Biology subjects

Damian-Serrano, A.

Publications and source records attributed to Damian-Serrano, A..

7 recordsLinked to original sources

bioRxiv2024

Global genomics of the man-o'-war (Physalia) reveal biodiversity at the ocean surface

The open ocean is a vast, highly connected environment, and the organisms found there have been hypothesized to represent massive, well-mixed populations. Of these, the Portuguese man-o-war (Physalia) is uniquely suited to dispersal, sailing the ocean surface with a muscular crest. We tested the hypothesis of a single, panmictic Physalia population by sequencing 133 genomes, and found five distinct lineages, with multiple lines of evidence showing strong reproductive isolation despite range overlap. We then scored thousands of citizen-science photos and identified four recognizable morphologies linked to these lineages. Within lineages, we detected regionally endemic subpopulations, connected by winds and currents, and identified individual long-distance dispersal events. We find that, even in these sailing species, genetic variation is highly partitioned geographically across the open ocean. SummaryThe open ocean is a vast and highly connected environment. The organisms that live there have a significant capacity for dispersal and few geographic boundaries to separate populations. Of these, the Portuguese man-o-war or bluebottle (genus Physalia) is uniquely suited to long-distance travel, using its gas-filled float and muscular crest to catch the wind and sail the sea surface. Physalia are distributed across the globe, and like many pelagic organisms, have been hypothesized to represent a massive, well-mixed population that extends across ocean basins. We tested this hypothesis by sequencing whole genomes of 133 samples collected from waters of over a dozen countries around the globe. Our results revealed five distinct lineages, with multiple lines of evidence indicating strong reproductive isolation, despite regions of range overlap. We combined these data with an independent dataset of thousands of images of Physalia uploaded to the citizen-science website inaturalist.org, which we scored for morphological characters including sail size, tentacle arrangement, and color. From these images, we identified four recognizable morphologies, described their geographical distribution, and linked them to four of the lineages identified with genomic data. We conclude there are at least four species, three of which correspond to species proposed by scientists in the 18th and 19th centuries: P. physalis, P utriculus, and P. megalista, along with one as yet unnamed species Physalia sp. from the Tasman Sea. Within each species, we observe significant population structure, with evidence of persistent subpopulations at a regional scale, as well as evidence for individual long-distance dispersal events. Our findings indicate that, instead of one well-mixed, cosmopolitan species, there are in fact multiple Physalia species with distinct but overlapping ranges, each made up of regionally endemic subpopulations that are connected by major ocean currents and wind patterns.

zoology↗

bioRxiv2024

Colonial Architecture Modulates the Speed and Efficiency of Multi-Jet Swimming in Salp Colonies

Salps are marine pelagic tunicates with a complex life cycle including a solitary and colonial stage. Salp colonies are composed of asexually budded individuals that coordinate their swimming by multi-jet propulsion. Colonies develop into species-specific architectures with distinct zooid orientations. We hypothesize that colonial architecture drives differences in swimming performance between salps due to differences in how frontal drag scales with the number of propeller zooids in the colony. Moreover, we hypothesize that faster-swimming taxa are more energetically efficient in their locomotion since less energy would be devoted to overcoming drag forces. We (1) compare swimming speed across salp species and architectures, (2) evaluate how swimming speed scales with the number of zooids in the colony in architectures with constant and scaling frontal cross-sectional area, and (3) compare the metabolic cost of transport across different species and how it scales with swimming speed. To measure their swimming speeds, we recorded swimming salp colonies using in situ videography while SCUBA diving in the open ocean. To estimate the cost of transport, we measured the respiration rates of swimming and anesthetized salps collected in situ using jars equipped with non-invasive oxygen sensors. We found that linear colonies generally swim faster and with a lower cost of transport due to their differential advantage in frontal drag scaling with an increasing number of zooids. These findings underscore the importance of considering propeller arrangement to optimize speed and energy efficiency in bioinspired underwater vehicle design, leveraging lessons learned from the diverse natural laboratory provided by salp diversity. Summary StatementLinear arrangements in multi-jet propelled marine colonial invertebrates are faster and more energetically efficient than less streamlined architectures, offering insights for bioinspired underwater vehicle design.

zoology↗

bioRxiv2023

Metabolic similarity and the predictability of microbial community assembly

AbstractWhen microbial communities form, their composition is shaped by selective pressures imposed by the environment. Can we predict which communities will assemble under different environmental conditions? Here, we hypothesize that quantitative similarities in metabolic traits across metabolically similar environments lead to predictable similarities in community composition. To that end, we measured the growth rate and by-product profile of a library of proteobacterial strains in a large number of single nutrient environments. We found that growth rates and secretion profiles were positively correlated across environments when the supplied substrate was metabolically similar. By analyzing hundreds of in-vitro communities experimentally assembled in an array of different synthetic environments, we then show that metabolically similar substrates select for taxonomically similar communities. These findings lead us to propose and then validate a comparative approach for quantitatively predicting the effects of novel substrates on the composition of complex microbial consortia.

ecology↗

bioRxiv2023

A developmental ontology for the colonial architecture of salps

Colonial animals are composed of clonal individuals that remain physically connected and physiologically integrated. Salps are urochordates with a dual life cycle including an asexual solitary stage that buds sexual colonies composed of jet-propelling zooids that efficiently swim together as a single unit by multi-jet propulsion. Colonies from different species develop distinct architectures characterized by their zooid arrangement patterns, but this diversity has received little attention. Thus, these architectures have never been formally defined using a framework of variables and axes that would allow comparative analyses. We set out to define an ontology of the salp colony architecture morphospace and describe the developmental pathways that build the different architectures. To inform these definitions, we collected and photographed live specimens of adult and developing colonies through offshore SCUBA diving. Since all salp colonies begin their development as a transversal double chain, we characterized each adult colonial architecture as a series of developmental transitions, such as rotations and translations of zooids, relative to their orientation at this early shared stage. We hypothesize that all adult architectures are either final or intermediate stages within three developmental pathways towards either bipinnate, cluster, or helical forms. This framework will enable comparative studies on the biomechanical implications, ecological functions, evolutionary history, and engineering applications of the diversity of salp colony architectures.

zoology↗

bioRxiv2020

Ecological load and balancing selection in circumboreal barnacles

Acorn barnacle adults experience environmental heterogeneity at various spatial scales of their circumboreal habitat, raising the question of how adaptation to high environmental variability is maintained in the face of strong juvenile dispersal and mortality. Here we show that 4% of genes in the barnacle genome experience balancing selection across the entire range of the species. Many of these genes harbor mutations maintained across 2 million years of evolution between the Pacific and Atlantic oceans. These genes are involved in ion regulation, pain reception, and heat tolerance, functions which are essential in highly variable ecosystems. The data also reveal complex population structure within and between basins, driven by the trans-Arctic interchange and the last glaciation. Divergence between Atlantic and Pacific populations is high, foreshadowing the onset of allopatric speciation, and suggesting that balancing selection is strong enough to maintain functional variation for millions of years in the face of complex demography.

evolutionary biology↗

bioRxiv2019

The Evolution of Siphonophore Tentilla as Specialized Tools for Prey Capture

Predator specialization has often been considered an evolutionary dead-end due to the constraints associated with the evolution of morphological and functional optimizations throughout the organism. However, in some predators, these changes are localized in separate structures dedicated to prey capture. One of the most extreme cases of this modularity can be observed in siphonophores, a clade of pelagic colonial cnidarians that use tentilla (tentacle side branches armed with nematocysts) exclusively for prey capture. Here we study how siphonophore specialists and generalists evolve, and what morphological changes are associated with these transitions. To answer these questions, we: (1) measured 29 morphological characters of tentacles from 45 siphonophore species, (2) mapped these data to a phylogenetic tree, and (3) analyzed the evolutionary associations between morphological characters and prey type data from the literature. Instead of a dead-end, we found that siphonophore specialists can evolve into generalists, and that specialists on one prey type have directly evolved into specialists on other prey types. Our results show that siphonophore tentillum morphology has strong evolutionary associations with prey type, and suggest that shifts between prey types are linked to shifts in the morphology, mode of evolution, and genetic correlations of tentilla and their nematocysts. The evolutionary history of siphonophore specialization helps build a broader perspective on predatory niche diversification via morphological innovation and evolution. These findings contribute to understanding how specialization and morphological evolution have shaped present-day food webs. Significance StatementPredatory specialization is often associated with the evolution of modifications in the morphology of the prey capture apparatus. Specialization has been considered an evolutionary dead-end due to the constraints associated with these morphological changes. However, in predators like siphonophores, armed with modular structures used exclusively for prey capture, this assumption is challenged. Our results show that siphonophores can evolve generalism and new prey-type specializations by modifying the morphological states, modes of evolution, and genetic correlations between the parts of their prey capture apparatus. These findings demonstrate how studying open-ocean non-bilaterian predators can reveal novel patterns and mechanisms in the evolution of specialization. Understanding these evolutionary processes is fundamental to the study of food-web structure and complexity.

evolutionary biology↗

bioRxiv2018

Improved phylogenetic resolution within Siphonophora (Cnidaria) with implications for trait evolution

Siphonophores are a diverse group of hydrozoans (Cnidaria) that are found at all depths of the ocean - from the surface, like the familiar Portuguese man of war, to the deep sea. Siphonophores play an important role in ocean ecosystems, and are among the most abundant gelatinous predators. A previous phylogenetic study based on two ribosomal RNA genes provided insight into the internal relationships between major siphonophore groups, however there was little support for many deep relationships within the clade Codonophora. Here, we present a new siphonophore phylogeny based on new transcriptome data from 30 siphonophore species analyzed in combination with 13 publicly available genomic and transcriptomic datasets. We use this new phylogeny to reconstruct several traits that are central to siphonophore biology, including sexual system (monoecy vs. dioecy), gain and loss of zooid types, life history traits, and habitat. The phylogenetic relationships in this study are largely consistent with the previous phylogeny, but we find strong support for new clades within Codonophora that were previously unresolved. These results have important implications for trait evolution within Siphonophora, including favoring the hypothesis that monoecy arose twice.

evolutionary biology↗