Papers by Alejandro Buschmann
Journal applied Phycology, 2026
Abstract
Ninety-five percent of the cultivated algal biomass is produced in Asia. Beyond the kelp... more Abstract
Ninety-five percent of the cultivated algal biomass is produced in Asia. Beyond the kelp Saccharina japonica and the eucheumatoid
red algae, the genera Gracilaria and Gracilariopsis rank third in FAO´s global aquaculture statistics by biomass as of
2022. Among them, the red alga Gracilaria chilensis, has played a central role in Chilean aquaculture for decades, although
production levels have shown fluctuations over time in response to market dynamics and environmental factors. Gracilarioids
are primarily produced for the hydrocolloid industry (agar), with a smaller proportion also sold for human consumption in
Asian countries (ogonori) or used to prepare beverages in the Caribbean islands. Gracilaria has also been demonstrated to
be an efficient alga for bioremediating coastal waters. The primary culture systems used for farming gracilarioid species are
floating culture lines. Bottom cultures on sandy shallow waters and intertidal systems are also used for farming. Land-based
tank cultures have also been developed in various regions; however, due to their high costs, they have not been commercially
implemented. Epiphytes and grazers are among the most relevant constraints that their cultivation faces today. Some pathogens
have been identified but remain cryptic threats to gracilarioid cultivation. As with eucheumatoid algae, gracilarioids
are clonally propagated. Studies support that these practices have reduced the genetic diversity of cultivated Gracilaria.
For this reason, efforts have been made to seed ropes with carpospores, thereby reducing the risk of genetic diversity erosion.
Nevertheless, the domestication of this species is still in its infancy; therefore, the potential success in facing stressful
events must still be demonstrated. In contrast to Southeast Asian countries, where gracilarioids are successfully produced,
cultivation in other regions, such as Chile, has decreased over the past few decades due to market demand restrictions. This
decrease in its value has prevented the global expansion of gracilarioid farming. Here, we primarily cover culture systems
and productivity, advantages and disadvantages of farming methods, the impact of epiphytes and grazers, and genetic and
domestication efforts. We also drew on our experience cultivating G. chilensis to provide management recommendations,
including integrated multitrophic aquaculture, biosecurity measures, and genetic diversification strategies, to guide the
sustainable development of farming globally.
BMC Microbiology, 2025
Background Identifying the microbial taxa that structure assemblages in response to local disturb... more Background Identifying the microbial taxa that structure assemblages in response to local disturbances along the Chilean Patagonian coast is critical for understanding community reorganization and ecological risk in this vulnerable marine environment. Here, we examined benthic microbial interactions across sixteen sites spanning 42-44°S in the Inner Sea of Chiloé and adjacent fjord systems. Using co-occurrence network analysis, we characterized spatial interaction patterns and identified keystone taxa whose relationships with environmental variables may serve as ecological indicators. The presence of keystone taxa supports the concept of microbial "seed banks, " which sustain community stability and ecosystem functionality under stress. Networks revealed structured communities dominated by niche-specialist taxa, consistent with ecological processes of niche differentiation and environmental filtering.
Marine Polution Bulletin, 2025
This study investigates prokaryotic communities within sub-Antarctic marine sediments impacted by... more This study investigates prokaryotic communities within sub-Antarctic marine sediments impacted by salmonid aquaculture in southern Chile, employing 16S rRNA gene sequencing to assess alpha and beta diversity, as well as the inferred functional roles of prokaryotes in sediment biogeochemistry, with particular emphasis on rocky seabeds exhibiting varying degrees of giant sulphur-oxidising bacteria (GSOB) mat coverage. Candidatus Isobeggiatoa was identified as the predominant member of the Beggiatoaceae GSOB, consistent with its established ecological role in sulphide-rich marine environments. A novel U-shaped pattern in prokaryotic alpha diversity was observed along the GSOB coverage gradient, characterised by a decline of up to 30 % in transitional zones followed by partial recovery in areas of extensive GSOB mat coverage; beta diversity analysis reflected this trend, confirming significant shifts in community structure across the gradient. Changes in community composition were primarily attributable to fluctuations in the relative abundance of key bacterial taxa, notably Sulfurovum and Sulfurimonas, which predominated in transitional zones but diminished at sites with extensive GSOB coverage. The partial recovery of alpha diversity in highly impacted sites with greater GSOB coverage was accompanied by an increase in anaerobic chemolithotrophic and fermentative groups, indicative of a successional dynamic. Collectively, these findings elucidate a clear relationship between GSOB mat coverage and prokaryotic community composition in aquaculture-affected sediments and support the recommendation of a standardised GSOB coverage scale as a bioindicator for the management of vulnerable sub-Antarctic marine ecosystems.
Functional Reproductive and Developmental Traits Differences Between Two Macrocystis Ecomorphs: Importance of Neutral Lipids
Ecology and Evolution
ABSTRACTThe kelp genus Macrocystis presents populations recognizable by distinct morphological tr... more ABSTRACTThe kelp genus Macrocystis presents populations recognizable by distinct morphological traits, which has raised discussions on its taxonomical status. Recently, whole genome sequencing arose global evidence of Macrocystis ecomorphs “integrifolia” and “pyrifera” being genetically distinct. In the southern hemisphere, both ecomorphs maintain a separated distribution that coincides, without overlap, in the area of 33° S. Besides the fact that both ecomorphs are interfertile, at least under laboratory conditions, several differences in their reproductive strategies and early developmental traits have arisen in over 20 years of ecological and ecophysiological studies. In this study, we evaluated the content of neutral lipids in zoospores of both ecomorphs as a proxy of the required energy to swim and settle. The finding showed that zoospores of “integrifolia” ecomorph have a significantly lower level of neutral lipids than the southern “pyrifera” ecomorph. This correlates with th...
Perspectiva técnica de las tecnologías de cultivo de macroalgas en América Latina y el Caribe., 2025
El cultivo de macroalgas marinas es aún incipiente en América Latina y el Caribe, aunque existe e... more El cultivo de macroalgas marinas es aún incipiente en América Latina y el Caribe, aunque existe experiencia con el alga roja Gracilaria chilensis. Este trabajo analiza la producción de las especies de macroalgas cultivadas en América Latina y el Caribe, los sistemas de cultivo utilizados y sus ventajas y desventajas en términos de productividad, riesgos ambientales y consecuencias económicas. Los antecedentes indican que el cultivo se basa principalmente en macroalgas clonales propagadas por fragmentación del talo. Los cultivos que requieren tecnologías más avanzadas, como el cultivo de diferentes fases del ciclo de vida y la reproducción sexual, no están presentes a nivel productivo. En consecuencia, las actividades de investigación básica y aplicada son un requisito fundamental para promover el desarrollo de esta actividad en la región. Por otro lado, las regulaciones en línea con los sistemas de producción de macroalgas parecen necesarias para permitir el desarrollo sostenible de las macroalgas.
Ecology and Evolution, 2025
The kelp genus Macrocystis presents populations recognizable by distinct morphological traits, wh... more The kelp genus Macrocystis presents populations recognizable by distinct morphological traits, which has raised discussions on its taxonomical status. Recently, whole genome sequencing arose global evidence of Macrocystis ecomorphs "integrifolia" and "pyrifera" being genetically distinct. In the southern hemisphere, both ecomorphs maintain a separated distribution that coincides, without overlap, in the area of 33° S. Besides the fact that both ecomorphs are interfertile, at least under laboratory conditions, several differences in their reproductive strategies and early developmental traits have arisen in over 20 years of ecological and ecophysiological studies. In this study, we evaluated the content of neutral lipids in zoospores of both ecomorphs as a proxy of the required energy to swim and settle. The finding showed that zoospores of "integrifolia" ecomorph have a significantly lower level of neutral lipids than the southern "pyrifera" ecomorph. This correlates with the lower motility of the cells and lower germination capacity in the 'integrifolia' ecomorph, which has been consistently seen over the years. Further, we have seen a highly consistent pattern of a higher zoospore production, germination rate, sexual reproductive success, and early developmental performance (growth and survival) of juvenile sporophytes of "pyrifera" compared to "integrifolia." Hence, both ecomorphs show, in addition to genetic and morphological differences, differential reproductive functional traits consistent in time and space that further support the hypothesis of an ongoing separation of these two Macrocystis ecomorphs. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Plants, 2024
The responses of seaweed species to increased CO2 and lowered pH (Ocean Acidification: OA) depend... more The responses of seaweed species to increased CO2 and lowered pH (Ocean Acidification: OA) depend on their carbon concentrating mechanisms (CCMs) and inorganic carbon (Ci) preferences. However, few studies have described these mechanisms in the early life stages of seaweeds or assessed the effects of OA and its interactions with other environmental drivers on their functionality and photophysiology. Our study evaluated the effects of pH, light (PAR), temperature, and their interactions on the Ci uptake strategies and photophysiology in the early stages of Macrocystis pyrifera. Gametophytes were cultivated under varying pH (7.80 and 8.20), light (20 and 50 μmol photons m−2s−1), and temperature (12 and 16 ◦C) conditions for 25 days. We assessed photophysiological responses and CCMs (in particular, the extracellular dehydration of HCO3 − to CO2 mediated by the enzyme carbonic anhydrase (CA) and direct HCO3− uptake via an anion exchange port). This study is the first to describe the Ci uptake strategies in gametophytes of M. pyrifera, demonstrating that their primary CCM is the extracellular conversion of HCO3 − to CO2 mediated by CA. Additionally, our results indicate that decreased pH can positively affect their photosynthetic efficiency and maximum quantum yield; however, this response is dependent on the light and temperature conditions.
Regional Studies Marine Science, 2024
The Inner Sea of Chilo´e (ISC), northern Patagonia is a topographically and hydrographically hete... more The Inner Sea of Chilo´e (ISC), northern Patagonia is a topographically and hydrographically heterogeneous area of critical interest to the Chilean blue economy due to the intensive artisanal benthic fisheries and aquaculture practices. Using benthic macroinvertebrate assemblages from Macrocystis pyrifera holdfasts, this study exposes how environmental heterogeneity inside the ISC can also be expressed in biological terms. Four zones were considered in the ISC from north to south (Reloncaví, Chacao, Quinchao, and Quellon), with five sampling sites within them. The spatial variability of macroinvertebrate density, composition, species/taxa richness (S), Shannon´s diversity (H´), and overall beta diversity (βsor) in 200 kelp holdfasts (n =50 per zone) between zones and sites were analyzed. ANOVA results showed that the holdfast size, zones and sites within zones explained the variability of density, S and H´. Tukey HSD test also indicated significant (p < 0.01) differences between sampling zones and sites. Distribution patterns included: i) a latitudinal increase in density from the north to the centre of the ISC (max. of 67 ind 10 cm 2, Quinchao); ii) higher S values in the north (max. of 37, Reloncaví); iii) a latitudinal decrease in H´(max. of 3.2, Reloncaví); iv) lower values for all the ecological attributes in the south (Quellon). Overall beta diversity analysis (βsor) showed high variability inside each zone, mainly driven by species turnover (βsim) rather than species nestedness (βsne). nMDs analysis suggested that the northern zones of ISC can be considered the same and differentiated from the others, but they are highly variable within them. PERMANOVA analysis showed that the macroinvertebrates’ composition patterns were significantly (p < 0.01) explained by the holdfast size, and sampling sites/zones. SIMPER analysis revealed the contribution of annelids, arthropods, and molluscs to dissimilarities between zones. The results highlighted the biological heterogeneity of the ISC, suggesting that site-specific environmental conditions affect M. pyrifera populations and, therefore, macroinvertebrates inhabiting their holdfasts. These findings contribute to a better understanding of the ecological complexity of the region, providing a baseline for future studies on the status and composition of benthic communities, and therefore their management and conservation.
Amphipod Food Preference and Iridaeaspp. (Rhodophyta) Spore Release and Dispersal
Journal of the Marine Biological Association of the United Kingdom, Nov 1, 1991
Using laboratory experiments, this study examines the nature of the grazing relationship between ... more Using laboratory experiments, this study examines the nature of the grazing relationship between the amphipod Hyale hirtipalma (Dana) and the red algae Iridaea spp., and the potential effects of grazing on the release and dispersal of algal spores. The results indicate that Hyale hirtipalma has a significant food preference for the cystocarpic stage of Iridaea laminarioides Bory when compared with consumption of Ulva rigida C. Ag. Hyale hirtipalma also shows a significantly greater food preference for cystocarpic tissues of Iridaea laminarioides and I. ciliata Kützing than for other karyological stages of these algae. By consuming the cystocarpic tissues, H. hirtipalma significantly increases the number of carpospores which are released and which settle at all measured distances from the mature cystocarpic I. laminarioides frond where measurements were taken. This evidence, together with information previously published, indicates that several Hyale species show similar food preferences towards the cystocarpic stage of Iridaea spp., and probably have the same ecological role as spore releasers and dispersal agents.
Evaluacion del metodo de inversion de la sacarosa como medida de la temperatura efectiva en la zona intermareal de chile central
Medio ambiente (Valdivia), 1988
Springer eBooks, Feb 10, 2009
Compounds that react irreversibly with cysteines have reemerged as potent and selective tools for... more Compounds that react irreversibly with cysteines have reemerged as potent and selective tools for altering protein function, serving as chemical probes and even clinically approved drugs. The exquisite sensitivity of human immune cell signaling pathways to oxidative stress indicates the likely, yet still underexploited, general utility of covalent probes for selective chemical immunomodulation. Here, we provide an overview of immunomodulatory cysteines, including identification of electrophilic compounds available to label these residues. We focus our discussion on three protein classes essential for cell signaling, which span the 'druggability' spectrum from amenable to chemical probes (kinases), somewhat druggable (proteases), to inaccessible (phosphatases). Using existing inhibitors as a guide, we identify general strategies to guide the development of covalent probes for selected undruggable classes of proteins and propose the application of such compounds to alter immune cell functions.
† This article has been accepted for publication and undergone full peer review but has not been ... more † This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as
Elevated cytokine expression of different PEEK wear particles compared to UHMWPE in vivo
Journal of Materials Science: Materials in Medicine, Sep 26, 2013
Austral Ecology, Jun 29, 2017
The effects of sedimentation and substrate orientation on algal and sessile invertebrate assembla... more The effects of sedimentation and substrate orientation on algal and sessile invertebrate assemblages were tested on an annual population of Macrocystis pyrifera in Metri Bay, southern Chile. In the laboratory, M. pyrifera zoospores were seeded on Crepipatella fecunda shells, the primary substrate for M. pyrifera in this system. The seeded shells were deployed at Metri Bay inside cages and were orientated vertically and horizontally under two sedimentation regimes (bottom and suspended). Due to differences in grazer accessibility and the species present between the sedimentation treatments, grazers (>1 cm) were excluded. We followed sporophyte development of M. pyrifera and the natural recruitment of other algal and invertebrate species. Sedimentation rates were significantly higher in the cages attached to the bottom compared to suspended cages (P < 0.001). In total M. pyrifera and three additional algal genera were detected and all algal recruits showed significantly greater recruitment on the horizontally orientated substrate compared to the vertical substrate. Macrocystis pyrifera sporophytes were present only on the horizontal, suspended (less sedimentation) treatment. In contrast, Ulva and Ectocarpus spp. also occurred in the horizontal, high sediment treatment. Invertebrate recruitment (amphipods, barnacles and spirorbids) dominated the vertically oriented shells regardless of sedimentation. Results indicate that high sedimentation negatively affected the development of M. pyrifera sporophytes while other opportunistic species were able to recruit under these conditions.
Un estudio comparativo del cultivo de oncorhynchus kisutch w . En estanques costeros y balsas jaulas en el sur de chile
Journal of Applied Phycology, Jun 19, 2020
Epiphytism is a common phenomenon in macroalgal aquaculture worldwide. This problem can affect th... more Epiphytism is a common phenomenon in macroalgal aquaculture worldwide. This problem can affect the productivity and quality of the farmed species which may have socioeconomic consequences for the human communities that depend on this activity. In southern Chile, the aquaculture of the red macroalga Agarophyton chilense in the area of Maullín River has suffered losses in local production (> 90%) due to the proliferation of the filamentous green epiphyte Rhizoclonium sp. This epiphyte becomes entangled with A. chilense fronds, diminishing its quality and preventing its sale as raw material. Thus, the aim of this study was to investigate the effects of light intensity (90 and 180 μmol photons m −2 s −1) on the competitive interaction between the epiphyte Rhizoclonium sp. and the basiphyte A. chilense co-cultured at different initial biomass proportions in a replace series experiment. At the end of the experiment, the presence of Rhizoclonium sp. did not affect negatively the growth of A. chilense, but both species showed stress responses (i.e. reduced F v /F m and C:N ratio, suggesting nutrient limitation) in co-culture compared with monocultures. The epiphyte-basiphyte interaction was not modulated by light availability at any initial co-culture proportion and could have been related to nutrient availability during experimentation. Using the replacement series approach, an interspecific competition was observed at all initial co-culture proportion under 180 μmol photons m −2 s −1 while competition was found at the initial co-culture 1:1 under 90 μmol photons m −2 s −1. Our results suggest that the interaction in co-culture between both A. chilense and Rhizoclonium sp. seems to be regulated by nutrient availability as well as it demands utilization rather than light availability.
Evaluation of artificial intertidal enclosures for Gracilaria farming in southern Chile
Aquacultural Engineering, 1992
... of Artificial Intertidal Enclosures for Gracilaria Farming in Southern Chile A. Bravo,* AH Bu... more ... of Artificial Intertidal Enclosures for Gracilaria Farming in Southern Chile A. Bravo,* AH Buschmann,* ME Valenzuela, M. Uribe, PA Vergara &amp; MS ... The agar was extracted from each sample according to the procedure described by Cancino and Orellana (1987) and dry weight ...
Revista Chilena de Historia Natural, 1997
This paper reviews the literature evidence on the herbivore-kelp interactions along the Chilean c... more This paper reviews the literature evidence on the herbivore-kelp interactions along the Chilean coast, basically the role of sea urchins and gastropods in the structure of rocky shallow subtidal marine communities. Due to the morphology of the Chilean coast, we divided our analysis in two large zones. In northern Chile, between 18°-42° S, the Cordillera de la Costa runs close to the coast generating extremely exposed habitats. In this zone two species of Lessonia are dominant in intertidal and subtidal habitats. Here, the sea urchin Tetrapygus niger is the most abundant grazer producing extensive intertidal and subtidal barren grounds. South of 42" S to Cape Horn, Macrocystis pyrifera forms the most conspicuous kelp association in a fjord zone, where hundreds of islands produce protected habitats. Four species of sea urchins and the gastropod Tegula atra graze on M. pyrifera. However, their effects are spatially and temporaly restricted. The foraging behavior of the principal herbivore. the sea urchin Loxechinus a/bus, is influenced by the degree of wave action, restricting its effect to exposed areas. In very protected areas Tegula atra affects the population dynamics of M. pyrifera.
Journal of Experimental Marine Biology and Ecology, Jun 1, 1987
Preferential consumption of algal reproductive tissues has been predicted to potentially reduce a... more Preferential consumption of algal reproductive tissues has been predicted to potentially reduce algal fitness by reduction of reproductive output. This study shows that the amphipod Hyale media (Dana) has a marked trophic preference for mature cystoearpie tissues of lridaea laminarioides Bory. However, during the feeding process the amphipod tears the cystocarps releasing large numbers of spores into the water column. Germination and growth rate experiments indicate that grazer-mediated release does not affect further spore development. Field populations of L laminarioides might have unopened cystocarps even in senescent, deca)ing fronds, while the total number of open cystocarps in mature and senescent fronds increases at higher amphipod density sites, suggesting a facilitation mechanism. Laboratory observations indicate spores can stick to the legs and body sides of the amphipods while a fraction of the ingested spores survives passage through the amphipod digestive tract. Thus, the amphipod seems ecologically important not only as a grazer but also as spore releaser and disperser.
Lancet Infectious Diseases, Jul 1, 2016
Aquaculture uses hundreds of tonnes of antimicrobials annually to prevent and treat bacterial inf... more Aquaculture uses hundreds of tonnes of antimicrobials annually to prevent and treat bacterial infection. The passage of these antimicrobials into the aquatic environment selects for resistant bacteria and resistance genes and stimulates bacterial mutation, recombination, and horizontal gene transfer. The potential bridging of aquatic and human pathogen resistomes leads to emergence of new antimicrobial-resistant bacteria and global dissemination of them and their antimicrobial resistance genes into animal and human populations. Eff orts to prevent antimicrobial overuse in aquaculture must include education of all stakeholders about its detrimental eff ects on the health of fi sh, human beings, and the aquatic ecosystem (the notion of One Health), and encouragement of environmentally friendly measures of disease prevention, including vaccines, probiotics, and bacteriophages. Adoption of these measures is a crucial supplement to eff orts dealing with antimicrobial resistance by developing new therapeutic agents, if headway is to be made against the increasing problem of antimicrobial resistance in human and veterinary medicine.
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Papers by Alejandro Buschmann
Ninety-five percent of the cultivated algal biomass is produced in Asia. Beyond the kelp Saccharina japonica and the eucheumatoid
red algae, the genera Gracilaria and Gracilariopsis rank third in FAO´s global aquaculture statistics by biomass as of
2022. Among them, the red alga Gracilaria chilensis, has played a central role in Chilean aquaculture for decades, although
production levels have shown fluctuations over time in response to market dynamics and environmental factors. Gracilarioids
are primarily produced for the hydrocolloid industry (agar), with a smaller proportion also sold for human consumption in
Asian countries (ogonori) or used to prepare beverages in the Caribbean islands. Gracilaria has also been demonstrated to
be an efficient alga for bioremediating coastal waters. The primary culture systems used for farming gracilarioid species are
floating culture lines. Bottom cultures on sandy shallow waters and intertidal systems are also used for farming. Land-based
tank cultures have also been developed in various regions; however, due to their high costs, they have not been commercially
implemented. Epiphytes and grazers are among the most relevant constraints that their cultivation faces today. Some pathogens
have been identified but remain cryptic threats to gracilarioid cultivation. As with eucheumatoid algae, gracilarioids
are clonally propagated. Studies support that these practices have reduced the genetic diversity of cultivated Gracilaria.
For this reason, efforts have been made to seed ropes with carpospores, thereby reducing the risk of genetic diversity erosion.
Nevertheless, the domestication of this species is still in its infancy; therefore, the potential success in facing stressful
events must still be demonstrated. In contrast to Southeast Asian countries, where gracilarioids are successfully produced,
cultivation in other regions, such as Chile, has decreased over the past few decades due to market demand restrictions. This
decrease in its value has prevented the global expansion of gracilarioid farming. Here, we primarily cover culture systems
and productivity, advantages and disadvantages of farming methods, the impact of epiphytes and grazers, and genetic and
domestication efforts. We also drew on our experience cultivating G. chilensis to provide management recommendations,
including integrated multitrophic aquaculture, biosecurity measures, and genetic diversification strategies, to guide the
sustainable development of farming globally.