DOCSLIB.ORG

Ascidian-Associated Polychaetes: Ecological Implications of Aggregation Size and Tube-Building Chaetopterids on Assemblage Structure in the Southeastern Pacific Ocean

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Ascidian-Associated Polychaetes: Ecological Implications of Aggregation Size and Tube-Building Chaetopterids on Assemblage Structure in the Southeastern Pacific Ocean Author's personal copy Mar Biodiv (2015) 45:733–741 DOI 10.1007/s12526-014-0283-7 ORIGINAL PAPER Ascidian-associated polychaetes: ecological implications of aggregation size and tube-building chaetopterids on assemblage structure in the Southeastern Pacific Ocean Roger D. Sepúlveda & Nicolás Rozbaczylo & Christian M. Ibáñez & Marcelo Flores & Juan M. Cancino Received: 13 May 2014 /Revised: 13 October 2014 /Accepted: 20 October 2014 /Published online: 4 November 2014 # Senckenberg Gesellschaft für Naturforschung and Springer-Verlag Berlin Heidelberg 2014 Abstract Epifaunal polychaetes inhabit a range of habitat chaetopterid tubes influenced the polychaete assemblage structures built by other organisms, such as ascidians. Here, structure, evidencing differences between morphotypes. We we examine: i) the polychaete fauna inhabiting aggregations suggest that both sample volume and the habitat structuring of the ascidian Pyura chilensis in central Chile; ii) the rela- capacity of the chaetopterid tubes change the habitat complex- tionship between sample volume (aggregation size) and poly- ity of the ascidian aggregations and, hence, produce differ- chaete assemblage variables; and iii) the effect of a tube- ences between morphotypes related to the polychaete assem- building chaetopterid on the polychaete assemblage structure. blage structure. The chaetopterid tube load on aggregations determines two ascidian morphotypes, those with a high load of chaetopterid Keywords Habitat complexity . Ecosystem engineering . tubes (HT morphotype) and those with a low load of Diversity . Tube-building . Ascidians chaetopterid tubes (LT morphotype). From a total of 38 ag- gregations studied, we found 5,524 specimens belonging to 35 species of polychaetes. Three species were the most abundant Introduction in the aggregations (Phyllochaetopterus socialis, Nicolea lobulata,andTyposyllis magdalena), reaching 22% of total Epifaunal polychaetes are an important component of hard abundance. The number of species and individuals increased and soft bottom marine communities, capable of colonizing a with sample volume, but only the number of species number variety of biogenic substrates such as algae (Fredriksen et al. varied between morphotypes. Sample volume and the 2005; Sánchez-Moyano and García-Asencio 2009), sponges (Cinar and Ergen 1998), mollusks (Thiel and Ullrich 2002; Vasconcelos et al. 2007), worm tubes (Dubois et al. 2002; R. D. Sepúlveda (*) Sepúlveda et al. 2003a), crustaceans (Hoberg et al. 1982; Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Hernández et al. 2001), echinoderms (Britayev and Universidad Austral de Chile, Casilla 567, Valdivia, Chile e-mail: [email protected] Zamishliak 1996) and ascidians (Fielding et al. 1994; Cerda and Castilla 2001), among others. Within these biogenic hab- N. Rozbaczylo itats, polychaetes may find food and refuge (Woodin 1978; Departamento de Ecología, Facultad de Ciencias Biológicas, Edgar and Aoki 1993). Moreover, some of these species such Pontificia Universidad Católica de Chile, Santiago, Chile as borers, drillers or tube-builders may change the surround- C. M. Ibáñez ing environmental conditions through perforations, excava- Departamento de Ciencias Ecológicas, Facultad de Ciencias, tions or simply disturbing the surface sediment, thereby af- Universidad de Chile, Santiago, Chile fecting the other components of the fauna (Bolam and M. Flores Fernández 2002;Duboisetal.2002; Sepúlveda et al. 2003a). Departamento de Ecología y Biodiversidad, Facultad de Ecología y Certain species of ascidians are gregarious and capable of Recursos Naturales, Universidad Andres Bello, Santiago, Chile generating complex aggregations of organisms of different sizes living in close proximity. Aggregations of this kind of J. M. Cancino Departamento de Ecología, Facultad de Ciencias, Universidad organisms are called ecosystem engineers (Jones et al. 1994) Católica de la Santísima Concepción, Concepción, Chile because they modify the primary substrate, providing Author's personal copy 734 Mar Biodiv (2015) 45:733–741 interstices and holes that serve as habitat for a diverse and Materials and methods abundant marine fauna (Guiler 1959; Cerda and Castilla 2001; Sepúlveda et al. 2003b). They also act as a biogenic substrate Study area and sample collection since the surface of the aggregation is a suitable substrate for direct settlement of many sessile organisms. Such aggrega- A total of 38 aggregations of the ascidian P. chilensis were tions therefore enhance local biodiversity by providing living obtained in San Vicente Bay, central Chile in 2000. From habitats that increase complexity (Voultsiadou et al. 2010). aggregations analysed and studied, 21 corresponded to aggre- The study of epibionts on ascidian aggregations is increasing gations with high density (average 0.465 tubes/ml., “hairy” because potential changes in the biogenic substrate resulting appearance, hereafter HT morphotype) and 17 to aggregations from disturbance or contamination will also impact the with low density (average 0.076 tubes/ml., “bald” appearance, associated fauna (Roberts et al. 2008). Moreover, some hereafter LT morphotype) of chaetopterid tubes (i.e., the load ascidians are commercially collected for human con- is six times greater in the HT than in LT morphotype). The sumption and their exploitation might produce cascading load of chaetopterid tubes displayed influences the number effects on the associated communities (Coleman and and size of individual ascidians, showing one to three ascid- Williams 2002; Monteiro et al. 2002). ians of small size in the HT morphotype, and two to six Pyura chilensis Molina, 1782, is a solitary ascidian species ascidians of medium size in the LT morphotype (Sepúlveda, that forms massive aggregations and/or patches on the subtidal pers. obs.). The LT morphotype samples were collected near seafloor, made up of one or several individuals (Guiler 1959). Roca Navia (36°44′49.71′S, 73°10′37.66”W) at a depth of Its geographic distribution range is between 10 and 44°S in the approximately 5 m below MLW, while the HT morphotype Southeast Pacific Ocean from the intertidal zone to a depth of samples were also collected at a depth of 5 m near playa 70 m (Vásquez 1983; Lancellotti and Vásquez 2000;Astorga Ramuntcho (36°45′11.99′S, 73°11′12.57”W) (Fig. 1); sam- and Ortíz 2006). Due to their high commercial value, these ples were collected by a diver equipped with “hookah” breath- ascidian aggregations are locally exploited along the Chilean ing gear. Samples of ascidians aggregations were removed coast by fishermen who recognize two types of aggregations from the rocky substrates using a spatula and metal hooks and depending on harvest location, “hairy” and “bald”; these two were wrapped in situ in a 1 mm-mesh polypropylene netting types can occur within the same area. The difference between to retain all associated polychaetes. The size (measured as aggregations is due to the high or low (or absent) load of tubes volume) of each aggregation was determined immersing the built by the chaetopterid polychaete Phyllochaetopterus sample in a 1,000-ml graduated cylinder and determining the socialis Claparède, 1869, which, when occurring at high volume of seawater displaced by the sample. Polychaetes densities on some ascidian aggregations, produces the “hairy” from each aggregation were separated with the aid of a ste- appearance. The polychaetes tubes are of considerable size reomicroscope and fixed in 10% formalin-seawater solution. (20–40 mm) and, since they are stiff and located on the surface Determination of total and per-sample taxonomic composition of the ascidian aggregation, change the external morphology of polychaete fauna was performed to the lowest possible as well as the effective size of the aggregations. Consequently, taxonomic level. Species abundance of all polychaetes was these tubes may change the hydrodynamics, increase the counted manually, and each species was assigned to trophic habitat complexity and oxygen demands and even produce and locomotion functional groups of polychaetes, following heterogeneous habitats in a uniform environment (Callaway Fauchald and Jumars (1979) and Jumars et al. (2014). 2006; Van Hoey et al. 2008). These effects of tube-building Although the results show differences between morphotypes, polychaetes may also influence larval settlement, dispersal we assume that the variations in polychaete assemblage may be patterns and, therefore, produce changes in the community due to the collection sites, since this study does not have variables and structure (Woodin 1978; Trueblood 1991;Qian replicated sites. Therefore, confounding effects between sites 1999;Zühlke2001;Callaway2006). and morphotypes are likely to affect the results of our study. In this study, we examine the polychaete fauna inhabiting the aggregations of the ascidian Pyura Data analysis chilensis in central Chile and evaluate the relationship between aggregation volume and polychaete assemblage Relative abundances between morphotypes for feeding and variables (number of species and individuals) and the locomotion functional groups were tested with contingency effect produced by the differential load of chaetopterid tables and statistical significance was evaluated through Chi- tubes on the polychaete assemblage structure. For this, square analysis (Quinn and Keough 2002). we compared different sizes of ascidian aggregations To assess the possible influence of sample size (aggregation
Load more

Recommended publications
  • Ascidian News #87 June 2021
    ASCIDIAN NEWS* Gretchen Lambert 12001 11th Ave. NW, Seattle, WA 98177 206-365-3734 [email protected] home page: http://depts.washington.edu/ascidian/ Number 87 June 2021 Well, here we are still in this pandemic! I asked how you all are and again received many responses. A number are included in the next two sections. Nearly everyone still expresses confidence at having met the challenges and a great feeling of accomplishment even though tired of the whole thing; congratulations to you all! There are 117 new publications since December! Thanks to so many for the contributions and for letting me know how important AN continues to be. Please keep in touch and continue to send me contributions for the next issue. Keep safe, keep working, and good luck to everyone. *Ascidian News is not part of the scientific literature and should not be cited as such. NEWS AND VIEWS 1. From Hiroki Nishida ([email protected]) : In Japan, we are very slow to be vaccinated, but the labs are ordinarily opened and we can continue working. Number of patients are gradually increasing though and we are waiting for vaccines. I have to stay in my home and the lab. Postponement of 11th ITM (International Tunicate Meeting) This is an announcement about 11th ITM that had been planned to be held in July 2021 in Kobe, Japan. It is postponed by a year because of the global spread of COVID-19. We had an 11th ITM board meeting, and came to the conclusion that we had to reschedule it for July 2022 at the same venue (Konan University, Kobe, Japan) and similar dates (July 11 to 16).
    [Show full text]
  • Ascidian-Associated Polychaetes
    See discussions, stats, and author profiles for this publication at: http://www.researchgate.net/publication/267868444 Ascidian-associated polychaetes: ecological implications of aggregation size and tube- building chaetopterids on assemblage structure in the Southeastern Pacific Ocean ARTICLE in MARINE BIODIVERSITY · OCTOBER 2014 Impact Factor: 1.1 · DOI: 10.1007/s12526-014-0283-7 READS 80 5 AUTHORS, INCLUDING: Nicolas Rozbaczylo Christian M. Ibáñez Pontifical Catholic University of Chile Universidad Andrés Bello 63 PUBLICATIONS 373 CITATIONS 42 PUBLICATIONS 298 CITATIONS SEE PROFILE SEE PROFILE Marcelo A. Flores Juan M Cancino Universidad Andrés Bello Catholic University of the Most Holy Conce… 14 PUBLICATIONS 23 CITATIONS 46 PUBLICATIONS 742 CITATIONS SEE PROFILE SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate, Available from: Roger D. Sepúlveda letting you access and read them immediately. Retrieved on: 28 December 2015 Mar Biodiv DOI 10.1007/s12526-014-0283-7 ORIGINAL PAPER Ascidian-associated polychaetes: ecological implications of aggregation size and tube-building chaetopterids on assemblage structure in the Southeastern Pacific Ocean Roger D. Sepúlveda & Nicolás Rozbaczylo & Christian M. Ibáñez & Marcelo Flores & Juan M. Cancino Received: 13 May 2014 /Revised: 13 October 2014 /Accepted: 20 October 2014 # Senckenberg Gesellschaft für Naturforschung and Springer-Verlag Berlin Heidelberg 2014 Abstract Epifaunal polychaetes inhabit a range of habitat chaetopterid tubes influenced the
    [Show full text]
  • 1 Phylogeny of the Families Pyuridae and Styelidae (Stolidobranchiata
    * Manuscript 1 Phylogeny of the families Pyuridae and Styelidae (Stolidobranchiata, Ascidiacea) 2 inferred from mitochondrial and nuclear DNA sequences 3 4 Pérez-Portela Ra, b, Bishop JDDb, Davis ARc, Turon Xd 5 6 a Eco-Ethology Research Unit, Instituto Superior de Psicologia Aplicada (ISPA), Rua 7 Jardim do Tabaco, 34, 1149-041 Lisboa, Portugal 8 9 b Marine Biological Association of United Kingdom, The Laboratory Citadel Hill, PL1 10 2PB, Plymouth, UK, and School of Biological Sciences, University of Plymouth PL4 11 8AA, Plymouth, UK 12 13 c School of Biological Sciences, University of Wollongong, Wollongong NSW 2522 14 Australia 15 16 d Centre d’Estudis Avançats de Blanes (CSIC), Accés a la Cala St. Francesc 14, Blanes, 17 Girona, E-17300, Spain 18 19 Email addresses: 20 Bishop JDD: [email protected] 21 Davis AR: [email protected] 22 Turon X: [email protected] 23 24 Corresponding author: 25 Rocío Pérez-Portela 26 Eco-Ethology Research Unit, Instituto Superior de Psicologia Aplicada (ISPA), Rua 27 Jardim do Tabaco, 34, 1149-041 Lisboa, Portugal 28 Phone: + 351 21 8811226 29 Fax: + 351 21 8860954 30 [email protected] 31 1 32 Abstract 33 34 The Order Stolidobranchiata comprises the families Pyuridae, Styelidae and Molgulidae. 35 Early molecular data was consistent with monophyly of the Stolidobranchiata and also 36 the Molgulidae. Internal phylogeny and relationships between Styelidae and Pyuridae 37 were inconclusive however. In order to clarify these points we used mitochondrial and 38 nuclear sequences from 31 species of Styelidae and 25 of Pyuridae. Phylogenetic trees 39 recovered the Pyuridae as a monophyletic clade, and their genera appeared as 40 monophyletic with the exception of Pyura.
    [Show full text]
  • Time Or Space?
    fmars-08-657411 April 16, 2021 Time: 17:33 # 1 ORIGINAL RESEARCH published: 22 April 2021 doi: 10.3389/fmars.2021.657411 Time or Space? Relative Importance of Geographic Distribution and Interannual Variation in Three Lineages of the Ascidian Pyura chilensis in the Southeast Pacific Coast Pilar A. Haye1,2, Xavier Turon3 and Nicolás I. Segovia1,2,4* 1 Departamento de Biología Marina, Facultad de Ciencias de Mar, Universidad Católica del Norte, Coquimbo, Chile, 2 Instituto Milenio en Socio-ecología Costera (SECOS), Santiago, Chile, 3 Centre for Advanced Studies of Blanes (CEAB, CSIC), Blanes, Spain, 4 Instituto de Ecología y Biodiversidad (IEB), Santiago, Chile Spatial and temporal variation of environmental parameters can affect dispersal, Edited by: recruitment and population persistence of marine benthic species. Studies including Sandie M. Degnan, The University of Queensland, inter-annual comparisons of genetic structure often indicate high/moderate temporal Australia heterogeneity in marine invertebrates, which may be a prevailing pattern. This Reviewed by: suggests that temporal studies are necessary to understand the dynamics of marine Pablo Saenz-Agudelo, metapopulations. In this study, we analyzed the spatio-temporal genetic structure of Austral University of Chile, Chile Carlos Vergara-Chen, the ascidian Pyura chilensis, a low dispersal sessile marine species endemic from the Technological University of Panama, Southeast Pacific coast and highly demanded for human consumption. We sequenced Panama S. López-Legentil, a fragment of the mitochondrial gene Cytochrome Oxidase I (COI) from 1,005 individuals University of North Carolina of six locations (30–40 individuals per site and year) spanning a wide latitudinal range at Wilmington, United States (24◦–42◦S) and sampled over 5 years (2012, 2014, 2015, 2016, and 2017).
    [Show full text]
  • Novel Microsatellite Markers for Pyura Chilensis Reveal Fine-Scale Genetic Structure Along the Southern Coast of Chile
    Mar Biodiv DOI 10.1007/s12526-017-0672-9 ORIGINAL PAPER Novel microsatellite markers for Pyura chilensis reveal fine-scale genetic structure along the southern coast of Chile E. C. Giles1 & C. Petersen-Zúñiga1 & S. Morales-González1 & S. Quesada-Calderón1 & Pablo Saenz-Agudelo1 Received: 25 August 2016 /Revised: 22 February 2017 /Accepted: 23 February 2017 # Senckenberg Gesellschaft für Naturforschung and Springer-Verlag Berlin Heidelberg 2017 Abstract Studying the geographic scale of gene flow and here, it seems possible that genetic structure at this spatial population structure in marine populations can be a powerful scale is driven to some extent by local population dynamics tool with which to infer patterns of larval dispersal averaged (deviations from random mating and/or a large proportion of across generations. Here, we describe the development of ten larvae settling in proximity of relatives), yet infrequent long- novel polymorphic microsatellite markers for an important distance dispersal events might also be responsible for the endemic ascidian, Pyura chilensis, of the southeastern relatively weak spatial heterogeneity between sites. Overall, Pacific, and we report the results from fine-scale genetic struc- our results both highlight the utility of this new marker set for ture analysis of 151 P. chilensis individuals sampled from five population genetic studies of this species and provide new sites constituting ∼80 km of coastline in southern Chile. All evidence regarding the complexity of the small-scale popula- microsatellite markers were highly polymorphic (number of tion structure of this species. alleles ranged from 12 to 36). Our results revealed significant deviations from Hardy–Weinberg equilibrium (HWE) for Keywords Population genetics .
    [Show full text]
  • Sustainability of the Artisanal Fishery in Northern Chile: a Case Study of Caleta Pisagua
    sustainability Article Sustainability of the Artisanal Fishery in Northern Chile: A Case Study of Caleta Pisagua Carola Espinoza 1,2,Víctor A. Gallardo 1, Carlos Merino 3, Pedro Pizarro 3 and Kwang-Ming Liu 1,4,5,* 1 Institute of Marine Affairs and Resource Management, National Taiwan Ocean University, 2, Pei-Ning Road, Keelung 20224, Taiwan; [email protected] (C.E.); [email protected] (V.A.G.) 2 Department of Oceanography, University of Concepción, Concepción 4030000, Chile 3 Faculty of Natural Renewables Resources, Arturo Prat University, Iquique 2210000, Chile; [email protected] (C.M.); [email protected] (P.P.) 4 George Chen Shark Research Center, National Taiwan Ocean University, 2, Pei-Ning Road, Keelung 20224, Taiwan 5 Center of Excellence for the Oceans, National Taiwan Ocean University, 2, Pei-Ning Road, Keelung 20224, Taiwan * Correspondence: [email protected]; Tel.: +886-2-2462-2192 (ext. 5018) Received: 14 August 2020; Accepted: 3 September 2020; Published: 5 September 2020 Abstract: The Humboldt Current, one of the most productive waters in the world, flows along the Chilean coast with high primary production level. However, living marine resources in these waters are declining due to overexploitation and other anthropogenic and environmental factors. It has been reported that deploying artificial reefs in coastal waters can improve the production of benthic resources. Toensure the sustainability of coastal fisheries in northern Chile this study aims to investigate fishermen’s perceptions on deploying artificial reefs and propose future management measures using Caleta Pisagua as a case study. Interviews of artisanal fishermen regarding four aspects: fishermen profile, fishing activity, resources, and artificial reefs were conducted.
    [Show full text]
  • Ascidian News*
    ASCIDIAN NEWS* Gretchen Lambert 12001 11th Ave. NW, Seattle, WA 98177 206-365-3734 [email protected] home page: http://depts.washington.edu/ascidian/ Number 79 June 2017 Rosana Rocha and I will be teaching the next tunicate workshop June 20-July 4 in Panama, at the Smithsonian’s Bocas del Toro Tropical Research Institute on the Caribbean. This is the 5th advanced workshop we have taught since 2006 at this lab; it is very gratifying to see that many of the participants are now faculty members at various institutions, with their own labs and students pursuing research projects on ascidians. A big thank-you to all who sent in contributions. There are 113 New Publications listed at the end of this issue. Please continue to send me articles, and your new papers, to be included in the next issue of AN. *Ascidian News is not part of the scientific literature and should not be cited as such. NEWS AND VIEWS 1. I hope to see many of you at the upcoming Intl. Tunicata meeting in New York City July 17-21, at New York University, hosted by Dr. Lionel Christiaen. There will be a welcome reception on the evening of July 16th. For more information see https://2017-tunicate- meeting.bio.nyu.edu/ . 2. The next International Summer Course will be held at Sugashima Marine Biological Laboratory, Toba, Mie Prefecture, Japan, from July 7 to July 14, 2017. This course deals with experiments and lectures on basic developmental biology of sea urchins and ascidians, basic taxonomy, and advanced course of experiments on genome editing and proteomics.
    [Show full text]
  • Contrasting Patterns of Native and Introduced Ascidians in Subantarctic and Temperate Chile
    Management of Biological Invasions (2016) Volume 7, Issue 1: 77–86 DOI: http://dx.doi.org/10.3391/mbi.2016.7.1.10 Open Access © 2016 The Author(s). Journal compilation © 2016 REABIC Proceedings of the 5th International Invasive Sea Squirt Conference (October 29–31, 2014, Woods Hole, USA) Research Article Too cold for invasions? Contrasting patterns of native and introduced ascidians in subantarctic and temperate Chile 1 2 3,4 5 6 Xavier Turon *, Juan I. Cañete , Javier Sellanes , Rosana M. Rocha and Susanna López-Legentil 1Center for Advanced Studies of Blanes (CEAB-CSIC), Accés Cala S. Francesc 14, 17300 Blanes, Girona, Spain 2Facultad de Ciencias, Universidad de Magallanes, Chile 3Departamento de Biología Marina, Facultad de Ciencias del Mar, Universidad Católica del Norte, Coquimbo, Chile 4Millenium Nucleus for Ecology and Sustainable Management of Oceanic Islands (ESMOI), Chile 5Departamento de Zoologia, Universidade Federal do Paraná, Curitiba, Brazil 6Dep. of Biology and Marine Biology, and Center for Marine Science, University of North Carolina Wilmington, Wilmington, NC 28409, USA *Corresponding author E-mail: [email protected] Received: 6 May 2015 / Accepted: 30 September 2015 / Published online: 26 November 2015 Handling editor: Mary Carman Abstract We analysed the biodiversity of ascidians in two areas located in southern and northern Chile: Punta Arenas in the Strait of Magellan (53º latitude, subantarctic) and Coquimbo (29º latitude, temperate). The oceanographic features of the two zones are markedly different, with influence of the Humboldt Current in the north, and the Cape Horn Current System, together with freshwater influxes, in the Magellanic zone. Both regions were surveyed twice during 2013 by SCUBA diving and pulling ropes and aquaculture cages.
    [Show full text]
  • 3 Castilla.Pmd
    Revista de Biología Marina y Oceanografía 43(3): 457-467, diciembre de 2008 Fifty years from the publication of the first two papers on Chilean rocky intertidal assemblages: Honoring Professor Eric R. Guiler Cincuenta años desde la publicación de los dos primeros trabajos sobre el intermareal rocoso de Chile: Homenaje al Profesor Eric R. Guiler Juan Carlos Castilla1*, D. Sc. 1Departamento de Ecología & Centre for Advances Studies in Ecology and Biodiversity (CASEB). Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile [email protected] Resumen.- En este trabajo, reviso y rindo honor a los Abstract.- In this paper I review and honor the scientific principales hallazgos científicos del investigador australiano, rocky intertidal findings made by the Australian investigator Profesor Eric R. Guiler, quien en 1955 visitó las costas de Chile Professor Eric R. Guiler, who visited Chile in 1955. He y realizó trabajos pioneros sobre zonaciones bióticas pioneered this line of research in the country and published intermareales. Producto de ello publicó los dos primeros the first two papers on the Chilean rocky intertidal biotic trabajos sobre las comunidades intermareales rocosas de Chile zonation for northern and central Chile: Guiler 1959a, b. I norte y central: Guiler 1959a, b. Además, destaco sus principales remark Guiler´s main observations and hypotheses about the observaciones e hipótesis sobre el funcionamiento de estas comunidades en relación con sus estructuras y dinámicas. En structure and dynamics of these systems. I highlight the particular, resalto las observaciones realizadas por Guiler al observations made by Guiler inside the Bay of Antofagasta and interior de la bahía de Antofagasta y las contrasto con trabajos contrast them with recent experimental ecological work carried experimentales de terreno recientes.
    [Show full text]
  • Marine Ecosystem Engineering by the Alien Ascidian Pyura Praeputialis on a Mid-Intertidal Rocky Shore
    MARINE ECOLOGY PROGRESS SERIES Vol. 268: 119–130, 2004 Published March 9 Mar Ecol Prog Ser Marine ecosystem engineering by the alien ascidian Pyura praeputialis on a mid-intertidal rocky shore Juan Carlos Castilla1,*, Nelson A. Lagos1, 2, Mauricio Cerda1 1Center For Advanced Studies in Ecology & Biodiversity (CASEB), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile 2Present address: Escuela de Ciencias Básicas, Universidad Santo Tomás, Manuel Rodríguez 97, Santiago, Chile ABSTRACT: Engineer species transform ecosystems due to their own growth, constitute an integral part of altered environments, and provide new habitats for other species, thus affecting biodiversity and the ecosystem. On rocky shores inside Antofagasta Bay (Northern Chile), the alien ascidian Pyura praeputialis, an engineer species, creates broad belts and dense 3-dimensional matrices that modify the intertidal habitat structure. In all, 116 species of macro-invertebrates and algae inhabit this habitat, compared with the 66 species inhabiting adjacent intertidal rocky shores which lack P. praeputialis. Of the 145 species recorded at the seascape scale (encompassing both mid-intertidal habitat), 55% were found exclusively in intertidal P. praeputialis matrices. Along the coastal gradi- ent, patterns in β-diversity emerge due to the addition of a new set of species to the community inhab- iting the P. praeputialis matrices and, to a lesser extent, from spatial turnover. We found differences in the shape of the species frequency distribution between the communities inhabiting the engi- neered and non-engineered mid-intertidal habitats. However, within the same habitat type, there was no difference in the species frequency distribution between functional groups.
    [Show full text]
  • The Peracarid Epifauna Associated with the Ascidian Pyura Chilensis (Molina, 1782) (Ascidiacea: Pyuridae)
    J N H, 2003, 37, 13, 1555–1569 The peracarid epifauna associated with the ascidian Pyura chilensis (Molina, 1782) (Ascidiacea: Pyuridae) R. SEPU´ LVEDA†, J. M. CANCINO† and M. THIEL‡* †Facultad de Ciencias, Universidad Cato´lica de la Santı´sima Concepcio´n, Casilla 297, Concepcio´n, Chile ‡Facultad de Ciencias del Mar, Universidad Cato´lica del Norte, Larrondo 1281, Coquimbo, Chile (Accepted 21 September 2001) Epifaunal peracarids inhabit a variety of biogenic substrata, including ascidians. Herein we examined the peracarid fauna living on the tunica of the sublittoral ascidian Pyura chilensis growing in offshore and nearshore conditions in Bahı´a San Vicente, Chile. From a total of 38 samples we collected 17 species of Amphipoda, five Isopoda and two Tanaidacea. The similarity between the sites was high (73.8%, Sorensen’s index). Species diversity (H∞) was 2.8 and 2.6, evenness (J) was 0.7 and 0.6 at the offshore and nearshore site, respectively. Both species and individual number increased significantly with the size (volume) of the ascidian samples, and these relationships did not differ between the sites. Many species, in particular the most abundant ones, occurred at both sites, but some species were restricted either to the offshore (three species) or to the nearshore site (seven species). Amphipods and tanaids were the most abundant taxa at both sites. The peracarid fauna at both sites was dominated by suspension- feeding peracarids (>80% of the individuals), which utilize the ascidians primarily as shelter, feeding on allochthonous material, i.e. not originating from the ascid- ians. It is suggested that the high percentage of suspension-feeding species among the epifaunal peracarids is due to the fact that ascidians settle and grow at sites that provide optimal feeding conditions for these organisms.
    [Show full text]
  • Ascidian Fauna (Tunicata, Ascidiacea) of Subantarctic and Temperate Regions of Chile
    Ascidian fauna (Tunicata, Ascidiacea) of subantarctic and temperate regions of Chile Running title: Ascidian fauna of Chile Xavier Turon1*, Juan I. Cañete2, Javier Sellanes3,4, Rosana M. Rocha5, Susanna López-Legentil6 1Center for Advanced Studies of Blanes (CEAB-CSIC), Blanes, Girona, Spain 2Facultad de Ciencias, Universidad de Magallanes, Punta Arenas, Chile 3Departamento de Biología Marina, Facultad de Ciencias del Mar, Universidad Católica del Norte, Coquimbo, Chile 4Millenium Nucleus for Ecology and Sustainable Management of Oceanic Islands (ESMOI), Chile 5Departamento de Zoologia, Universidade Federal do Paraná, Curitiba, Brazil 6Department of Biology and Marine Biology, and Center for Marine Science, University of North Carolina Wilmington, Wilmington, NC, USA ABSTRACT We studied the ascidian fauna from two zones located in subantarctic (Punta Arenas, latitude 53º) and temperate Chile (Coquimbo, latitude 29º). The different oceanographic features of the two zones, with influence of the Humboldt Current in the north and the Cape Horn Current System and freshwater inputs in the south, led to markedly different ascidian faunas. A total of 22 species were recorded, with no shared species across the two areas (11 species each). The new species Polyzoa iosune is described, Lissoclinum perforatum is found for the first time in the Pacific Ocean, and Synoicum georgianum and Polyzoa minor are new to the Chilean fauna. The populations of Ciona in the Coquimbo area (formerly attributed to Ciona intestinalis) correspond to the species Ciona robusta. A total of 35 Cytochrome oxidase (COI) sequences of the standard barcode region have been obtained for 17 of the 22 species reported. INTRODUCTION The Chilean coasts provide a unique scenario for biodiversity studies, as it spans a wide range of latitude (ca.
    [Show full text]