerance to water movement in the limpet Patina pellucida (L.) (Gastropoda: Prosobranchia)

The diotocardian gastropod Patina pellucida (L.) is a macro-herbivore common upon the fronds of laminarian algae. Considerations of shell shape, adhesive tenacity, and current tolerance, together with calculations of expected hydrodynamic drag, indicate that this limpet is effectively streamlined. Smaller individuals are relatively more resistant to dislodgement than are larger ones. Experimental animals of 6.0–13.5 mm shell length resisted constant flows of up to 0.9-1.3 m s −1. An orientation, in which the longitudinal axis of a limpet is aligned parallel to the direction of the prevailing flow, is induced by currents faster than ≈ 0.5 m s −1, and is an adaptation to conditions of directional water streaming. P. pellucida appears to show a seasonal change in orientatory preference, individuals tending to point distally with respect to the algal lamina in spring and proximally in autumn: this change may be associated with the annual growth cycle of the host plant.

The distribution of epizoites on the hydroid Nemertesia antennina (L.)

Studies on the distribution of epifaunal species on their host have concentrated on those of plants, particularly laminarian algae (Fowell, 1939; Ebling, Kitching, Purchon& Bassindale, 1948; Sloane, Ebling, Kitching & Lilly, 1957; Scarratt, 1961, Ph.D. Thesis, University College of Wales, Aberystwyth; Norton, 1971), Sargassum algae (Kato et al., 1961; Nishihira, 1971; Ryland, 1974) and eel grasses (Nishihira, 1968; Nagle, 1968). Recently, however, the distributions of the animals living on ascidians Microcosmus sp. (Monniot, 1965) and the bryozoan Flustra foliacea (L.) (Stebbing, 1971) have been investigated.

An Ecological Study of the Fauna Inhabiting the Sublittoral Marine Alga Saccorhiza polyschides (Lightf.) Batt.

The animals found on the fronds of the laminarian alga Saccorhiza polyschides are described. The sporophytes supported a fauna which was distinct from that of the surrounding rock, but was basically similar to that of other laminarian algae. Several animal species were however, much more abundant on S. polyschides than on other laminarians. A number of species were found to have a localised distribution on the host plant. The distribution of the epifauna on the alga seems to be chiefly the result of factors in the external environment particularly the degree of water movement and of silting. The epifauna varied in abundance and composition at different sites. In localities exposed to excessive water turbulence only a few species survived, although the gastropods Patina pellucida and Lacuna vincta were at their most abundant in such localities. Marked seasonal variations in the composition of the epifauna were found at Port Erin, Isle of Man, over a period of two years. The variations were related to both the seasonal behaviour of the animal species and to the annual cycle of growth and decay exhibited by the host plant. It is clear that the plant and its epifauna are each an important factor in the ecology of the other.

Influence of Reduced Salinity on the Distribution of Two Laminarian Algae

Two species of marine algae, Chorda filum and Saccorhiza polyschides were cultured in the laboratory in a wide range of salinities from the full salinity of sea water down to that of fresh water. Both species were found to develop from spores at a progressively slower rate at lower salinities. The development of S. polyschides was irreversibly inhibited at salinities below 9 %o whereas C. filum was able to produce sporophytes at salinities as low as 5 %0. The narrow tolerance of S. polyschides to reduced salinity was correlated with the absence of this species from areas of reduced salinity in nature. The tolerance of C. filum to low salinity agreed remarkably well with the distribution of this species in the Baltic Sea. The wide salinity tolerance exhibited by British plants of C. filum suggests that it is unlikely that the plants growing at the limits of the range of this species in the Baltic Sea are a different physiological strain specially adapted to the extreme environmental conditions prevailing there. PeBXoMe