Marine protists are defined by their habitat as protists that live in marine environments, that is, in the saltwater of seas or oceans or the brackish water of coastal estuaries. Life originated as single-celled prokaryotes (bacteria and archaea) and later evolved into more complex eukaryotes .
- Foundations of Productive Ecosystems
- Reproduction and Host Development
- Biofouling and Microbial Community Assembly
- Biogeochemical Cycling
- Marine Holobionts
- Further References
Within the vast biological diversity that inhabits the world’s oceans, it would be challenging to find a eukaryotic organism that does not live in close relationship with a microbial partner. Such symbioses, i.e., persistent interactions between host and microbe in which none of the partners gets harmed and at least one of them benefits, are ubiquitous from shallow reefs to deep-sea hydrothermal vents. Studies on corals, sponges, and mollusks have revealed some of the profoundly important symbiotic roles microbes play in the lives of their hosts. These studies, however, have tended to focus on a small number of specific microbial taxa. In contrast, most hosts retain groups of many hundreds of different microbes (i.e., a microbiome, which themselves can vary throughout the ontogeny of the host and as a result of environmental perturbations.Rather than host-associated microbes functioning independently, complex multi-assemblage microbiomes have major impact on the fitness and function...
Ecosystem engineers, such as many types of corals, deep-sea mussels, and hydrothermal vent tubeworms, contribute to primary productivity and create the structural habitats and nutrient resources that are the foundation of their respective ecosystems. All of these taxa engage in mutualistic nutritional symbioses with microbes. There are many examples of marine nutritional mutualisms in which microbes enable hosts to utilize resources or substrates otherwise unavailable to the host alone. Such symbioses have been described in detail in reduced and anoxic sediments (e.g., lucinid clams, stilbonematid nematodes, and gutless oligochaetes) and hydrothermal vents (e.g., the giant tube worm or deep-sea mussels). Moreover, many foundational species of marine macroalgae are vitamin auxotrophs (for example, half of more than 300 surveyed species were unable to synthesize cobalamin), and their productivity depends on provisioning from their epiphytic bacteria. Reefs often consist of stony coral...
Extending beyond nutritional symbioses, microbial symbionts can alter the reproduction, development, and growth of their hosts. Specific bacterial strains in marine biofilms often directly control the recruitment of planktonic larvae and propagules, either by inhibiting settlement or by serving as a settlement cue. For example, the settlement of zoospores from the green alga Ulva intestinalis onto the biofilms of specific bacteria is mediated by their attraction to the quorum-sensing molecule, acyl-homoserine lactone, secreted by the bacteria. Classic examples of marine host–microbe developmental dependence include the observation that algal cultures grown in isolation exhibited abnormal morphologies and the subsequent discovery of morphogenesis-inducing compounds, such as thallusin, secreted by epiphytic bacterial symbionts. Bacteria are also known to influence the growth of marine plants, macroalgae, and phytoplankton by secreting phytohormones such as indole acetic acid and cytok...
Some host-associated microbes produce compounds that prevent biofouling and regulate microbiome assembly and maintenance in many marine organisms, including sponges, macroalgae, and corals. For example, tropical corals harbor diverse bacteria in their surface mucus layer that produce quorum-sensing inhibitors and other antibacterial compounds as a defense against colonization and infection by potential microbial pathogens. Epiphytic bacteria of marine macroalgae excrete a diverse chemical arsenal capable of selectively shaping further bacterial colonization and deterring the settlement of biofouling marine invertebrates such as bryozoans. As in corals, these diverse, microbially secreted compounds include not only bactericidal and bacteriostatic antibiotics but also compounds like halogenated furanones, cyclic dipeptides, and acyl-homoserine lactone mimics that disrupt bacterial quorum sensing and inhibit biofilm formation. The bacteria likely are able to utilize the carbon-rich exu...
Host-associated microbiomes also influence biogeochemical cycling within ecosystems with cascading effects on biodiversity and ecosystem processes. For example, microbial symbionts comprise up to 40% of the biomass of their sponge hosts. Through a process termed the “sponge-loop,” they convert dissolved organic carbon released by reef organisms into particulate organic carbon that can be consumed by heterotrophic organisms. Along with the coral–Symbiodiniaceae mutualism, this sponge-bacterial symbiosis helps explain Darwin’s paradox, i.e., how highly productive coral reef ecosystems exist within otherwise oligotrophic tropical seas. Some sponge symbionts play a significant role in the marine phosphorus cycle by sequestering nutrients in the form of polyphosphate granules in the tissue of their host and nitrogen cycling, e.g., through nitrification, denitrification, and ammonia oxidation.]. Many macroalgal-associated bacteria are specifically adapted to degrade complex algal polysacc...
The microbiomes of diverse marine animals are currently under study, from simplistic organisms including sponges and ctenophores to more complex organisms such as sea squirtsand sharks. The relationship between the Hawaiian bobtail squid and the bioluminescent bacterium Aliivibrio fischeriis one of the best studied symbiotic relationships in the sea and is a choice system for general symbiosis research. This relationship has provided insight into fundamental processes in animal-microbial symbioses, and especially biochemical interactions and signaling between the host and bacterium. The gutless marine oligochaete worm Olavius algarvensis is another relatively well-studied marine host to microbes. These three centimetre long worms reside within shallow marine sediments of the Mediterranean Sea. The worms do not contain a mouth or a digestive or excretory system, but are instead nourished with the help of a suite of extracellular bacterial endosymbionts that reside upon coordinated us...
Reef-building corals are holobionts that include the coral itself (a eukaryotic invertebrate within class Anthozoa), photosynthetic dinoflagellates called zooxanthellae (Symbiodinium), and associated bacteria and viruses.Co-evolutionary patterns exist for coral microbial communities and coral phylogeny. 1. Coral holobiont 2. Seagrass holobiont 3. Sponge holobiont 4. Climate change and the rhodolith holobiont
Stal, L. J. and Cretoiu, M. S. (Eds.) (2016) The marine microbiome: an untapped source of biodiversity and biotechnological potential Springer. ISBN 9783319330006.
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Marine microorganisms are defined by their habitat as microorganisms living in a marine environment, that is, in the saltwater of a sea or ocean or the brackish water of a coastal estuary. A microorganism (or microbe ) is any microscopic living organism or virus , that is too small to see with the unaided human eye without magnification.
Marine protists are defined by their habitat as protists that live in marine environments, that is, in the saltwater of seas or oceans or the brackish water of coastal estuaries. Protists are eukaryotes that cannot be classified as plants, fungi or animals. They are usually single-celled and microscopic. Life originated as single-celled prokaryotes (bacteria and archaea) and later evolved into ...
- Marine Primary Producers
- Biological Pigments
- Marine Algae
- Marine Plants
- See Also
- Further Reading
Primary producers are the autotroph organisms that make their own food instead of eating other organisms. This means primary producers become the starting point in the food chain for heterotroph organisms that do eat other organisms. Some marine primary producers are specialised bacteria and archaea which are chemotrophs, making their own food by gathering around hydrothermal vents and cold seeps and using chemosynthesis. However most marine primary production comes from organisms which use photosynthesis on the carbon dioxide dissolved in the water. This process uses energy from sunlight to convert water and carbon dioxide:186–187 into sugars that can be used both as a source of chemical energy and of organic molecules that are used in the structural components of cells.:1242 Marine primary producers are important because they underpin almost all marine animal life by generating most of the oxygenand food that provide other organisms with the chemical energy they need to exist. The...
Cyanobacteria are a phylum (division) of bacteria, ranging from unicellular to filamentous and including colonial species, which fix inorganic carbon into organic carbon compounds. They are found almost everywhere on earth: in damp soil, in both freshwater and marine environments, and even on Antarctic rocks. In particular, some species occur as drifting cells floating in the ocean, and as such were amongst the first of the phytoplankton. These bacteria function like algae in that they can process nitrogen from the atmosphere when none is in the ocean. The first primary producers that used photosynthesis were oceanic cyanobacteria about 2.3 billion years ago. The release of molecular oxygen by cyanobacteria as a by-product of photosynthesis induced global changes in the Earth's environment. Because oxygen was toxic to most life on Earth at the time, this led to the near-extinction of oxygen-intolerant organisms, a dramatic changewhich redirected the evolution of the major animal and...
Biological pigments are any coloured material in plant or animal cells. All biological pigments selectively absorb certain wavelengths of light while reflecting others. The primary function of pigments in plants is photosynthesis, which uses the green pigment chlorophyll and several colorful pigments that absorb as much light energy as possible. Chlorophyll is the primary pigment in plants; it is a chlorin that absorbs yellow and blue wavelengths of light while reflecting green. It is the presence and relative abundance of chlorophyll that gives plants their green color. Green algae and plants possess two forms of this pigment: chlorophyll a and chlorophyll b. Kelps, diatoms, and other photosynthetic heterokonts contain chlorophyll c instead of b, while red algae possess only chlorophyll a. All chlorophylls serve as the primary means plants use to intercept light in order to fuel photosynthesis.
Algae is an informal term for a widespread and diverse collection of photosynthetic eukaryotic organisms which are not necessarily closely related and are thus polyphyletic. Unlike higher plants, algae lack roots, stems, or leaves.
Back in the Silurian, some phytoplankton evolved into red, brown and green algae. These algae then invaded the land and started evolving into the land plants we know today. Later, in the Cretaceous, some of these land plants returned to the sea as mangroves and seagrasses. Plant life can flourish in the brackish waters of estuaries, where mangroves or cordgrass or beach grass might grow. Flowering plants grow in sandy shallows in the form of seagrass meadows, mangroves line the coast in tropical and subtropical regions and salt-tolerant plants thrive in regularly inundated salt marshes. All of these habitats are able to sequester large quantities of carbon and support a biodiverse range of larger and smaller animal life. Marine plants can be found in intertidal zones and shallow waters, such as seagrasses like eelgrass and turtle grass, Thalassia. These plants have adapted to the high salinity of the ocean environment. Light is only able to penetrate the top 200 metres (660 ft) so t...Falkowski, Paul (Ed.) (2013) Primary Productivity in the Sea Springer. ISBN 9781468438901.Falkowski, Paul and Raven, John A. (2013) Aquatic Photosynthesis Second edition revised, Princeton University Press. ISBN 9781400849727.Falkowski P and Knoll AH (2011) Evolution of Primary Producers in the Sea Academic Press. ISBN 9780080550510.Kirk, John T. O. (2010) Light and Photosynthesis in Aquatic Ecosystems Third edition revised, Cambridge University Press. ISBN 9781139493918.
Marine microorganisms are defined by their habitat as the microorganisms living in a marine environment, that is, in the saltwater of a sea or ocean or the brackish water of a coastal estuary. A microorganism (or microbe) is any microscopic living organism, that is, any life form too small for the naked human eye to see, needing a microscope. Microorganisms are very diverse. They can be single ...
Thomas Cavalier-Smith 2010, 2013, 2014, 2017 and 2018 places the eukaryotic tree's root between Excavata (with ventral feeding groove supported by a microtubular root) and the grooveless Euglenozoa, and monophyletic Chromista, correlated to a single endosymbiotic event of capturing a red-algae.
Dec 12, 2020 · Microbial symbiosis in marine animals was not discovered until 1981. In the time following, symbiotic relationships between marine invertebrates and chemoautotrophic bacteria have been found in a variety of ecosystems, ranging from shallow coastal waters to deep-sea hydrothermal vents.
Marine protists. By 2015, about 40 viruses affecting marine protists had been isolated and examined, most of them viruses of microalgae.  The genomes of these marine protist viruses are highly diverse.   Marine algae can be infected by viruses in the family Phycodnaviridae.