Coral larval settlement and post-settlement survival facilitated by crustose coralline algae with or without living tissue

AbstractSelection of a permanent attachment site of coral larvae can be a critical determinant of recruitment success affecting the structure of coral communities and underpins the ability of coral reef ecosystems to recover from disturbance. Settlement specificity of a threatened coral in Sanya reefs, Acropora millepora, was tested by measuring the larval metamorphosis preferences and post-settlement survival in response to crustose coralline algae (CCA) species Hydrolithon reinboldii and other substrata. In the no-choice experiments, the larvae of A. millepora had similar rates of total metamorphosis with the presence of CCA regardless of the algae tissue being alive or not, and settlement success induced by CCA was higher than by other substrata (tile or glass). In the paired-choice experiments, when CCA was in presence, the coral larvae preferred the surface of the dish and the side of living CCA. In the absence of CCA, total larvae metamorphosis was lower than in the treatments where CCA was present. New recruits of A. millepora had approximately 68% mean survival on all the settlement substrata after 2 weeks maintained in aquaria with flow-through seawater similar to the coral larval sampling site, but with no coral spat survival in the treatments where CCA was absent. However, there were statistical differences between the larvae survival of dead CCA and glass chips treatment and the others where CCA was present. Our results were consistent with the conclusion that some CCA species could facilitate coral larval settlement and post-settlement survivorship, highlighting the importance of substrata selection success for facilitating coral recruitment in the threatened coral reefs.

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Community assessment of crustose calcifying red algae as coral recruitment substrates

10.1101/2021.09.27.461929 ◽

2021 ◽

Author(s):

Mari E. Deinhart ◽

Matthew S. Mills ◽

Tom Schils

Keyword(s):

Dna Sequences ◽

Red Algae ◽

Taxonomic Diversity ◽

Coralline Algae ◽

Crustose Coralline Algae ◽

Coral Recruitment ◽

Successful Recruitment ◽

Ecological Roles ◽

Coral Reef Ecosystems ◽

Species Specific

AbstractSuccessful recruitment of invertebrate larvae to reef substrates is essential to the health of tropical coral reef ecosystems and their capacity to recover from disturbances. Crustose calcifying red algae (CCRA) have been identified as important recruitment substrates for scleractinian corals. As such, CCRA as a whole or subgroups (e.g., crustose coralline algae, CCA) are often used at the functional group level in experimental, ecological, and monitoring studies. Species of CCRA, however, differ in their ecological roles and their value as coral recruitment substrates. Here, we (1) investigate the species richness and community composition of CCRA on experimental coral recruitment tiles, and (2) assess if there is a recruitment preference of the coral Acropora surculosa for any of these CCRA species. 27 species of two orders of CCRA (Corallinales and Peyssonneliales) were identified from the recruit tiles. None of the DNA sequences of these species matched released sequences in GenBank or sequences of CCRA collected from natural reef systems in Guam. The similarity in CCRA communities between the recruitment tiles was high. Two species of CCRA were significantly preferred as recruitment substrates over the other CCRA species. Both of these species belonged to the subfamily of the Lithophylloideae. These two species are closely related to Pacific species that have been referred to as Titanoderma -but probably have to be assigned to another genus- and many of the latter have been attributed to be preferred coral recruitment substrates. Of all CCRA, Lithophylloideae sp. 1 had the highest benthic cover on the recruitment tiles and was the most preferred recruitment substrate. These findings highlight the high taxonomic diversity of CCRA communities and provide insight into species-specific ecological roles of CCRA that are often overlooked.

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Bacterial Communities Associated With Healthy and Bleached Crustose Coralline Alga Porolithon onkodes

Frontiers in Microbiology ◽

10.3389/fmicb.2021.646143 ◽

2021 ◽

Vol 12 ◽

Author(s):

Fangfang Yang ◽

Zhiliang Xiao ◽

Zhangliang Wei ◽

Lijuan Long

Keyword(s):

Community Structure ◽

Bacterial Community ◽

Bacterial Communities ◽

Larval Settlement ◽

Crustose Coralline Alga ◽

Coralline Algae ◽

Pocillopora Damicornis ◽

Crustose Coralline Algae ◽

Settlement And Metamorphosis ◽

Relative Abundances

Crustose coralline algae (CCA) play vital roles in producing and stabilizing reef structures and inducing the settlement and metamorphosis of invertebrate larvae in coral reef ecosystems. However, little is known about the bacterial communities associated with healthy and bleached CCA and their interactions with coral larval settlement. We collected samples of healthy, middle semi-bleached, and bleached CCA Porolithon onkodes from Sanya Bay in the South China Sea and investigated their influences on the larval settlement and metamorphosis of the reef-building coral Pocillopora damicornis. The larval settlement/metamorphosis rates all exceeded 70% when exposed to healthy, middle semi-bleached, and bleached algae. Furthermore, the compositions of bacterial community using amplicon pyrosequencing of the V3–V4 region of 16S rRNA were investigated. There were no obvious changes in bacterial community structure among healthy, middle semi-bleached, and bleached algae. Alphaproteobacteria, Bacteroidetes, and Gammaproteobacteria were dominant in all samples, which may contribute to coral larval settlement. However, the relative abundances of several bacterial communities varied among groups. The relative abundances of Mesoflavibacter, Ruegeria, Nautella, and Alteromonas in bleached samples were more than double those in the healthy samples, whereas Fodinicurvata and unclassified Rhodobacteraceae were significantly lower in the bleached samples. Additionally, others at the genus level increased significantly from 8.5% in the healthy samples to 22.93% in the bleached samples, which may be related to algal bleaching. These results revealed that the microbial community structure associated with P. onkodes generally displayed a degree of stability. Furthermore, bleached alga was still able to induce larval settlement and metamorphosis.

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Coral larvae change their settlement preference for crustose coralline algae dependent on availability of bare space

Coral Reefs ◽

10.1007/s00338-018-1665-2 ◽

2018 ◽

Vol 37 (2) ◽

pp. 397-407 ◽

Cited By ~ 7

Author(s):

Franziska Elmer ◽

James J. Bell ◽

Jonathan P. A. Gardner

Keyword(s):

Coralline Algae ◽

Crustose Coralline Algae ◽

Coral Larvae

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Coral larvae for restoration and research: a large-scale method for rearing Acropora millepora larvae, inducing settlement, and establishing symbiosis

PeerJ ◽

10.7717/peerj.3732 ◽

2017 ◽

Vol 5 ◽

pp. e3732 ◽

Cited By ~ 28

Author(s):

F. Joseph Pollock ◽

Sefano M. Katz ◽

Jeroen A.J.M. van de Water ◽

Sarah W. Davies ◽

Margaux Hein ◽

...

Keyword(s):

Large Scale ◽

Larval Settlement ◽

Larval Survival ◽

Coralline Algae ◽

Larval Rearing ◽

Crustose Coralline Algae ◽

Minimal Impact ◽

Acropora Millepora ◽

Wide Range ◽

Order Of Magnitude

Here we describe an efficient and effective technique for rearing sexually-derived coral propagules from spawning through larval settlement and symbiont uptake with minimal impact on natural coral populations. We sought to maximize larval survival while minimizing expense and daily husbandry maintenance by experimentally determining optimized conditions and protocols for gamete fertilization, larval cultivation, induction of larval settlement by crustose coralline algae, and inoculation of newly settled juveniles with their dinoflagellate symbiont Symbiodinium. Larval rearing densities at or below 0.2 larvae mL−1 were found to maximize larval survival and settlement success in culture tanks while minimizing maintenance effort. Induction of larval settlement via the addition of a ground mixture of diverse crustose coralline algae (CCA) is recommended, given the challenging nature of in situ CCA identification and our finding that non settlement-inducing CCA assemblages do not inhibit larval settlement if suitable assemblages are present. Although order of magnitude differences in infectivity were found between common Great Barrier Reef Symbiodinium clades C and D, no significant differences in Symbiodinium uptake were observed between laboratory-cultured and wild-harvested symbionts in each case. The technique presented here for Acropora millepora can be adapted for research and restoration efforts in a wide range of broadcast spawning coral species.

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Recruitment of the limpet Patella ulyssiponensis and its relationship with crustose coralline algae: patterns of juvenile distribution and larval settlement – CORRIGENDUM

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315420000089 ◽

2020 ◽

Vol 100 (2) ◽

pp. 329-329

Author(s):

M. I. Seabra ◽

T. Cruz ◽

J. N. Fernandes ◽

T. Silva ◽

S. J. Hawkins

Keyword(s):

Larval Settlement ◽

Coralline Algae ◽

Crustose Coralline Algae ◽

Patella Ulyssiponensis

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Low recruitment due to altered settlement substrata as primary constraint for coral communities under ocean acidification

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2017.1536 ◽

2017 ◽

Vol 284 (1862) ◽

pp. 20171536 ◽

Cited By ~ 21

Author(s):

Katharina E. Fabricius ◽

Sam H. C. Noonan ◽

David Abrego ◽

Lindsay Harrington ◽

Glenn De'ath

Keyword(s):

Coral Reefs ◽

Ocean Acidification ◽

Field Experiments ◽

Later Life ◽

Coralline Algae ◽

Life Stages ◽

Crustose Coralline Algae ◽

Coral Recruitment ◽

Recovery Potential ◽

Coral Communities

The future of coral reefs under increasing CO 2 depends on their capacity to recover from disturbances. To predict the recovery potential of coral communities that are fully acclimatized to elevated CO 2 , we compared the relative success of coral recruitment and later life stages at two volcanic CO 2 seeps and adjacent control sites in Papua New Guinea. Our field experiments showed that the effects of ocean acidification (OA) on coral recruitment rates were up to an order of magnitude greater than the effects on the survival and growth of established corals. Settlement rates, recruit and juvenile densities were best predicted by the presence of crustose coralline algae, as opposed to the direct effects of seawater CO 2 . Offspring from high CO 2 acclimatized parents had similarly impaired settlement rates as offspring from control parents. For most coral taxa, field data showed no evidence of cumulative and compounding detrimental effects of high CO 2 on successive life stages, and three taxa showed improved adult performance at high CO 2 that compensated for their low recruitment rates. Our data suggest that severely declining capacity for reefs to recover, due to altered settlement substrata and reduced coral recruitment, is likely to become a dominant mechanism of how OA will alter coral reefs.

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Recruitment of the limpet Patella ulyssiponensis and its relationship with crustose coralline algae: patterns of juvenile distribution and larval settlement

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315419000869 ◽

2019 ◽

Vol 99 (8) ◽

pp. 1787-1796 ◽

Cited By ~ 2

Author(s):

M. I. Seabra ◽

T. Cruz ◽

J. N. Fernandes ◽

T. Silva ◽

S. J. Hawkins

Keyword(s):

Intertidal Zone ◽

Larval Settlement ◽

Coralline Algae ◽

Rock Pools ◽

Crustose Coralline Algae ◽

Bare Rock ◽

Naturally Occurring ◽

Patella Ulyssiponensis ◽

Maximum Shell Length ◽

Sw Portugal

AbstractRecruitment of the limpet Patella ulyssiponensis was investigated in relation to the presence of living crustose coralline algae (CCA) in rocky-shore habitats. Juvenile limpets (≤10 mm maximum shell length) were counted in CCA-present and CCA-absent habitats, on three shores in SW Portugal during summer 2007 and winter 2009. Furthermore, the settling response of laboratory-reared larvae of P. ulyssiponensis to CCA-covered substratum, and bare-rock, was examined. Across the intertidal zone, we found a clear association between the distribution and abundance of juveniles and the presence of CCA. Although the presence of CCA was not an absolute requisite for juvenile occurrence, null juvenile densities were mostly recorded in CCA-absent areas. The highest juvenile densities (maximum of 64 individuals in 15 × 15 cm) were consistently found in CCA-dominated habitats, namely steep wave-exposed areas at low-shore and rock-pools. The hypothesis of CCA-enhanced settlement was not supported, as settlement intensities of laboratory-reared larvae were similar between chips of rock encrusted by CCA and chips of bare-rock. From the overall number of settlers onto CCA-encrusted rock chips, 51% were found in tiny pits lacking CCA. This was the first study of the settlement patterns of larvae of the genus Patella using naturally occurring rocky substrata. These results are preliminary and should be confirmed with choice-experiments and improved monitoring of the position of settlers. We suggest that CCA plays a role in the recruitment of P. ulyssiponensis, potentially promoting survivorship of early benthic stages, but possibly not enhancing settlement.

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Larval culture and settlement of the intertidal gastropod Siphonaria australis

10.26686/wgtn.17019188.v1 ◽

2021 ◽

Author(s):

◽

Stephanie Marinus

Keyword(s):

Current Knowledge ◽

Larval Settlement ◽

Larval Growth ◽

Coralline Algae ◽

Crustose Coralline Algae ◽

High Concentration ◽

Laboratory Rearing ◽

Growth And Survival ◽

Laboratory Conditions ◽

Newly Hatched Larvae

<p>Laboratory rearing studies on the larvae of benthic marine invertebrates are important in providing information on the development of marine species, particularly those with complex life history cycles. Intertidal gastropods of the genus Siphonaria have been well studied in aspects of their physiology, behaviour, ecology, and reproduction. However, to our current knowledge, there are no cases on the successful laboratory rearing, from hatching through to metamorphosis, of larvae within this genus. Siphonariids are a primitive family of basommatophoran limpets in which the majority produce encapsulated embryos that hatch into feeding, planktonic veliger larvae. For such larvae, the quality and quantity of phytoplankton food can strongly affect larval growth, survival, and the ability to settle and metamorphose successfully. The primary aim of this study was to identify the optimal algal feeding diet for culturing the larvae of Siphonaria australis to competence in laboratory conditions, with a focus on algal composition and quantity. Once having defined the preferred feeding conditions, a secondary aim was to successfully culture larvae through to metamorphosis, by identifying the required settlement cue(s). First, I exposed newly hatched larvae to diets of three different algal compositions (all at a high concentration of 20,000 cells/mL): two unialgal diets of Isochrysis galbana and Pavlova lutheri, and a mixed diet consisting of a 1:1 ratio of both species. The results revealed that, although they grew in all diets, S. australis larvae exhibited highest growth and survival when fed the unialgal I.galbana diet. In a second experiment, I exposed newly hatched larvae to three different food concentrations of the unialgal I. galbana diet; low (1,000 cells/mL), medium (10,000 cells/mL) and high (20,000 cells/mL). Larval growth and survival were highest when fed a high food concentration, with development and survival severely reduced in low food treatments. At the end of this experiment it was discovered that once larvae grew to ~350µm in length, at an age of approximately one month post-hatching, they began to demonstrate signs of competence and growth rates plateaued. Finally, I exposed newly hatched larvae to optimum feeding conditions in an attempt to achieve larval settlement using different potential cues. Once larvae began to show signs of competence, they were exposed to five settlement cues: (1) live adults in filtered seawater (FSW), (2) adult-conditioned FSW, (3) rocks in adult-conditioned FSW, (4) rocks in regular FSW, and (5) crustose coralline algae-covered rocks in FSW. Larvae only successfully metamorphosed (i.e. exhibited loss of the larval velum) in treatments containing live adults. In total, my results provide a successful method in culturing Siphonaria australis larvae in laboratory conditions, as well as determines the cue required to induce settlement and metamorphosis. Not only can this method aid in providing more information on the development of this species, but it may also be applied to other members in this genus as well, and further our knowledge on the overall biology of Siphonariid limpets.</p>

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Symbiodinium identity alters the temperature-dependent settlement behaviour of Acropora millepora coral larvae before the onset of symbiosis

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2014.2260 ◽

2015 ◽

Vol 282 (1801) ◽

pp. 20142260 ◽

Cited By ~ 9

Author(s):

Natalia S. Winkler ◽

John M. Pandolfi ◽

Eugenia M. Sampayo

Keyword(s):

Marine Species ◽

Habitat Choice ◽

Larval Survival ◽

Temperature Treatment ◽

Coralline Algae ◽

Crustose Coralline Algae ◽

Coral Larvae ◽

Acropora Millepora ◽

Larval Stages ◽

Settlement Behaviour

The global distribution of marine species, many of which disperse during the larval stages, is influenced by ocean temperature regimes. Here, we test how temperature and the coral symbionts ( Symbiodinium ) affect survival, symbiont uptake, settlement success and habitat choice of Acropora millepora larvae. Experiments were conducted at Heron Island (Australia), where larvae were exposed to 22.5, 24.5, 26.5 and 28.5°C. Within each temperature treatment, larvae were offered symbionts with distinct characteristics: (i) homologous Symbiodinium type C3, (ii) regionally homologous thermo-tolerant type D1, and (iii) heterologous thermo-tolerant type C15, as well as controls of (iv) un-filtered and (v) filtered seawater. Results show that lower instead of higher temperatures adversely affected recruitment by reducing larval survival and settlement. Low temperatures also reduced recruit habitat choice and initial symbiont densities, both of which impact on post-settlement survival. At lower temperatures, larvae increasingly settle away from preferred vertical surfaces and not on crustose coralline algae (CCA). Surprisingly, substrate preference to CCA was modified by the presence of specific symbiont genotypes that were present ex-hospite (outside the coral larvae). When different symbionts were mixed, the outcomes were non-additive, indicating that symbiont interactions modify the response. We propose that the observed influence of ex-hospite symbionts on settlement behaviour may have evolved through ecological facilitation and the study highlights the importance of biological processes during coral settlement.

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