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  • 1
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    Resilience in moving water: Effects of turbulence on the predatory impact of the lobate ctenophore Mnemiopsis leidyi (2018)
    ASLO (Association for the Sciences of Limnology and Oceanography) | Wiley
    In:  Limnology and Oceanography, 63 (1). pp. 445-458.
    Details
    Publication Date: 2021-02-08
    Description: Despite its delicate morphology, the lobate ctenophore Mnemiopsis leidyi thrives in coastal ecosystems as an influential zooplankton predator. Coastal ecosystems are often characterized as energetic systems with high levels of natural turbulence in the water column. To understand how natural wind-driven turbulence affects the feeding ecology of M. leidyi, we used a combination of approaches to quantify how naturally and laboratory generated turbulence affects the behavior, feeding processes and feeding impact of M. leidyi. Experiments using laboratory generated turbulence demonstrated that turbulence can reduce M. leidyi feeding rates on copepods and Artemia nauplii by 〉 50%. However, detailed feeding data from the field, collected during highly variable surface conditions, showed that wind-driven turbulence did not affect the feeding rates or prey selection of M. leidyi. Additional laboratory experiments and field observations suggest that the feeding process of M. leidyi is resilient to wind-driven turbulence because M. leidyi shows a behavioral response to turbulence by moving deeper in the water column. Seeking refuge in deeper waters enables M. leidyi to maintain high feeding rates even under high turbulence conditions generated by wind driven mixing. As a result, M. leidyi exerted a consistently high predatory impact on prey populations during highly variable and often energetic wind-driven mixing conditions. This resilience adds to our understanding of how M. leidyi can thrive in a wide spectrum of environments around the world. The limits to this resilience also set boundaries to its range expansion into novel areas.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: other
    Format: text
    Format: text
    DOI: 10.1002/lno.10642
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 2
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    Elevating the predatory effect: Sensory‐scanning foraging strategy by the lobate ctenophore Mnemiopsis leidyi (2015)
    ASLO (Association for the Sciences of Limnology and Oceanography)
    In:  Limnology and Oceanography, 60 (1). pp. 100-109.
    Details
    Publication Date: 2018-01-01
    Description: The influential predatory role of the lobate comb jellyfish Mnemiopsis leidyi has largely been attributed to the generation of a hydrodynamically silent feeding current to entrain and initiate high encounter rates with prey. However, for high encounter rates to translate to high ingestion rates, M. leidyi must effectively capture the entrained prey. To investigate the capture mechanisms, we recorded and quantified, using three-dimensional videography, the outcome of encounter events with slow swimming Artemia prey. The auricles, which produce the feeding current of M. leidyi, were the primary encounter structures, first contacting 59% of the prey in the feeding current. Upon detection, the auricles manipulated the Artemia to initiate captures on the tentillae, which are coated with sticky cells (colloblasts). Using this mechanism of sensory-scanning to capture prey entrained in the feeding current, M. leidyi uses a similar foraging strategy to that of feeding-current foraging copepods. As such, M. leidyi has a higher capture efficiency than do medusae, contributing to the greater predatory effect of M. leidyi in both its endemic and invasive ecosystems.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1002/lno.10007
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 3
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    Propulsion in cubomedusae : mechanisms and utility (2013)
    Public Library of Science
    Details
    Publication Date: 2022-05-25
    Description: © The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS ONE 8 (2013): e56393, doi:10.1371/journal.pone.0056393.
    Description: Evolutionary constraints which limit the forces produced during bell contractions of medusae affect the overall medusan morphospace such that jet propulsion is limited to only small medusae. Cubomedusae, which often possess large prolate bells and are thought to swim via jet propulsion, appear to violate the theoretical constraints which determine the medusan morphospace. To examine propulsion by cubomedusae, we quantified size related changes in wake dynamics, bell shape, swimming and turning kinematics of two species of cubomedusae, Chironex fleckeri and Chiropsella bronzie. During growth, these cubomedusae transitioned from using jet propulsion at smaller sizes to a rowing-jetting hybrid mode of propulsion at larger sizes. Simple modifications in the flexibility and kinematics of their velarium appeared to be sufficient to alter their propulsive mode. Turning occurs during both bell contraction and expansion and is achieved by generating asymmetric vortex structures during both stages of the swimming cycle. Swimming characteristics were considered in conjunction with the unique foraging strategy used by cubomedusae.
    Description: This work was supported by an ONR MURI award (N000140810654) and National Science Foundation grant OCE 0623508 to JHC, SPC, JOD. And the work was supported by the Roger Williams University Foundation to Promote Scholarship.
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
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  • 4
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    Passive energy recapture in jellyfish contributes to propulsive advantage over other metazoans (2013)
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of National Academy of Sciences. for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences of the United States of America 110 (2013): 17904-17909, doi:10.1073/pnas.1306983110.
    Description: Gelatinous zooplankton populations are well known for their ability to take over perturbed ecosystems. The ability of these animals to outcompete and functionally replace fish that exhibit an effective visual predatory mode is counterintuitive because jellyfish are described as inefficient swimmers that must rely on direct contact with prey in order to feed. We show that jellyfish exhibit a novel mechanism of passive energy recapture, which is exploited to allow jellyfish to travel 30 percent further each swimming cycle, thereby reducing metabolic energy demand by swimming muscles. By accounting for large interspecific differences in net metabolic rates, we demonstrate, contrary to prevailing views, the jellyfish (Aurelia aurita) is one of the most energetically efficient propulsors on the planet, exhibiting a cost-of-transport (J kg-1 m-1) lower than other metazoans. We estimate that reduced metabolic demand by passive energy recapture improves cost-of-transport by 48%, allowing jellyfish to achieve the large sizes required for sufficient prey encounters. Pressure calculations, using both computational fluid dynamics (CFD) and a new method from empirical velocity field measurements demonstrate that this extra thrust results from positive pressure created by a vortex ring underneath the bell during the refilling phase of swimming. These results demonstrate a physical basis for the ecological success of medusan swimmers despite their simple body plan. Results from this study also have implications for bio-inspired design where low-energy propulsion is required.
    Description: BG, JHC, SPC, CS, DT and SP were supported from the MURI grant through the Office of Naval Research (N00014-08-1-0654), JOD (N00014-10-1-0137).
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
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  • 5
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    Effects of non-uniform stiffness on the swimming performance of a passively-flexing, fish-like foil model (2015)
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here by permission of IOP Science for personal use, not for redistribution. The definitive version was published in Bioinspiration & Biomimetics 10 (2015): 056019, doi:10.1088/1748-3190/10/5/056019.
    Description: Simple mechanical models emulating fish have been used recently to enable targeted study of individual factors contributing to swimming locomotion without the confounding complexity of the whole fish body. Yet, unlike these uniform models, the fish body is notable for its non-uniform material properties. In particular, flexural stiffness decreases along the fish’s anterior-posterior axis. To identify the role of non-uniform bending stiffness during fish-like propulsion, we studied four foil model configurations made by adhering layers of plastic sheets to produce discrete regions of high (5.5x10-5 Nm2) and low (1.9x10-5 Nm2) flexural stiffness of biologically-relevant magnitudes. This resulted in two uniform control foils and two foils with anterior regions of high stiffness and posterior regions of low stiffness. With a mechanical flapping foil controller, we measured forces and torques in three directions and quantified swimming performance under both heaving (no pitch) and constant 0o angle of attack programs. Foils self-propelled at Reynolds number 21,000-115,000 and Strouhal number ~0.20-0.25, values characteristic of fish locomotion. Although previous models have emphasized uniform distributions and heaving motions, the combination of non-uniform stiffness distributions and 0o angle of attack pitching program was better able to reproduce the kinematics of freely-swimming fish. This combination was likewise crucial in maximizing swimming performance and resulted in high self-propelled speeds at low costs of transport and large thrust coefficients at relatively high efficiency. Because these metrics were not all maximized together, selection of the “best” stiffness distribution will depend on actuation constraints and performance goals. These improved models enable more detailed, accurate analyses of fish-like swimming.
    Description: This work was supported by an NSF Graduate Research Fellowship under grant DGE-1144152 to KNL and by ONR MURI Grant N000141410533 monitored by Dr Bob Brizzolara to GVL.
    Description: 2016-10-08
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
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  • 6
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    Prey capture by the cosmopolitan hydromedusae, Obelia spp., in the viscous regime (2016)
    John Wiley & Sons
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © Association for the Sciences of Limnology and Oceanography, 2016. This article is posted here by permission of Association for the Sciences of Limnology and Oceanography for personal use, not for redistribution. The definitive version was published in Limnology and Oceanography 61 (2016): 2309–2317, doi:10.1002/lno.10390.
    Description: Obelia spp. are cnidarian hydromedusae with a cosmopolitan distribution but very little is known about their feeding. The small size of Obelia (bell diameter ∼ 1 mm, tentacle width ∼ 0.05 mm) suggests that feeding occurs in a viscous regime characterized by thick boundary layers. During feeding observations with a natural prey assemblage the majority of prey were captured at the tentacle tips during the contraction phase. Swimming kinematics from high speed videography confirmed that swimming was a low Re number process (Re 〈 50) and showed that maximum tentacle velocities occurred at the tentacle tips midway through a bell contraction. Flow visualizations from particle image velocimetry demonstrated that fluid motion between the tentacles was limited and that velocities were highest at the tentacle tips, leading to a thinning of boundary layer in this region. The highest nematocyst densities were observed in this same region of the tentacle tips. Taken together, the body kinematics, flow visualizations and nematocyst distributions of Obelia explain how these predators are able to shed viscous boundary layers to effectively capture microplanktonic prey. Our findings help explain how other small feeding-current medusae whose feeding interactions are governed by viscosity are able to successfully forage.
    Description: National Science Foundation Grant Numbers: OCE- 1155084, DBI- 1455471, OCE- 1536672, OCE- 1536688
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 7
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    How the bending kinematics of swimming lampreys build negative pressure fields for suction thrust (2016)
    Company of Biologists
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © Company of Biologists, 2016. This article is posted here by permission of Company of Biologists for personal use, not for redistribution. The definitive version was published in Journal of Experimental Biology 219 (2016): 3884-3895, doi:10.1242/jeb.144642.
    Description: Swimming animals commonly bend their bodies to generate thrust. For undulating animals such as eels and lampreys, their bodies bend in the form of waves that travel from head to tail. These kinematics accelerate the flow of adjacent fluids, which alters the pressure field in a manner that generates thrust. We used a comparative approach to evaluate the cause-and-effect relationships in this process by quantifying the hydrodynamic effects of body kinematics at the body–fluid interface of the lamprey, Petromyzon marinus, during steady-state swimming. We compared the kinematics and hydrodynamics of healthy control lampreys to lampreys whose spinal cord had been transected mid-body, resulting in passive kinematics along the posterior half of their body. Using high-speed particle image velocimetry (PIV) and a method for quantifying pressure fields, we detail how the active bending kinematics of the control lampreys were crucial for setting up strong negative pressure fields (relative to ambient fields) that generated high-thrust regions at the bends as they traveled all along the body. The passive kinematics of the transected lamprey were only able to generate significant thrust at the tail, relying on positive pressure fields. These different pressure and thrust scenarios are due to differences in how active versus passive body waves generated and controlled vorticity. This demonstrates why it is more effective for undulating lampreys to pull, rather than push, themselves through the fluid.
    Description: This work was funded by a National Science Foundation (NSF) CBET grant awarded to S.P.C., J.H.C., B.J.G. and J.O.D. (award numbers 1510929, 1511996), by the Marine Biological Laboratory (J.R.M.) and by the Roger Williams University Foundation to Promote Teaching and Scholarship.
    Description: 2017-12-14
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 8
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    Effects of capture surface morphology on feeding success of scyphomedusae : a comparative study (2018)
    Inter-Research
    Details
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Marine Ecology Progress Series 596 (2018): 83-93, doi:10.3354/meps12549.
    Description: Predation by feeding-current foraging medusae can have detrimental effects on prey populations. Understanding the mechanics that control prey selection and ingestion rates with different types of prey enables us to better predict the predatory impact of these medusae. We quantified the outcomes of each post-entrainment stage of the feeding process in multiple scyphozoan jellyfish species to understand how post-entrainment feeding events influence feeding patterns. Using 3-dimensional video, we observed and quantified the fate of both passive and actively swimming prey that were entrained in the feeding current of 5 different scyphomedusan species belonging to the orders Semaeostomeae and Rhizostomeae. Less than 65% of entrained prey contacted the capture surfaces (termed contact efficiency) of the semaeostome medusae, while the rhizostome medusae came into contact with less than 35% of the prey entrained in the feeding current. However, when contacted, prey were very likely to be ingested (〉90%) by all species examined. These results suggest that prey capture by oblate medusae appears to be largely limited by the probability that prey entrained in the feeding current will contact a capture surface. As a passive process, this contact stage of the feeding process is directly affected by the morphology of the contact surfaces. The importance of the contact stage of the feeding process suggests that differences in prey selection patterns observed among oblate medusan taxa are likely dominated by the morphology of contact surfaces as opposed to traits which influence the other stages of the feeding process, i.e. bell shape and nematocysts.
    Description: This work was funded by a NSF Biological Oceanography grant awarded to S.P.C. and J.H.C. (OCE 1536688) and supported by the Roger Williams University Foundation to Promote Teaching and Scholarship.
    Keywords: Predator-prey interactions ; Prey selection ; Mechanistic ecology ; Post-encounter
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 9
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    An algorithm to estimate unsteady and quasi-steady pressure fields from velocity field measurements (2014)
    Company of Biologists
    Details
    Publication Date: 2022-05-25
    Description: © The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Experimental Biology 217 (2014): 331-336, doi:10.1242/​jeb.092767.
    Description: We describe and characterize a method for estimating the pressure field corresponding to velocity field measurements such as those obtained by using particle image velocimetry. The pressure gradient is estimated from a time series of velocity fields for unsteady calculations or from a single velocity field for quasi-steady calculations. The corresponding pressure field is determined based on median polling of several integration paths through the pressure gradient field in order to reduce the effect of measurement errors that accumulate along individual integration paths. Integration paths are restricted to the nodes of the measured velocity field, thereby eliminating the need for measurement interpolation during this step and significantly reducing the computational cost of the algorithm relative to previous approaches. The method is validated by using numerically simulated flow past a stationary, two-dimensional bluff body and a computational model of a three-dimensional, self-propelled anguilliform swimmer to study the effects of spatial and temporal resolution, domain size, signal-to-noise ratio and out-of-plane effects. Particle image velocimetry measurements of a freely swimming jellyfish medusa and a freely swimming lamprey are analyzed using the method to demonstrate the efficacy of the approach when applied to empirical data.
    Description: This research was supported by Office of Naval Research awards N000140810918 and N000141010137 to J.O.D.
    Keywords: Swimming ; Flying ; Wakes ; Feeding ; Particle image velocimetry
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
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  • 10
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    Carbon content of Mnemiopsis leidyi eggs and specific egg production rates in northern Europe (2014)
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of Oxford University Press for personal use, not for redistribution. The definitive version was published in Journal of Plankton Research 37 (2015): 11-15, doi:10.1093/plankt/fbu102.
    Description: The comb jelly Mnemiopsis leidyi is considered to be a successful invasive species, partly due to its high reproduction potential. However, due to the absence of direct carbon measurements of eggs, specific reproduction rates remain uncertain. We show that egg carbon is 0.22 ± 0.02 µg C and up to 21 times higher than previously extrapolated. With maximum rates of 11 232 eggs ind−1 day−1, largest animals in northern Europe invest ∼10% day−1 of their body carbon into reproduction.
    Description: This work was supported by a grant from the German Exchange Service (DAAD) to CJ; NSF –grant OCE1061353 to JHC and SPC.
    Keywords: Comb jelly ; Ctenophore ; Invasive species
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
    Format: application/pdf
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