Biological BulletinPub Date : 2024-08-01Epub Date: 2025-08-18DOI: 10.1086/736931
Karina Brocco French, Michelle J Herrera, Donovan P German
{"title":"Sea Urchin Larvae (<i>Strongylocentrotus purpuratus</i>) Select and Maintain a Unique Microbiome Compared to Environmental Sources.","authors":"Karina Brocco French, Michelle J Herrera, Donovan P German","doi":"10.1086/736931","DOIUrl":"https://doi.org/10.1086/736931","url":null,"abstract":"<p><p>AbstractMany organisms may rely on microbes that seed the host body and are typically maintained as a consortial symbiosis. Marine invertebrates have highly diverse microbiomes and offer many different life history traits across which to explore the members and functions of these symbionts but are largely absent from the holobiont and microbiome literature compared to humans and vertebrates. We tracked the microbiome of <i>Strongylocentrotus purpuratus</i> larvae and examined the role of vertical transmission <i>via</i> gametes and the role of horizontal transmission <i>via</i> diet and seawater for seeding the developing larvae with microbes potentially critical to holobiont health and fitness. We used <i>16S</i> short-read sequencing to track the composition and relative abundances of bacteria associated with diet (microalgae) and with habitat (filtered seawater), as well as with <i>S. purpuratus</i> gametes and larvae under standard lab rearing conditions. The larval microbiome differed across developmental stages and between filtered seawater and algae, and specific bacterial taxa were associated with those differences. In this experiment, developing larvae selected and maintained a unique microbiome compared to their diet and habitat. Eggs were a potentially significant source of vertical transmission during embryonic development (genus <i>Psychromonas</i>), while horizontal transmission <i>via</i> filtered seawater was the main contributor to larval feeding stages, suggesting that filtered seawater is likely the most important source of potential symbionts. Gaining new insights into how marine invertebrate larval microbiomes are seeded and with what taxa is important for endangered-species aquaculture and for ecosystem restoration and management to protect inoculation sources for early-life stage organisms.</p>","PeriodicalId":55376,"journal":{"name":"Biological Bulletin","volume":"247 1","pages":"56-73"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145082528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biological BulletinPub Date : 2024-08-01Epub Date: 2025-07-21DOI: 10.1086/736498
Matthew Clements, Paulina Selvakumaraswamy, Ronan Hill, Maria Byrne
{"title":"Teratogenic Effects of Larval Low-Salinity Experience in Development of the Juvenile Body in <i>Acanthaster</i> sp.","authors":"Matthew Clements, Paulina Selvakumaraswamy, Ronan Hill, Maria Byrne","doi":"10.1086/736498","DOIUrl":"https://doi.org/10.1086/736498","url":null,"abstract":"<p><p>AbstractMetamorphosis appears to be a particularly sensitive stage in marine invertebrate development, with potential carryover effects of larval experience on the postlarval stage. We investigated the impact of salinity exposure history (22‰-34‰) for 2-4 days on the ability of competent crown-of-thorns sea star (<i>Acanthaster</i> sp.; CoTS) brachiolaria larvae to form a normal five-armed juvenile. The decreased salinity levels used were commensurate with levels that these larvae may encounter in their habitat on the Great Barrier Reef (25‰-34‰), and the extreme low level (22‰) was used to assess salinity tolerance. At metamorphosis, low-salinity stress (<34‰) for a few days prior to settlement-as may be experienced by larvae during a runoff pulse-resulted in negative carryover effects, even when the larvae were placed in control salinity during settlement assays. A larval experience of ≤30‰ resulted in smaller juveniles. The low-salinity treatment (22‰) resulted in a large proportion of juveniles deviating from the normal five-armed profile of newly metamorphosed CoTS. Juvenile mortality was high if they were generated from larvae exposed to 22‰ and 25‰ salinity levels. Our findings highlight the importance of ecological developmental biology in understanding potential carryover effects beyond metamorphosis. These insights could help link the exposure of CoTS larvae to terrestrial runoff conditions with juvenile performance and the postmetamorphic processes that influence recruitment into the adult population.</p>","PeriodicalId":55376,"journal":{"name":"Biological Bulletin","volume":"247 1","pages":"1-13"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145082461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biological BulletinPub Date : 2024-08-01Epub Date: 2025-07-28DOI: 10.1086/736843
Jessica R Zehnpfennig, Matthew R Graham, Nichelle M VanTassel, Kenneth M Halanych, Andrew R Mahon
{"title":"I Am Your Father: Investigating the Genetic Mating System in the Antarctic Sea Spider <i>Nymphon australe</i>.","authors":"Jessica R Zehnpfennig, Matthew R Graham, Nichelle M VanTassel, Kenneth M Halanych, Andrew R Mahon","doi":"10.1086/736843","DOIUrl":"https://doi.org/10.1086/736843","url":null,"abstract":"<p><p>AbstractPycnogonids (sea spiders) are benthic invertebrates exhibiting unique reproductive strategies including paternal brood care by the male in many species. To date, the mating systems of brooding Antarctic sea spiders have yet to be investigated <i>via</i> molecular methods, despite their dominance and importance in the Southern Ocean. To better understand how sea spiders reproduce and maintain their natural populations in this region, we employed 3RAD-derived single nucleotide polymorphisms to investigate genetic mating systems of the abundant, and putatively circumpolar, Antarctic sea spider <i>Nymphon australe</i>. By analyzing single nucleotide polymorphisms in genomes of individual larvae taken from offspring-carrying males, we inferred paternal full- and half-sibships and parentage for specimens of <i>N. australe</i> collected from the eastern Antarctic continental shelf. Notably, <i>N. australe</i> exhibits a polygynandrous mating system where both males and females engage in multiple mating events. Male brood partitioning on their ovigerous legs varied, with some males partitioning offspring into clutches by female genotypes and others carrying progeny from multiple female genotypes in a single clutch. However, we found no evidence of cuckoldry, where males inadvertently raise offspring sired by other males, indicating that this species has a high assurance of paternity for the progeny carried by each individual male. These findings provide foundational insights into the genetic mating system of Antarctic sea spiders and contrast with the cuckoldry frequently observed in other male brood care systems. This contrast highlights some of the evolutionary pressures acting on reproductive strategies in polar environments.</p>","PeriodicalId":55376,"journal":{"name":"Biological Bulletin","volume":"247 1","pages":"14-22"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145082458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biological BulletinPub Date : 2024-08-01Epub Date: 2025-08-14DOI: 10.1086/737021
Ana Paula Andrieu, Sandra Marcela Fiori
{"title":"Do Structural Changes in the Macrobenthic Community Drive Differences in the Reproductive Performance of the Pea Crab <i>Austinixa patagoniensis</i>?","authors":"Ana Paula Andrieu, Sandra Marcela Fiori","doi":"10.1086/737021","DOIUrl":"https://doi.org/10.1086/737021","url":null,"abstract":"<p><p>AbstractFecundity and egg size vary among females, depending on environmental conditions experienced by mothers, known as maternal effects. Temperature, salinity, food availability, competition, and predation can influence maternal allocation. We evaluated temporal changes in the reproductive biology of the pea crab <i>Austinixa patagoniensis</i> in the context of local spatial competition with the yellow clam <i>Amarilladesma mactroides</i> mediated by the ghost shrimp <i>Audacallichirus mirim</i>. We assessed physical environmental variables and compared size-dependent reproductive parameters-fecundity and egg volume-between two contrasting periods at Monte Hermoso Beach (38°59' S, 61°19' W): clam-period, characterized by the dominance of <i>A. mactroides</i> in the macrobenthic community, and crab-period, marked by the dominance of <i>A. patagoniensis</i>. Additionally, we calculated reproductive output for crab-period and examined the relationship between brood and female size. Fecundity did not differ between periods, whereas egg volume was greater during clam-period across all female sizes. Since no differences were found in physical environmental variables, larger egg volume was interpreted as increased allocation per offspring, suggesting adaptive allocation to counteract the negative effects of density-dependent exclusion of pea crabs, leading to offspring with greater dispersal potential and/or better ability to survive and perform under adverse conditions. Larger eggs without fecundity cost indicate greater reproductive allocation during clam-period, possibly reducing investment in other life history traits. While no correlation was found between brood and female weight, an isometric relationship was observed between brood weight and female size. Future studies should focus on how maternal effects influence the population dynamics of the species.</p>","PeriodicalId":55376,"journal":{"name":"Biological Bulletin","volume":"247 1","pages":"23-31"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145082506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biological BulletinPub Date : 2024-08-01Epub Date: 2025-08-29DOI: 10.1086/737257
Rebha Raviraj, Sarah Corman Crosby, Marisa Fajardo, Domenic Romanello, Samantha Marlene Rowland, Justin Philip Susarchick
{"title":"Systematic Review of Threats to Horseshoe Crabs and Implications for Conservation of <i>Limulus polyphemus</i> in Long Island Sound, USA.","authors":"Rebha Raviraj, Sarah Corman Crosby, Marisa Fajardo, Domenic Romanello, Samantha Marlene Rowland, Justin Philip Susarchick","doi":"10.1086/737257","DOIUrl":"https://doi.org/10.1086/737257","url":null,"abstract":"<p><p>AbstractHorseshoe crabs (<i>Carcinoscorpius rotundicauda</i>, <i>Limulus polyphemus</i>, <i>Tachypleus gigas</i>, and <i>Tachypleus tridentatus</i>) are experiencing population decline. A systematic review of 326 papers was conducted to assess the state of conservation of these species and provide recommendations for horseshoe crab conservation in Long Island Sound, USA. Major present-day threats to horseshoe crabs include overharvest and bycatch, habitat loss and degradation, climate change, and insufficient management. The declining populations of horseshoe crabs impact shorebirds and marine organisms, contributing to the threats facing endangered species. Protecting and restoring spawning areas and juvenile habitat, adopting alternative sources for use in the fishing and the biomedical industry, exploring captive breeding and head-starting programs, and public education present promising conservation strategies. Urgent action will be necessary to conserve horseshoe crabs and their vital ecological role in Long Island Sound.</p>","PeriodicalId":55376,"journal":{"name":"Biological Bulletin","volume":"247 1","pages":"32-55"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145082551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biological BulletinPub Date : 2024-04-01Epub Date: 2025-05-13DOI: 10.1086/735939
Weam S El Rahmany, Anthony J Fanizza, Victor Ryzhov, Neil W Blackstone
{"title":"The Warburg Effect in a Metazoan Capable of Anaerobic Mitochondrial Metabolism.","authors":"Weam S El Rahmany, Anthony J Fanizza, Victor Ryzhov, Neil W Blackstone","doi":"10.1086/735939","DOIUrl":"https://doi.org/10.1086/735939","url":null,"abstract":"<p><p>AbstractThe Warburg effect-aerobic glycolysis, diminished oxygen uptake, and lactate secretion-has been characterized in proliferative mammalian cells and in some cancers. Lactate formation remains puzzling, variously attributed to reoxidizing NADH or activating the cell cycle. Forming lactate provides the only anaerobic pathway available to mammalian cells but not for most eukaryotes or metazoans. With the purely mitotic polyp stage of a colonial marine hydroid, <i>Eirene</i> sp., differential feeding was used to create rapidly and slowly proliferating colonies of a genetically identical clone. The former were fed to excess three times per week, the latter once per week. Under aerobic conditions, assays using gas chromatography/mass spectrometry show that colonies of both treatments produce short-chain fatty acids, indicating end products of anaerobic mitochondrial metabolism and thus providing an alternative pathway to reoxidize NADH. After 1 h of incubation in fully aerated seawater, the concentration of acetate, propionate, and butyrate was higher in the medium than in the tissue of the colonies, suggesting that these are waste products. Colorimetric assays showed that colonies of both treatments nevertheless produced lactate. Further, the rapidly proliferating colonies produced significantly more. <i>Eirene</i> sp. thus carries out anaerobic mitochondrial metabolism, but this apparently has no effect on lactate production. Since earlier data show that the proliferative colonies exhibit diminished oxygen uptake, anaerobic mitochondrial metabolism appears to have little impact on the Warburg effect. This contrasts with the expectation from the literature that an alternative pathway to reoxidize NADH will abolish lactate production.</p>","PeriodicalId":55376,"journal":{"name":"Biological Bulletin","volume":"246 2-3","pages":"116-123"},"PeriodicalIF":2.1,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144499448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Index to Volume 246, June 2024.","authors":"","doi":"10.1086/736682","DOIUrl":"https://doi.org/10.1086/736682","url":null,"abstract":"","PeriodicalId":55376,"journal":{"name":"Biological Bulletin","volume":"246 2-3","pages":"124-125"},"PeriodicalIF":2.1,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144499443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biological BulletinPub Date : 2024-04-01Epub Date: 2025-06-04DOI: 10.1086/736174
Kharis Schrage, Kirstin S Meyer-Kaiser
{"title":"Larvae in the Dark: Evidence of Diverse and Functionally Active Meroplankton Communities in an Arctic Fjord during the Polar Night.","authors":"Kharis Schrage, Kirstin S Meyer-Kaiser","doi":"10.1086/736174","DOIUrl":"https://doi.org/10.1086/736174","url":null,"abstract":"<p><p>AbstractIn the high Arctic polar night, the sun remains below the horizon for a period ranging from several weeks to 6 months, providing insufficient solar radiation for photosynthesis to support the marine ecosystem. Despite this, recent studies have found evidence of active feeding, growth, and reproduction in multiple marine organisms during this period. Here, we describe the polar night diversity and activity levels of early pelagic life stages of benthic invertebrates (meroplankton), a group that has historically been largely overlooked. We assessed the taxa richness, reproductive and developmental biology, feeding, and competence to settle of meroplanktonic larvae in January 2023 in Kongsfjorden, Svalbard, using plankton tows, experiments, and DNA bar coding. Although meroplankton densities were lower than in other seasons, DNA bar coding allowed us to assess richness, which was much higher than other studies and seasons, with 48 unique taxa belonging to six phyla observed. Most were planktotrophic (feeding) larvae. Using laboratory assays and direct observations, we documented feeding in several of these planktotrophic larvae, including bryozoan cyphonautes, bivalve veligers, and an ophiuroid pluteus. We found numerous embryos, suggesting that several taxa are actively reproducing in the polar night. We observed settlement in two polychaete taxa in the laboratory, as well as metamorphosed echinoderms in our samples, showing competency to settle across phyla. Overall, we show that early life-history stages of a diverse range of benthic invertebrates are actively feeding and developing during the polar night. Further targeted research should focus on the polar night to better understand seasonal patterns in reproduction and development.</p>","PeriodicalId":55376,"journal":{"name":"Biological Bulletin","volume":"246 2-3","pages":"69-86"},"PeriodicalIF":2.1,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144499444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Sex Determination by a Univalent Chromosome in the Rhizocephalan <i>Peltogasterella gracilis</i> (Cirripedia: Rhizocephala: Peltogasterellidae).","authors":"Asami Kajimoto, Ryuzo Yanagimachi, Tohru Takahashi, Yoichi Yusa","doi":"10.1086/734711","DOIUrl":"https://doi.org/10.1086/734711","url":null,"abstract":"<p><p>AbstractKentrogonid rhizocephalans show remarkable sexual dimorphism, with large females and much smaller (=dwarf) males as adults, although males are larger than females from the eggs to the larval stages. The kentrogonid <i>Peltogasterella gracilis</i> shows seasonal variation in sex ratio in that most females produce only male or female offspring, although some mixed-sex broods appear in autumn. Moreover, a link between chromosome number and the single-sex broods has been suggested, wherein females producing only male offspring are considered to have a chromosome number of 2n=30, whereas females producing only female offspring are 2n=31. Thus, there appear to be both genetic and environmental effects on variation in sex ratio. However, the mechanism of sex determination has not been fully studied in <i>P. gracilis</i> or any other rhizocephalans. We examined the number of chromosomes in male (larger) and female (smaller) unfertilized eggs and early-stage embryos of specimens collected in Otaru, Hokkaido, Japan. Chromosome number of unfertilized eggs was n=16 for female eggs and n=15 for male eggs, without exception. Moreover, chromosome number in most (97.4%) female embryos was 2n=31, while that of all male embryos was 2n=30. We suggest that a univalent chromosome of females acts as a sex chromosome and <i>P. gracilis</i> has a special type of female heterogamety (OW/OO system). This sex determination system appears to be suitable for controlling offspring sex ratio seasonally, as is known in this rhizocephalan.</p>","PeriodicalId":55376,"journal":{"name":"Biological Bulletin","volume":"246 2-3","pages":"98-107"},"PeriodicalIF":2.1,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144499445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biological BulletinPub Date : 2024-04-01Epub Date: 2025-03-19DOI: 10.1086/734629
Jackson Deneka, Madeleine Rumingan, Patrick Rodriguez, McCourry Gortney, Emma Howell, Seif S Aldalil, Bea Richardson, Chris Shelley
{"title":"Spontaneous Electrical Activity of Sea Urchin Lantern Protractor Muscle.","authors":"Jackson Deneka, Madeleine Rumingan, Patrick Rodriguez, McCourry Gortney, Emma Howell, Seif S Aldalil, Bea Richardson, Chris Shelley","doi":"10.1086/734629","DOIUrl":"https://doi.org/10.1086/734629","url":null,"abstract":"<p><p>AbstractThe many different muscles of sea urchins are used to control tube foot and spine movement, feeding, excretion, respiration, and gamete release. Unlike in most other animals, the delineation between skeletal and smooth muscles in sea urchins is not clear cut, with many muscles showing characteristics of both muscle types. To further our understanding of sea urchin muscle function, we sought to characterize the electrical properties of protractor muscles of the Aristotle's lantern. Aristotle's lantern comprises a complex of multiple different muscles, ligaments, and calcite ossicles and is primarily involved in feeding. Within the lantern, antagonistic muscle pairs of protractor and retractor muscles act to raise or withdraw the lantern, respectively. The protractor muscles are unstriated, similar to smooth muscle, but connected to the calcite skeleton, as with skeletal muscles. We isolated single muscle cells from the protractor muscles and measured their membrane potentials and found that they generate spontaneous currents at a frequency that ranged from 25 to 30 Hz, a functional property found in many smooth muscles. Furthermore, these currents occurred in the absence of any extraneous cellular or chemical input. Measurement of the reversal potential of the currents under control and ion-substituted conditions suggests that they may be due to the activity a nonspecific cation channel or the synchronous activity of K<sup>+</sup> and Na<sup>+</sup> channels.</p>","PeriodicalId":55376,"journal":{"name":"Biological Bulletin","volume":"246 2-3","pages":"108-115"},"PeriodicalIF":2.1,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144499446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}