Gretchen Lambert

Alien species and other notable records from a rapid assessment survey of marinas on the south coast of England

Arenas, F., Bishop, J.D.D., Carlton, J.T., Dyrynda, P.J., Farnham, W.F., Gonzalez, D.J., Jacobs, M.W., Lambert, C., Lambert, G., Nielsen, S.E., Pederson, J.A., Porter, J.S., Ward, S., Wood, C.A. (2006). Alien species and other notable records from a rapid assessment survey of marinas on the south coast of England. Journal of the Marine Biological Association of the United Kingdom, 86, (6), 1329-1337. Sponsorship: National Science Foundation grant IOB 0407527; Esme Fairbairn Foundation ALIENS project

Rapid Assessment Survey for exotic organisms in southern California bays and harbors, and abundance in port and non-port areas

In recent decades, the world has witnessed an array of harmful invasions by exotic marine organisms. To provide the public and policymakers with better information on the status of exotic species in southern California waters, and to assess differences between port and non-port areas, a Rapid Assessment Survey of selected habitat types in sheltered waters between San Diego and Oxnard was conducted in the summer of 2000. The objectives included comparing the prevalence of exotic species among habitats and regions and between recent and past surveys; obtaining reference data for future assessments of changes in invasion status and the effectiveness of prevention or control efforts; detecting new invasions; and documenting significant range extensions. Twenty-two sites were sampled to include the three major commercial port areas in southern California, non-port-area marinas and lagoon sites. Sampling included dock fouling and adjacent soft-bottom benthos, nearby intertidal sites, and selected subtidal lagoon habitats. Samples were collected by a variety of manual techniques. Sixty-nine of the species collected are exotic, including representatives from two algal divisions and six invertebrate phyla. Ascidians are especially well-represented (14 exotic species) and widely occurring, and some bivalves and bryozoans also occur very widely. The numbers and proportions of exotic taxa were not significantly greater in port areas than in non-port areas.

A Global Overview of Ascidian Introductions and Their Possible Impact on the Endemic Fauna

Recent surveys of invertebrates in many coastal areas throughout the world demonstrate the ever-increasing rate of introduction of nonindigenous ascidians. Harbors, with their protected waters and large marinas, are usually the entry points for organisms carried in ballast water or on boat hulls. Marina floats, harbor buoys and boat hulls provide a huge surface area for settlement. Introductions may be further aided by transport of contaminated shells or live bivalves between mariculture facilities. Many ascidians reach sexual maturity and produce a second generation in just a few weeks. This review summarizes the results of recent studies of coastal areas, ballast water and harbor structures in many parts of the world, and sampling of U.S. Navy drydocks recently moved between major Pacific ports. Some of these studies include companion surveys of neighboring natural shallow environments. Most natural areas appear to have resisted invasions of nonindigenous ascidians except where perturbation has resulted in a decrease in species diversity.

Tunicate Eggs Utilize Ammonium Ions for Flotation

Unlike most solitary ascidians, Corella willmeriana retains its eggs and embryos well past hatching. The early stages float to the top of the enlarged atrium from which they cannot escape. Ammonium ions replace other more dense substances in the cell sap of the float cells surrounding the embryo. Energy derived from glycolysis but not mitochondrial processes supports this process.

Anthropogenic Biotic Interchange in a Coral Reef Ecosystem: A Case Study from Guam

Guam is the administrative and economic hub of Micronesia, hosts one of the largest U.S. military bases in the Pacific, and lies at the crossroads among Pacific islands, the United States, and Asia. Although terrestrial introductions, exemplified by the brown tree snake, have received much attention, marine introductions have been little studied until now. We have documented a diverse assemblage of marine species brought to Guam by human-mediated transport: a few intentionally, most unintentionally. Sessile species dominate the nonindigenous biota. Because of Guams tourism-based economy, ballast water is not a major source of introductions, but ships hulls have brought many invaders. A study of the fauna associated with two dry docks demonstrates the large impact of such structures, moved slowly from harbor to harbor after long residence times. The majority of nonindigenous species have remained confined to artificial substrata in the harbor, but some have invaded adjacent coral reef habitats and spread islandwide. Although several nonindigenous species are now well established, major impacts to reefs on Guam remain to be identified. Space on reefs is vastly dominated by indigenous species; in contrast artificial substrata often have an abundance of nonindigenous species.

Ascidian eggs block polyspermy by two independent mechanisms: One at the egg plasma membrane, the other involving the follicle cells

Many ascidians live in clumps and usually release sperm before the eggs. Consequently, eggs are often spawned into dense clouds of sperm. Because fertilization by more than a single sperm is lethal, ascidians have evolved at least two successive blocks to polyspermy: the rapid release of a glycosidase that inhibits sperm binding to the vitelline coat (VC) and a subsequent change in membrane potential that prevents supernumerary sperm–egg fusion. This paper shows that (1) these two blocks can be uncoupled by the use of suramin, and (2) most of the glycosidase appears to be from the follicle cells, which are accessory cells on the outside of the egg VC. Phallusia mammillata eggs initially bind numerous sperm but, after the glycosidase is released, only a few additional sperm bind. Intact eggs in 20 μM suramin release glycosidase, but the electrical response is inhibited; sperm swim actively and bind to the VC but fail to penetrate. Suramin treatment is completely reversible; intact eggs exhibit the electrical response an average of 11 minutes after the drug is washed out. Sperm must contact the follicle cells before passing through the VC; eggs with the VC removed and fertilized in the presence of 20 μM suramin show the electrical response 35% of the time, thus VC removal enhances sperm entry. Like the intact eggs, 100% of the naked eggs respond electrically to fertilization after the drug is washed out. Follicle cells that are isolated by calcium magnesium free seawater and then returned to complete seawater release N‐acetylglucosaminidase activity in response to sperm. Thus, these eggs have two blocks to polyspermy that operate in sequence: an early first block resulting from enzymatic modification of the VC by N‐acetylglucosaminidase released primarily from follicle cells and a second electrical block operating at the egg plasma membrane level and requiring sperm–egg fusion. Mol. Reprod. Dev. 48:137‐143, 1997.

Isodiplamine, cystodytin K and lissoclinidine: novel bioactive alkaloids from the New Zealand ascidian Lissoclinum notti

Abstract A study of the bioactive crude extract of the New Zealand ascidian Lissoclinum notti led to the isolation of the new pyridoacridine alkaloids isodiplamine ( 4 ), cystodytin K ( 5 ) and lissoclinidine ( 6 ), as well as the known pyridoacridine alkaloids diplamine ( 7 ) and cystodytin J ( 8 ) and the benzopentathiepin varacin ( 3 ) and related trithiane varacin A. The new alkaloids were characterised using standard spectroscopic techniques, including 2D 1H–15N NMR experiments. Pyridoacridine alkaloids 4–8 were assayed for a range of biological activities including antitumour and antibiotic properties.

Spicule formation in the solitary ascidian, Herdmania momus

Two types of calcareous spicules occur abundantly in Herdmania momus, a solitary pyurid ascidian with a worldwide warm water distribution. The large spindle‐shaped body spicules are 1.5–2.5‐mm long and are located primarily in the mantle, siphons, and branchial basket. Each body spicule possesses 100 or more rows of overlapping, unidirectional fringing spines. Numerous body spicules occur regularly spaced within a long common sheath of complex structure, and there are many sheaths per animal. Between neighboring body spicules and overlying the fringing spines are the tightly connected pseudopodial sclerocytes. Spine formation is hypothesized to occur within these cells. The body spicules apparently continue to increase in size throughout the animals life.

The role of actin and myosin in ascidian sperm mitochondrial translocation

Fertilization-related sperm mitochondrial movement occurs at a rate comparable to other actin-myosin-driven movements and is inhibited by cytochalasin B and N-ethyl maleimide in Ascidia ceratodes sperm. F-actin was demonstrated in the tails and mitochondria using NBD-phallacidin fluorescence. Both actin and myosin were also detected on the mitochondrion and in the tail by indirect immunofluorescence. Western blot analysis verified the presence of these proteins. Boltenia villosa and Cnemidocarpa finmarkiensis also have mitochondrion and tail localized actin and myosin. In the tails of all 3 species the fluorescence takes the form of discrete spots 0.25-0.5 micron apart. Boltenia and Cnemidocarpa sperm have additional actin at the tip of the head and additional myosin at the base of the head. The presence of actin and myosin on the mitochondrion and in the tail supports a means by which the force for mitochondrial movement is generated.

Algal symbionts in the tunics of six New Zealand ascidians (Chordata, Ascidiacea)

Filamentous eukaryotic algae were found completely embedded in the tunic matrix of 6 species of ascidians from the cold-temperate waters of southern New Zealand: the aplousobranch Aplidium thomsoni (Polyclinidae) and 5 solitary stolidobranchs, Asterocarpa humilis (Styelidae) and Pyura cancellata, P. carnea, P. pulla, and P. suteri (Pyuridae). All the ascidians appeared to be completely healthy, and the stolidobranchs showed evidence of tunic blood vessel hypertrophy in the regions of algal filaments. Only those individuals growing in at least a low-light environment contained algae; individuals of the same species growing in dark conditions contained none. The algal symbionts include Neevea repens (Rhodophyta), Pseudendoclonium submarinum and Ostreobium quekettii (Chlorophyta), and an unidentified filamentous (probable) phaeophyte. Dense growths of Neevea and Pseudendoclonium were found in the tunic matrix in all six ascidians, most abundantly just under the tunic cuticle but extending several millimeters into the tunic. Subsequent recent discovery of filamentous chlorophytes in the tunic of two species of American Pacific coast solitary ascidians leads us to conclude that this algal habitat may be a widespread phenomenon that has been overlooked in the supposition that the algae were merely epizoic. Most of these ascidians also contained numerous alga-filled tunic pockets probably formed during the incorporation of sand grains with epipsammic algae that later proliferated. Though previously noted anecdotally in the literature, this report is the first compilation of this algal assemblage. They include Sarcinochrysis marina (Chrysophyta), unidentified diatoms, unicellular chlorophytes, and the prokaryote cyanobacteria Dermocarpa, Xenococcus, and Synechococcus. Similar species, along with Oscillatoria, Spirulina, and Anabaena, were also found in the inter-tunic cavity of the peculiar double-tunic ascidians Pyura cancellata and P. carnea. Additional key words: Pyura, Pseudendoclonium, Neevea, Ostreobium, algae Adult ascidians are sessile, filter-feeding organisms usually found attached to rocks in the low intertidal and subtidal. The body of adult ascidians is covered by a tunic consisting of a vascularized extracellular matrix comprised of proteins and polysaccharides in which free cells move about. The matrix is covered by a thin cuticle (Hirose et al. 1992). In some species, sand grains incorporated into the growing tunic impart an extra rigidity to this covering. Most ascidians have a well-developed immune system and do not harbor endobionts, but a few species have evolved a mutualistic relationship with endobiotic algae (Lewin & Cheng 1989). With a single exception, all the algal species examined to date that live within ascidian tunics are prokaryotes: Prochloron and filamentous cyanophytes. These have been recorded only in tropical waters (the Great Barrier Reef and many islands in the Indo-Pacific and Caribbean; see Lewin & Cheng 1989 for review). The only record of a eukaryotic alga growing completely within an ascidian tunic is a brief report of the filamentous red alga Neevea repens embedded in the tunic of the phlebobranchs Phallusia mammillata and Ascidia mentula from Brittany, France (Feldmann 1967). In this paper we report the presence of filamentous eukaryotic algae occurring completely embedded within the tunic matrix of 6 species of ascidians from the cold-temperate waters of southern New Zealand. The ascidians include the solitary stolidobranchs Asterocarpa humilis (Styelidae), Pyura cancellata, P. carnea, P. pulla, and P. suteri (Pyuridae), and the aplousobranch Aplidium thomsoni (Polyclinidae). The This content downloaded from 207.46.13.110 on Fri, 09 Dec 2016 05:19:07 UTC All use subject to http://about.jstor.org/terms Lambert, Lambert, & Waaland algal symbionts include 4 filamentous species: Neevea repens (Rhodophyta), Pseudendoclonium submarinum and Ostreobium quekettii (Chlorophyta), and an unidentified species (probably Phaeophyta). This is the first record of algal symbionts in the tunic of solitary ascidians of the order Stolidobranchia, only the second record of eukaryotic algae in ascidian tunic and the first from the southern hemisphere. Several of the above-mentioned ascidians also contain numerous tunic pockets, apparently formed during incorporation of sand grains. These pockets are packed with diatoms and unicellular and filamentous cyanobacteria, probably as a result of proliferation of cells adherent on the trapped sand. Although these algae are not actually within the tunic matrix, they frequently constitute a large bulk of the tunic. They form an assemblage never before described in detail; we include here descriptions of the most abundant forms. Similar algal species are described from the seawater-filled inter-tunic cavity of Pyura cancellata and P. carnea, two New Zealand ascidians that have an unusual double tunic with the two layers connected by struts of