DOCSLIB.ORG

Ascophyllum Nodosum) and Associated Epifaunal Communities Following Cutter Rake Harvesting in Maine

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Ascophyllum Nodosum) and Associated Epifaunal Communities Following Cutter Rake Harvesting in Maine Evaluation of short-term changes in rockweed (Ascophyllum nodosum) and associated epifaunal communities following cutter rake harvesting in Maine Thomas J. Trott Friedman Field Station, Suffolk University, Edmunds, Maine 04628 Department of Biology, Suffolk University, Boston, Massachusetts 02114 and Peter F. Larsen Bigelow Laboratory, PO Box 475, 180 McKown Point Rd. West Boothbay, Maine 04575 Report to Department of Marine Resources Marine Resources Laboratory P.O. Box 8 194 McKown Point Rd. W. Boothbay Harbor, Maine 04575-0008 INTRODUCTION North Atlantic intertidal areas are often dominated by the rockweed Ascophyllum nodosum which can grow to greatest length and mass on wave protected shores. Rockweed is a long-lived canopy alga. In some areas it can achieve near mono-specific cover. The holdfasts and three-dimensional canopy of rockweed beds provide habitat for intertidal invertebrates and fish, and offer a place for attachment of their eggs and epiphytic algae. Rockweed is harvested for use in cosmetics, processed foods, domestic animal feeds and fertilizers. It has been harvested commercially for decades in the Gulf of Maine. Concerns about harvesting have generated numerous publications and workshops (e.g., Rangeley and Davies, 2000). While it is well documented that harvesting rockweed stimulates growth (Lazo and Chapman, 1996; Ugarte, et al., 2006), less attention has been directed towards disturbance effects at the community level. If associated animal communities are affected by rockweed harvesting, then the way that harvesting is done with a cutter-rake would produce a patchwork of disturbance. Harvesting with a cutter-rake removes rockweed in patches over large areas on an incoming tide. Once in a rockweed bed, a harvester targets the largest or bulkier plants in the water that can be reached with his rake. The harvester’s boat moves with the wind and tide to a random position where the bulkiest floating plants are targeted. As a result, the cut plant is chosen by the harvester but position in the bed is not. The goal is to harvest maximum biomass, although the lengths that plants are cut can vary from changes in visibility, the harvester’s stroke and depth perception. Harvesting is conducted in accordance to regulations requiring a 16” length minimum of plant along with its holdfast remain. Potential effects on fauna associated with rockweed at the scale of a rockweed bed would be linked to the patches where targeted plants were removed. The degree of disturbance might fluctuate according to the varying amount of plant removed. A recent increase in harvesting rockweed has raised public concern in Maine and re- stimulated interest to evaluate some basic potential impacts. This study was undertaken to examine the effectiveness of current regulations on cutter-rake harvesting for preventing and/or minimizing impact on rockweed and associated macroinvertebrates. Short-term recovery, two months following a single harvest, was the time course for evaluating disturbance effects. 1 METHODS A field experiment was conducted using a modified Before-After, Control-Impact (BACI) experimental design with stratified random destructive sampling to evaluate some potential effects of harvesting. The study site was located in Shackford Head State Park, Cobscook Bay, Maine to minimize uncontrolled disturbance from anthropogenic activities (Figure 1). In July 2008, rockweed biomass and associated epifaunal species on rockweed thalli and holdfasts with contiguous substrate were assessed in adjacent control and experimental plots (Figure2). In each plot, four quadrats were sampled per tidal stratum (high, mid, low intertidal). Positions of randomly selected 1/16-m2 quadrats were recorded with GPS. Within each quadrat, plants were sheared just above their holdfasts (<1cm) and transported to the laboratory where they were washed with freshwater under pressure above a 0.5 mm screen to collect mobile epifauna. Material retained on the sieve was preserved in 10% formalin and stained with Rose Bengal. Rockweed samples were drained of excess water and weighed. Individual thalli were examined for attached and remaining mobile epifauna, and eggs. All mobile fauna was saved with sieved material. In the field, epifauna within each quadrat exposed after removing rockweed was collected with forceps. Surfaces were scraped to collect rockweed holdfasts and remaining epifauna (Figure 3). Samples were washed and material retained on a 0.5mm sieve was preserved in 10% formalin and stained with Rose Bengal. Animals were sorted, identified to the lowest taxon possible, and counted. Species names were checked in the World Register of Marine Species database (http://www.marinespecies.org/) to insure use of current valid names. All formalin preserved samples were transferred to ethanol for archiving at the Maine Department of Marine Resources. The impact of harvesting as it is done commercially was a priority so treatments could not be randomly assigned to quadrats within each plot with plants cut at uniform heights. That would not match how rockweed is commercially harvested. Instead, immediately after sampling, rockweed was harvested in the experimental plot by a professional harvester from Acadian Seaplants Limited, New Brunswick, using a cutter rake (Figure 4). The harvester followed Maine Department of Marine Resources harvesting regulations and their activities observed and 2 documented (Figure 5). During harvesting, plants were not cut below 16 inches or the first branch of the primary thalli. Approximately 1.25 wet tons of rockweed was harvested by one person in 1.5 h and an estimated 17% of the biomass of rockweed in the study area was removed. Both plots were re-sampled in September leaving two months of recovery for the harvested experimental plot. Re-sampling the same quadrat was avoided since the GPS location of each quadrat sampled in July was known. Making a priority on assessing the effects of harvesting rockweed commercially rather than through experimentally consistent, controlled hand removal from much smaller patches placed conditions on how data were analyzed. Although each plot had 12 sample quadrats, these were not independent replicates. This meant that parametric analyses were not valid. Keeping this in mind, analyses performed were for summarizing results observed and not for statistical significance. When statistical significance is given, it is for presentation purposes only. None- the- less, these results are clearly evident in graphical illustrations even without statistics. Another constraint on the experimental design was financial. This dictated the number of plots that could be studied. In keeping with the priority of commercial harvesting effects, having more than one experimental plot was not financially feasible. These caveats need to be held in mind by the reader throughout the presentation of data, results and conclusions. Rockweed biomass and epifauna data were analyzed with a paired BACI design where the differences in measurements before and after in control and experimental plots were tested for using a two-sample t-test. This procedure tests for the significance of impact (Smith et al. 1993; Stewart-Oaten et. al., 1986; Stewart-Oaten and Bence, 2001) which in this case is harvesting. Specifically, before harvest measurements from experimental plots are subtracted from control plot measurements and the mean difference compared using a two-sample t-test with that derived using the same method but with measurements taken after harvesting. Additional tests for differences in epifauna distribution according to habitat were conducted using ANOVA. When warranted, multiple comparison tests were performed using the Student Newman-Keuls Test to identify significant differences among groups. Rockweed biomass was analyzed using simple linear regression to examine relationships. Cluster analysis and non-parametric multidimensional scaling were performed on epifauna data using PRIMER ver. 6 (Plymouth Routines in Multivariate Ecological Research) 3 (Clarke and Warwick, 2001). Species counts were filtered according to statistical test protocols for cluster analysis and multidimensional scaling. This included eliminating all colonial species from the analysis since these did not represent counts. Also, species which occurred in 10% or less of all samples were designated as rare and removed from the analysis. The remaining species counts which represented the bulk of the data were square root transformed to allow intermediate abundant species to contribute to the similarity matrix calculated using the Bray-Curtis Index. Cluster and non-parametric multidimensional scaling analyses were performed on the resulting Bray-Curtis coefficients. Significant differences (P<0.05) between species grouped according to cluster analysis were determined using the PRIMER SIMPROF routine. For all analyses in this study, α = 0.05 was the level for significance. When statistical significance is given, it is for presentation purposes only for reasons described earlier. RESULTS Harvesting had a significant impact on rockweed Ascophyllum nodosum biomass (t= 2.117, P= 0.046) (Figure 6A). Biomass of rockweed in the experimental plot was greater following harvesting. September biomass was significantly different from July in the harvested plot (Student Newman-Keuls Test, q= 4.032, P=0.007), while the control plot showed no significant change (Figure 6B). There was a significant (P<0.05) direct linear relationship between the number of thalli and weight
Load more

Recommended publications
  • National Monitoring Program for Biodiversity and Non-Indigenous Species in Egypt
    UNITED NATIONS ENVIRONMENT PROGRAM MEDITERRANEAN ACTION PLAN REGIONAL ACTIVITY CENTRE FOR SPECIALLY PROTECTED AREAS National monitoring program for biodiversity and non-indigenous species in Egypt PROF. MOUSTAFA M. FOUDA April 2017 1 Study required and financed by: Regional Activity Centre for Specially Protected Areas Boulevard du Leader Yasser Arafat BP 337 1080 Tunis Cedex – Tunisie Responsible of the study: Mehdi Aissi, EcApMEDII Programme officer In charge of the study: Prof. Moustafa M. Fouda Mr. Mohamed Said Abdelwarith Mr. Mahmoud Fawzy Kamel Ministry of Environment, Egyptian Environmental Affairs Agency (EEAA) With the participation of: Name, qualification and original institution of all the participants in the study (field mission or participation of national institutions) 2 TABLE OF CONTENTS page Acknowledgements 4 Preamble 5 Chapter 1: Introduction 9 Chapter 2: Institutional and regulatory aspects 40 Chapter 3: Scientific Aspects 49 Chapter 4: Development of monitoring program 59 Chapter 5: Existing Monitoring Program in Egypt 91 1. Monitoring program for habitat mapping 103 2. Marine MAMMALS monitoring program 109 3. Marine Turtles Monitoring Program 115 4. Monitoring Program for Seabirds 118 5. Non-Indigenous Species Monitoring Program 123 Chapter 6: Implementation / Operational Plan 131 Selected References 133 Annexes 143 3 AKNOWLEGEMENTS We would like to thank RAC/ SPA and EU for providing financial and technical assistances to prepare this monitoring programme. The preparation of this programme was the result of several contacts and interviews with many stakeholders from Government, research institutions, NGOs and fishermen. The author would like to express thanks to all for their support. In addition; we would like to acknowledge all participants who attended the workshop and represented the following institutions: 1.
    [Show full text]
  • Mild Osmotic Stress in Intertidal Gastropods Littorina Saxatilis and Littorina Obtusata (Mollusca: Caenogastropoda): a Proteomic Analysis
    CORE Metadata, citation and similar papers at core.ac.uk Provided by Saint PetersburgFULL State University COMMUNICATION PHYSIOLOGY Mild osmotic stress in intertidal gastropods Littorina saxatilis and Littorina obtusata (Mollusca: Caenogastropoda): a proteomic analysis Olga Muraeva1, Arina Maltseva1, Marina Varfolomeeva1, Natalia Mikhailova1,2, and Andrey Granovitch1 1 Department of Invertebrate Zoology, Faculty of Biology, Saint Petersburg State University, Universitetskaya nab. 7–9, St. Petersburg, 199034, Russian Federation; 2 Center of Cell Technologies, Institute of Cytology RAS, Tikhoretsky prospect, 4, St. Petersburg, 194064, Russian Federation Address correspondence and requests for materials to Arina Maltseva, [email protected] Abstract Salinity is a crucial abiotic environmental factor for marine animals, affecting their physiology and geographic ranges. Deviation of environmental salin- ity from the organismal optimum range results in an osmotic stress in osmo- conformers, which keep their fluids isotonic to the environment. The ability to overcome such stress is critical for animals inhabiting areas with considerable salinity variation, such as intertidal areas. In this study, we compared the reac- tion to mild water freshening (from 24 to 14 ‰) in two related species of inter- tidal snails, Littorina saxatilis and L. obtusata, with respect to several aspects: survival, behavior and proteomic changes. Among these species, L. saxatilis is Citation: Muraeva, O., Maltseva, A., Varfolomeeva, M., Mikhailova, N., more tolerant to low salinity and survives in estuaries. We found out that the Granovitch, A. 2017. Mild osmotic response of these species was much milder (with no mortality or isolation re- stress in intertidal gastropods Littorina saxatilis and Littorina obtusata (Mollusca: action observed) and involved weaker proteomic changes than during acute Caenogastropoda): a proteomic analysis.
    [Show full text]
  • OREGON ESTUARINE INVERTEBRATES an Illustrated Guide to the Common and Important Invertebrate Animals
    OREGON ESTUARINE INVERTEBRATES An Illustrated Guide to the Common and Important Invertebrate Animals By Paul Rudy, Jr. Lynn Hay Rudy Oregon Institute of Marine Biology University of Oregon Charleston, Oregon 97420 Contract No. 79-111 Project Officer Jay F. Watson U.S. Fish and Wildlife Service 500 N.E. Multnomah Street Portland, Oregon 97232 Performed for National Coastal Ecosystems Team Office of Biological Services Fish and Wildlife Service U.S. Department of Interior Washington, D.C. 20240 Table of Contents Introduction CNIDARIA Hydrozoa Aequorea aequorea ................................................................ 6 Obelia longissima .................................................................. 8 Polyorchis penicillatus 10 Tubularia crocea ................................................................. 12 Anthozoa Anthopleura artemisia ................................. 14 Anthopleura elegantissima .................................................. 16 Haliplanella luciae .................................................................. 18 Nematostella vectensis ......................................................... 20 Metridium senile .................................................................... 22 NEMERTEA Amphiporus imparispinosus ................................................ 24 Carinoma mutabilis ................................................................ 26 Cerebratulus californiensis .................................................. 28 Lineus ruber .........................................................................
    [Show full text]
  • Rough Periwinkles at Emersion Presence Or Absence of Response in Gene Expression of Aspartate Aminotransferase?
    Rough periwinkles at emersion Presence or absence of response in gene expression of aspartate aminotransferase? CH-14 Cecilia Helmerson Degree project for Master of Science (Two Years) in Marine Sciences and Biology Degree course in Marine ecology 45 hec Spring and Autumn 2014 Department of Biological and Environmental Sciences University of Gothenburg Examiner: Kerstin Johannesson Department of Biological and Environmental Sciences University of Gothenburg Supervisors: Marina Panova and Olga Ortega Martinez Department of Biological and Environmental Sciences University of Gothenburg Illustration: Cecilia Helmerson 2014 Index ABSTRACT ............................................................................................................................................................ 4 1. INTRODUCTION ............................................................................................................................................. 5 2. MATERIALS AND METHODS ................................................................................................................... 7 2.1 SAMPLING AND ACCLIMATION ....................................................................................................................................... 7 2.2 EMERSION EXPERIMENT .................................................................................................................................................. 8 2.3 DISSECTION AND EXTRACTION ..................................................................................................................................
    [Show full text]
  • Littorina Saxatilis Olivi and Littorina Neritoides L
    HELGOLANDER MEERESUNTERSUCHUNGEN I Helgol~nder Meeresunters. 44, 125-134 (1990) Heat production in Littorina saxatilis Olivi and Littorina neritoides L. (Gastropoda: Prosobranchia) during an experimental exposure to air Inge Kronberg Zoologisches Institut der Christian-Albrechts-Universit~t, Abt. Marine Okologie und Systematik; Olshausenstrai~e 40-60, D-2300 Kiel, Federal Republic of Germany ABSTRACT: The adaptation of littorinid molluscs to prolonged aerial exposure was investigated by the determination of heat production. I_ittorina saxatilis, inhabiting the upper euhttoral, reached a maximum metabolic activity during submersion (heat production: 3.26x 10-3J S-l(gadw)-1. On the first three days of desiccation, the heat production was continuously reduced to 40% of the submersed value. A prolonged aerial exposure was lethal for this species. In the supralittoral L. neritoides, three stages of energy metabohsm could be observed: an intermediate heat production during submersion {1.97 x I0-3j s-l{gaaw)-1), an increased metabohsm during the first hour of aerial exposure (heat production 204 % of submersed value), and a minimal metabolism (39% of the submersed value and 19 % of maximum value) during the following days and weeks of desiccation. Recovery depended on water salinity; L. saxatilis proved to be less euryhaline than L. neritoides. Thus, the metabolic adaptations correlate with the level of littoral habitat; inactivity combined with a drastically reduced energy consumption is a metabolically economic way to survive in periodically dry environments. INTRODUCTION Littorinid snails are characteristic molluscan inhabitants of rocky shores worldwide and mark the upper limit of marine influence. They live in a habitat of unpredictable change in moisture, salinity and temperature (Kronberg, 1988).
    [Show full text]
  • Number of Species of Vascular Plants, Which We Had Anticipated Would Be Higher
    PagelS4 CHAPTER 5. RESULTS A! TAXONOMIC GROUPS OF INTRODUCED SPECIES In all,we documented 212species ofintroduced organisms inthe Estuary. Thenumbers of speciesper taxonomic group are presented in Figures 2 and3 at lowerand higher levels of aggregation.Invertebrates arethe most common major groupof introducedspecies, accounting for nearly 70'/o of the total, followed by vertebratesand plants with respectivelyabout 15 and 12 percent of thetotaL The mostabundant invertebrates were the arthropods 6'to of invertebrates! followed by molluscs0'10!, annelids 4'/o! andcnidarians 2'fo!. Nearly all thevertebrates were fish,and most of theplants were vascular plants, which were about evenly split between monocots and dicots. Thesenumbers are generally in accordwith our expectations prior to this study,based upon our knowledge of theEstuary's biota and consideration of other regionalreviews of introduced marine and aquatic species, with the exception ofthe numberof species ofvascular plants, which we had anticipated would be higher. Thisresult is in partdue to ourapplication of relatively more restrictive criteria for theinclusion of marsh-edge plants, as discussed inChapter 2. Pagel55 Results For example,a studyof introduced speciesin theGreat Lakes using less restrictive criteriaproduced a listof 139introduced speciesof which59 species 2%!were vascular plants Mills et al., 1993!, and a similarstudy of the HudsonRiver produced a listof 154 introducedspecies with 97 3%! vascular plants Mills et al., 1995!. As suggested inthe "Methods"section, adding the plants in Appendix1 essentiaByterrestrial plants that havebeen reported in orat theedge of the tidaIwaters of theEstuary! to thelist of organismsin Table 1 producesa list of introducedspecies that can more reasonably be comparedto the Great Lakes and Hudson Riverlists, Thisexpanded list for the Estuary contains 240 introducedspecies of which49 0%!are vascular plants.
    [Show full text]
  • Phylogenetics of Hydroidolina (Hydrozoa: Cnidaria) Paulyn Cartwright1, Nathaniel M
    Journal of the Marine Biological Association of the United Kingdom, page 1 of 10. #2008 Marine Biological Association of the United Kingdom doi:10.1017/S0025315408002257 Printed in the United Kingdom Phylogenetics of Hydroidolina (Hydrozoa: Cnidaria) paulyn cartwright1, nathaniel m. evans1, casey w. dunn2, antonio c. marques3, maria pia miglietta4, peter schuchert5 and allen g. collins6 1Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66049, USA, 2Department of Ecology and Evolutionary Biology, Brown University, Providence RI 02912, USA, 3Departamento de Zoologia, Instituto de Biocieˆncias, Universidade de Sa˜o Paulo, Sa˜o Paulo, SP, Brazil, 4Department of Biology, Pennsylvania State University, University Park, PA 16802, USA, 5Muse´um d’Histoire Naturelle, CH-1211, Gene`ve, Switzerland, 6National Systematics Laboratory of NOAA Fisheries Service, NMNH, Smithsonian Institution, Washington, DC 20013, USA Hydroidolina is a group of hydrozoans that includes Anthoathecata, Leptothecata and Siphonophorae. Previous phylogenetic analyses show strong support for Hydroidolina monophyly, but the relationships between and within its subgroups remain uncertain. In an effort to further clarify hydroidolinan relationships, we performed phylogenetic analyses on 97 hydroidolinan taxa, using DNA sequences from partial mitochondrial 16S rDNA, nearly complete nuclear 18S rDNA and nearly complete nuclear 28S rDNA. Our findings are consistent with previous analyses that support monophyly of Siphonophorae and Leptothecata and do not support monophyly of Anthoathecata nor its component subgroups, Filifera and Capitata. Instead, within Anthoathecata, we find support for four separate filiferan clades and two separate capitate clades (Aplanulata and Capitata sensu stricto). Our data however, lack any substantive support for discerning relationships between these eight distinct hydroidolinan clades.
    [Show full text]
  • Marlin Marine Information Network Information on the Species and Habitats Around the Coasts and Sea of the British Isles
    MarLIN Marine Information Network Information on the species and habitats around the coasts and sea of the British Isles Ascophyllum nodosum, sponges and ascidians on tide-swept mid eulittoral rock MarLIN – Marine Life Information Network Marine Evidence–based Sensitivity Assessment (MarESA) Review Frances Perry & Charlotte Marshall 2015-10-05 A report from: The Marine Life Information Network, Marine Biological Association of the United Kingdom. Please note. This MarESA report is a dated version of the online review. Please refer to the website for the most up-to-date version [https://www.marlin.ac.uk/habitats/detail/100]. All terms and the MarESA methodology are outlined on the website (https://www.marlin.ac.uk) This review can be cited as: Perry, F. & Marshall, C., 2015. [Ascophyllum nodosum], sponges and ascidians on tide-swept mid eulittoral rock. In Tyler-Walters H. and Hiscock K. (eds) Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. DOI https://dx.doi.org/10.17031/marlinhab.100.1 The information (TEXT ONLY) provided by the Marine Life Information Network (MarLIN) is licensed under a Creative Commons Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales License. Note that images and other media featured on this page are each governed by their own terms and conditions and they may or may not be available for reuse. Permissions beyond the scope of this license are available here. Based on a work at www.marlin.ac.uk (page left blank) Date: 2015-10-05 Ascophyllum nodosum, sponges and ascidians on tide-swept mid eulittoral rock - Marine Life Information Network Ascophyllum nodosum, sponges and ascidians on tide-swept mid eulittoral rock Photographer: Rohan Holt Copyright: Joint Nature Conservation Committee (JNCC) 17-09-2018 Biotope distribution data provided by EMODnet Seabed Habitats (www.emodnet-seabedhabitats.eu) Researched by Frances Perry & Charlotte Marshall Refereed by This information is not refereed.
    [Show full text]
  • Environmental DNA and Specific Primers for Detecting the Invasive
    sustainability Article Environmental DNA and Specific Primers for Detecting the Invasive Species Ectopleura crocea (Hydrozoa: Anthoathecata) in Seawater Samples Philjae Kim 1 , Tae Joong Yoon 2 and Sook Shin 2,3,* 1 Research & Development Division, National Science Museum, Daejeon 34143, Korea; [email protected] 2 Institute of Marine Life Resources, Sahmyook University, Seoul 01795, Korea; [email protected] 3 Department of Animal Biotechnology & Resource, Sahmyook University, Seoul 01795, Korea * Correspondence: [email protected]; Tel.: +82-2-3399-1717 Received: 31 January 2020; Accepted: 16 March 2020; Published: 18 March 2020 Abstract: In marine environments, environmental DNA (eDNA) can be effectively detected and possibly quantified when combined with molecular techniques, as demonstrated by several recent studies. In this study, we developed a species-specific primer set and a probe to detect the distribution and biomass of an invasive hydrozoan in South Korea, Ectopleura crocea. These molecular markers were designed to amplify a 187 bp region based on mitochondrial cytochrome c oxidase subunit I (COI) of E. crocea and were tested on seawater samples from 35 Korean harbors in 2017. Of the 35 sites we investigated, only nine harbors returned positive detections when using traditional survey methods, while surveys based on the use of eDNA techniques detected E. crocea DNA in all seawater samples. These results suggest that eDNA surveys based on molecular techniques are more effective at identifying species distribution and estimating biomass than traditional surveys based on visual assessment of morphology. Keywords: Ectopleura crocea; environmental DNA; invasive species; monitoring; species-specific markers; quantitative PCR 1. Introduction Environmental DNA (eDNA) refers to DNA that can be extracted from environmental samples such as soil, sediments, water, or snow [1], and species detection methods using eDNA have become new monitoring tools for the study and management of organisms in various ecosystems [2–4].
    [Show full text]
  • Homogenization of Rafting Assemblages on Floating
    Journal of Sea Research 95 (2015) 161–171 Contents lists available at ScienceDirect Journal of Sea Research journal homepage: www.elsevier.com/locate/seares Castaways can't be choosers — Homogenization of rafting assemblages on floating seaweeds Lars Gutow a,⁎, Jan Beermann b, Christian Buschbaum c, Marcelo M. Rivadeneira d,e,MartinThield,e a Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Box 12 01 61, 27515 Bremerhaven, Germany b Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Biologische Anstalt Helgoland, Box 180, 27483 Helgoland, Germany c Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Wadden Sea Station Sylt, Hafenstraße 43, 25992 List/Sylt, Germany d Facultad Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, 1781421 Coquimbo, Chile e Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Av. Ossandón 877, CP. 1781681, Coquimbo, Chile article info abstract Article history: After detachment from benthic habitats, the epibiont assemblages on floating seaweeds undergo substantial Received 29 November 2013 changes, but little is known regarding whether succession varies among different seaweed species. Given that Received in revised form 12 June 2014 floating algae may represent a limiting habitat in many regions, rafting organisms may be unselective and Accepted 10 July 2014 colonize any available seaweed patch at the sea surface. This process may homogenize rafting assemblages on Available online 19 July 2014 different seaweed species, which our study examined by comparing the assemblages on benthic and floating individuals of the fucoid seaweeds Fucus vesiculosus and Sargassum muticum in the northern Wadden Sea Keywords: Epibiota (North Sea). Species richness was about twice as high on S.
    [Show full text]
  • Resolving the 150 Year Debate Over the Ecological History of the Common Periwinkle Snail, Littorina Littorea, in Northeast North America
    University of New Hampshire University of New Hampshire Scholars' Repository Doctoral Dissertations Student Scholarship Spring 2007 Resolving the 150 year debate over the ecological history of the common periwinkle snail, Littorina littorea, in northeast North America April M H Blakeslee University of New Hampshire, Durham Follow this and additional works at: https://scholars.unh.edu/dissertation Recommended Citation Blakeslee, April M H, "Resolving the 150 year debate over the ecological history of the common periwinkle snail, Littorina littorea, in northeast North America" (2007). Doctoral Dissertations. 364. https://scholars.unh.edu/dissertation/364 This Dissertation is brought to you for free and open access by the Student Scholarship at University of New Hampshire Scholars' Repository. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of University of New Hampshire Scholars' Repository. For more information, please contact [email protected]. RESOLVING THE 150 YEAR DEBATE OVER THE ECOLOGICAL HISTORY OF THE COMMON PERIWINKLE SNAIL, Littorina littorea, IN NORTHEAST NORTH AMERICA. BY APRIL M.H. BLAKESLEE B.A., Boston University, 1998 M.A., Boston University, 2001 DISSERTATION Submitted to the University of New Hampshire in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Zoology May, 2007 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. UMI Number: 3260587 INFORMATION TO USERS The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleed-through, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted.
    [Show full text]
  • Eutely, Cell Lineage, and Fate Within the Ascidian Larval Nervous System: Determinacy Or to Be Determined?1
    184 REVIEW / SYNTHÈSE Eutely, cell lineage, and fate within the ascidian larval nervous system: determinacy or to be determined?1 Ian A. Meinertzhagen Abstract: The larval central nervous system (CNS) of the ascidian Ciona intestinalis (L., 1767) arises from an embry- onic neural plate and contains sufficiently few cells, about 330, to enable definitive counts. On the basis of such counts, there is evidence both for cell constancy (eutely) in the larval CNS and for small variations in the overall num- bers of cells and among defined cell types within this total. However, evidence for the range of such deviations and the existence of a true phenotypic wild type are lacking. The record of cell lineage, i.e., the mitotic ancestry of each cell, and the fates of some of these cells have recently received increased documentation in both the genus Ciona and Halocynthia roretzi (von Drasche, 1884). Relatively few generations of cells, between 10 and 14, form the entire CNS in C. intestinalis, and cell death does not occur prior to larval hatching. The tiny complement of larval CNS cells can therefore be seen as the product of a small fixed number of determinate cleavages, and variations in cell number as the product of minor deviations in this mitotic ancestry. Within these lineage records, some cell fates have already been identified, but knowledge of most is lacking because the cells lack markers or other identifying features. Nevertheless, this tiny nervous system offers the prospect that all its cells can one day be identified, and their developmental histo- ries and larval functions analyzed, cell by cell.
    [Show full text]