Download or read book Diversity dynamics and function of host associated microbiomes in marine organisms written by Yunyun Zhuang and published by Frontiers Media SA. This book was released on 2024-01-25 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Microbial Symbiosis of Marine Sessile Hosts Diversity Function and Applications written by Suhelen Egan and published by Frontiers Media SA. This book was released on 2015-12-21 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern molecular -omics tools (metagenomics, metaproteomics etc.) have greatly contributed to the rapid advancement of our understanding of microbial diversity and function in the world’s oceans. These tools are now increasingly applied to host-associated environments to describe the symbiotic microbiome and obtain a holistic view of marine host-microbial interactions. Whilst all eukaryotic hosts are likely to benefit from their microbial associates, marine sessile eukaryotes, including macroalgae, seagrasses and various invertebrates (sponges, acidians, corals, hydroids etc), rely in particular on the function of their microbiome. For example, marine sessile eukaryotes are under constant grazing, colonization and fouling pressure from the millions of micro- and macroorganisms in the surrounding seawater. Host-associated microorganisms have been shown to produce secondary metabolites as defense molecules against unwanted colonization or pathogens, thus having an important function in host health and survival. Similarly microbial symbionts of sessile eukaryotes are often essential players in local nutrient cycling thus benefiting both the host and the surrounding ecosystem. Various research fields have contributed to generating knowledge of host-associated systems, including microbiology, biotechnology, molecular biology, ecology, evolution and biotechnology. Through a focus on model marine sessile host systems we believe that new insight into the interactions between host and microbial symbionts will be obtained and important areas of future research will be identified. This research topic includes original research, review and opinion articles that bring together the knowledge from different aspects of biology and highlight advances in our understanding of the diversity and function of the microbiomes on marine sessile hosts.

Download or read book Microbiomes of Soils Plants and Animals written by Rachael E. Antwis and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A comparative, holistic synthesis of microbiome research, spanning soil, plant, animal and human hosts.

Download or read book Microbial Ecology of the Oceans written by Josep M. Gasol and published by John Wiley & Sons. This book was released on 2018-03-27 with total page 571 pages. Available in PDF, EPUB and Kindle. Book excerpt: The newly revised and updated third edition of the bestselling book on microbial ecology in the oceans The third edition of Microbial Ecology of the Oceans features new topics, as well as different approaches to subjects dealt with in previous editions. The book starts out with a general introduction to the changes in the field, as well as looking at the prospects for the coming years. Chapters cover ecology, diversity, and function of microbes, and of microbial genes in the ocean. The biology and ecology of some model organisms, and how we can model the whole of the marine microbes, are dealt with, and some of the trophic roles that have changed in the last years are discussed. Finally, the role of microbes in the oceanic P cycle are presented. Microbial Ecology of the Oceans, Third Edition offers chapters on The Evolution of Microbial Ecology of the Ocean; Marine Microbial Diversity as Seen by High Throughput Sequencing; Ecological Significance of Microbial Trophic Mixing in the Oligotrophic Ocean; Metatranscritomics and Metaproteomics; Advances in Microbial Ecology from Model Marine Bacteria; Marine Microbes and Nonliving Organic Matter; Microbial Ecology and Biogeochemistry of Oxygen-Deficient Water Columns; The Ocean’s Microscale; Ecological Genomics of Marine Viruses; Microbial Physiological Ecology of The Marine Phosphorus Cycle; Phytoplankton Functional Types; and more. A new and updated edition of a key book in aquatic microbial ecology Includes widely used methodological approaches Fully describes the structure of the microbial ecosystem, discussing in particular the sources of carbon for microbial growth Offers theoretical interpretations of subtropical plankton biogeography Microbial Ecology of the Oceans is an ideal text for advanced undergraduates, beginning graduate students, and colleagues from other fields wishing to learn about microbes and the processes they mediate in marine systems.

Download or read book The Social Biology of Microbial Communities written by Institute of Medicine and published by National Academies Press. This book was released on 2012-12-10 with total page 633 pages. Available in PDF, EPUB and Kindle. Book excerpt: Beginning with the germ theory of disease in the 19th century and extending through most of the 20th century, microbes were believed to live their lives as solitary, unicellular, disease-causing organisms . This perception stemmed from the focus of most investigators on organisms that could be grown in the laboratory as cellular monocultures, often dispersed in liquid, and under ambient conditions of temperature, lighting, and humidity. Most such inquiries were designed to identify microbial pathogens by satisfying Koch's postulates.3 This pathogen-centric approach to the study of microorganisms produced a metaphorical "war" against these microbial invaders waged with antibiotic therapies, while simultaneously obscuring the dynamic relationships that exist among and between host organisms and their associated microorganisms-only a tiny fraction of which act as pathogens. Despite their obvious importance, very little is actually known about the processes and factors that influence the assembly, function, and stability of microbial communities. Gaining this knowledge will require a seismic shift away from the study of individual microbes in isolation to inquiries into the nature of diverse and often complex microbial communities, the forces that shape them, and their relationships with other communities and organisms, including their multicellular hosts. On March 6 and 7, 2012, the Institute of Medicine's (IOM's) Forum on Microbial Threats hosted a public workshop to explore the emerging science of the "social biology" of microbial communities. Workshop presentations and discussions embraced a wide spectrum of topics, experimental systems, and theoretical perspectives representative of the current, multifaceted exploration of the microbial frontier. Participants discussed ecological, evolutionary, and genetic factors contributing to the assembly, function, and stability of microbial communities; how microbial communities adapt and respond to environmental stimuli; theoretical and experimental approaches to advance this nascent field; and potential applications of knowledge gained from the study of microbial communities for the improvement of human, animal, plant, and ecosystem health and toward a deeper understanding of microbial diversity and evolution. The Social Biology of Microbial Communities: Workshop Summary further explains the happenings of the workshop.

Download or read book Socio Ecology of Microbes in a Changing Ocean written by Matthias Wietz and published by Frontiers Media SA. This book was released on 2019-08-02 with total page 209 pages. Available in PDF, EPUB and Kindle. Book excerpt: Socio-ecological interactions between microbes and associated organisms are integral elements of marine ecosystem dynamics. This Research Topic combines sixteen papers on interactions across the major domains of marine life, including prokaryotes, phytoplankton, macroalgae, cnidarians, viruses and fungi. These studies offer exciting insights into microbial cooperation and competition, holobiont ecology, interkingdom signaling, chemical microdiversity, and biogeography. Understanding such network processes is essential for the interpretation of ecosystem functioning and biogeochemical events, particularly in the wake of climate change.

Download or read book Microbial Symbiosis of Marine Sessile Hosts Diversity and Function written by and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern molecular -omics tools (metagenomics, metaproteomics etc.) have greatly contributed to the rapid advancement of our understanding of microbial diversity and function in the world's oceans. These tools are now increasingly applied to host-associated environments to describe the symbiotic microbiome and obtain a holistic view of marine host-microbial interactions. Whilst all eukaryotic hosts are likely to benefit from their microbial associates, marine sessile eukaryotes, including macroalgae, seagrasses and various invertebrates (sponges, acidians, corals, hydroids etc), rely in particular on the function of their microbiome. For example, marine sessile eukaryotes are under constant grazing, colonization and fouling pressure from the millions of micro- and macroorganisms in the surrounding seawater. Host-associated microorganisms have been shown to produce secondary metabolites as defense molecules against unwanted colonization or pathogens, thus having an important function in host health and survival. Similarly microbial symbionts of sessile eukaryotes are often essential players in local nutrient cycling thus benefiting both the host and the surrounding ecosystem. Various research fields have contributed to generating knowledge of host-associated systems, including microbiology, biotechnology, molecular biology, ecology, evolution and biotechnology. Through a focus on model marine sessile host systems we believe that new insight into the interactions between host and microbial symbionts will be obtained and important areas of future research will be identified. This research topic includes original research, review and opinion articles that bring together the knowledge from different aspects of biology and highlight advances in our understanding of the diversity and function of the microbiomes on marine sessile hosts.

Download or read book Biodiversity of Marine Microbes written by Savvas Genitsaris and published by MDPI. This book was released on 2021-08-31 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book entitled “Biodiversity of Marine Microbes” aims at highlighting the significance of marine microbes as primary producers, their contribution in complex ecological processes and their roles in biogeochemical cycles and ecosystem functioning. The book includes five research papers covering the diversity and composition of marine microbial communities representing all three domains of life in various marine environments, including coastal eutrophic areas, ice waters, and lagoons. One paper examines the diversity and succession of bacterial and archaeal communities from coastal waters in mesocosm experiments. The combination of classical tools with novel technological advances implemented in the methods of the papers offered an opportunity to answer fundamental questions and shed light on the complex and diverse life of marine microbes.

Download or read book Diversity Form and Function Within the Marine Mammal Microbiota written by Natasha K. Dudek and published by . This book was released on 2018 with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt: Animals can be viewed as complex, co-evolving networks of microbes and host cells. Understanding the diversity, form, and function of microbes associated with different animals is therefore essential to understanding the patterns and processes underlying evolution across all domains of life. Extant marine mammals present an interesting opportunity to study the microbiota of animals with an unusual lifestyle that has arisen independently six times since the time of their last common ancestor. The manner in which the marine mammal-associated microbiota has evolved in response to the host's marine lifestyle remains unclear. In this thesis, I describe three studies of the microbiota of marine mammals. In the first, I characterize bacterial community composition associated with sea otters, which are a keystone species that is listed as endangered by the IUCN. They are also the sole representatives of an entire lineage of marine mammal. The findings suggest that environment plays a major role in structuring sea otter-associated bacterial community composition and raises the question of whether sea otters may have a reduced bacterial biomass in their guts compared to other mammals. As seen in other marine mammal species, results show that sea otters host a diversity of 'microbial dark matter'. In chapter two of this thesis, I study such 'microbial dark matter' present in the dolphin mouth and propose two new bacterial phyla (Candidatus Delphibacteria and Candidatus Fertabacteria), the former of which our metabolic reconstruction suggests may have a direct effect on dolphin physiology and health. In the third chapter of my thesis, I operate under the assumption that novel phylogenetic diversity is correlated with novel functional diversity, and thereby discover a previously uncharacterized rectangular microbe in dolphin oral samples with several unusual morphological features, such as pili-like appendages whose architecture differs substantially from known surface structures seen in bacteria and archaea. A single-cell genomics experiment suggested that this microbe was a type of bacteria from one of the following three groups: Bacteroidetes, TM7, or Epsilonproteobacteria. Collectively, these studies provide insight into diversity, form, and function within the marine mammal microbiota, and contribute towards our understanding of the microbial diversity, both phylogenetic and functional, which has evolved on Earth.

Download or read book Spatial and Temporal Patterns of Diversity and Community Composition in Marine Molluscan Microbiomes written by Alexander Theodore Neu and published by . This book was released on 2021 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ecological communities have been shown to vary in some predictable ways through space, time, and along environmental gradients, suggesting there may be underlying "rules" in ecology which govern these patterns and processes. However, nearly all our knowledge of these trends comes from studies of large eukaryotes such as plants and animals, and we know very little about how these eukaryotic patterns compare to those of bacteria and archaea, the most dominant life forms on the planet. The goal of this dissertation is to determine whether ecological patterns that are evident in plants and animals are also applicable to host-associated microbes. First, I investigated whether these microbes exhibit large-scale spatial trends in diversity and community composition that are concordant with those of their eukaryotic hosts. Specifically, I investigated changes in community composition across a marine biogeographic boundary and changes in diversity along a latitudinal transect. Results showed that microbiome compositions varied significantly between geographic sites, but that the identity of the host species played a greater role than geography in determining community composition. Further, microbes associated with the California mussel, Mytilus californianus, did not show a traditional latitudinal diversity gradient, and latitudinal diversity patterns varied based on microbial group and host body site. Next, I investigated whether host-associated microbial communities vary over time and in response to environmental change in similar ways to their eukaryotic hosts. I found that over an 11-year period, and in response to environmental change, microbial communities of the bean clam, Donax gouldii, significantly differed in composition, but not in richness. Further, I found that microbes did not regularly diverge in concordance with their intertidal gastropod hosts in the ~3.5 million years since the closure of the Isthmus of Panama, though this was dependent on the host taxa and the body site from which the microbes were collected. Finally, I investigated whether current methodologies for determining the core microbiome are guided by ecological and evolutionary principles and identify critical areas for future research. Overall, this dissertation shows that large-scale patterns in host-associated microbial taxa are often context-dependent and distinct from those of their hosts.

Download or read book The Marine Microbiome written by Lucas J. Stal and published by Springer. This book was released on 2016-06-03 with total page 501 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the state-of-the-art concerning the ‘marine microbiome’ and its uses in biotechnology. The first part discusses the diversity and ecology of marine microorganisms and viruses, including all three domains of life: Bacteria, Archaea, and Eukarya. It discusses whether marine microorganisms exist and, if so, why they might be unique. The second part presents selected marine habitats, their inhabitants and how they influence biogeochemical cycles, while the third discusses the utilization of marine microbial resources, including legal aspects, dissemination, and public awareness. The marine microbiome is the total of microorganisms and viruses in the ocean and seas and in any connected environment, including the seafloor and marine animals and plants. The diversity of microbial life remains unquantified and largely unknown, and could represent a hidden treasure for human society. Accordingly, this book is also intended to connect academics and industry, providing essential information for microbiologists from both fields.

Download or read book Marine Microbiology written by Colin Munn and published by Garland Science. This book was released on 2003-10-16 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine micro-organisms play a vital role in the maintenance of our planet, a fact which will have great bearing on our ability to respond to problems such as population increase, over-exploitation of fisheries, climate change and population. Powerful new tools, especially in molecular biology, remote sending and deep-sea exploration, have led to astonishing discoveries of the abundance and diversity of marine microbial life and its role in global ecology. New tools and an increased interest in ecological factors have caused an upsurge of interest in this field of study. The book aims to convey the fascinating discoveries and great importance of this fast moving discipline to the student. Marine Microbiology is divided into three sections: the first reviews the main features of the marine environment and key aspects of marine microbial life; the second looks at the role of marine microorganisms in ecology, and the final section considers some of the applications of this knowledge, looking into areas such as disease and biodegradation.

Download or read book Actinomycetes in Biotechnology written by Bozzano G Luisa and published by Elsevier. This book was released on 2012-12-02 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: The actinomycetes are a group of bacteria well known as producers of antibiotics. With the advent of molecular biology they have become important to biotechnologists in the search for new antibiotics, vitamins, enzyme inhibitors, etc. They also play an important role in the biodegradation of wastes, and their wide (natural) distribution in soil, composts, water and elsewhere in the environment makes them important to the agricultural and waste industries. This research book presents a broad view of the current interest in actinomycetes, ranging from isolation/screening of actinomycetes, discovery of new antibiotics, a substantial contribution on genetic manipulation to actinomycetes in agriculture, forestry, and the threat of actinomycetes as pollutants in the environment. The chapters, which have been written by experts, are intended to provide a balanced view of the opportunities and problems in an expanding field of interest.

Download or read book The Structure and Function of Aquatic Microbial Communities written by Christon J. Hurst and published by Springer. This book was released on 2019-05-13 with total page 351 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses how aquatic microbial communities develop interactive metabolic coordination both within and between species to optimize their energetics. It explains that microbial community structuration often includes functional stratification among a multitude of organisms that variously exist either suspended in the water, lodged in sediments, or bound to one another as biofilms on solid surfaces. The authors describe techniques that can be used for preparing and distributing microbiologically safe drinking water, which presents the challenge of successfully removing the pathogenic members of the aquatic microbial community and then safely delivering that water to consumers. Drinking water distribution systems have their own microbial ecology, which we must both understand and control in order to maintain the safety of the water supply. Since studying aquatic microorganisms often entails identifying them, the book also discusses techniques for successfully isolating and cultivating bacteria. As such, it appeals to microbiologists, microbial ecologists and water quality scientists.

Download or read book Their World A Diversity of Microbial Environments written by Christon J. Hurst and published by Springer. This book was released on 2016-05-02 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume summarizes recent advances in environmental microbiology by providing fascinating insights into the diversity of microbial life that exists on our planet. The first two chapters present theoretical perspectives that help to consolidate our understanding of evolution as an adaptive process by which the niche and habitat of each species develop in a manner that interconnects individual components of an ecosystem. This results in communities that function by simultaneously coordinating their metabolic and physiologic actions. The third contribution addresses the fossil record of microorganisms, and the subsequent chapters then introduce the microbial life that currently exists in various terrestrial and aquatic ecosystems. Coverage of the geosphere addresses endolithic organisms, life in caves and the deep continental biosphere, including how subsurface microbial life may impact spent nuclear fuel repositories. The discussion of the hydrosphere includes hypersaline environments and arctic food chains. By better understanding examples from the micro biosphere, we can elucidate the many ways in which the niches of different species, both large and small, interconnect within the overlapping habitats of this world, which is governed by its microorganisms.

Download or read book Bacterial Predation in Host Microbiomes written by Rory M. Welsh and published by . This book was released on 2015 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: In host-associated microbiomes, the mechanisms that regulate community composition or the principles that govern dynamics remain far from clear. However, understanding how the structure of microbial communities shift as the system moves away from a healthy state is critical to assessing disease progression and to formulate any potential mitigation strategy. In this dissertation, I targeted a relatively understudied genus of predatory bacteria, Halobacteriovorax, capable of preying on known pathogens, and aimed to determine the ecological role of these unusual predators in the microbiome of their coral host. Halobacteriovorax are a genus of delta proteobacteria which exhibit a biphasic lifestyle. In attack phase they are small (1 to 2 [micro]m in length and 0.35[micro]m in width), highly motile, single flagellated vibriod shaped bacteria that must attach to other bacteria before penetrating their periplasm where they undergo filamentous growth and genome replication without competition. As nutrients become exhausted from the prey cell, the elongated Halobacteriovorax filament divides into multiple attack phase progeny that lyse the bdelloplast. The ecological role of these predators is still relatively understudied, but given their predatory lifestyle, high grazing rates, and broad prey range, Halobacteriovorax could play a major role in structuring microbial communities. In order to study how cell-cell interactions impact microbial community structure and function, I employed a wide range of methods and technologies utilizing culture dependent and independent techniques. Using high throughput sequencing I detailed shifts in community structure of the microbiome of the mucosal surface layer of multiple coral species in their natural environment by repeatedly sampling individuals over a two-year time scale. Halobacteriovorax were a core microbiome component detected in over 78 percent of the 198 samples. Using network analysis I was able to obtain the temporal and spatial dynamics of Halobacteriovorax, and show that despite their predatory nature they predominately co-occur with their potential prey in our networks. I also isolated and cultured novel Halobacteriovorax strains from multiple coral species, and characterized these coral-associated predatory bacterial isolates using full-length 16S rRNA sequencing of cultures, phylogenetic analysis of the full length reads, prey range evaluation, and microscopic documentation of unique predatory lifecycle stages. In order to study cell-cell interactions I employed microfluidic devices and high-resolution video microscopy, image analysis, and cell tracking to observe individual predator-prey interactions utilizing predatory Halobacteriovorax and a common pathogen to a variety of aquatic host organisms, Vibrio coralliilyticus, as the prey. In this co-culture system, I captured striking microscale observations that demonstrate Halobacteriovorax's ability to effectively prey on and reduce pathogenic V. coralliilyticus populations. To illuminate the role of Halobacteriovorax on the host microbiome, I challenged specimens of the important reef-building coral Montastraea cavernosa with V. coralliilyticus pathogens in the presence or absence of Halobacteriovorax predators, and then detailed the changes in the microbial communities over time using 16S rRNA amplicon sequencing. The pathogen challenge reshaped coral microbiomes by increasing richness and reducing stability (increased beta-diversity) of the rest of the microbiome, suggesting strong secondary effects of pathogen invasion on commensal and mutualistic coral bacteria. The addition of Halobacteriovorax alone had only minor effects on the microbiome, and no infiltration of Halobacteriovorax into coral tissues was detected in amplicon libraries. Simultaneous challenges with both pathogen and predator eliminated detectable V. coralliilyticus infiltration into coral tissue samples, ameliorated changes to the rest of the coral microbiome, and prevented secondary blooms of opportunistic bacteria. All together my results suggest predation by Halobacteriovorax may act as a mechanism to regulate population size of a wide range of opportunistic pathogens and illustrates the powerful role of these predatory bacteria in the marine microbiome.

Download or read book Microbes Among Marine Giants written by and published by . This book was released on 2018 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Kelp forest ecosystems are distributed on the rocky reefs of coastal regions worldwide. Kelps (order Laminariales) are a diverse group of brown macroalgae containing numerous species including giant kelp, Macrocystis pyrifera. The giant kelp dominates the kelp forests of southern California, engineering complex three-dimensional habitat which provides foundational shelter, nursery, and nutrients to marine organisms including invertebrates, fish, and marine mammals. While the kelp forests of southern California are well-regarded for their ecological and economic importance, traditional ecological surveys have ignored the most abundant fraction within the ecosystem - microbes. Microbes, including bacteria, archaea, and micro-eukaryotes, are present on all submerged surfaces in marine ecosystems, including microbiomes on macroorganisms. Microbes serve key ecological roles, including cycling of nutrients such as carbon and nitrogen to higher trophic levels within the ecosystem. Host-associated microbes have a symbiotic relationship with the host, providing environmentally-limited nutrients and protection from pathogen invasion in exchange for settlement substrate and host-derived metabolic exudates. Despite the known importance of microbes in marine ecosystems, microbes are absent from classic ecological models describing the top-down and bottom-up regulating forces structuring kelp populations. Thus, for my dissertation I aimed to address the lack of knowledge on the microbial ecology of southern California kelp forests, including the interactions between the predominant macroalgae and the associated microbiomes. In Chapter 1, I established a baseline description of the taxonomic structure and functional potential of microbial communities residing within the Macrocystis pyrifera-dominated kelp forest of Point Loma, CA, and identified sources of variation in microbiome profiles. The Point Loma kelp forest is subject to fluctuations in environmental conditions resulting from seasonality and stratification, which has an influence on kelp forest productivity. However, the potential direct and indirect effects of altered kelp forest environmental conditions on the microbial community structure and function has yet to be described, and as such I aimed to address this for Chapter 1. I sampled microbiomes from both the M. pyrifera biofilm and the adjacent water column seasonally over a three year investigation (2013-2016). I described the microbiomes in great depth using culture-independent whole genome shotgun metagenomics, and assessed the spatial and temporal variability in microbiome composition, function, and diversity. The microbiomes of the kelp and water were distinct in both taxonomic composition and functional potential. Kelp microbiomes remained stable across vertical depth, did not change significantly across season, and were not influenced by biophysical measurements of the surrounding environmental conditions. In contrast, the water-associated microbiomes varied significantly across depth with distinct community profiles above and below the thermocline stratification, showed significant changes across season, and seasonal changes within microbiome structure were strongly correlated with biophysical measurements of kelp forest productivity. Overall, my results showed that while free-living microbiomes were structured by the surrounding environmental conditions, host factors outweighed environmental factors in structuring hostassociated microbiomes. In Chapter 2, I examined the potential shifts in the baseline kelp forest microbiomes resulting from disturbance caused by the spread of an invasive alga, and the potential microbial influence in the alga's invasion strategy. This investigation took place at Santa Catalina Island within the Channel Islands 40 km offshore southern California, throughout the progression of the species invasion (2014-2018). Catalina Island has historically boasted dense populations of the native alga Macrocystis pyrifera, but has undergone disturbance due to the invasion and spread of invasive alga, Sargassum horneri. Invasive species cause significant alterations to ecosystems with both physical and chemical influences which deter and inhibit recovery of native species; however, whether there is a microbial influence in the invasion strategy of alga S. horneri is unknown. First, I described the microbiome of the invasive S. horneri and compared it to the native M. pyrifera, and found the microbiomes of the two macroalgal species to be distinct; specifically, the S. horneri microbiome was enriched in potentially pathogenic Vibrios. Next, I identified the potential for S. horneri presence to induce changes in the surrounding microbiomes. In 2018 as the native alga M. pyrifera was attempting to recover from disturbance, M. pyrifera and S. horneri existed in an interface at some sites. Where the two were in direct contact, I observed evidence of tissue bleaching and deterioration of the native alga, and investigated whether this detriment was a direct result of microbial pathogens. I did not find evidence of S. horneri microbiome inoculation onto the adjacent M. pyrifera; rather, the bleached M. pyrifera showed dysbiosis where the microbiome was lost completely compared to healthy M. pyrifera individuals nearby. However, I did find evidence of S. horneri microbiome inoculation onto the benthic substrate directly below the invasive alga, which resulted in an enrichment of Vibrios compared to the microbiome from benthic substrate beneath native M. pyrifera, and the enrichment of Vibrios on the benthic substrate occurred concurrently with a lack of native algal recovery at those locations. My findings suggest that the invasive species S. horneri has altered the baseline microbiome structure in the kelp forest, and the induced microbial changes may have an ongoing influence on the native species as they attempt to recover from disturbance. In Chapter 3, I investigated the microbial influence on a key stage of recruitment of the giant kelp, Macrocystis pyrifera. Macroalgae, including kelps, rely on recruitment processes to maintain adult populations and recover from disturbances. During kelp recruitment processes, microscopic propagules are released into the kelp forest water column where they are suspended until settlement onto the benthic substrate. Microscopic propagules are highly susceptible to abiotic conditions including UV irradiation, temperature, and nutrients, and biotic conditions including grazing. However, the influence of microbes on kelp propagule success has not been widely studied. Given that microbes are abundant in marine ecosystems (106 cells per ml of seawater) and are present on every submerged surface, microbes are likely to interact with kelp propagules during recruitment processes. For this investigation I reared M. pyrifera microscopic propagules in laboratory microcosms and exposed them to environmentally-sourced microbial communities within treatments. First, I investigated whether the presence of microbes influenced M. pyrifera propagules, and found that removing microbes in seawater increased propagule recruitment success. I then assessed the propagule success when exposed to a nearshore (Point Loma, CA) microbial community compared to an offshore (Santa Catalina Island, CA) microbial community, at multiple levels of microbial abundance. At the time the experiment was conducted, Catalina Island fostered a pristine kelp forest with lower anthropogenic influence compared to the nearshore Point Loma kelp forest. The nearshore (Point Loma) microbial community treatments yielded similar results to the first experiment, where removing microbes resulted in higher kelp propagule success. In contrast, kelp propagules exposed to offshore (Catalina) microbes had the greatest success when microbes were present at intermediate abundances, rather than removed completely. In both treatments, a microbialization of the seawater resulted in observed morphological detriment to kelp propagules. This study suggests that kelp forest microbes have an influence on a key stage of kelp recruitment, and the composition of the microbial community is important in recruitment success. Collectively, my dissertation shows that microbes influence kelp forest ecosystem dynamics and must be incorporated into future population and community models for a more holistic description of the ecosystem.