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Durvillaea incurvata is a brown macroalgae of ecological, social, and economic importance subjected to a drastic increase in harvesting pressure over the last decade in Chile. In this study, we performed an experimental transplantation of juveniles of D. incurvata, assessing the potential use as a restocking technique. Different types of restocking devices and attaching substrates were constructed. Differences in the D. incurvata re-attachment probability among the substrates and devices were not observed, and a high percentage of juvenile mortality was observed. However, reattached juveniles increased their length, holdfast diameter, and weight. The experiment revealed that juveniles of D. incurvata have a good capacity for reattachment and growth on artificial substrates after transplantation. This technique could be used for the species stock enhancement, although further studies are needed to optimize the process and increase the juvenile's reattachment. [ABSTRACT FROM AUTHOR]

Seaweeds, as a dietary protein source originated in Asian countries and later expanded towards France, Chile, etc. Food applications have been narrowed down due to complications in extraction. Therefore, products are not yet available in the market. Extraction of other phytochemicals along with seaweed proteins provides value addition in food products. Therefore, a trend has emerged to extract protein from edible seaweeds with many health beneficial applications. Also, consumption of many animal proteins like meat are now becoming a threat on humans due to infectious viral diseases. Hence, seaweed proteins are emerging as a global alternative source of protein. [ABSTRACT FROM AUTHOR]

The sea urchin Loxechinus albus is of great commercial value due to its nutritional content. The main diet of the urchin in the north of Chile in its natural habitat is the macroalgae Ulva lactuca. This work evaluated the growth of L. albus juvenile fed diets based on vegetable lettuce Lactuca sativa and macroalgae Ulva sp. Ingestion, growth, survival, and proximal analysis of the diets were registered for 13 weeks. At the end of the experience (90 days), no mortality and greater consumption of L. sativa were observed. In the proximal analysis, L. sativa presented the highest percentage (lipids, proteins, ashes, carotenoids, chlorophyll). The greatest growth and weight gain were observed with the Ulva sp. diet. Finally, the incorporation of L. sativa in the diets of urchins would imply a supplement of minerals and carotenoids, so we propose the addition of this lettuce as a nutritional supplement during the first stage of the cultivation of the L. albus. [ABSTRACT FROM AUTHOR]

Carbon isotope fingerprinting, or multivariate analysis using δ13C values of individual compounds, is a powerful tool in ecological studies, particularly measurements of essential amino acids (EAA δ13C). Despite the widespread application of this technique, there has been little methodological validation to determine (a) whether multivariate EAA δ13C signatures (fingerprints) of primary producer groups vary across space and time and (b) what biochemical mechanisms drive these patterns.Here, we evaluate the spatiotemporal consistency in EAA δ13C fingerprints among nearshore primary producers: Chlorophyta (Ulva sp.), Ochrophyta (kelps), particulate organic matter (POM) and phytoplankton, and Rhodophyta. We analysed 135 samples from 14 genera collected in Alaska, California and Chile. The collections included historical museum samples (1896–1980 CE) of the giant kelp, Macrocystis pyrifera. We employed canonical analysis of principal coordinates and generalized linear models (GLMs) to, respectively, characterize isotopic fingerprints and evaluate the effect of taxonomy, local upwelling regimes, ecological setting, and time on individual EAA δ13C values and associated fingerprints. We also calculated amino acid discrimination values (∆13C) to identify key biochemical pathways responsible for these patterns.We found remarkable consistency in EAA δ13C fingerprints of marine algae across space and through time. Kelps and rhodophytes exhibited statistically distinct multivariate isotopic patterns regardless of geographical location, species identity or time (kelps). In contrast, isotopic fingerprints of POM/phytoplankton and Ulva overlapped substantially. GLMs indicated that producer family, presumably due to the presence/absence of carbon concentrating mechanisms, and site locality are important determinants of individual amino acid δ13C values. Taxonomy was also a key variable for EAA δ13C fingerprints. The calculated discrimination values suggest variation in (a) metabolism of pyruvate and oxaloacetate‐derived amino acids and (b) production of storage and structural carbohydrates are responsible for taxonomic differences in isotopic fingerprints.We conclude EAA δ13C fingerprinting is a robust method for tracing the contribution of diverse primary producer taxa to coastal food webs. We show that this technique can be applied to modern and historical samples, as well as consumers collected across continental scales. The high fidelity of EAA δ13C multivariate patterns coupled with biochemical mechanisms provides a powerful framework for future studies of carbon flow across broad biogeographical and ecological contexts. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Seaweed exploitation in Chile has increased over the last decades, resulting in a reduction of seaweeds landings and the overharvesting of natural beds. In response, ecological baselines for their sustainable exploitation and the development of seaweed aquaculture have been implemented. In recent years, the culture of commercial red seaweed Chondracanthus chamissoi has been developed experimentally by spore and vegetative reproduction. These methods are facilitated by the formation of secondary attachment discs (SADs), generated to fasten the inoculated algae to substrates. In this study, the vegetative propagation was carried over an artificial substrate installed in a sea bottom culture system. The biomass yields, total amount of epiphytes, length of new thalli and number of SADs, per season and culture times (1, 2, 3 and 4 months) are reviewed in this work. Chondracanthus chamissoi showed growth under all treatments, with a maximum accumulated biomass of 60 g m−1, recorded in summer, and with no significant differences in biomass yield reported in autumn and spring seasons. A similar pattern was observed for epiphyte biomass, while the greatest SAD number and thalli lengths were recorded in winter. [ABSTRACT FROM AUTHOR]

Protistan pathogens have been found to infect populations of some large brown macroalgae. Infection could reduce the ability of macroalgae to withstand hydrodynamic pressures through weakening tissues and reducing flexibility. Widespread mortality of macroalgae if disease outbreaks were to occur could have important flow-on consequences for biodiversity and ecosystem function. Recent discoveries of the protistan pathogen Maullinia infecting the ecologically keystone southern bull kelp Durvillaea in Chile, Australia, and on Marion Island, raise the possibility that this pathogen is dispersing across ocean basins with buoyant hosts. To determine whether Maullinia also infects southern bull kelp in New Zealand, samples of gall-like tissue from Durvillaea antarctica, D. poha, and D. willana were collected from intertidal sites, and genetic analyses (sequencing of partial 18S rRNA) carried out. Maullinia infections were detected in all three species of Durvillaea. Phylogenetic analyses show a close relationship of New Zealand Maullinia to M. braseltonii previously detected in Chile and on Marion Island. Based on its genetic similarity to distant lineages and its presence on buoyant hosts that have been shown to drift long distances at seas, we infer that Maullinia has dispersed across the Southern Ocean through rafting of infected bull kelp. Understanding the capacity of pathogens to disperse across oceans is critical part of forecasting and managing ecosystem responses to environmental change. [ABSTRACT FROM AUTHOR]

Here we present a multi-taxa inventory of naturalized alien species recorded on continental Chile and adjacent marine habitats, including eight taxonomic groups. We identified 1,122 species. These comprise 790 vascular plants (terrestrial and aquatic); 31 nonvascular plants [Bryophyta (mosses), Marchantiophyta (liverworts) and Anthocerotophyta (hornworts)]; 18 marine and freshwater macro and micro algae; 71 fungi; 39 terrestrial vertebrates (amphibians, reptiles, mammals and birds); 108 insects; 37 marine and freshwater invertebrates and vertebrates (6 polychaetes, 3 mollusks and 28 Pisces); and 28 terrestrial gastropods. For all taxonomic groups, naturalized species were found to mainly be distributed in regions with Mediterranean and temperate climates, with few at either extreme of the country. The invasion curves show that naturalized species first underwent a positive increment, followed by an apparent plateau phase, mainly in vascular plants, insects and vertebrates. In fungi, marine and freshwater macro and microalgae, vertebrates and invertebrates, the cumulative number of naturalized species increased sharply starting in the early 20th century; the lack of collections before 1900 is also evident. When considering naturalized species as a whole, this inventory highlights that the rate of new naturalizations consistently increased after 1950, especially for some taxonomic groups such as insects, fungi, and vascular plants. This multi-taxa inventory of naturalized species provides a platform for national reporting on biodiversity indicators and highlights areas where Chile must invest resources to manage biological invasions. [ABSTRACT FROM AUTHOR]

Floating seaweeds are important dispersal vectors in marine ecosystems. However, the relationship between benthic populations and stranded seaweeds has received little attention. After detachment, a fraction of floating specimens returns to the shore, resulting in strandings that fluctuate in space and time. It has been hypothesized that the availability of stranded seaweeds is related to their benthic abundance on adjacent coasts. Using the large fucoid Durvillaea antarctica, we tested whether stranded biomasses are higher at sites with dense adjacent benthic populations. Benthic abundance of D. antarctica along the continental coast of Chile was estimated using three approximations: (i) availability of potentially suitable habitat (PSH), (ii) categorical visual abundance estimates in the field, and (iii) abundance measurements in the intertidal zone. Higher PSH for D. antarctica was observed between 31° S–32° S and 40° S–42° S than between 33° S and 39° S. Lowest benthic biomasses were estimated for the northern latitudes (31° S–32° S). Regression models showed that the association between stranded biomass and PSH was highest when only the extent of rocky shore 10 km to the south of each beach was included, suggesting relatively short‐distance dispersal and asymmetrical transport of floating kelps, which is further supported by low proportions of rafts with Lepas spp. (indicator of rafting). The results indicate that stranded biomasses are mostly subsidized by nearby benthic populations, which can partly explain the low genetic connectivity among populations in the study region. Future studies should also incorporate other local factors (e.g., winds, currents, wave‐exposure) that influence stranding dynamics. [ABSTRACT FROM AUTHOR]

Background: The marine alga Ulva compressa is the dominant species in copper-polluted coastal areas in northern Chile. It has been shown that the alga tolerates micromolar concentrations of copper and accumulates copper at the intracellular level. Transcriptomic analyses were performed using total RNA of the alga cultivated with 10 μ M copper for 0, 1, 3 and 5 days using RNA-seq in order to identify processes involved in copper tolerance. Results: The levels of transcripts encoding proteins belonging to Light Harvesting Complex II (LHCII), photosystem II (PSII), cytochrome b6f, PSI, LHCI, ATP synthase and proteins involved in repair of PSII and protection of PSI were increased in the alga cultivated with copper. In addition, the level of transcripts encoding proteins of mitochondrial electron transport chain, ATP synthase, and enzymes involved in C, N and S assimilation were also enhanced. The higher percentages of increase in the level of transcripts were mainly observed at days 3 and 5. In contrast, transcripts involved protein synthesis and degradation, signal transduction, and replication and DNA repair, were decreased. In addition, net photosynthesis and respiration increased in the alga cultivated with copper, mainly at days 1 to 3. Furthermore, the activities of enzymes involved in C, N and S assimilation, rubisco, glutamine synthase and cysteine synthase, respectively, were also increased, mainly at days 1 and 3. Conclusions: The marine alga U. compressa tolerates copper excess through a concomitant increase in expression of proteins involved in photosynthesis, respiration, and C, N and S assimilation, which represents an exceptional mechanism of copper tolerance. [ABSTRACT FROM AUTHOR]

With ongoing climate change, aquaculture faces environmental challenges similar to those of natural ecosystems. These include increasing stress for calcifying species, e.g. macroalgae and shellfish. In this context, ocean acidification (OA) has the potential to affect important socioeconomic activities, including shellfish aquaculture, due to changes in the seawater carbonate system. However, coastal environments are characterised by strong diurnal pH fluctuations associated with the metabolic activity of macroalgae; that is, photosynthesis and respiration. This suggests that calcifying organisms that inhabit these ecosystems are adapted to this fluctuating pH environment. Macrophyte-dominated environments may have the potential to act as an OA buffering system in the form of a photosynthetic footprint, by reducing excess of CO2 and increasing the seawater pH and Ωarg. This can support calcification and other threatened physiological processes of calcifying organisms under a reduced pH environment. Because this footprint is supportive beyond the macroalgal canopy spatial area, this chemical refuge mechanism can be applied to support shellfish aquaculture, e.g. mussels. However, this approach should be tested in commercial shellfish farms to determine critical aspects of implementation. This includes critical factors such as target species and productivity rates. The degree of OA buffering capacity caused by the metabolic activity of macroalgae might depend on community structure and hydrodynamic conditions, creating site-specific responses. This concept might aid the development of future adaptive strategies, supporting marine ecological planning for the mussel aquaculture industry in Chile. [ABSTRACT FROM AUTHOR]

Current knowledge about the performance of floating seaweeds as dispersal vectors comes mostly from mid latitudes (30°–40°), but phylogeographic studies suggest that long-distance dispersal (LDD) is more common at high latitudes (50°–60°). To test this hypothesis, long-term field experiments with floating southern bull kelp Durvillaea antarctica were conducted along a latitudinal gradient (30°S, 37°S and 54°S) in austral winter and summer. Floating time exceeded 200d in winter at the high latitudes but in summer it dropped to 90d, being still higher than at low latitudes (<45d). Biomass variations were due to loss of buoyant fronds. Reproductive activity diminished during long floating times. Physiological changes included mainly a reduction in photosynthetic (F v /F m and pigments) rather than in defence variables (phlorotannins and antioxidant activity). The observed long floating persistence and long-term acclimation responses at 54°S support the hypothesis of LDD by kelp rafts at high latitudes. MERE 2019_145 Tala et al. • Long-distance rafting of seaweeds is more prevalent at high latitudes. • Floating persistence and physiological acclimation of Durvillaea antarctica depended on latitude and season. • The proportion of thalli with mature conceptacles were reduced during long floating times. • Morphological changes were more important for sinking of floating D. antarctica than physiological changes. • The results confirm that kelp rafting is favored at high latitudes. [ABSTRACT FROM AUTHOR]

Chile, located in the southeastern Pacific, possess a high richness of seaweed species, some of which have been traditionally extracted from natural beds for the production of hydrocolloids (e.g. agar, carrageenan and alginates), but still a high proportion of the biomass is being exported as dried material to processors in Asia and Europe. During the period 2006–2016, this tendency has been maintained, but has also started to show signs of changing towards a more sustainable, localized seaweed industry as new actions by the Chilean government provided subsidies to seaweed farming activities and also to investments in local valorization of the resources. This "sea change" has been further supported by an increase in the number of localized scientific and technical studies related to Chilean seaweed resources which has prepared the foundation required in order to move to more advanced stages of local seaweed farming and development of local processing. [ABSTRACT FROM AUTHOR]

• Chilean seaweeds are a rich source of dietary fiber, minerals, and proteins. • Good dietary contribution for essential minerals and low Na/K ratio were observed. • Health risk assessment indicated low hazard for seaweed meal as a food ingredient. • As, Hg, and Pb levels were below the limits set for food and feed ingredients. • Cd levels should be monitored in brown seaweeds destined for food and feed ingredients. Seaweeds are a rich source of nutritional and functional compounds, but they also accumulate heavy metals. Here, the chemical composition (crude protein, total lipids, Nitrogen Free Extract and fiber) and the presence of minerals (Na, K, Ca, Mg, P, Fe, Mn, Cu, Zn, Mo, Se) and unwanted elements (As, Cd, Hg, Pb, Ni, Cr, Al) were determined in eleven seaweeds from Chile. Depending on the species, a good contribution to the Recommended Dietary Allowance for K, Ca, Mg, Fe, Mn and Se was observed, and low Na/K ratios (<1.0) as well. The health risk assessment indicated low hazard due to intake of seaweed meal. The mean values of As, Hg, and Pb were below the maximum limits set for food supplements and feed ingredients. The seaweeds studied have a suitable chemical composition for their uses as food and feed ingredients, although Cd levels should be monitoring especially in brown seaweeds. [ABSTRACT FROM AUTHOR]

Invasive species such as seaweeds often have a broad tolerance, allowing them to colonize novel habitats. During invasion, also new epibacteria can be formed on seaweeds, which have important chemo-ecological effects. Since UV-radiation (UVR) is one of the main factors affecting seaweeds and their epibacteria, we tested its effect on intertidal and subtidal thalli of the invasive seaweed Codium fragile from three sites and monitored photosynthesis, antioxidant activity and epibacteria. Exposure to UV-radiation resulted in photoinhibition with a subsequent low recovery in subtidal thalli from 23°S compared to 27°S and 30°S, which both showed a higher and almost complete recovery. However, a high antioxidant activity was present in all thalli, permitting to explain its relatively high tolerance to new environments. UV-radiation modified the composition of the epibacteria community by reducing its diversity and evenness. Our results showed that C. fragile responds plastic to variable UV-radiation (depending on site and water depth), which contributes to its high invasion potential. • Exposure of the invasive seaweed Codium fragile to UV-radiation resulted in photoinhibition. • Low recovery of photosynthesis was only present in subtidal thalli from 23°S compared to 27°S and 30°S. • UV-radiation also modified the epibacteria composition on thalli of C. fragile by reducing their diversity and evenness. • Codium fragile responded with a high plasticity to UV-radiation, which makes it a successful invader. [ABSTRACT FROM AUTHOR]

Abstract: Chondracanthus chamissoi is a carragenophyte and edible red seaweed which is harvested from its natural habitat, and which, in recent years, has been diminishing along the Chilean coast. It is in this location that a new technique for the vegetative propagation of C. chamissoi by secondary attachment disc (SAD) was evaluated for the first time. In order to achieve this, SAD development was seasonally analyzed on natural and artificial substrata submitted to different water exchange and nutrient enrichment conditions. Cystocarpic and vegetative thalli were able to reattach and develop SADs during winter and summer under all tested conditions. However, higher values were observed in vegetative thalli cultivated in the winter. The size of shoots formed from SADs was higher in summer than in winter, varying in length between 0.2 and 5.4mm after 40days of cultivation. A continuous seawater exchange was the appropriate condition for SAD development whereas nutrient enrichment was not necessary. High adaptability of these structures to outdoor conditions was observed, as expressed in high survival rates of SADs. This study shows the technical feasibility of culturing C. chamissoi by means of SADs, which could be an alternative to spore and macrofragmentation strategies. [Copyright &y& Elsevier]

Polysiphonia morrowii, a species native to the North Pacific, is believed to have been introduced to Chile, Turkey, Italy and France. This species was first recorded from New Zealand in 2011, based on collections made in 2004 from two sites on South Island, but no commentary was provided in the distribution or characteristics of the material collected. In 2009, as part of a study on macroalgae associated with soft sediment habitats in New Zealand, several samples of P. morrowii were collected from Otago Harbour, a location already known to host 17 non-indigenous macroalgal species. However, this species has gone unnoticed in New Zealand. We present the current understanding of the distribution of this species in New Zealand, and the distinguishing features of the specimens collected, to assist with biosecurity and monitoring programmes. Including this report of P. morrowii, there are now seven species of Polysiphonia and Neosiphonia that are regarded as non-indigenous in New Zealand. [ABSTRACT FROM AUTHOR]

Several large kelp species are capable of long-distance dispersal via rafting. However, seasonal changes in environmental conditions at the sea surface may variably affect the physiological status of the floating thalli; challenging conditions during summer may accelerate disintegration and cause rapid sinking. We used the bull kelp Durvillaea antarctica from northern-central Chile (30°S) to test seasonal variation in floating persistence. Experiments with tethered specimens were conducted in all seasons to assess how variable environmental conditions influence the morphology and photosynthetic characteristics of floating D. antarctica. Floating specimens stayed afloat at the surface for more than 1 month during moderate environmental conditions that prevailed in winter, spring, and fall. However, higher water temperatures and intense solar radiation in summer resulted in significant biomass losses and rapid disintegration of the floating kelps; consequently, they sank within <1 month. These strong seasonal effects were reflected in decreasing maximal quantum yield as well as in maximum relative electron transport rates of photosynthesis. Understanding physiological responses of floating algae is important because increasing global temperatures and shifts in solar radiation may strongly affect the survival of floating algae, potentially reducing the distances and frequencies of rafting dispersal. [ABSTRACT FROM AUTHOR]

Many intertidal rocky habitats of the Chilean coast were dominated by the dark green thalli of a mat-forming Codium. This green seaweed was ecologically important because it formed a permanent belt by coalescence between conspecific thalli, and thus it affected substrate dominance and community structure. Six species of mat-forming Codium have been recorded in Chile; the adherent Codium in central and northern Chile has been recognized as C. dimorphum, a species first described from the Guaitecas Islands in southern Chile. We analyzed 320 Codium specimens collected from 11 sites spanning the entire Chilean coastline. Morphological and rbcL sequence data revealed the presence of two distinct species with non-overlapping geographical distributions. Codium dimorphum, which is characterized by dimorphic utricles (inner utricles having thin apical walls, and outer utricles having thick apical walls), was found to be restricted to the southern Chilean coast. Specimens from central and northern Chile with uniform utricles were described as a new species, C. bernabei. [ABSTRACT FROM AUTHOR]

Abstract: Chile is one of the major producers of phytocolloids extracted from seaweed. Multicellular algae are considered to be primary accumulators of arsenic. We analyzed 14 species of algae belonging to the groups Rhodophyceae (10), Phaeophyceae (3) and Chlorophyceae (1) from different coastal zones of Chile in 2003–2004. Dry ashing mineralization (for total As) and acid digestion (for inorganic As) together with quantification by flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS) were employed. In general, total arsenic concentrations varied between 3.0 and 68mgkg−1, whereas inorganic arsenic concentrations ranged between 0.15 and 1.06mgkg−1. The algal species Durvillaea antarctica and Porphyra columbina, used for direct human consumption, did not have inorganic arsenic levels that represent a health risk to consumers. Among species used for phytocolloids production, such as Macrocystis piryfera, Gracilaria chilensis and Gigartina skottsbergii, observed levels of inorganic arsenic were greater than 1mgkg−1, the limit value established by the regulations of some countries. Among the 14 species of algae tested, inorganic arsenic levels were between 0.8% and 13% of the total arsenic concentrations; that is, arsenic present in these algae was found primarily as organic arsenic. [Copyright &y& Elsevier]

Intertidal pools represent restricted habitats for macroalgal assemblages, and their structure is determined by physical and biotic factors. The establishment of the exotic oyster Crassostrea gigas on the north Patagonian Atlantic coast led to the formation of intertidal pools; these provide habitats for macroalgal settlement. We aimed to determine the composition, distribution and abundance of the macroalgal assemblage inhabiting these pools, and to establish the structuring variables. Several biotic and abiotic variables were evaluated in 36 pools in winter and summer. Correlations were calculated and permutation analysis of variance and constrained redundancy analysis were conducted to determine the structuring variables. Unlike other Patagonian coasts, richness was low and pools were characterized by a dominance of red algae. Richness was higher in winter, while diversity was lower because of the dominance of Polysiphonia abscissa, which had the highest percentage of occurrence. Temperature was a putative factor determining seasonal richness and diversity. Elevation and surface area of the pools were structuring factors for assemblage biomass. We demonstrated distinct assemblage dynamics. Polysiphonia abscissa developed large populations in winter, which declined towards the summer, while Gelidium maggsiae and Gelidiella calcicola formed dense turfs during summer stress. [ABSTRACT FROM AUTHOR]

Background: The Chilean shoreline, a nearly strait line of coast expanding across 35 latitudinal degrees, represents an interesting region to assess historical processes using phylogeographic analyses. Stretching along the temperate section of the East Pacific margin, the region is characterized by intense geologic activity and has experienced drastic geomorphological transformations linked to eustatic and isostatic changes during the Quaternary. In this study, we used two molecular markers to evaluate the existence of phylogeographic discontinuities and detect the genetic footprints of Pleistocene glaciations among Patagonian populations of Mazzaella laminarioides, a low-dispersal benthic intertidal red seaweed that inhabits along ~3,700 km of the Chilean coastal rocky shore. Results: Three main genetic lineages were found within M. laminarioides. They are distributed along the Chilean coast in strict parapatry. The deep divergence among lineages suggests that they could be considered putative genetic sibling species. Unexpectedly, genetic breaks were not strictly concordant with the biogeographic breaks described in the region. A Northern lineage was restricted to a broad transition zone located between 30°S and 33°S and showed signals of a recent bottleneck. The reduction of population size could be related to warm events linked to El Niño Southern Oscillation, which is known to cause massive seaweed mortality in this region. To the south, we propose that transient habitat discontinuities driven by episodic tectonic uplifting of the shoreline around the Arauco region (37°S-38°S); one of the most active forearc-basins in the South East Pacific; could be at the origin of the Central/South genetic break. The large beaches, located around 38°S, are likely to contribute to the lineages' integrity by limiting present gene flow. Finally, the Southern lineage, occupies an area affected by ice-cover during the last glaciations. Phylogeny suggested it is a derived clade and demographic analyses showed the lineage has a typical signature of postglacial recolonization from a northern glacial refugium area. Conclusions: Even if environmental adaptation could have strengthened divergence among lineages in M. laminarioides, low dispersal capacity and small population size are sufficient to generate phylogeographic discontinuities determined by genetic drift alone. Interestingly, our results confirm that seaweed populationconnectivity over large geographic scales does not rely only on dispersal capacity but also seem to depend highly on substratum availability and population density of the receiving locality. [ABSTRACT FROM AUTHOR]

Abstract: The spectral attenuation of solar irradiation was measured during summer in two types of coastal waters in southern Chile, a north Patagonian fjord (Seno Reloncaví) and open coast (Valdivia). In order to relate the light availability with the light requirements of upper subtidal seaweeds, the saturating irradiance for photosynthesis (E k) from P–I curves was measured. In addition the UV risk was assessed. Based on the z 1% of PAR, the lower limit of the euphotic zone in the studied systems averaged 21m (K d 0.24m−1) in Seno Reloncaví and 18m (K d 0.27m−1) in the coast of Valdivia. Photosynthesis of the studied seaweeds was saturated at markedly lower irradiances than found in their natural depths at the time of the study. Solar radiation penetrating into these depths at both locations largely supports the light requirements for the photosynthesis of subtidal species: 50–160μmolm−2 s−1 for seaweeds from Seno Reloncaví (7m tidal range) and 20–115μmolm−2 s−1 for Valdivia assemblages (2m tidal range). Optimal light conditions to saturate photosynthesis (E k) were present at 10–16m water depth. The attenuation of solar irradiation did not vary significantly between the fjord and coastal sites of this study. However, the underwater light climates to which seaweeds are exposed in these sites vary significantly because of the stronger influence of tidal range affecting the fjord system as compared with the open coastal site. The patterns of UV-B penetration in these water bodies suggest that seaweeds living in upper littoral zones such as the intertidal and shallow subtidal (<3m) may be at risk. [Copyright &y& Elsevier]

Abstract: Macroalgae build biogenic habitats which give shelter and provide a suitable physical environment for a great variety of organisms. Structural complexity of algal substrates may influence the composition of their attached epifauna. The aim of this study is to test whether the taxonomic relatedness of the algal hosts and the functional groups to which they belong influence the species richness and composition of their epifaunal bryozoans. We analysed 36 algal genera from the Atlantic coast of South America between 42°S and Cape Horn. Changes in bryozoan species richness (number of species) among different algal functional groups (filamentous algae, foliose algae, corticated foliose algae, corticated macrophytes) were non-significant. The composition of the epifaunal assemblages differed significantly only between filamentous and foliose algae. Sheet-like bryozoans (i.e. encrusting, pluriserial colonies) were more frequent on foliose than on filamentous algae, while runner-like species (i.e. uniserial stolons) were characteristic epibionts on filamentous thallii. Similarity of bryozoan assemblages increased with increasing taxonomic relatedness of their hosts. As most filamentous seaweeds analysed in this study are members of the Order Ceramiales, the influence of algal taxonomic relatedness and functional groups on the composition of their bryozoan assemblages can be viewed as two different aspects of the same phenomenon. [ABSTRACT FROM AUTHOR]

Since the establishment of abalone farming, there has been an increase in the demand for Macrocystis as a food source. Therefore, the pressure on natural stock has also augmented and the sustainability of the actual harvesting practices has been questioned. In this article, an attempt to farm Macrocystis pyrifera by zoospores in northern Chile is described; initially under laboratory conditions and subsequently by cultivation in the sea. The experiments were executed during 1 year and two different cultivation methodologies were used: a direct and an indirect method. A maximum frond length of 175 cm was reached and 22 kg mof rope was produced after 120 to 150 days of cultivation in the sea. The algae grew under both methodologies, and no differences in algal length and biomass were detected between the two cultivation systems. However, the direct culture method can be recommended for productive and practical reasons. [ABSTRACT FROM AUTHOR]

A new genus, Glaphyrosiphon Hommersand & Leister gen. nov., is proposed to contain the generitype Glaphyrosiphon intestinalis (Harvey) Leister & W.A. Nelson comb. nov., a species known in New Zealand under the name Grateloupia intestinalis (Hooker. f. & Harvey) Setchell ex P.G. Parkinson, and two additional species: Glaphyrosiphon lindaueri W.A. Nelson & P.W. Gabrielson sp. nov. from the northern part of New Zealand and Glaphyrosiphon chilensis M.E. Ramírez, Leister, and P.W. Gabrielson sp. nov. in the southern part of Chile from Valdivia (Regiín de Los Ríos), to Punta Arenas in the Strait of Magellan (Regiín de Magallanes). Thalli are borne singly or in clusters from a small discoid holdfast and consist of simple or one- to three-times-branched slippery tubes that are copiously filled with mucilage. The medulla consists of a one- to several-layered network inside the cortex composed of stellate cells that interconnect by short to long extensions linked by pit connections. Primary rhizoidal filaments are absent. Spermatangia are superficial on terminal cortical cells. Carpogonial and auxiliary-cell ampullae are formed separately and link by unsegmented tubular connecting filaments, as in other Halymeniaceae. The auxiliary-cell ampulla consists of a basal cell and four unilaterally branched filaments in which the auxiliary cell is the basal cell of one of the four filaments. The auxiliary cell and inner ampullar filaments unite forming a fusion cell. Ampullar filaments connect terminally to inner cortical cells and laterally with one another by short filaments and pit connections that form an involucral network surrounding the gonimolobes. Tetrasporangia are cruciately divided and borne laterally on filaments produced secondarily from surface cortical cells. Sequence analyses of the rbcL gene place Glaphyrosiphon sister to Polyopes in the Halymeniaceae. The two New Zealand species consist of southern and northern clades separated by 1.2% to 1.7% base-pair distances in rbcL analyses and a Chilean species that forms a single clade separated from the New Zealand clades by 3.9% to 4.4% base-pair distances. Records of Grateloupia intestinalis from Tasmania have not been studied. [ABSTRACT FROM AUTHOR]

Abstract: The availability of limiting resources can potentially influence the intensity of intra- and interspecific interactions. Stranded macroalgae exported from adjacent coastal ecosystems supports abundant intertidal consumers on oceanic sandy beaches, including talitrid amphipods, which can be one of the numerically dominant invertebrates of the upper shore. The allochthonous nature of this donor-controlled food subsidy and its unpredictable delivery by waves and currents, results in highly variable and potentially limiting resource availability for these consumers. In Chile, adults of the talitrid amphipod, Orchestoidea tuberculata Nicolet, can influence the survival of juvenile conspecifics through cannibalism, a type of intraspecific interaction we hypothesized could be affected by the availability of macroalgal resources. We experimentally investigated the potential influence of food availability on cannibalism between age classes in O. tuberculata in laboratory mesocosms. Juvenile mortality in presence of conspecific adults was significantly higher when juveniles and adults were maintained without food. However, adult mortality was neither density dependent or food dependent. Further, juveniles did not influence adult mortality, either with or without food. The strong effect of food limitation on juvenile mortality from cannibalism by adults of O. tuberculata found here, supports our hypothesis that food resource availability on beaches can affect this intraspecific interactions. In addition these results provide evidence of the potential importance of biological interaction in the population dynamics of intertidal consumers on oceanic sandy beaches. [ABSTRACT FROM AUTHOR]

Abstract: Compensation of tissue loss has been considered an alternative strategy for seaweeds that have no or only minor chemical or structural defense against herbivory. Compensatory responses are facilitated by resource transfer among different tissues and have been suggested for large kelps. Macrocystis integrifolia (Bory) is a common kelp species from northern-central Chile, which is characterized by high growth rates and the absence of lipophilic chemical defenses against herbivore grazing. Herein, we used the giant kelp M. integrifolia to test for compensatory growth in response to grazing by the nest-dwelling amphipod Peramphithoe femorata (Krøyer). Amphipods were allowed to graze inside nests on subapical blades of M. integrifolia sporophytes for 14days. We measured growth and chemical composition (C, N, laminaran and mannitol) of apical and subapical blades of grazed and ungrazed (control) sporophytes. Our results revealed the capability of M. integrifolia to maintain elongation rates in grazed subapical blades, which were similar to those of subapical blades from ungrazed sporophytes. Apical blades grew slower in grazed than in ungrazed sporophytes indicating a trade-off between apical and subapical blades when herbivores were present. Thus, compensation occurs in blades directly attacked by grazers and is probably mediated by vertical resource allocation within sporophytes to subapical blades, a suggestion supported by the fact that stipe internodes in these regions grew more on grazed sporophytes. In general, our study indicates that M. integrifolia exhibits compensatory growth against the herbivore amphipod P. femorata, and we suggest that this could be an important strategy of large kelp species to tolerate moderate grazing intensities. [Copyright &y& Elsevier]

Abstract  Increased market demand for algal raw materials has stimulated research and development into new cultivation technologies, particularly in countries with economically important seaweed industries. Chondrus canaliculatus is a red alga endemic to the temperate Pacific coast of South America and produces a complex carrageenan. In Chile, this potential marine resource has been underutilized since the early 1990s, after it was replaced mainly by imports of Kappaphycus and Eucheum from Asia. The study of the cultivation of C. canaliculatus in outdoor tanks demonstrates the potential to produce large quantities of algal material due to the high productivity observed. The material produced may be important in Chile as feed for cultured algal herbivores such as Haliotis spp. Data were obtained on the key factors affecting the growth of this alga, including light, temperature, and nutrient concentrations. The results showed that, on a dry weight basis, productivity varied seasonally between 40 g m−3 wk−1 in autumn and 200 g m−3 wk−1 in spring, and the optimal stocking density in our experiments was 8 kg m−3. Effects of self-shading were among the most important limiting factors in the culture. Discussion is presented on the interactions between temperature, pH, salinity, enrichment with N and P, and water exchange on the maximal growth of C. canaliculatus in this culture. [ABSTRACT FROM AUTHOR]

The article focuses on a study that adds evidence for a Pre-Clovis occupation at Monte Verde II (MVII) near the Pacific Coast of Chile. It reports important new radiocarbon dates on seaweeds, which the author declares a convincing evidence that Paleoindians at MVII foraged in estuarine and marine ecosystems or traded with people who did. Other significant evidences include radiocarbon dates on red algae and coal.

Scytosiphon lomentaria (Lingb.) Link. (Phaeophyceae) is one of the two dominant seaweeds in a coastal area of northern Chile affected by copper mine wastes, where the concentration of copper in water and algal tissues remains higher than in nonimpacted sites. Copper-loaded plants develop oxidative stress, as demonstrated by the increased levels of reactive oxygen species and lipoperoxides. This stress was associated with 1) an enhanced activity of the antioxidant enzymes catalase, glutathione peroxidase, ascorbate peroxidase, monodehydroascorbate reductase, and dehydroascorbate reductase and 2) an inhibition of the glutathione reductase activity. Furthermore, stressed plants showed a decrease in glutathione and phenolic compounds levels and an increase in total ascorbate. Reciprocal transplants revealed that plants rapidly adjusted their antioxidant system in response to the conditions of the receiving site. In individuals transplanted from the copper-enriched environment to the control site, normal levels of lipoperoxides and antioxidant compounds were restored in 48 h and antioxidant enzymes recovered their basal activities in 96 h. Individuals transplanted from the control site to the copper-enriched area adjusted their antioxidant compounds and antioxidant enzymes within 48 h and 96 h, respectively, and reached the functional status of the local plants. We conclude that S. lomentaria inhabiting the copper-enriched area buffered oxidative stress by a simultaneous involvement of antioxidant enzymes and water-soluble antioxidant compounds. These antioxidant responses were rapid and reversible, suggesting that copper resistance in S. lomentaria is a constitutive trait and that copper enrichment of the area did not result in a locally adapted copper-tolerant ecotype. [ABSTRACT FROM AUTHOR]

Chondracanthus chamissoi is an important source of carrageenan in Chile. Presently, all the production is harvested from wild populations. This study reports the first attempt to cultivate C. chamissoi. Experiments were conducted with female gametophytic and sporophytic thalli by inserting them among braids of a 7 mm polypropylene rope. Inoculated ropes were placed at 1, 3 and 5 m depths in two sheltered bays in northern Chile. The fronds adapted well to cultivation and grew at all the depths tested, although the greatest increase in biomass was observed at 1 m depth. On a yearly cycle, higher biomass increases were observed in autumn and winter months compared with the spring and summer. We believe that by adapting the cultivation methodology, this species could be cultivated year round. [ABSTRACT FROM AUTHOR]

Exploitation of carrageenophytic seaweeds in Chile has increased significantly over the past few years. Gigartina skottsbergii is one of the species exploited and the harvesting pressure could have negative consequences on the sustainability of this resource. Although demand for raw material of G. skottsbergii continues to increase, basic knowledge needed to cultivate this unique carrageenophyte is lacking. In this study, we determined the light, temperature, and nutrient requirements for juvenile G. skottsbergii cultivation, as well as the culture system and stocking densities required to optimize its indoor cultivation. An optimal temperature range of 10–14 °C combined with dim light conditions are recommended. Nutrients do not need to be constantly added and ammonium instead of nitrate should be used, whereas phosphate must be also added. Floating cultures provide an adequate alternative, where containers support loads of 13–14 g (fresh weight) L−1. Only in very precise combination of factors, the specific growth rate can be over 2% per day. [Copyright &y& Elsevier]

Chilean specimens identified as Laingia hookeri (Lyall) Kylin and serving as the basis for the first report of this genus from Chile have been examined. Because of their apical structure and the tristromatic structure of their blades and because the cystocarps are borne directly on the primary blade in a scattered arrangement, these specimens have been determined to be Pseudophycodrys phyllophora (J. Agardh) Skottsberg. This species was previously known for southern Chile and with a distribution including the Subantarctic (Falkland Islands, Macquarie Island, Tristan da Cunha, and southern Argentina). Therefore, Laingia is removed from the marine algal flora of Chile. [ABSTRACT FROM AUTHOR]

The identification of human artifacts at the early archaeological site of Monte Verde in southern Chile has raised questions of when and how people reached the tip of South America without leaving much other evidence in the New World. Remains of nine species of marine algae were recovered from hearths and other features at Monte Verde II, an upper occupational layer, and were directly dated between 14,220 and 13,980 calendar years before the present (-12,310 and 12,290 carbon-14 years ago). These findings support the archaeological interpretation of the site and indicate that the site's inhabitants used seaweed from distant beaches and estuarine environments for food and medicine. These data are consistent with the ideas that an early settlement of South America was along the Pacific coast and that seaweeds were important to the diet and health of early humans in the Americas. [ABSTRACT FROM AUTHOR]