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Biofouled debris from the 2011 Great East Japan earthquake and tsunami has landed in the Northeast Pacific and along the Hawaiian Islands since 2012. As of 2017, >630 biofouled debris items with >320 living species of algae, invertebrates, and fish have been examined. The invasive mussel Mytilus galloprovincialis was present on >50% of those items. Size, reproduction, and growth of this filter-feeding species were examined to better understand long-distance rafting of a coastal species. The majority of mussels (79%) had developing or mature gametes, and growth rates averaged 0.075±0.018 SE mm/day. Structural and elemental (barium/calcium) analysis of mussel shells generated estimates of growth in coastal waters (mean=1.3 to 25mm total length), which provides an indication of residence times in waters along North America and the Hawaiian Islands prior to landing. Detailed studies of individual species contribute to our understanding of debris as a transport vector and aid efforts to evaluate potential risks associated with marine debris., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

We announce the nearly complete mitochondrial genome sequences of two hexactinellid sponges, Bathydorus laniger and Docosaccus maculatus A contiguous region of over 15,000 bp was sequenced from each genome. An uncommon structural element was identified as a series of repetitive elements with sequences matching cob in the genome of D. maculatus ., (Copyright © 2018 Kahn and Geller.)

The 2011 East Japan earthquake generated a massive tsunami that launched an extraordinary transoceanic biological rafting event with no known historical precedent. We document 289 living Japanese coastal marine species from 16 phyla transported over 6 years on objects that traveled thousands of kilometers across the Pacific Ocean to the shores of North America and Hawai'i. Most of this dispersal occurred on nonbiodegradable objects, resulting in the longest documented transoceanic survival and dispersal of coastal species by rafting. Expanding shoreline infrastructure has increased global sources of plastic materials available for biotic colonization and also interacts with climate change-induced storms of increasing severity to eject debris into the oceans. In turn, increased ocean rafting may intensify species invasions., (Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

The advancement of metabarcoding techniques, declining costs of high-throughput sequencing and development of systematic sampling devices, such as autonomous reef monitoring structures (ARMS), have provided the means to gather a vast amount of diversity data from cryptic marine communities. However, such increased capability could also lead to analytical challenges if the methods used to examine these communities across local and global scales are not standardized. Here we compare and assess the underlying biases of four ARMS field processing methods, preservation media, and current bioinformatic pipelines in evaluating diversity from cytochrome c oxidase I metabarcoding data. Illustrating the ability of ARMS-based metabarcoding to capture a wide spectrum of biodiversity, 3,372 OTUs and twenty-eight phyla, including 17 of 33 marine metazoan phyla, were detected from 3 ARMS (2.607 m2 area) collected on coral reefs in Mo'orea, French Polynesia. Significant differences were found between processing and preservation methods, demonstrating the need to standardize methods for biodiversity comparisons. We recommend the use of a standardized protocol (NOAA method) combined with DMSO preservation of tissues for sessile macroorganisms because it gave a more accurate representation of the underlying communities, is cost effective and removes chemical restrictions associated with sample transportation. We found that sequences identified at ≥ 97% similarity increased more than 7-fold (5.1% to 38.6%) using a geographically local barcode inventory, highlighting the importance of local species inventories. Phylogenetic approaches that assign higher taxonomic ranks accrued phylum identification errors (9.7%) due to sparse taxonomic coverage of the understudied cryptic coral reef community in public databases. However, a ≥ 85% sequence identity cut-off provided more accurate results (0.7% errors) and enabled phylum level identifications of 86.3% of the sequence reads. With over 1600 ARMS deployed, standardizing methods and improving databases are imperative to provide unprecedented global baseline assessments of understudied cryptic marine species in a rapidly changing world.

Anthropogenic vectors have moved marine species around the world leading to increased invasions and expanded species' ranges. The biotic resistance hypothesis of Elton (in The ecology of invasions by animals and plants, 1958) predicts that more diverse communities should have greater resistance to invasions, but experiments have been equivocal. We hypothesized that species richness interacts with other factors to determine experimental outcomes. We manipulated species richness, species composition (native and introduced) and availability of bare space in invertebrate assemblages in a marina in Monterey, CA. Increased species richness significantly interacted with both initial cover of native species and of all organisms to collectively decrease recruitment. Although native species decreased recruitment, introduced species had a similar effect, and we concluded that biotic resistance is conferred by total species richness. We suggest that contradictory conclusions in previous studies about the role of diversity in regulating invasions reflect uncontrolled variables in those experiments that modified the effect of species richness. Our results suggest that patches of low diversity and abundance may facilitate invasions, and that such patches, once colonized by non-indigenous species, can resist both native and non-indigenous species recruitment., (© 2015 The Author(s).)

We evaluated mercury (Hg) exposure and two biomarkers, metallothionein (MT) gene expression and histopathological alterations in a wild fish species, largemouth bass (Micropterus salmoides), collected from the Sacramento-San Joaquin Delta, CA, a region polluted with Hg from historic mining activities. Hg is highly toxic and can disrupt multiple physiological systems in vertebrate species, including the immune system. Total mercury (THg) concentration in muscle tissue ranged from 0.12 to 0.98 ppm (wet weight) and was not related to body condition (r (2) = 0.005, p = 0.555). Using linear regression analysis, we found a positive relationship between MT gene expression (as determined using quantitative polymerase chain reaction) and copper, zinc, manganese, aluminum, and nickel (decreased to one variable by way of principal component analysis) (r (2) = 0.379, p = 0.044), a negative relationship with selenium (r (2) = 0.487, p = 0.017), and a weak, negative relationship with THg concentrations (r (2) = 0.337, p = 0.061). Juvenile largemouth bass collected from Hg-contaminated areas displayed histopathological features of immunosuppression compared with those collected from less contaminated areas as evidenced by significantly lower macrophage density in kidney and liver tissue (p = 0.018 and 0.020, respectively), greater trematode density in liver tissue (p = 0.014), and a greater number of adult trematodes. Our results suggest that largemouth bass may be experiencing sublethal effects from chronic Hg exposure. Furthermore, our findings illustrate the utility of examining multiple sublethal markers of effect to assess the impacts of contaminant exposure on physiological function in wild species.

Two new species of glass sponge were discovered from the abyssal plain 200 km west of the coast of California (Station M). The sponges have similar gross morphology--an unusual plate-like form with basalia stilling the body above soft abyssal sediments. Bathydorus laniger sp. n. differs from its congeners by the presence of dermal and atrial stauractins; it is also supported by smooth hypodermal pentactins and hypoatrial hexactins. Microscleres include oxyhexasters and oxyhemihexasters. Docosaccus maculatus sp. n. contains large hexactins (>1 cm), characteristic of the genus. Megascleres include dermal hexactins, atrial pentactins, and choanosomal hexactins and diactins. Microscleres include oxytipped hemihexasters and floricomes. Several features serve to differentiate this species from its only known congener.

Watersipora is an invasive genus of bryozoans, easily dispersed by fouled vessels. We examined Cytochrome c oxidase subunit I haplotypes from introduced populations on the US Pacific coastline to investigate geographic segregation of species and/or haplotypes. In California, the W. subtorquata group fell into three major sub-groups: W. subtorquata clades A and B, and W. "new sp.". W. subtorquata clades A and B were common in southern California south of Point Conception, a recognized biogeographic boundary, whereas further north, W. subtorquata clade A and W. n. sp. were frequent. The southern California region also had colonies of a morphologically distinct species, W. arcuata, also found in southern Australia and Hawaii; COI variation indicates a common ancestral source(s) in these introductions. The distribution of Watersipora-complex lineages on different coastlines is shown to be temperature correlated. Accordingly, pre-exisitng temperature-based adaptations may play a key role in determining invasion patterns.

The extent to which the geographic distributions of marine organisms have been reshaped by human activities remains underappreciated, and so does, consequently, the impact of invasive species on marine ecosystems. The application of molecular genetic data in fields such as population genetics, phylogeography, and evolutionary biology have improved our ability to make inferences regarding invasion histories. Genetic methods have helped to resolve longstanding questions regarding the cryptogenic status of marine species, facilitated recognition of cryptic marine biodiversity, and provided means to determine the sources of introduced marine populations and to begin to recover the patterns of anthropogenic reshuffling of the ocean's biota. These approaches stand to aid materially in the development of effective management strategies and sustainable science-based policies. Continued advancements in the statistical analysis of genetic data promise to overcome some existing limitations of current approaches. Still other limitations will be best addressed by concerted collaborative and multidisciplinary efforts that recognize the important synergy between understanding the extent of biological invasions and coming to a more complete picture of both modern-day and historical marine biogeography.

The European green crab Carcinus maenas is one of the world's most successful aquatic invaders, having established populations on every continent with temperate shores. Here we describe patterns of genetic diversity across both the native and introduced ranges of C. maenas and its sister species, C. aestuarii, including all known non-native populations. The global data set includes sequences from the mitochondrial cytochrome c oxidase subunit I gene, as well as multilocus genotype data from nine polymorphic nuclear microsatellite loci. Combined phylogeographic and population genetic analyses clarify the global colonization history of C. maenas, providing evidence of multiple invasions to Atlantic North America and South Africa, secondary invasions to the northeastern Pacific, Tasmania, and Argentina, and a strong likelihood of C. maenas x C. aestuarii hybrids in South Africa and Japan. Successful C. maenas invasions vary broadly in the degree to which they retain genetic diversity, although populations with the least variation typically derive from secondary invasions or from introductions that occurred more than 100 years ago.

Sea anemones (Phylum Cnidaria; Class Anthozoa, Order Actiniaria) exhibit a diversity of developmental patterns that include cloning by fission. Because natural histories of clonal and aclonal sea anemones are quite different, the gain and loss of fission is an important feature of actiniarian lineages. We have used mitochondrial DNA and nuclear intron DNA phylogenies to investigate the evolution of longitudinal fission in sixteen species in the genus Anthopleura, and reconstructed an aclonal ancestor that has given rise at least four times to clonal descendents. For A. elegantissima from the northeastern Pacific Ocean, a transition to clonality by fission was associated with an up-shore habitat shift, supporting prior hypotheses that clonal growth is an adaptation to the upper shore. Fission in Actiniaria likely precedes its advent in Anthopleura, and its repeated loss and gain is perplexing. Field studies of the acontiate sea anemone Aiptasia californica provided insight to the mechanisms that regulate fission: subtidal Aiptasia responded to experimentally destabilized substrata by increasing rates of pedal laceration. We put forth a general hypothesis for actiniarian fission in which sustained tissue stretch (a consequence of substratum instability or intrinsic behavior) induces tissue degradation, which in turn induces regeneration. The gain and loss of fission in Anthopleura lineages may only require the gain and loss of some form of stretching behavior. In this view, tissue stretch initiates a cascade of developmental events without requiring complex gene regulatory linkages.

The perceived wide geographic range of organisms in the sea, facilitated by ready dispersal of waterborne dispersal stages, is a challenge for hypotheses of marine speciation but a boon to efforts of marine conservation. Wide species ranges are especially striking in the reef-rich Indo-west Pacific, the largest and most diverse marine biogeographic region, extending across half the planet. The insular marine biota of the tropical Pacific is characterized by wide-ranging species and provides the most striking examples of long distance dispersal, with endemism largely confined to the most remote island groups. Here we show that the gastropod Astralium "rhodostomum" has developed endemic clades on almost every Pacific archipelago sampled, a pattern unprecedented in marine biogeography, and reminiscent of the terrestrial biota of oceanic islands. Mitochondrial DNA sequences indicate that this species-complex is comprised of at least 30 geographically isolated clades, separated by as little as 180 km. Evidence suggests that such fine scale endemism and high diversity is not exceptional, but likely characterizes a substantial fraction of the reef biota. These results imply that (1) marine speciation can regularly occur over much finer spatial scales than generally accepted, (2) the diversity of coral reefs is even higher than suggested by morphology-based estimates, and (3) conservation efforts need to focus at the archipelagic level in the sea as on land.

Clonal growth and symbiosis with photosynthetic zooxanthellae typify many genera of marine organisms, suggesting that these traits are usually conserved. However, some, such as Anthopleura, a genus of sea anemones, contain members lacking one or both of these traits. The evolutionary origins of these traits in 13 species of Anthopleura were inferred from a molecular phylogeny derived from 395 bp of the mitochondrial 16S rRNA gene and 410 bp of the mitochondrial cytochrome oxidase subunit III gene. Sequences from these genes were combined and analyzed by maximum-parsimony, maximum-likelihood, and neighbor-joining methods. Best trees from each method indicated a minimum of four changes in growth mode and that symbiosis with zooxanthellae has arisen independently in eastern and western Pacific species. Alternative trees in which species sharing growth modes or the symbiotic condition were constrained to be monophyletic were significantly worse than best trees. Although clade composition was mostly consistent with geographic sympatry, A. artemisia from California was included in the western Pacific clade. Likewise, A. midori from Japan was not placed in a clade containing only other Asian congeners. The history of Anthopleura includes repeated shifts between clonality and solitariness, repeated attainment of symbiosis with zooxanthellae, and intercontinental dispersal.

Diagnostic length differences in a PCR amplified fragment of the gene for byssal adhesive protein were used to study the zoogeographic distribution of Mytilus galloprovincialis and M. trossulus along the west coast of North America and in Japan. The distributions of M. galloprovincialis and M. trossulus are patchy, although an overall geographic pattern emerges. M. galloprovincialis was the only species found on either Kyushu or Honshu, and it was the most abundant mussel from Tomales Bay to San Diego, California. M. trossulus was the only bay mussel found on Hokkaido and in Alaska, and it was by far the most abundant mussel along the coasts of Washington and Oregon. Mytilus galloprovincialis and M. trossulus are sympatric and hybridize near Whidbey Island, Washington, in San Francisco Bay, and in San Diego Bay. A second diagnostic anonymous nuclear PCR marker was used to examine the extent of hybridization at Palo Alto, California. At this site, genotypes appeared to be a mixture of M. galloprovincialis, F1 hybrids between M. galloprovincialis and M. trossulus, and backcrosses between the F1's and M. galloprovincialis. The discontinuity between the zoogeographic distributions of these two species at about 40{deg}-41{deg}N latitude in both the eastern and western Pacific suggests that temperature is a factor in determining their present distribution and limiting their dispersal to other regions.

Coastal marine ecosystems world-wide are threatened by invasions of nonindigenous species. The ubiquity of marine sibling species identifiable only by genetic analysis suggests that many invasions are cryptic and therefore undetected, causing an underestimation of the actual number and impacts of invading species. We test this hypothesis with European crabs in the genus Carcinus that have invaded five regions globally. Partial 16S ribosomal RNA gene sequences confirm sibling species status of morphologically similar Atlantic C. maenas and Mediterranean C. aestuarii. Based on 16S rRNA haplotypes, crabs from California, New England and Tasmania were all C. maenas. However, we report the cryptic multiple invasion of both species in Japan and South Africa, where only C. aestuarii and C. maenas, respectively, were previously recognized.

Ocean-going ships carry, as ballast, seawater that is taken on in port and released at subsequent ports of call. Plankton samples from Japanese ballast water released in Oregon contained 367 taxa. Most taxa with a planktonic phase in their life cycle were found in ballast water, as were all major marine habitat and trophic groups. Transport of entire coastal planktonic assemblages across oceanic barriers to similar habitats renders bays, estuaries, and inland waters among the most threatened ecosystems in the world. Presence of taxonomically difficult or inconspicuous taxa in these samples suggests that ballast water invasions are already pervasive.

A 560-base pair portion of the mitochondrial 16S ribosomal DNA (16S rDNA) from three morphologically similar mussels, Mytilus edulis, M. galloprovincialis, and M. trossulus, was amplified with the polymerase chain reaction, and 349 base pairs were sequenced. These data showed that this gene in M. edulis and M. galloprovincialis has not diverged; however, the north Pacific mussel, M. trossulus, showed fixed differences from M. edulis and M. galloprovincialis at 5 nucleotide positions. Furthermore, the population of M. trossulus at Tillamook Bay, Oregon, was found to contain two very divergent 16S rDNA genotypes that differ at 37 nucleotide positions. Thus, intraspecific variation in this gene in M. trossulus is greater than that seen interspecifically in M. edulis and M. galloprovincialis. Despite this large difference, in the absence of evidence of genetic isolation between these groups of M. trossulus, no taxonomic changes are proposed. These data are consistent with a north Pacific origin of the genus with subsequent dispersal to the Atlantic Ocean across the Artic Sea, giving rise to M. edulis in northern Europe and subsequently M. galloprovincialis in southern Europe and the Mediterranean Sea.

In a 17-year-old woman, motor aphasia developed during her second bout of multiple sclerosis, characterized by absent spontaneous speech, paraphasias in naming and repetition, and marked orofacial apraxia, with relative preservation of written language and intact auditory comprehension. A mild right hemiparesis was associated. Bilateral cerebral lesions were demonstrated on a computerized tomographic brain scan. The aphasia remitted over 1 month.