Stevick_R_27November_2017

Graduate School of Oceanography - OCG 695
27 November, 3:30 PM, Coastal Institute Auditorium

Probiotic-Driven Changes in Microbial Communities in an Oyster Hatchery

Larval oysters in hatcheries are susceptible to diseases caused by marine bacterial pathogens, including Vibrio spp. These diseases can be prevented by daily addition of probiotics like Bacilus pumilus RI06-95 to water in rearing tanks. We propose that the presence of probiotics may change how the larvae respond to pathogens, regulate their environment, and recruit beneficial microbes. During three separate trials spanning the 2012-2015 growing seasons, rearing water samples (<2 liters) were collected from control and probiotic-treated tanks in an oyster hatchery at timepoints between Day 0 (spawning) and Day 12. Water samples were filtered onto 0.22 μm Sterivex filters and DNA was extracted directly from the filters, then prepared for sequencing. All tanks were analyzed using 16S rDNA sequencing of the V3-V4 or V6 regions and direct taxonomic classification, in order to determine microbial community structures. Overall, there was a significant effect of time, but no major effect of probiotics on the rearing water bacterial communities (Bray-Curtis k=2, 95% confidence). However, the presence of a higher proportion of Oceanospirillales spp. and Bacillus spp. was detected in the treated tanks. Co-occurrence network analysis suggests that the probiotic effect on the rearing water is mediated through select associated taxa. The results of this project will inform interactions between probiotics and microbial communities in oyster hatcheries, and how new probiotics may be designed.

Rebecca Stevick earned a B.S in Bioengineering from the University of Maryland in 2015. She enrolled in the PhD program at GSO in fall 2015. Her co-major professors are Dr. Anton Post and Dr. Marta Gómez-Chiarri.

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* 1. EVALUATOR FIRST NAME

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* 2. EVALUATOR LAST NAME

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* 3. EVALUATOR ROLE

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* 4. What aspects of the presentation were successful? Why?

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* 5. What do you suggest to improve?

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* 6. ABSTRACT METHODS/RESULTS: Methods succinctly identified the methods used. Results are succinct and provide a specific explanation of what was discovered, accomplished, collected or produced.

EXCELLENT: Describes methodology in an organized, specific and concise manner. Describes what they have learned. Relates results to the research question. Results include quantitative data.

VERY GOOD: Discusses the methods or resources. States results only qualitatively.

GOOD: Discusses the methods or resources, but is lacking in specifics. Provides superficial explanation of results.

FAIR: Provides little or no discussion of the methods or resources used.
Provides no results or does not explain why results were not possible.

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* 7. ABSTRACT MOTIVATION/IMPACT: Succinctly describes and appropriately connects the subject and background to the purpose of the research . Provides a succinct interpretation of the results and evaluates what the results mean to the investigation and the field of study.

EXCELLENT: Describes how the investigation, whether completed or not, fits within a larger field or continuing investigation in a clear and concise manner.

VERY GOOD: Indicates main subject and purpose of the research. Provides an interpretation of results

GOOD: Indicates main subject and purpose of the research and indicates why research is important but is somewhat lacking in specifics. Provides an interpretation of results but fails to place results in the larger context of the field.

FAIR: Indicates main subject and purpose of the research but lacks organization, or lacks specific details or fails to make connections, or contains no introduction. Provides a conclusion that specificity or provides no conclusion.

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* 8. PRESENTATION ORGANIZATIONAL PATTERN: Specific introduction and conclusion, sequenced material within the body and transitions.

EXCELLENT: Organizational pattern is clearly and consistently observable and is skillful and makes the content of the presentation cohesive. Listener can follow the line of reasoning.

VERY GOOD: Organizational pattern is clearly and consistently observable

GOOD: Organizational pattern is intermittently observable. A few minor points may be confusing.

FAIR: Organizational pattern is not observable. Organization seems haphazard.

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* 9. PRESENTATION STYLE: Posture, gestures, eye contact and use of the voice. Speaker stands and moves with authority, looks more often at the audience than notes, uses the voice expressively, and uses few vocal fillers (‘um” “uh,” “like,” “you know,” etc.).

EXCELLENT: Delivery techniques (posture, gesture, eye contact, and vocal expressiveness) make the presentation compelling and the speaker appears polished and confident.

VERY GOOD: Delivery techniques (posture, gesture, eye contact, and vocal expressiveness) make the presentation interesting and speaker appears comfortable. Speaker uses pointer appropriately.

GOOD: Delivery techniques (posture, gesture, eye contact, and vocal expressiveness) make the presentation understandable and speaker appears tentative. Speaker reads from text rather than too the audience. Speaker does not use pointer to clarify material.

FAIR: Delivery techniques (posture, gesture, eye contact, and vocal expressiveness) detract from the understandability of the presentation and speaker appears uncomfortable

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* 10. PRESENTATION SUPPORTING MATERIAL: Slide contents, figures, table, supporting material support the presentation and facility the central message.

EXCELLENT: Font is large enough to be seen by all. Information is organized to maximize audience understanding. Details are minimized so that main points stand out. All figures/table clearly labeled.

VERY GOOD: Font size is appropriate. Appropriate information is included.

GOOD: Font size is appropriate. Appropriate information is included. Some material is not supported by visual aids. Colors may be used inappropriately. Layout is confusing.

FAIR: Font size is too small to be easily seen. Too much information is included, layout is crowded, not enough time is spent on each graphic to allow audience to follow along. Listeners become confused.

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* 11. PRESENTATION CENTRAL MESSAGE AND CONTENT: The main point/thesis/bottom line/take away of the presentation. A clear central message is easy to identify and compelling (broader impacts.)

EXCELLENT: Central message is precisely stated, appropriately repeated, memorable and strongly supported. Speaker provides accurate and complete explanation of key concepts and theories. Listeners gain insights. Information included is consistently accurate. Study is placed in large context.

VERY GOOD: Central message is clear and consistent and supported. For the most part, explanations of concepts and theories are accurate and complete. No significant errors.

GOOD: Central message is basically understandable but is not often repeated and is not memorable. Any significant errors are attributable to nervousness.

FAIR: Central message can be deduced but is not explicitly stated in the presentation. Explanations of concepts are inaccurate or incomplete. Listeners gain little from the presentation.

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* 12. PRESENTATION - ANSWER QUESTIONS: Speaker demonstrates understanding of material and answers the questions asked and is respectful.

EXCELLENT: Demonstrates deep understanding of topic.

VERY GOOD: Answers most questions with knowledge.

GOOD: Has some difficulty answering challenging questions.

FAIR: Does not understand the question or has difficulty answering questions.

Other (please specify)