MBL scientists to present research at 2006 Ocean Sciences Meeting

February 20, 2006

Several scientists from the MBL (Marine Biological Laboratory) will be presenting their research at the 2006 Ocean Sciences Meeting, February 20-24, 2006 in Honolulu, Hawaii. The Ocean Sciences Meeting is a joint meeting of the American Society of Limnology and Oceanography (ASLO), the Estuarine Research Foundation (ERF), The Oceanography Society (TOS) and the American Geophysical Union (AGU).

Researcher: James McClelland
Title: Synthesis and Scaling of Hydrological and Biogeochemical data from the North Slope of Alaska: A Basis for Estimating Riverine Fluxes From Small Coastal Watersheds to the Arctic Ocean
Type of Presentation: Oral
Time & Location: Monday, February 20, 3:15 pm, Hawaii Convention Center, Room 321
Topic: Rivers deliver an average of about 3500 km3 of freshwater directly into the Arctic Ocean each year. Two thirds of this water comes from seven very large rivers with watersheds extending far south of the Arctic Circle, whereas the remaining one third comes from numerous smaller rivers that drain fully arctic watersheds. In both cases, the waters are high in organic matter and low in inorganic nutrient content relative to average river waters globally. Estimating fluxes of organic matter and nutrients from these rivers is difficult because flow and constituent concentrations vary widely over the year and getting measurements that are well distributed over the annual hydrograph is a challenge. This is particulay true of the smaller rivers, many of which are neither gauged nor sampled routinely for chemical analyses. In our presentation, we will discuss preliminary results from a study of discharge-constituent relationships on the North Slope of Alaska that is designed to improve estimates of organic matter and nutrient fluxes from small coastal watersheds to the Arctic Ocean. Although the North Slope represents only a fraction of the coastal watershed area around the Arctic, modeling tools and analytical approaches being developing as a central part of this work will be more broadly applicable. Such tools are needed not only to better quantify contemporary fluxes, but to help us think about future changes in organic matter, nutrient, and water fluxes as a consequence global warming. Changes in the carbon and water balances of the Arctic may in turn exert strong feedbacks on the global climate system.

Researcher: David Patterson, Senior Scientist
Title: Names based services for improving connections between information about microbes on the internet - example of micro*scope
Type of Presentation: Poster
Time & Location: Monday, February 20, 4:30 pm, Hawaii Convention Center, Hall 3
Topic: Micro*scope (http://microscope.mbl.edu) is a communal web environment that has been designed to improve connections among distributed bodies of information about organisms. The site relies on the principle that all items of information are labeled with a name or a surrogate for a name. A system that manages names as metadata within network services can be used to organize local and distributed data. Micro*scope collaborates with NameBank (http://www.ubio.org) and calls upon its registry of over 4,000,000 names for use in a unified indexing structure. Micro*scope has been developed as a template structure so that it is portable, and can enable teams of collaborators to create co-operative distributed web resources. The use of names as the core of the organizational structure allows micro*scope to act as a bridge between data environments that are often isolated - with the vision of providing dynamic bridges that will link molecular data with traditional descriptive data and environmental data. These larger scale issues are being explored within MICROBIS, the data management environment for the International Census of Marine Microbes.

Speaker: Maureen Conte, Adjunct Scientist
Title: Modulation of Particle Scavenging in the Ocean Interior in Response to Mesoscale Surface Ocean Forcing
Type of Presentation: Poster
Time & Location: Monday, February 20, 4:30 pm, Hawaii Convention Center, Hall 3
Topic: Results from the Oceanic Flux Program time-series off Bermuda have shown that "episodic" flux peaks are often associated with transient surface forcing. In late November 1996, a phytoplankton bloom occurred that was forced by the interplay between seasonal destratification and perturbation of mixing dynamics due to passage of a mesoscale feature. Coincident with the feature's passage, mass flux at 3200 m abruptly increased by 2.5x. Lipid biomarker analyses indicated that at the onset of the event there was an increase in the flux of refractory materials that preceded the arrival of main pulse of surface-derived bloom detritus. We hypothesized that zooplankton grazing rates within the midwater column were stimulated by the increase in nutritive quality of the export flux which, in turn, led to an increase in suspended particle repackaging. Here we present new elemental data in support of this hypothesis. At the onset of this event, fluxes of lithogenic elements (Al, Ti, V, Fe) increased by a factor of four and remained elevated, indicating increased aggregation of suspended particles from the water column. In contrast, fluxes of biogenic elements (Ca, Si, Sr, Ni) covaried with the flux of surface-derived phytoplankton detritus. The flux patterns of P, Mn, Co, Mg and Ba suggested both surface-derived and scavenged sources. These results indicate that biological scavenging within the midwater column is modulated by the nutritive quality of particles encountered. Hence, mesoscale physical features that alter surface ocean productivity and the quality of the export flux will also affect the ecosystem processes that regulate biogeochemical cycling within the ocean interior.

Researcher: Linda Amaral-Zettler, Assistant Research Scientist
Title: A Microbial Diversity Survey of a Sewage- and Thermally- Impacted Estuary: Mt. Hope Bay, Massachusetts
Type of Presentation: Poster
Time & Location: Tuesday, February 21, 4:30 pm, Hawaii Convention Center, Hall 3
Topic: Coastal marine environments have been impacted by human activity for several centuries, including shoreline alteration, nutrient introduction, sedimentation, toxic compound release, and thermal modification. Mount Hope Bay, Massachusetts is an ideal site to base a study of human pathogen presence and distribution because it has several important sources of human impact, including sewage disposal sites and the thermal outfall of a power plant within a mile of each other. The Bay is currently undergoing limited monitoring for several different parameters, including fish populations, river runoff, meteorological forcing, tidal cycles and water chemistry as part of the Mt. Hope Bay Natural Laboratory (MHBNL) program, a 5-year interdisciplinary project at the University of Massachusetts Dartmouth School of Marine Science and Technology (SMAST). While phytoplankton and zooplankton communities in the water column have been fairly well monitored, although not at a molecular level, microbial communities remain relatively uncharacterized. We report the first comprehensive (eukaryal, bacterial, archaeal) data from small-subunit ribosomal RNA gene clone libraries for samples collected near the thermal plume and underlying sediments of the Brayton Point Power Plant. We have partial sequences of nearly 4,000 clones from two different sites and have further sequenced 1,000 unique clones from these to full-length. Not surprising, our findings reveal a highly diverse consortium of the three domains including relatives of sludge bacteria, polyaromatic hydrocarbon-degrading bacteria, and representatives related to the genera Staphylococcus, Streptococcus, and Clostridium. Phylogenetic analyses will further unveil the relationships of many of these clones and determine whether they are related to known pathogens and may possibly represent undescribed taxa. It is clear that even limited knowledge about the overall microbial community composition can lead to important observations about the ecosystem as a whole. Furthermore, understanding whether free-living pathogens participate in relationships with other members of the microbial community will be important in understanding their distributions and persistence.

Researcher: Linda Amaral-Zettler, Assistant Research Scientist
Title: Amoebae and Legionella Species in Mt. Hope Bay
Type of Presentation: Poster
Time & Location: Tuesdsay, February 21, 4:30 pm, Hawaii Convention Center, Hall 3
Topic: Amoebae are known to serve as environmental reservoirs for species of Legionella. Most of these reports come from freshwater environments, but we have recently documented the occurrence and repeated recovery of amoeba cultures positive for legionellae from the coastal marine environment of Mt Hope Bay, Massachusetts. Sediment and water from four sites in this New England estuarine system were examined over a full year. The sites included the thermal plume region of a power plant, a secondary sewage outfall, a brackish environment and a coastal marine region considered impacted by normal bay conditions. Nucleic acids were extracted directly from water and sediment samples. Sediments were also enriched for amoeba cultures by agar plate methods, and amoeba isolates were processed for nucleic acids. All samples were amplified by a nested PCR procedure specific for Legionella species. Positive amplifications were recovered from sediment samples and amoeba cultures, and these products were collected for sequence analysis to determine what species of the bacterium were present. Although most of the legionellae were more similar to undescribed environmental isolates, at least one was similar to L. anisa, a human pathogen. Amoeba cultures positive for legionellae were also amplified using 18S ribosomal gene primers and are currently being sequenced to determine whether there is a relationship between the type of amoebae present and the type of Legionella present. There is potentially a seasonal pattern to the occurrence of legionellae and amoebae in Mt Hope Bay, and this will be discussed with reference to basic water column measurements taken during sample collection. These results do suggest the prevalence of potentially pathogenic legionellae in saline environments may be higher than previously thought, and could represent potential human health issues.

Researcher: Linda Amaral-Zettler, Assistant Research Scientist
Title: SARST-V6 Reveals Interesting Aspects of the Ecological Diversity in the Extremely Acidic Rio Tinto (Spain)
Type of Presentation: Poster
Time & Location: Tuesday, February 21, 4:30 pm, Hawaii Convention Center, Hall 3
Topic: The Rio Tinto is an extremely acidic, heavy metal laden river that runs through the Iberian Pyritic Belt in Southwestern Spain. Several studies have previously investigated the microbial communities in this extreme environment at both the prokaryotic and eukaryotic levels using culture-dependent and independent methods. We studied the bacterial diversity in the water column using a new high-throughput sequencing method called SARST-V6. We chose to study three key stations in the river because of their particular physico-chemical characteristics. Direct sequencing information obtained with SARST-V6 revealed a hidden bacterial diversity in the river. We observed what appears to be possible microheterogeneity of the predominant bacterial strains that represented more than 50% of all 10,000 tags sequenced. These are tags that matched known typical species from this river we well as other tags never reported before in this environment that matched uncultured bacteria typical from similar environments. The SARST-V6 method as applied to the Rio Tinto shows that an in-depth analysis of the community composition and structure reveals a level of microbial diversity not seen with traditional methods, and should help to understand the general principles that control microbial dynamics under variable environmental conditions.

Researcher: Linda Amaral-Zettler, Assistant Research Scientist
Title: ICoMM, The International Census of Marine Microbes: Unveiling the Ocean's Hidden Majority
Type of Presentation: Poster
Time & Location: Wednesday, February 22, 4:30 pm, Hawaii Convention Center, Hall 3
The International Census of Marine Microbes (ICoMM), http://icomm.mbl.edu, a recent addition to the Census of Marine Life Program (CoML) seeks to determine what is known, what is unknown but knowable, and what may never be known about the biodiversity of marine microorganisms. ICoMM is a joint venture between The Royal Netherlands Institute for Sea Research (NIOZ) and the MBL. The ICoMM Secretariat at Woods Hole hosts the website and the distributed database network, MICROBIS. It has sponsored meetings for the four primary working groups and its Scientific Advisory Council. Through a series of workshops that engage the international community of marine microbiologists, ICoMM is forging a large-scale strategic plan to characterize microbial diversity in the sea through molecular approaches and build a cyberinfrastructure to index and organize the emerging body of information. The community of microbial oceanographers represented within ICoMM (>100 and growing) recognizes the enormity of the task at hand both in terms of total volume of the oceans (estimated to be ~1-4 X 1018 m3) and marine sediments with a potential population of more than 1030 microbial cells. Although a complete census is most likely beyond our grasp, the scientific return will be considerable if the information is integrated with contextual information that can inform us about the interplay between microbial mediated activities and oceanic processes.

Speaker: Gabriele Gerlach, Associate Scientist
Title: Population Genetic Structure Of Three Coral Reef Fish Species
Type of Presentation: Oral Presentation
Time & Location: Thursday, February 23, 10:00 AM, Hawaii Convention Center, Room 318
Topic: Many reef animals, including fishes, have pelagic larval stages thought to enhance dispersal by ocean currents. We investigated the limits of dispersal and potential recruitment to natal spawning sites in three reef fish species with different larval pelagic dispersal characteristics: the neon damselfish, Pomacentrus coelestis, the cardinalfish, Apogon doederleini, and the spiny damselfish, Acanthochromis polyacanthus. We compared populations at five reefs of the Capricorn-Bunker group of Australia's Great Barrier Reef.

Speaker: Maureen Conte, Adjunct Scientist
Title: Advection of Detrital Carbonate Sediment to the Deep Ocean by Passage of Hurricane Fabian over Bermuda
Type of Presentation: Oral Presentation
Time & Location: Friday, February 24, 4:15 pm, Hawaii Convention Center, Room 317B
Topic: In September 2003, Hurricane Fabian passed over Bermuda with sustained winds of >190 km/hr. As evidenced by sensors on the Bermuda Testbed Mooring, Fabian induced large internal waves and strong rotational currents down to depths exceeding 200 m that scoured the southern slopes of the Bermuda pedestal. Large plumes of remobilized carbonate sediments were visible by SeaWiFS for several days following Fabian. This talk will explore the material intercepted and collected by the Oceanic Flux Program sediment traps, located 75 km SE of Bermuda. The flux generated by Fabian was, by far, the largest episodic deep ocean flux event observed in the entire 28-year time series.
The MBL is an international, independent, nonprofit institution dedicated to improving the human condition through creative research and education in the biological, biomedical and environmental sciences. Founded in 1888 as the Marine Biological Laboratory, the MBL is the oldest private marine laboratory in the Western Hemisphere. For more information, visit www.mbl.edu.

Marine Biological Laboratory

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