Bayer Skylar R.

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Skylar R.

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  • Article
    Detecting the influence of initial pioneers on succession at deep-sea vents
    (Public Library of Science, 2012-12-04) Mullineaux, Lauren S. ; Le Bris, Nadine ; Mills, Susan W. ; Henri, Pauline ; Bayer, Skylar R. ; Secrist, Richard G. ; Siu, Nam
    Deep-sea hydrothermal vents are subject to major disturbances that alter the physical and chemical environment and eradicate the resident faunal communities. Vent fields are isolated by uninhabitable deep seafloor, so recolonization via dispersal of planktonic larvae is critical for persistence of populations. We monitored colonization near 9°50′N on the East Pacific Rise following a catastrophic eruption in order to address questions of the relative contributions of pioneer colonists and environmental change to variation in species composition, and the role of pioneers at the disturbed site in altering community structure elsewhere in the region. Pioneer colonists included two gastropod species: Ctenopelta porifera, which was new to the vent field, and Lepetodrilus tevnianus, which had been rare before the eruption but persisted in high abundance afterward, delaying and possibly out-competing the ubiquitous pre-eruption congener L. elevatus. A decrease in abundance of C. porifera over time, and the arrival of later species, corresponded to a decrease in vent fluid flow and in the sulfide to temperature ratio. For some species these successional changes were likely due to habitat requirements, but other species persisted (L. tevnianus) or arrived (L. elevatus) in patterns unrelated to their habitat preferences. After two years, disturbed communities had started to resemble pre-eruption ones, but were lower in diversity. When compared to a prior (1991) eruption, the succession of foundation species (tubeworms and mussels) appeared to be delayed, even though habitat chemistry became similar to the pre-eruption state more quickly. Surprisingly, a nearby community that had not been disturbed by the eruption was invaded by the pioneers, possibly after they became established in the disturbed vents. These results indicate that the post-eruption arrival of species from remote locales had a strong and persistent effect on communities at both disturbed and undisturbed vents.
  • Article
    Effects of prior experience on shelter-seeking behavior of juvenile American lobsters
    (University of Chicago, 2017-05-24) Bayer, Skylar R. ; Bianchi, Katherine M. ; Atema, Jelle ; Jacobs, Molly W.
    Shelter-seeking behaviors are vital for survival for a range of juvenile benthic organisms. These behaviors may be innate or they may be affected by prior experience. After hatching, American lobsters Homarus americanus likely first come into contact with shelter during the late postlarval (decapodid) stage, known as stage IV. After the subsequent molt to the first juvenile stage (stage V), they are entirely benthic and are thought to be highly cryptic. We hypothesized that postlarval (stage IV) experience with shelter would carry over into the first juvenile stage (stage V) and reduce the time needed for juveniles to locate and enter shelters (sheltering). We found some evidence of a carryover effect, but not the one we predicted: stage V juveniles with postlarval shelter experience took significantly longer to initiate sheltering. We also hypothesized that stage V juveniles would demonstrate learning by relocating shelters more quickly with immediate prior experience. Our findings were mixed. In a maze, juveniles with immediate prior experience were faster to regain visual contact with shelter, suggesting that they had learned the location of the shelter. In contrast, there was no significant effect of immediate prior experience on time to initiate sheltering in an open arena, or in the maze after juveniles had regained visual contact. We conclude that very young (stage V) juvenile lobsters modify their shelter-seeking behavior based on prior experiences across several timescales. Ecologically relevant variation in habitat exposure among postlarval and early juvenile lobsters may influence successful recruitment in this culturally and commercially important fishery species.
  • Thesis
    Reproductive traits of pioneer gastropod species colonizing deep-sea hydrothermal vents after an eruption
    (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2011-06) Bayer, Skylar R.
    The colonization dynamics and life histories of pioneer species are vital components in understanding the early succession of nascent hydrothermal vents. The reproductive ecology of pioneer species at deep-sea hydrothermal vents may provide insight into their dispersal, population connectivity, and ability to colonize after disturbance. An opportunity to study the reproductive traits of two pioneer gastropod species, Ctenopelta porifera and Lepetodrilus tevnianus, presented itself in 2006 after an eruption on the East Pacific Rise (EPR) eliminated vent communities near 9°50ʹ′N. Standard histological techniques were used to determine whether reproductive characteristics, such as timing of gamete release, fecundity, or time to maturation, differed from other vent gastropods in ways that might explain arrival of these two species as early colonizers. Both species exhibited two-component oocyte size frequency distributions that indicated they were quasi-continuous reproducers with high fecundity. In C. porifera, the oocyte size distributions differed slightly between two collection dates, suggesting that environmental cues may introduce some variability in gamete release. In samples collected within one year of the estimated eruption date, individuals in populations of both C. porifera and L. tevnianus were reproductively mature. The smallest reproducing C. porifera were 4.2 mm (males) and 5.4 mm (females) in shell length, whereas reproductive L. tevnianus were smaller (2.3 and 2.4 mm in males and females respectively). Most C porifera in the population were large (> 6.0 mm) compared to their settlement size and reproductively mature. In contrast, most L tevnianus were small (< 1.0 mm) and immature. Reproductive traits of the two species are consistent with opportunistic colonization, but are also similar to those of other Lepetodrilus species and peltospirids at vents, and do not explain why these particular two species were the dominant pioneers. It is likely that their larvae were in high supply immediately after the eruption due to oceanographic transport processes from remote source populations.