The Upside-Down Jellyfish Cassiopea xamachana as an Emerging Model System to Study Cnidarian–Algal Symbiosis

Medina, Mónica; Sharp, Victoria; Ohdera, Aki; Bellantuono, Anthony J.; Dalrymple, Justin; Gamero‐Mora, Edgar; Steinworth, Bailey; Hofmann, D. K.; Martindale, Mark Q.; Morandini, André C.; DeGennaro, Matthew; Fitt, William K.

doi:10.1201/9781003217503-9

Cited by 21 publications

(14 citation statements)

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“…(Arossa et al, 2021), measured depth profiles of O 2 concentrations in non-symbiotic jellyfish like Aurelia appear to have the highest O 2 concentration near the tissue-water interface, with a steady decline towards the center of the bell (Thuesen et al, 2005). In contrast our measurements indicate that the presence of photosynthetic endosymbionts harbored within amoebocytes in the mesoglea (Colley and Trench, 1985; Medina et al, 2021) leads to internal O 2 production and accumulation in deeper tissue layers during photo periods (Kühl et al, 1995; Arossa et al, 2021).…”

Section: Discussioncontrasting

confidence: 70%

“…In contrast our measurements indicate that the presence of photosynthetic endosymbionts harbored within amoebocytes in the mesoglea (Colley and Trench, 1985;Medina et al, 2021) leads to internal O2 production and accumulation in deeper tissue layers during photo periods (Kühl et al, 1995;Arossa et al, 2021).…”

Section: Cassiopea Harbors Its Photosymbionts In a Buffered Chemical ...contrasting

confidence: 76%

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The mesoglea buffers the physico-chemical microenvironment of photosymbionts in the upside-down jellyfishCassiopeasp

Lyndby

Murray

Trampe

et al. 2022

Preprint

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The jellyfish Cassiopea has a conspicuous lifestyle positioning itself upside-down on sediments in shallow waters, exposing its photosynthetic endosymbionts (Symbiodiniaceae) to light. While several studies have shown how the photosymbionts benefit the jellyfish host in terms of nutrition and O2 availability, little is known about the internal physico-chemical microenvironment of Cassiopea during light-dark periods. In this study, we used fiber-optic sensors to investigate how light is modulated at the water-tissue interface of Cassiopea sp., and how light is scattered inside host tissue. We additionally used electrochemical and fiber-optic microsensors to investigate the dynamics of O2 and pH in response to changes in the light availability in intact living specimens of Cassiopea sp. Mapping of photon scalar irradiance revealed a distinct spatial heterogeneity over different anatomical structures of the host, where oral arms and the manubrium had overall higher light availability, while shaded parts underneath the oral arms and the bell had less light available. White host pigmentation, especially in the bell tissue, showed higher light availability relative to similar bell tissue without white pigmentation. Microprofiles of scalar irradiance into white pigmented bell tissue showed intense light scattering and enhanced light penetration, while light was rapidly attenuated over the upper 0.5 mm in tissue with symbionts only. Depth profiles of O2 concentration into bell tissue of intact, active jellyfish showed increasing concentrations deeper into the mesoglea, with no apparent saturation point during light periods. O2 was slowly depleted in the mesoglea in darkness, and O2 concentration remained higher than ambient water in large individuals, even after 50 min in darkness. Light-dark shifts in large medusae showed that the mesoglea slowly turns from a net sink during photoperiods into a net source of O2 during darkness. Contrary, small medusae showed a more dramatic change similar to corals, with immediate responses in O2 buildup/consumption with light-dark shifts. These effects on O2 production/consumption were also reflected in moderate pH fluctuations in the mesoglea. The mesoglea thus buffers O2 and pH dynamics during dark-periods.

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Section: Discussioncontrasting

confidence: 70%

Section: Cassiopea Harbors Its Photosymbionts In a Buffered Chemical ...contrasting

confidence: 76%

The mesoglea buffers the physico-chemical microenvironment of photosymbionts in the upside-down jellyfishCassiopeasp

Lyndby

Murray

Trampe

et al. 2022

Preprint

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“…For increased clarity standard errors are not shown in panel (A,B), but are reflected in the ± SEM shown for integrated values in panel (C). Lyndby et al 10.3389/fevo.2023.1112742 Frontiers in Ecology Evolution 07 frontiersin.org mesoglea (Colley and Trench, 1985;Medina et al, 2021) leads to internal O 2 production and accumulation in deeper tissue layers during photo periods (Kühl et al, 1995;Arossa et al, 2021). The diffusion of O 2 through cnidarian tissue and mesoglea has received little attention.…”

Section: Cassiopea Harbors Its Photosymbionts In a Buffered Chemical ...mentioning

confidence: 99%

The mesoglea buffers the physico-chemical microenvironment of photosymbionts in the upside-down jellyfish Cassiopea sp.

et al. 2023

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IntroductionThe jellyfish Cassiopea has a conspicuous lifestyle, positioning itself upside-down on sediments in shallow waters thereby exposing its photosynthetic endosymbionts (Symbiodiniaceae) to light. Several studies have shown how the photosymbionts benefit the jellyfish host in terms of nutrition and O2 availability, but little is known about the internal physico-chemical microenvironment of Cassiopea during light–dark periods.MethodsHere, we used fiber-optic sensors to investigate how light is modulated at the water-tissue interface of Cassiopea sp. and how light is scattered inside host tissue. We additionally used electrochemical and fiber-optic microsensors to investigate the dynamics of O2 and pH in response to changes in the light availability in intact living specimens of Cassiopea sp.Results and discussionMapping of photon scalar irradiance revealed a distinct spatial heterogeneity over different anatomical structures of the host, where oral arms and the manubrium had overall higher light availability, while shaded parts underneath the oral arms and the bell had less light available. White host pigmentation, especially in the bell tissue, showed higher light availability relative to similar bell tissue without white pigmentation. Microprofiles of scalar irradiance into white pigmented bell tissue showed intense light scattering and enhanced light penetration, while light was rapidly attenuated over the upper 0.5 mm in tissue with symbionts only. Depth profiles of O2 concentration into bell tissue of live jellyfish showed increasing concentration with depth into the mesoglea, with no apparent saturation point during light periods. O2 was slowly depleted in the mesoglea in darkness, and O2 concentration remained higher than ambient water in large (> 6 cm diameter) individuals, even after 50 min in darkness. Light–dark shifts in large medusae showed that the mesoglea slowly turns from a net sink during photoperiods into a net source of O2 during darkness. In contrast, small medusae showed a more dramatic change in O2 concentration, with rapid O2 buildup/consumption in response to light–dark shifts; in a manner similar to corals. These effects on O2 production/consumption were also reflected in moderate pH fluctuations within the mesoglea. The mesoglea thus buffers O2 and pH dynamics during dark-periods.

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“…The so-called up-side-down jellyfish Cassiopea is currently promoted as an important model system for cnidarian photo-symbiosis (Medina et al, 2021;Ohdera et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

“…The so-called up-side-down jellyfish Cassiopea is currently promoted as an important model system for cnidarian photo-symbiosis (Medina et al, 2021; Ohdera et al, 2018). Cassiopea hosts photosynthetic algae belonging to the same dinoflagellate family (Symbiodiniaceae) as symbionts in scleractinian corals (Lampert, 2016).…”

Section: Introductionmentioning

confidence: 99%

Non-invasive investigation of the morphology and optical properties of the upside-down jellyfishCassiopeawith optical coherence tomography

Lyndby

Murthy

Bessette

et al. 2023

Preprint

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The jellyfishCassiopealargely cover their organic carbon demand via photosynthates produced by their microalgal endosymbionts, but how holobiont morphology and optical properties affect the light microclimate and symbiont photosynthesis inCassiopearemain unexplored. Here, we use optical coherence tomography (OCT) to study the morphology of liveCassiopeamedusae at high spatial resolution. We include detailed 3D reconstructions of external micromorphology, and show the spatial distribution of endosymbionts clustered in amoebocytes and white granules in the bell tissue. Furthermore, we use OCT data to extract inherent optical properties from light scattering white granules inCassiopeaand show that white granules enhance local light availability for symbionts in close proximity. Individual granules had a scattering coefficient of μs= 200-300 cm-1, and a scattering anisotropy factor ofg= 0.7, while large tissue regions filled with white granules had a lower μs= 40-100 cm-1, andg= 0.8-0.9. We combined OCT information with an isotopic labelling experiment to investigate the effect of enhanced light availability in whitish tissue regions. Algal symbionts located in whitish tissue exhibited significantly higher carbon fixation as compared to symbionts in anastomosing tissue (i.e., tissue without light scattering white granules). Our findings support previous suggestions that white granules inCassiopeaplay an important role in the host modulation of the light-microenvironment.

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The Upside-Down Jellyfish Cassiopea xamachana as an Emerging Model System to Study Cnidarian–Algal Symbiosis

Cited by 21 publications

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The mesoglea buffers the physico-chemical microenvironment of photosymbionts in the upside-down jellyfishCassiopeasp

The mesoglea buffers the physico-chemical microenvironment of photosymbionts in the upside-down jellyfishCassiopeasp

The mesoglea buffers the physico-chemical microenvironment of photosymbionts in the upside-down jellyfish Cassiopea sp.

Non-invasive investigation of the morphology and optical properties of the upside-down jellyfishCassiopeawith optical coherence tomography

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