Balanus Research Articles

Location and natural history are key to determining impact of the 2021 atmospheric heatwave on Pacific Northwest rocky intertidal communities

IntroductionIn late June 2021, the Pacific Northwest region of the United States and Canada experienced an unprecedented atmospheric heatwave that co-occurred with one of the lowest day-time tide series of the year. Several consecutive days of air temperatures 10-20°C above normal, coupled with mid-afternoon low tides proved deadly for many rocky intertidal organisms, which live at the margin of land and sea.MethodsTo assess short (weeks) and longer-term (1 year) impacts of the heatwave on rocky intertidal communities, we used long-term monitoring data collected annually at 16 sites throughout Washington State.Results and discussionOur findings indicate that impacts were most severe at sites within the Salish Sea region of WA, where peak low tides occurred during the hottest, mid-afternoon hours. Focal species assemblages at Olympic coast sites, where low tides occurred in the morning, were largely spared. In addition, while the heatwave was associated with substantial short-term changes in acorn barnacle, rockweed, and California mussel assemblages, lasting impacts (1 year) were only observed in the mussel assemblage at the one Salish Sea site where this species is common. These findings will aid in forecasting both short-term and longer lasting impacts of future heatwave events and help direct potential mitigation efforts to regions and species assemblages where impacts will likely be greatest.

The effects of parasitism on sex allocation of a hermaphroditic acorn barnacle.

Sex allocation theory predicts the adaptive allocation of resources to male versus female reproduction in simultaneous hermaphrodites in response to individual characteristics or environmental factors. Because parasites uptake resources from their hosts, their presence could affect the sex allocation of the hosts. We investigated the effects of infestation status and infestation intensity by the rhizocephalan barnacle Boschmaella japonica on reproduction, including sex allocation, of the host intertidal barnacle Chthamalus challengeri. Feeding activity was also examined as a factor related to resource intake. Both male and female reproductive investment decreased with increasing parasite infestation, and the sex allocation of large infested hosts was more male-biased than that of large uninfested hosts. Moreover, in contrast to the model prediction that male investment does not change under resource limitation, male investment decreased in infested hosts whose resources were taken by parasites. This reduction in male investment could be explained by changes in mating group size, since infested hosts have shorter penises and consequently are able to access fewer mating partners.

Miocene bioerosion in a Cretaceous metamorphic basement from the Arzew Mountains (Oran, northwestern Algeria): First evidence of a Tortonian rocky shore in the southwestern Mediterranean area

Bioerosive trace fossils at the Guessiba Valley (Arzew Mountains) document an ancient Tortonian shoreline cut into Barremian calcschists at the lowermost part of the Tortonian Balanid Marl Formation. Four ichnogenera produced by endolithic bivalves (Gastrochaenolites) and polychaete annelids (Caulostrepsis, Maeandropolydora, Trypanites) have been identified. The four traces consist of dwelling structures (domichnia). The encrusting epifauna on the rockground include acorn barnacles of the genus Balanus and scarce, poorly preserved bivalves. These epibionts exhibit Trypanites and Entobia, respectively. This ichnoassociation identifies the Entobia ichnosubfacies as part of the Trypanites ichnofacies. The fossil rocky shore described in this paper is related to a transgression that occurred during the Tortonian, characterising a stratigraphic surface corresponding to a sequence boundary. The Guessiba Valley succession marks the first Mediterranean marine transgression affecting the southern flank of the Arzew Mountains, characterised by three distinct phases. The calcschists reported here are among the rare examples of non-carbonate rocky substrates colonised by endolithic boring organisms.

Recruitment and growth of the xylophagous bivalve Bankia martensi ( ) with different levels of wood biofouling species cover

Teredinid bivalves (shipworms) are the main wood degraders in marine environments. However, little is known about the biological interactions between these marine wood borers and wood-associated biofouling species. Filter-feeding species and seaweeds are frequent biofoulers on the submerged wood. Using the marine xylophagous bivalve Bankia martensi (Stempell, 1899) as a model, we hypothesized that increasing the abundance of biofouling species on wood will decrease the recruitment and subsequent growth of the shipworm B. martensi. During the springs of 2020 and 2021, experiments manipulating biofouling cover were carried out using pine panels in Bahía Metri, southern Chile. Three experimental levels of biofouling cover were established (low: 0%–10%, intermediate: 40%–50%, and high: 90%–100%). After five months, the number of B. martensi perforations (as proxy as larval settlement density) and specimen sizes (length, width and volume) in the panels were measured. An inverse relationship between the perforation densities of B. martensi and biofouling cover on the wooden panels was observed. The most frequent biofouling species were mussels and seaweeds which tended to settle on the upper and lateral surfaces, while acorn barnacles and bryozoans were more frequent on the lower surface. Bankia martensi perforations were reduced with increasing biofouling cover. The number of perforations varied according to the panel surface, higher density on the upper and lateral surfaces and lower on the underside. Bankia martensi specimens were larger, both in length and in volume, in panels with low biofouling compared to intermediate and high biofouling cover, while width did not vary with treatment. Our results suggest that the biofouling cover decreases B. martensi recruitment and growth rates, which in turn reduces the wood degradation rate caused by this teredinid. Future manipulative experiments with selected biofouling species (filter-feeders, such as mussels and barnacles), as well as incorporating measurements of reproductive traits of shipworms could help in understanding the biological interactions between these marine communities of wood-boring and biofouling species.

Systematic histology and evidence for the male reproductive activity of Amphibalanus amphitrite (Darwin, 1854)

AbstractThe striped acorn barnacle, Amphibalanus amphitrite, a taxon of Balanidae, is commonly found along Thailand's coastline. In this study, we used histological methods to describe the microscopic anatomy of A. amphitrite. All samples (n = 30) were obtained from the seagrass beds of Libong Island, Thailand, in the Andaman Sea. Histological observation of various longitudinal sections from specimens of A. amphitrite provides clear insights into the organization of organ systems in the species. The digestive tract was observed to be mainly divided into four subregions, including the cuticle‐lined mouth and esophagus, which is characterized by a high columnar epithelium, the stomach, and the intestine. The accessory organ, including the digestive gland, exhibited lobulated structures and was covered with low columnar epithelial cells on a thin layer of smooth muscle. Furthermore, we examined the reproductive system, including both the ovary and testes, as well as the process of gametogenesis. Testicular development was predominantly observed during active breeding seasons throughout the observation.

Proteomic comparison of the organic matrices from parietal and base plates of the acorn barnacle Amphibalanus amphitrite.

Acorn barnacles are efficient colonizers on a wide variety of marine surfaces. As they proliferate on critical infrastructure, their settlement and growth have deleterious effects on performance. To address acorn barnacle biofouling, research has focused on the settlement and adhesion processes with the goal of informing the development of novel coatings. This effort has resulted in the discovery and characterization of several proteins found at the adhesive substrate interface, i.e. cement proteins, and a deepened understanding of the function and composition of the biomaterials within this region. While the adhesive properties at the interface are affected by the interaction between the proteins, substrate and mechanics of the calcified base plate, little attention has been given to the interaction between the proteins and the cuticular material present at the substrate interface. Here, the proteome of the organic matrix isolated from the base plate of the acorn barnacle Amphibalanus amphitrite is compared with the chitinous and proteinaceous matrix embedded within A. amphitrite parietal plates. The objective was to gain an understanding of how the basal organic matrix may be specialized for adhesion via an in-depth comparative proteome analysis. In general, the majority of proteins identified in the parietal matrix were also found in the basal organic matrix, including nearly all those grouped in classes of cement proteins, enzymes and pheromones. However, the parietal organic matrix was enriched with cuticle-associated proteins, of which ca 30% of those identified were unique to the parietal region. In contrast, ca 30-40% of the protease inhibitors, enzymes and pheromones identified in the basal organic matrix were unique to this region. Not unexpectedly, nearly 50% of the cement proteins identified in the basal region were significantly distinct from those found in the parietal region. The wider variety of identified proteins in the basal organic matrix indicates a greater diversity of biological function in the vicinity of the substrate interface where several processes related to adhesion, cuticle formation and expansion of the base synchronize to play a key role in organism survival.

New genes helped acorn barnacles adapt to a sessile lifestyle.

Barnacles are the only sessile lineages among crustaceans, and their sessile life begins with the settlement of swimming larvae (cyprids) and the formation of protective shells. These processes are crucial for adaptation to a sessile lifestyle, but the underlying molecular mechanisms remain poorly understood. While investigating these mechanisms in the acorn barnacle, Amphibalanus amphitrite, we discovered a new gene, bcs-6, which is involved in the energy metabolism of cyprid settlement and originated from a transposon by acquiring the promoter and cis-regulatory element. Unlike mollusks, the barnacle shell comprises alternate layers of chitin and calcite and requires another new gene, bsf, which generates silk-like fibers that efficiently bind chitin and aggregate calcite in the aquatic environment. Our findings highlight the importance of exploring new genes in unique adaptative scenarios, and the results will provide important insights into gene origin and material development.

Morphological variation of the cirri and penis in the hermaphroditic sea-turtle barnacle Chelonibia testudinaria (Linnaeus, 1758) (Cirripedia: Balanomorpha: Chelonibiidae)

Abstract Phenotypic plasticity of the penis and cirri of acorn barnacles is well documented for intertidal species. We investigated whether these phenomena also occur in the epizoic sea-turtle barnacle, Chelonibia testudinaria (Linnaeus, 1758). We compared the morphologies of the penis and cirri, and fertilization rates for adult, hermaphroditic barnacles on different regions of the carapace of sea turtles, and at different levels of crowding on the carapace. Barnacles were more abundant in the posterior position of loggerhead sea turtles, Caretta caretta (Linnaeus, 1758), followed by the central, central costal, and anterior positions. Barnacles in clustered groups were fertilized 68% more often than solitary individuals. Penis size increased with barnacle size and among individual sea turtles. Cirrus length and width also varied with barnacle size, among individual sea turtles, and among positions. Larger barnacles had longer and wider feeding cirri, and cirri were longer and wider in the central and posterior positions of the carapace than in the anterior and central costal positions. The phenotypic plasticity of the morphologies of the penis and cirrus is far less dramatic in Ch. testudinaria than in intertidal species. This may be explained by the epizoic barnacles not being permanently fixed and able to move to preferred positions on the host shell.

Population Genetics of the Deep-sea Acorn Barnacle Bathylasma hirsutum (Hoek, 1883) and the First Report of its Affiliation with a Hydrothermal Vent Field.

Confined by the Mid-Atlantic Ridge and the European continental shelf, the deep-sea acorn barnacle Bathylasma hirsutum (Hoek, 1883) lives in the northeast Atlantic deep sea, where it has been frequently reported in high current areas. Cemented to a solid substrate during its entire adult life, the species can only disperse by means of planktotrophic nauplius larvae. This study reports on the occurrence, ecology and genetic connectivity of B. hirsutum from four sites within the northeastern Iceland Basin and presents the first record of the species living affiliated with hydrothermal vent field on the Reykjanes Ridge axis. Vent-associated specimens were found to differ extrinsically from their naturally shaded conspecifics by a prominent brown-black shell precipitate. Energy Dispersive Spectroscopy revealed ferromanganese oxides to be the main component of these shell precipitates. Morphometric measurements of shell plates revealed specimens from the vent-associated habitat to be smaller compared to non-venting sites. Molecular species delimitation based on the mitochondrial COI and nuclear EF1 genetic markers aided species identification and revealed a low intraspecific genetic variability. Our findings suggest a pronounced genetic connectivity of B. hirsutum within the studied region and provide a first step towards a biogeographic study. As such, habitats of hydrothermal influence along the Mid-Atlantic Ridge are discussed as possible niches, as are deep-sea basins in the western Atlantic. In light of the reported affiliation with hydrothermal activity, we elaborate on the potential for the sister species Bathylasma corolliforme (Hoek, 1883) and Bathylasma chilense Araya & Newman, 2018 to utilise equivalent habitats in the Antarctic and Pacific Ocean, respectively. Our record of the unacquainted ecological niche occupation for B. hirsutum emphasises the need for further research on bathylasmatid acorn barnacles along the extensive Mid-Atlantic Ridge, where many biological communities remain to be discovered.

Optimization of plastic polymers for shellfish aquaculture infrastructures: in situ antifouling performance assessment

Biofouling poses a significant challenge to bivalve aquaculture affecting both the target culture and/or the immersed infrastructure. In suspended bivalve cultures (e.g., oysters and scallops), biofouling accumulation leads to additional labor demands and increased costs for the maintenance of underwater structures. Given that the inherent properties of materials used in farming infrastructure influence the formation of fouling communities, evaluating how these materials perform under diverse environmental conditions can help the industry select the most effective materials for preventing or minimizing biofouling growth. This study evaluates the impact of aquaculture material and environmental conditions on biofouling, focusing on two commonly used plastic polymers in marine aquaculture: polyamide (PA) and high-density polyethylene (PE). Both untreated and color-additive treated polymers were tested for their response to fouling development. Performance was gauged by total fouling wet weight and the extent of fouling-induced mesh occlusion. Experimental panels were deployed for 4 months (from May to September 2021) in estuarine (oyster farm) and marine (port) environments on the northern coast of Portugal. The marine sites exhibited greater fouling species diversity, while higher biofouling loads were found in the subtidal estuarine area. Within 3 months, complete mesh occlusion occurred mainly due to colonial hydroids (Obelia dichotoma) in the subtidal site. In contrast, panels deployed in the intertidal estuarine area had lower fouling biomass and mesh occlusion. Notably, significant differences between polymer types and treatments were only evident in the estuarine intertidal area, with long air exposure during low tide. White panels outperformed orange ones in fouling biomass, and PA panels outperformed PE panels in mesh occlusion. These differences were attributed to the settlement and growth of the acorn barnacle Austrominius modestus, known to favor dark-colored and less hydrophilic surfaces. Considering that oyster production in intertidal areas is one of the most important aquaculture industries globally, these findings offer valuable insights into material selection and characteristics that can mitigate fouling loads and their associated impacts. These results could also be relevant for other forms of bivalve aquaculture where infrastructure-related biofouling presents a challenge.

Biomineralization in Barnacle Base Plate in Association with Adhesive Cement Protein.

Barnacles strongly attach to various underwater substrates by depositing and curing a proteinaceous cement that forms a permanent adhesive layer. The protein MrCP20 present within the calcareous base plate of the acorn barnacle Megabalanus rosa (M.rosa) was investigated for its role in regulating biomineralization and growth of the barnacle base plate, as well as the influence of the mineral on the protein structure and corresponding functional role. Calcium carbonate (CaCO3) growth on gold surfaces modified by 11-mercaptoundecanoic acid (MUA/Au) with or without the protein was followed using quartz crystal microbalance with dissipation monitoring (QCM-D), and the grown crystal polymorph was identified by Raman spectroscopy. It is found that MrCP20 either in solution or on the surface affects the kinetics of nucleation and growth of crystals and stabilizes the metastable vaterite polymorph of CaCO3. A comparative study of mass uptake calculated by applying the Sauerbrey equation to the QCM-D data and quantitative X-ray photoelectron spectroscopy determined that the final surface density of the crystals as well as the crystallization kinetics are influenced by MrCP20. In addition, polarization modulation infrared reflection-absorption spectroscopy of MrCP20 established that, during crystal growth, the content of β-sheet structures in MrCP20 increases, in line with the formation of amyloid-like fibrils. The results provide insights into the molecular mechanisms by which MrCP20 regulates the biomineralization of the barnacle base plate, while favoring fibril formation, which is advantageous for other functional roles such as adhesion and cohesion.

Predator effects on behavior and anaerobic capacity in the common acorn barnacle (Balanus glandula)

ABSTRACT Differences in the stress experience of sessile organisms across the intertidal zone can differentially influence phenotype. For example, Balanus glandula barnacles from the low intertidal zone have higher lactate levels, greater lactate dehydrogenase (LDH) activity and reduced cirral activity compared to conspecifics from the high intertidal zone. We tested the hypothesis that enhanced anaerobic capacity in lower intertidal B. glandula results from increased predation and hypoxia-inducing shell closure. To investigate this hypothesis, we compared the density of whelk predators across the intertidal zone, and quantified the behavioral response and LDH activity levels of B. glandula exposed to predators in the lab. We consistently found more predators in the low intertidal zone, although the response of B. glandula to predators was short-term operculum closure (<1hr) which did not result in significant differences in LDH activity. Thus, increased predation is not the cause of high anaerobic capacity in lower intertidal B. glandula.

The rangeomorph Pectinifrons abyssalis: Hydrodynamic function at the dawn of animal life

Rangeomorphs are among the oldest putative eumetazoans known from the fossil record. Establishing how they fed is thus key to understanding the structure and function of the earliest animal ecosystems. Here, we use computational fluid dynamics to test hypothesized feeding modes for the fence-like rangeomorph Pectinifrons abyssalis, comparing this to the morphologically similar extant carnivorous sponge Chondrocladia lyra. Our results reveal complex patterns of flow around P.abyssalis unlike those previously reconstructed for any other Ediacaran taxon. Comparisons with C. lyra reveal substantial differences between the two organisms, suggesting they converged on a similar fence-like morphology for different functions. We argue that the flow patterns recovered for P.abyssalis do not support either a suspension feeding or osmotrophic feeding habit. Instead, our results indicate that rangeomorph fronds may represent organs adapted for gas exchange. If correct, this interpretation could require a dramatic reinterpretation of the oldest macroscopic animals.

Experimental accumulation of microplastics in acorn barnacle Amphibalanus amphitrite and its use in estimating microplastic concentration in coastal waters

Microplastic (MP) pollution has been an emerging problem in the marine environment over the last few decades. Considering wide-ranging negative impacts of MPs on marine organisms, monitoring MP pollution in marine ecosystems is essential and urgent for developing effective management of the problem. An exposure experiment was conducted to assess the potential of the striped barnacle Amphibalanus amphitrite as a bioindicator of MPs. The barnacles were exposed to either polypropylene fibers or fragments for 8 days. A full factorial experiment was conducted, with the shape (fragment, fiber), exposure concentration (10, 100, and 1000 items L-1) and exposure duration (2, 4, and 8 days) as independent factors. The highest number of MPs in A. amphitrite was 21.04 ± 15.22 fragments g-1 and 17.60 ± 13.8 fibers g-1 wet weight recorded after 4 days of exposure, and the MP concentration in the barnacles was positively correlated with the exposure concentration, regardless of the form of MPs. A regression equation relating the MP concentration in the barnacles and that in the water was computed to estimate the MP concentration in the coastal waters of Hong Kong. The predicted values were close to the published data, indicating the potential of A. amphitrite as a bioindicator of MP pollution.

Periodicity in Chthamalus fissus reproduction does not guarantee periodicity in settlement

The timing of life history events can have profound implications for populations and communities, especially those events that influence species dispersal and recruitment. In benthic invertebrates, the majority of dispersal occurs during the larval phase of life. Yet the extent to which timing of reproduction (the beginning of the larval phase) directly influences timing of settlement (the end of the larval phase) is unclear, because biological and hydrodynamic processes can act to decouple these 2 events, and because reproduction and settlement are seldom studied together. Here, we used long-term (2014-2019) daily and weekly data from Bird Rock, La Jolla, California, USA, to look for lunar and seasonal cycles in reproduction and settlement timing of the acorn barnacle Chthamalus fissus, and we incorporated measurements of nearshore currents to examine the implications of reproduction timing on alongshore larval transport distances. We found evidence of lunar and seasonal cycles in reproduction but only limited cyclicality in settlement, possibly due to plasticity in larval development coupled with variable larval transport and dispersal. Our results demonstrate the complex nature of relationships between reproduction, larval transport, and settlement, which must be disentangled before accurate predictions can be made regarding the impacts of climate change on the population dynamics of marine species.

Understanding the biological impact of organic pollutants absorbed by nanoplastics

Many organisms are consuming food contaminated with micro- and nanoparticles of plastics, some of which absorb persistent organic pollutants (POPs) from the environment and acting as carrier vectors for increasing the bioavailability in living organisms. We recently reported that polymethylmethacrylate (PMMA) nanoparticles at low concentrations are not toxic to animal models tested. In this study, the toxicity of diphenylamine (DPA) incorporated PMMA nanoparticles are assessed using barnacle larvae as a model organism. The absorption capacity of DPA from water for commercially available virgin PMMA microparticles is relatively low (0.14 wt%) during a 48 h period, which did not induce exposure toxicity to barnacle nauplii. Thus, PMMA nanoparticles encapsulated with high concentrations of DPA (DPA-enc-PMMA) were prepared through a reported precipitation method to achieve 40% loading of DPA inside the particles. Toxicity of DPA-enc-PMMA nanoparticles were tested using freshly spawned acorn barnacle nauplii. The observed mortality of nauplii from DPA-enc-PMMA exposure was compared to the values obtained from pure DPA exposure in water. The mortality among the exposed acorn barnacle nauplii did not exceed 50% even at a high concentration of DPA inside the PMMA nanoparticles. The results suggest that the slow release of pollutants from polymer nanoparticles may not induce significant toxicity to the organism living in a dynamic environment. The impact of long-term exposure of DPA absorbed plastic nanoparticles need to be investigated in the future.

Variation of Carbon–Nitrogen Contents and Allelopathic Disruption of Renieramycin M–Producing Sponge Xestospongia sp. in the Gulf of Thailand

Allelopathy is commonly found in marine sponges. However, information on allelopathic activities of sponge extracts is limited. In this study, variations of nutritional values of Xestospongia sp. were investigated. Xestospongia did not unequally distribute its nutritional values for predatory defense. Carbon–nitrogen contents and renieramycin M concentrations were not significantly different among the areas of Xestospongia sp. (edge, inner, and outer). However, carbon–nitrogen contents and renieramycin M concentrations of Xestospongia sp. coexisting with different organisms were not significantly different. In the laboratory, bleaching and necrosis of coral nubbins were not observed in every treatment, and renieramycin M did not show any allelopathic effect on its coexisting organisms (Porites lutea and Palythoa caesia). However, renieramycin M inhibited settlement of acorn barnacle (Semibalanus balanoides) but did not inhibit the settlement of pelecypods. When testing for antimicrobial effect, renieramycin M did not inhibit the growth of aerobic bacteria in any treatments. This study provides evidence that renieramycin M found in Xestospongia was uniform; however, it can possess strong inhibitory activities against some marine organisms.

Toxic effects of pristine and aged polystyrene microplastics on selective and continuous larval culture of acorn barnacle Amphibalanus amphitrite.

This study evaluates the toxicity of pristine (Unwashed) and aged, clean (Biofilm-) or fouled (Biofilm+), PS microspheres (3 µm,10 µm), using Washed particles as a reference material, on selective and continuous larval culture of Amphibalanus amphitrite. Exposure to 3 µm Unwashed and Biofilm+ particles for 24 h induced significant mortality (60 % and 57 % respectively) in stage II larvae. Stage II and VI nauplii showed greater uptake of 3 µm Biofilm- particles. Accumulative exposure to microplastics in continuous larval culture significantly affected the naupliar survival, particularly of stage III and IV. Cumulative mortality was > 70% after exposure to 3 µm Unwashed and 10 µm Biofilm+ particles. Unwashed particles with increasing concentration and aged particles with increasing size, delayed the development of nauplii to cyprids. Though,> 50% cyprids showed successful settlement however the highest concentration of 3 µm Biofilm+ microspheres inhibited the settlement and induced precocious metamorphosis in 9 % of the cyprids.

Marine turtles and their barnacles from Scottish waters and adjacent seas

The history of marine turtles in Scottish waters and adjacent seas is reviewed. The recording and reporting schemes for stranded marine animals in Scotland and the U.K. are highlighted. Detailed descriptions are provided of strandings of a loggerhead turtle (Caretta caretta) at Irvine, Ayrshire in December 2015, with numerous attached goose barnacles (Lepas anatifera) and a leatherback turtle (Dermochelys coriacea) at St. Cyrus, Aberdeenshire in January 2016, with several acorn barnacles (Stomatolepas dermochelys). A review of U.K. marine animal strandings reports revealed additional records of L. anatifera and L. hillii, from stranded loggerheads in Carmarthenshire in 2006 and in Cornwall in 2016 respectively, as well as another leatherback with S. dermochelys in Cornwall in 2018. The occurrence of lepadomorph and balanomorph barnacles on turtles is discussed including historical records from the U.K. and Ireland, and adjacent waters in the Mediterranean and the north-east Atlantic. Taxonomic confusion within the genus Stomatolepas is clarified. Other species of barnacle that might occur on turtles reaching the waters of the U.K. and Ireland in the future are discussed along with other exotic fauna that can accompany turtles. The impact of barnacles on turtles and how turtles remove attached epibionts is summarised.

A comparative investigation of toxicity of three polymer nanoparticles on acorn barnacle (Amphibalanus amphitrite)

Pollution from plastic waste is increasingly prevalent in the environment and beginning to generate significant adverse impact on the health of living organisms. In this study, we investigate the toxicity of polymer nanoparticles exposed to Acorn Barnacle (Amphibalanus amphitrite) nauplii, as an animal model. Highly stable aqueous dispersion of luminescent nanoparticles from three common polymers: polymethylmethacrylate (PMMA), polystyrene (PS), and polyvinylchloride (PVC), were prepared via nanoprecipitation and fully characterised. Exposure studies of these polymer particles to freshly spawned barnacle nauplii were performed within a concentration range from 1 to 25 mg/L under laboratory-controlled conditions. The exposure to PMMA and PS nanoparticles did not show detrimental toxicity and did not cause sufficient mortality to compute a LC50 value. However, PVC nanoparticles were significantly toxic with a mortality rate of up to 99% at 25 mg/L, and the calculated LC50 value for PVC nanoparticles was 7.66 ± 0.03 mg/L, 95% CI. Interestingly, PVC nanoparticle aggregates were observed to adhere to the naupliar carapace and appendages at higher concentrations and could not be easily removed by washings. To explore the possibility of chemical toxicity of polymer nanoparticles, analysis of the polymer powders which was used to prepare the nanoparticles was conducted. The presence of low molecular weight oligomers such as dimers, trimers and tetramers were observed in all polymer samples. The chemical nature and concentration of such compounds are likely responsible for the observed toxicity to the barnacle nauplii. Overall, our study shows that care should be exercised in generalising the findings of exposure studies performed using one type of plastic particles, as the use of different plastic particles may elicit different responses inside a living organism.