scholarly journals Larval culture and settlement of the intertidal gastropod Siphonaria australis

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>

scholarly journals Larval culture and settlement of the intertidal gastropod Siphonaria australis

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>

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

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.

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

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3732 ◽  
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.

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

2019 ◽  
Vol 99 (8) ◽  
pp. 1787-1796 ◽  
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.

scholarly journals Influence of Different Algal Diets on Larval Growth Rates in the Marine Serpulidae Polychaete Worm Spirobranchus kraussii

2019 ◽  
Vol 77 (2) ◽  
pp. 93-98
Author(s):  
Fatemeh Lavajoo
Keyword(s):  
Survival Rate ◽  
Growth Rates ◽  
Larval Growth ◽  
Single Species ◽  
Growth And Survival ◽  
Food Size ◽  
Algal Diets ◽  
Alternative Sources ◽  
Newly Hatched Larvae ◽  
Algal Diet

Abstract Effects of food availability on larval growth and survival of Spirobranchus kraussii were studied by feeding larvae different algal diets. Newly hatched larvae of S. kraussii were fed four different marine microalgae species, singly and in various mixtures. The best growth was observed when fed C. vulgaris, N. oculata as a single species and mixed-algal diet during day 15 after fertilization. Mortality was low for larvae (max. 5%); survival rate more than 95%. These results suggest that S. kraussii larvae have the capacity to feed using alternative sources of energy, and food size and quality can affect their growth and sustainability.

Crustose coralline algae that promote coral larval settlement harbor distinct surface bacterial communities

Coral Reefs ◽  
2020 ◽  
Vol 39 (6) ◽  
pp. 1703-1713
Author(s):  
Nachshon Siboni ◽  
David Abrego ◽  
Eneour Puill-Stephan ◽  
William L. King ◽  
David G. Bourne ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Larval Settlement ◽  
Coralline Algae ◽  
Crustose Coralline Algae

scholarly journals Crustose Coralline Algae and a Cnidarian Neuropeptide Trigger Larval Settlement in Two Coral Reef Sponges

PLoS ONE ◽  
2012 ◽  
Vol 7 (1) ◽  
pp. e30386 ◽  
Author(s):  
Steve Whalan ◽  
Nicole S. Webster ◽  
Andrew P. Negri
Keyword(s):  
Coral Reef ◽  
Larval Settlement ◽  
Coralline Algae ◽  
Crustose Coralline Algae

scholarly journals Early life history of the Caribbean coral Orbicella faveolata (Scleractinia: Merulinidae)

2020 ◽  
Vol 68 (4) ◽  
Author(s):  
Elvira M. Alvarado-Chacón ◽  
Luis A. Gómez-Lemos ◽  
Nireth P. Sierra-Sabalza ◽  
Ana M. Hernández-Chamorro ◽  
Juan P. Lozano-Peña ◽  
...  
Keyword(s):  
Early Life ◽  
Coral Species ◽  
Larval Settlement ◽  
Scale Up ◽  
Coralline Algae ◽  
Larval Rearing ◽  
Crustose Coralline Algae ◽  
Orbicella Faveolata ◽  
The Caribbean ◽  
Assisted Fertilization

Abstract. Introduction: Rehabilitation of hermatypic coral species that have declined in the Caribbean in recent decades is a priority. Production of sexual recruits is considered the best restoration method to aid affected populations. Objective: To gain knowledge of early life stages of Orbicella faveolata and to enhance production of new sexual recruits. Methods: Gamete bundles from the coral species O. faveolata were collected over three years (2016, 2018, and 2019) from Los Corales del Rosario y de San Bernardo Natural National Park, Cartagena, Colombia. Assisted fertilization, larval rearing, settlement (onto crustose coralline algae, CCA) and post settlement survival in laboratory conditions were monitored. Results: Embryonic and larval development were documented over 55 hours after the first cleavage, when larvae were fully developed and started pre-settlement behavior. Settlement began 7 days after first cleavage and after 37 days polyps had acquired zooxanthellae. Larval settlement was higher on Lythophyllum congestum and Titanoderma prototypum than in response to Porolithon pachydermum, Neogoniolithon sp., Hydrolithon sp., and Lythophyllum sp. Larvae did not settle on dead coral or on the negative control (sterilized seawater). After the first week post settlement survival was 59 % amongst O. faveolata recruits. During the second week, survival dropped to 42 %, and was further reduced to 0 % at the end of the third week. Conclusions: O. faveolata larvae require cues from certain CCA species to settle, they do not settle in absence of CCA. Increased larvae availability is possible through assisted fertilization in the laboratory, however, due to the high mortality in early post-settlement phases, additional research needs to be conducted in order to scale up larvae production and improve understanding of the cues that enhance settlement and the factors which cause post-settlement mortality.

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