Anemonefish facilitate bleaching recovery in a host sea anemone

Abstract Ocean warming is causing the symbioses between cnidarians and their algal symbionts to breakdown more frequently, resulting in bleaching. For sea anemones, nutritional benefits derived from hosting anemonefishes increase their algal symbiont density. The sea anemone-anemonefish relationship could, therefore, facilitate bleaching recovery. To test this, bleached and unbleached sea anemones, both with and without anemonefish, were monitored in the laboratory. At the start of our experiment, algal symbiont density and colour score were lower in the bleached than unbleached sea anemones, whereas total chlorophyll remained similar. After 106 days, bleached sea anemones with anemonefish had an algal symbiont density and colour score equal to the controls (unbleached sea anemones and without anemonefish), indicating recovery had occurred. Furthermore, total chlorophyll was 66% higher in the bleached sea anemones with anemonefish than the controls. In contrast, recovery did not occur for the bleached sea anemones without anemonefish as they had 78% fewer algal symbionts than the controls, and colour score remained lower. Unbleached sea anemones with anemonefish also showed positive changes in algal symbiont density and total chlorophyll, which increased by 103% and 264%, respectively. Consequently, anemonefishes give their host sea anemones a distinct ecological advantage by enhancing resilience to bleaching, highlighting the benefits of symbioses in a changing climate.

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Flexibility of nutritional strategies within a mutualism: food availability affects algal symbiont productivity in two congeneric sea anemone species

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2020.1860 ◽

2020 ◽

Vol 287 (1940) ◽

pp. 20201860

Author(s):

Samuel A. Bedgood ◽

Sarah E. Mastroni ◽

Matthew E. S. Bracken

Keyword(s):

Food Availability ◽

Sea Anemone ◽

Symbiotic Association ◽

Sea Anemones ◽

External Resources ◽

Carbon And Nitrogen ◽

Algal Symbionts ◽

Algal Symbiont ◽

Nutritional Strategy ◽

Nutritional Strategies

Mutualistic symbioses are common, especially in nutrient-poor environments where an association between hosts and symbionts can allow the symbiotic partners to persist and collectively out-compete non-symbiotic species. Usually these mutualisms are built on an intimate transfer of energy and nutrients (e.g. carbon and nitrogen) between host and symbiont. However, resource availability is not consistent, and the benefit of the symbiotic association can depend on the availability of resources to mutualists. We manipulated the diets of two temperate sea anemone species in the genus Anthopleura in the field and recorded the responses of sea anemones and algal symbionts in the family Symbiodiniaceae to our treatments. Algal symbiont density, symbiont volume and photosynthetic efficiency of symbionts responded to changes in sea anemone diet, but the responses depended on the species of sea anemone. We suggest that temperate sea anemones and their symbionts can respond to changes in anemone diet, modifying the balance between heterotrophy and autotrophy in the symbiosis. Our data support the hypothesis that symbionts are upregulated or downregulated based on food availability, allowing for a flexible nutritional strategy based on external resources.

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Photo-movement in the sea anemone Aiptasia influenced by light quality and symbiotic association

Coral Reefs ◽

10.1007/s00338-019-01866-w ◽

2019 ◽

Vol 39 (1) ◽

pp. 47-54 ◽

Cited By ~ 1

Author(s):

Shawna A. Foo ◽

Lauren Liddell ◽

Arthur Grossman ◽

Ken Caldeira

Keyword(s):

White Light ◽

Red Light ◽

Normal Animal ◽

Sea Anemone ◽

Symbiotic Association ◽

Phototactic Behavior ◽

Algal Symbionts ◽

Algal Symbiont ◽

The Relationship ◽

Selection Of

Abstract The relationship between cnidarians and their micro-algal symbionts is crucial for normal animal function and the formation of coral reefs. We used the sea anemone Exaiptasia pallida (Aiptasia) as a model cnidarian–dinoflagellate system to determine the effects of white, blue and red light on photo-movement. In white light, phototropism and phototaxis of Aiptasia were dependent on the presence of symbionts; anemones with symbionts bent and moved toward the light, whereas aposymbiotic anemones (lacking algal symbionts) moved, but without strong directionality. Phototaxis and phototropism also occurred in blue light, but to a lesser extent than in white light, with no apparent response to red light. Phototactic behavior was also sensitive to the specific anemone–symbiont pairing. The ability to sense and move in response to light would presumably allow for selection of favorable habitats. Overall, this study demonstrates that the algal symbiont is required for photo-movement of the host and that the extent of movement is influenced by the different anemone–symbiont associations.

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Gametogenesis and the reproductive cycle in the deep-sea anemone Paracalliactis stephensoni (Cnidaria: Actiniaria)

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400034287 ◽

1990 ◽

Vol 70 (1) ◽

pp. 163-172 ◽

Cited By ~ 13

Author(s):

Michel Praet-Van

Keyword(s):

Organic Matter ◽

Shallow Water ◽

Deep Sea ◽

Phytoplankton Bloom ◽

Sea Anemone ◽

Bay Of Biscay ◽

Sea Anemones ◽

Spring Phytoplankton Bloom ◽

Sea Floor ◽

Ultrastructural Investigation

This ultrastructural investigation of gametogenesis in a deep-sea anemone of the Bay of Biscay trawled around 2000 m depth, contributes to the knowledge of biology and strategy of reproduction of deep-sea benthos.This sea anemone is dioecious. The sperm appears very similar to those of shallow water sea anemones of the genus, Calliactis. The ultrastructural investigation of oogenesis allows the characteristics of the stages of previtellogenesis and vitellogenesis to be defined. The latter begins with a period of lipogenesis correlated with the formation of a trophonema. Mature oocytes measure up to 180 (im in diameter. Study of spermatogenesis and oogenesis reveals that spawning occurs in April/May. In males, the main area of testicular cysts, full of sperm, reaches maximal development from March to May and, in females, the percentage of mature oocytes decreases from 33% in April to 1% in May.Spawning may be induced by the advent in the deep-sea of the products of the spring phytoplankton bloom. This period of spawning, during the increased deposition of organic matter to the deep-sea floor, may be an advantageous strategy for early development of Paracalliactis.

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Differential protein profiles reflect the different lifestyles of symbiotic and aposymbiotic Anthopleura elegantissima, a sea anemone from temperate waters

Journal of Experimental Biology ◽

10.1242/jeb.199.4.883 ◽

1996 ◽

Vol 199 (4) ◽

pp. 883-892

Author(s):

V M Weis ◽

R P Levine

Keyword(s):

Steady State ◽

Regulation Of Gene Expression ◽

Sea Anemone ◽

Protein Profiles ◽

Post Translational Modification ◽

Two Dimensional Gel Electrophoresis ◽

Differential Protein ◽

Algal Symbionts ◽

Anthopleura Elegantissima ◽

Endodermal Cells

Mutualistic associations are prevalent in virtually all environments yet relatively little is known about their complex biochemical and molecular integration and regulation. The endosymbiosis between cnidarians such as the sea anemone Anthopleura elegantissima and the photosynthetic dinoflagellate Symbiodinium californium, in which the algal symbionts are housed in vacuoles within animal endodermal cells, is an ideal model for the study of highly integrated associations at the biochemical and molecular levels. This study describes differential protein synthesis between symbiotic A. elegantissima, collected from environments with high levels of light in the intertidal zone and A. elegantissima that naturally lack symbionts (aposymbiotic), collected from nearby deep-shade habitats. Two-dimensional gel electrophoresis profiles of both steady-state and newly synthesized proteins were compared between the two types of animals using scanning densitometry and image analysis. Symbiotic and aposymbiotic animals share a majority of proteins; however, striking differences in several abundant proteins in steady-state profiles occur. Two proteins are unique to symbiotic animals, one at 32 kDa with an isoelectric point (pI) of 7.9 and another at 31 kDa, pI 6.3. Levels of six proteins with an apparent molecular mass of 25 kDa and pI values ranging from 4.8 to 5.5 are greatly enhanced in aposymbiotic animals. Furthermore, profiles of newly synthesized proteins from symbiotic animals contain a unique cluster of proteins ranging from 25 to 30 kDa and pI 6.6 to 6.9. These marked differences in protein profiles must be a reflection either of underlying differences in the regulation of gene expression or in post-translational modification of common proteins. Identifying the symbiosis-specific products present in A. elegantissima and identifying the inter-partner signaling and cues that result in differential expression will provide an insight into the understanding of these highly integrated associations.

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The Behaviour and Neuromuscular System of Gonactinia Prolifera, A Swimming Sea-Anemone

Journal of Experimental Biology ◽

10.1242/jeb.55.3.611 ◽

1971 ◽

Vol 55 (3) ◽

pp. 611-640

Author(s):

ELAINE A. ROBSON

Keyword(s):

Electrical Stimulation ◽

Mechanical Stimulation ◽

Motor Units ◽

Nerve Cells ◽

Sea Anemone ◽

Neuromuscular System ◽

Sea Anemones ◽

Nerve Net ◽

Local Contraction ◽

Electric Shocks

1. In Gonactinia well-developed ectodermal muscle and nerve-net extend over the column and crown and play an important part in the anemone's behaviour. 2. Common sequences of behaviour are described. Feeding is a series of reflex contractions of different muscles by means of which plankton is caught and swallowed. Walking, in the form of brief looping steps, differs markedly in that it continues after interruptions. Anemones also swim with rapid tentacle strokes after contact with certain nudibranch molluscs, strong mechanical disturbance or electrical stimulation. 3. Swimming is attributed to temporary excitation of a diffuse ectodermal pacemaker possibly situated in the upper column. 4. From the results of electrical and mechanical stimulation it is concluded that the endodermal neuromuscular system resembles that of other anemones but that the properties of the ectodermal neuromuscular system require a new explanation. The size and spread of responses to electric shocks vary with intensity, latency is variable and there is a tendency to after-discharge. There is precise radial localization, for example touching a tentacle or the column causes it to bend towards or away from the stimulus. 5. A model to explain these and other features includes multipolar nerve cells closely linked to the nerve-net which would act as intermediate motor units, causing local contraction of the ectodermal muscle. This scheme can be applied to other swimming anemones but there is no evidence that it holds for sea anemones generally.

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A new vermiform sea anemone (Anthozoa: Actiniaria) from Argentina: Harenactis argentina sp. nov.

Zootaxa ◽

10.11646/zootaxa.3027.1.2 ◽

2011 ◽

Vol 3027 (1) ◽

pp. 9 ◽

Cited By ~ 3

Author(s):

DANIEL LAURETTA ◽

ESTEFANÍA RODRÍGUEZ ◽

PABLO E. PENCHASZADEH

Keyword(s):

New Species ◽

Southern Hemisphere ◽

First Record ◽

Sea Anemone ◽

Soft Bottom ◽

Sea Anemones ◽

A New Species

During 2007, 2008, and 2010, 23 specimens of an undescribed vermiform sea anemone were collected on Punta Pardelas and Fracaso Beach (Península Valdés, Argentina). The specimens have longitudinal rows of cinclides distally, all mesenteries perfect, tentacles hexamerously arranged without acrospheres, column not divisible into regions, no marginal sphincter and no conchula. We describe these specimens as a new species within the genus Harenactis (family Haloclavidae). Harenactis argentina sp. nov. is the second species of Harenactis; it represents the first record of this genus in the southern hemisphere and the first record of a soft bottom-dwelling sea anemone in the Argentine continental zone. Furthermore, we discuss the familial placement and relationships of the genus Harenactis and other athenarian sea anemones.

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The Influence of Symbiont Diversity on the Functional Biology of a Model Sea Anemone

10.26686/wgtn.17003383.v1 ◽

2021 ◽

Author(s):

◽

Dorota Ewa Starzak

Keyword(s):

Coral Reefs ◽

Host Cell ◽

Metabolic Cost ◽

Global Scale ◽

Sea Anemone ◽

Host Tissue ◽

Sea Anemones ◽

Dominant Type ◽

Symbiodinium Type ◽

Symbiont Type

<p>Cnidarian–dinoflagellate symbioses, particularly those between anthozoans and dinoflagellates of the genus Symbiodinium (commonly referred to as zooxanthellae) are widespread in the marine environment. They are responsible for the formation of coral reefs and are thus of great ecological importance. In recent years there has been an increase in the frequency and severity of episodes of coral bleaching resulting in degradation and mortality of coral reefs on a global scale. In order to gain a deeper understanding of how corals can adapt to changing environmental conditions, the effect that symbiont type has on the persistence and physiology of an association needs to be ascertained. The aim of this research was to determine how different symbiont types affect the nutritional biology and intracellular physiology of the symbiosis when in association with the sea anemone Aiptasia pulchella. The specific objectives of the study were to; (1) determine whether different symbiont types are equally as adept at supporting the energetic demands of the same host; (2) determine if internal pH (pHi) is a reflection of symbiont type and whether the optimal pH for photosynthesis coincides with the host cell pHi; and (3) test the influence of Symbiodinium type on host tissue glycerol and glucose pools. In order to answer these questions, aposymbiotic (i.e. symbiont-free) sea anemones were infected with different Symbiodinium types and the relationship between symbiont type, photosynthetic performance and autotrophic potential was tested. A range of ‘normal’ and novel cnidarian–dinoflagellate symbioses was also used to measure host cell pHi and to determine the optimal pHi of isolated intact symbiosomes (i.e. the vacuoles that house the symbionts), as well as to compare the amounts of free glycerol and glucose (metabolites) present in the host tissues. Different host-symbiont combinations were found to have different photosynthetic and respiratory attributes. Earlier onset of full autotrophy (i.e. when all metabolic carbon demands of the symbiosis were met by photosynthesis) and higher CZAR values (i.e. the contribution of zooxanthellae to animal respiration) were demonstrated by symbioses hosting Symbiodinium B1 both from the original (homologous) and different (heterologous) host. The study showed that Symbiodinium types differ in their pH optima and that the optimal pHi for photosynthesis does not always match the actual measured pHi. Symbiont type was also shown to have an effect on host tissue glycerol and glucose pools, with the associations harbouring the homologous Symbiodinium B1 attaining the highest concentrations of both metabolites. Findings from this study suggest that corals may be able to maintain an association with a range of Symbiodinium types, and hence potentially switch as a consequence of bleaching. The new symbiont type may not be as nutritionally advantageous as the original type however, which could have implications for the growth and survivorship of the coral, unless it is able to supplement its carbon demands heterotrophically. The rapid proliferation of some of the heterologous Symbiodinium types (e.g. Symbiodinium E2) inside the host indicates that, after bleaching, there is potential for fast symbiont establishment. The reduced carbon contribution of these heterologous symbionts may not be a major concern should the coral be able to reinstate the more nutritionally advantageous symbiont as the dominant type during bleaching recovery. Finally, the rapid proliferation demonstrated by the heterologous Symbiodinium types and the associated metabolic cost to the host, could be an indication of the opportunistic nature of some of these types and may indicate a shift towards parasitism. It is imperative to extend this type of work to corals in the field to determine how these associations behave in nature. Also, in order to get a clearer picture of the diversity in symbiosis physiology, a wider range of Symbiodinium types needs to be investigated.</p>

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Phylogenetic relationships among the clownfish-hosting sea anemones

10.1101/560045 ◽

2019 ◽

Author(s):

Benjamin M. Titus ◽

Charlotte Benedict ◽

Robert Laroche ◽

Luciana C. Gusmão ◽

Vanessa Van Deusen ◽

...

Keyword(s):

Phylogenetic Reconstruction ◽

Taxonomic Revision ◽

Sea Anemone ◽

Coral Triangle ◽

Sea Anemones ◽

Ecological Processes ◽

Holistic Understanding ◽

The Family ◽

Genus 2 ◽

Insight Into

AbstractThe clownfish-sea anemone symbiosis has been a model system for understanding fundamental evolutionary and ecological processes. However, our evolutionary understanding of this symbiosis comes entirely from studies of clownfishes. A holistic understanding of a model mutualism requires systematic, biogeographic, and phylogenetic insight into both partners. Here, we conduct the largest phylogenetic analysis of sea anemones (Order Actiniaria) to date, with a focus on expanding the biogeographic and taxonomic sampling of the 10 nominal clownfish-hosting species. Using a combination of mtDNA and nuDNA loci we test 1) the monophyly of each clownfish-hosting family and genus, 2) the current anemone taxonomy that suggests symbioses with clownfishes evolved multiple times within Actiniaria, and 3) whether, like the clownfishes, there is evidence that host anemones have a Coral Triangle biogeographic origin. Our phylogenetic reconstruction demonstrates widespread poly-and para-phyly at the family and genus level, particularly within the family Stichodactylidae and genus Sticodactyla, and suggests that symbioses with clownfishes evolved minimally three times within sea anemones. We further recover evidence for a Tethyan biogeographic origin for some clades. Our data provide the first evidence that clownfish and some sea anemone hosts have different biogeographic origins, and that there may be cryptic species of host anemones. Finally, our findings reflect the need for a major taxonomic revision of the clownfish-hosting sea anemones.

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Identification of microsatellite loci in sea anemones Aulactinia stella and Cribrinopsis albopunctata (family Actiniidae)

F1000Research ◽

10.12688/f1000research.13724.1 ◽

2018 ◽

Vol 7 ◽

pp. 232

Author(s):

Ekaterina S. Bocharova ◽

Alexey A. Sergeev ◽

Aleksandr A. Volkov

Keyword(s):

Population Genetics ◽

Microsatellite Loci ◽

Sea Anemone ◽

Sea Anemones ◽

Polymorphic Loci ◽

Dna Libraries

From the DNA libraries enriched by the repeat motifs (AAAC)6, (AATC)6, (ACAG)6, (ACCT)6, (ACTC)6, ACTG)6, (AAAT)8, (AACT)8, (AAGT)8, (AGAT)8, for two viviparous sea anemones Aulactinia stella and Cribrinopsis albopunctata, 41 primer pairs were developed. These primer pairs resulted in the identification of 41 candidate microsatellite loci in either A. stella or C. albopunctata. Polymorphic loci were identified in both sea anemone species for 13 of the primer pairs and can be applicable for population genetics researches.

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Masquerade, mimicry and crypsis of the polymorphic sea anemone Phyllodiscus semoni and its aggregations in South Sulawesi

Contributions to Zoology ◽

10.1163/18759866-08004003 ◽

2011 ◽

Vol 80 (4) ◽

pp. 251-268 ◽

Cited By ~ 12

Author(s):

Bert W. Hoeksema ◽

Andrea L. Crowther

Keyword(s):

Sea Anemone ◽

Soft Corals ◽

Sea Anemones ◽

Stony Corals ◽

South Sulawesi ◽

Toxicological Studies ◽

The Subject ◽

High Level ◽

Intraspecific Morphological Variation ◽

Spermonde Archipelago

Phyllodiscus semoni is a morphologically variable sea anemone species from the Indo-Pacific with morphotypes ranging from upright and branched to low-lying and rounded. The apparent camouflage strategies of this sea anemone allow it to resemble other species or objects in its environment, such as stony corals, soft corals, seaweeds, or rocky boulders covered by algae, which may help it to avoid recognition by potential predators. Occasionally, it occurs in aggregations that may result from asexual reproduction. A high level of intraspecific morphological variation, including co-occurring aggregations of three different morphotypes, was observed in the Spermonde Archipelago off Makassar, South Sulawesi, Indonesia. The co-occurrence of aggregations with different morphotypes suggests that Phyllodiscus is a highly polymorphic monospecific genus. Sea anemones of this genus are not frequently encountered at other localities and the number of morphotypes seems large. Therefore, it is unlikely that we are dealing with more than one species that are all concentrated in a single area. Phyllodiscus sea anemones are considered dangerous to humans because their nematocysts contain highly toxic venoms that may inflict harmful stings. Therefore they are the subject of recent toxicological studies. The present paper aims to assist in the recognition of these highly variable hazardous animals and to discuss the appearance of their aggregations.

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