630 research outputs found
The Ellis Island Effect: Invasive Species in the Mid-Atlantic
Global invasions of marine species often follow human migration pathways and primary commerce routes. Exploration, immigration, and commerce to the United States has created hot spots for invasive species to become established. In particular, Ellis Island served as a primary spot for European immigrants over the last century. During the last 3 years, we have documented for the first time four non-native hydrozoans in New Jersey using molecular techniques.
Gonionemusvertens, Moerisiainkermanica, and Bougainvilliatriestinahave origins potentially linked to the Mediterranean indicating a potential group invasion from that region. Aequoreaaustralisis a Pacific hydrozoan whose origin pathway is yet unknown, but has now been documented in our region. As the benthic polyp stages of these species are diminutive
The Wonders of the Galapagos Islands: Experiential Learning is Deep Learning
Experiential learning is one way of creating deep understanding of subject matter, as well as developing a passion for the field. I have been engaged in leading extended field experiences with students for almost 20 years to ‘immerse’ students in the natural world. In March 2020, Dr. Krumins and I led a group of graduate and undergraduate students to Ecuador to explore and learn about the incredible wildlife and the enduring legacy of revolutionary ideas that this region has generated. Our time in the Galapagos, while short, spanned centuries of scientific thought and millions of years of geologic history. The Galapagos Islands have shaped our understanding of chemosynthesis and the origins of life on Earth and that radical idea of Evolution. Join me on an immersive journey
Proposals from the ERNCIP Thematic Group, “Case Studies for the Cyber-security of Industrial Automation and Control Systems”, for a European IACS Components Cyber-security Compliance and Certification Scheme. Thematic Area Industrial Control Systems and Smart Grids
All studies recently published agree. Industrial Automation and Control Systems (IACS) increasingly constitutes a target for cyber-attacks aiming at disturbing Member States’ economies, at disabling our critical infrastructures or at taking advantage from our people. Such hostile acts take place in a context of geostrategic tensions, for the satisfaction of organised crime’s purposes, or else in support of possible activist causes. In this context, the ERNCIP Thematic Group (TG) “Case studies for the cybersecurity of Industrial Automation & Control Systems” was started in January 2014 to answer the question: “Do European critical infrastructure operators need to get IACS’ components or subsystems tested and “certified” (T&C) with regards to their cybersecurity?” And should the answer have been yes, it had to answer a corollary question: “What are (roughly) the conditions of feasibility for implementing successfully a European IACS components cybersecurity Compliance & Certification Scheme?” This TG’s undertaking was a research project, not a task force seeking to deliver an immediately applicable standard. It mobilised representatives of IACS vendors, industrial operators, European Istitutions and national cybersecurity authorities.JRC.G.5-Security technology assessmen
Assessment of Seagrass Plant Demography Within and Among Beds of Turtle Grass (Thalassia testudinum), Manatee Grass (Syringodium filiforme), and Shoal Grass (Halodule wrightii) From the Northern Gulf of Mexico
Variability in the demographic patterns of seagrasses may affect a variety of physical and biological processes in aquatic communities. We investigated seasonal seagrass demography, sediment size structure, and sediment organic carbon from two sites (north and south) in St. Joseph Bay, Florida, for Thalassia testudinum, Syringodium filiforme, and Halodule wrightii. Geologically, sands dominated both sites, but the south site had significantly greater proportions of fine and very fine sands, whereas the north site was dominated by coarse and medium sands. Within each site, demographic parameters were assessed for edge (\u3c1 m) and interior portions (\u3e10 m) of grass beds. The objective was to quantify within-habitat demographic characteristics and assess whether differences in plant biomass and shoot density existed between edge and interior portions. Results for T. testudinum showed significantly greater shoot density (P \u3c 0.05) and plant biomass (P \u3c 0.001) from interior portions of the bed than from the edge for the north site, but there were no significant differences for the south site. Syringodium filiforme showed significantly greater shoot density from bed interiors than from edges for both the north and south sites (P \u3c 0.0001, P \u3c 0.001, respectively) as well as plant biomass (P \u3c 0.0001, P \u3c 0.01, respectively). Halodule wrightii showed a similar response, with greater shoot densities from the north interior (P \u3c 0.008) and significantly greater plant biomass from interior portions of beds for both the north and south sites (P \u3c 0.003, P \u3c 0.01, respectively). Within-bay comparisons showed that plant biomass and shoot density were generally greater from the north site than from the south site for T. testudinum and H. wrightii, but the reverse was true for S. filiforme. Although sands dominated both sites, the south site showed greater percentages of finer sediments, and S. filiforme biomass has been shown to be inversely related to sediment size. Although we were unable to resolve within-habitat differences in sediment size structure, which may suggest sediment baffling and water velocity changes, we surmise that physical and sedimentary differences exist between edge and interior portions of seagrass beds. These differences may have dramatic effects on processes such as larval settlement, predator-prey interactions, and per unit area primary production. As such, further investigations into within-habitat variability and edge effects in plant demography and associated biological and physical processes are needed
Use of Diadema antillarum Spines by Juvenile Fish and Mysid Shrimp
This research has the following objectives: 1) identify the size structure of D. antillarum among 3 coastal bays of St. John, United States Virgin Islands and 2) determine relationships between urchin presence and spine utilization by fish and mysid shrimp
Assessment of Seagrass Floral Community Structure from Two Caribbean Marine Protected Areas
Seagrass communities represent spatially complex and biomass producing systems comprised of intermixed seagrass and algal species. We investigated shallow water communities from two Marine Protected Areas (MPAs) in the Caribbean: St. John, United States Virgin Islands and Cayos Cochinos, Honduras. St. John sites (4) lie within the Virgin Islands National Park and the Coral Reef National Monument and are designated within an UNESCO Biosphere Reserve. Honduran sites (4) lie within the designated Marine National Monument. Our results indicate that both MPAs were dominated by Thalassia testudinum with spatial coverage and shoot density significantly greater in Honduras. Many sites also showed substantial cover of Syringodium filiforme, which was significantly greater in St. John. Most major algal groups showed significant differences between MPAs and among sites within locations. Specifically, Halimeda, Penicillus, Udotea, Galaxaura, and Dictyosphaeria were significantly more abundant in Honduras, while Padina and Avrainvillea were significantly greater from St. John. Additionally, only Honduran sites showed the presence of coral colonies (Montastrea and Porites) within their seagrass beds. Floral community level analyses demonstrated significant differences among almost all site comparisons suggesting relatively distinct floral communities exist within each of these regions, but both MPAs maintain high spatial coverage of seagrasses providing critical ecosystem services
Relationship Between Pea Crab (Pinnotheres maculatus) Parasitism and Gonad Mass of the Bay Scallop (Argopecten irradians)
We investigated the prevalence of pea crabs (Pinnotheres maculatus) in bay scallops (Argopecten irradians) from 1994 through 1996 in a scallop population from St. Joseph Bay, Florida. We also assessed their impacts on scallop reproductive potential. Our results showed that prevalence in bay scallops varied between 0 and 20% and were extremely low during 1996 (\u3c2%). Comparing Gonadal-Somatic Indices (GSI) between infested and non-infested bay scallops in samples assessed the impact of pinnotherid parasitism. Results showed that GSI was significantly reduced in infested individuals compared to non-infested individuals of the same size range (t12 = 2.3, P \u3c0.04). These results suggest that P. maculatus infestation may lower the reproductive potential of individual scallops, but the low rates of parasitism may only minimally impact the host population
Diet assessment of the Atlantic Sea Nettle Chrysaora quinquecirrha in Barnegat Bay, New Jersey, using next-generation sequencing
Next-generation sequencing (NGS) methodologies have proven useful in deciphering the food items of generalist predators, but have yet to be applied to gelatinous animal gut and tentacle content. NGS can potentially supplement traditional methods of visual identification. Chrysaora quinquecirrha (Atlantic sea nettle) has progressively become more abundant in Mid-Atlantic United States’ estuaries including Barnegat Bay (New Jersey), potentially having detrimental effects on both marine organisms and human enterprises. Full characterization of this predator’s diet is essential for a comprehensive understanding of its impact on the food web and its management. Here, we tested the efficacy of NGS for prey item determination in the Atlantic sea nettle. We implemented a NGS ‘shotgun’ approach to randomly sequence DNA fragments isolated from gut lavages and gastric pouch/tentacle picks of eight and 84 sea nettles, respectively. These results were verified by visual identification and co-occurring plankton tows. Over 550 000 contigs were assembled from ~110 million paired-end reads. Of these, 100 contigs were confidently assigned to 23 different taxa, including soft-bodied organisms previously undocumented as prey species, including copepods, fish, ctenophores, anemones, amphipods, barnacles, shrimp, polychaete worms, flukes, flatworms, echinoderms, gastropods, bivalves and hemichordates. Our results not only indicate that a ‘shotgun’ NGS approach can supplement visual identification methods, but targeted enrichment of a specific amplicon/gene is not a prerequisite for identifying Atlantic sea nettle prey items
First occurrence of the invasive hydrozoan Gonionemus vertens A. Agassiz, 1862 (Cnidaria: Hydrozoa) in New Jersey, USA
Gonionemus vertens A. Agassiz, 1862 is a small hydrozoan native to the Pacific Ocean. It has become established in the northern and southern Atlantic Ocean as well as the Mediterranean Sea. We report on the first occurrence of this species in estuaries in New Jersey, USA,and confirm species identification through molecular sequence analysis. Given the large number of individuals collected, we contend that this is a successful invasion into this region with established polyps. The remaining question is the vector and source of these newly established populations
A New Baseline for Diadema antillarum, Echinometra viridis, E. lucunter, and Eucidaris tribuloides Populations Within the Cayos Cochinos MPA, Honduras
We investigated the density of 4 urchin species from 5 shallow reefs in the Cayos Cochinos Marine Protected Area in Honduras. Individual species density varied among reefs with total urchin density ranging from 3.2–7.9 individuals/m2. Echinometra viridis (Agassiz, 1863) was the numerically dominant species (2.29/m2) followed by E. lucunter (Linnaeus, 1758) (1.76/m2) with Eucidaris tribuloides (Lamarck 1816) representing the fewest individuals (0.42/m2). Our results indicated that density of Diadema antillarum (Philippi, 1845) differed significantly among reefs (0.4-1.3/m2, mean = 0.63/m2), but are three times greater than data collected 12 years after the mass mortality event of the 1980’s. Size frequency analysis of D. antillarum indicated that test diameter also differed significantly among reef sites while correlation analysis showed that D. antillarum density was negatively related to both coral and algal cover. Echinometra viridis density, however, was positively related to coral cover (p \u3c 0.05). When all urchins were combined, they showed a negative correlation with algal cover and a positive correlation with coral cover indicating a potential top-down effect within the reefs. While urchin densities remain relatively low compared to other sites in the Caribbean, the D. antillarum population appears to be recovering in this Honduran MPA. If overall grazer abundance continues to increase then they may limit macroalgae on reefs, thereby encouraging coral settlement
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