SUMMARY Flow patterns generated by medusan swimmers such as jellyfish are known to differ according the morphology of various animal species. Oblate medusae have been previously observed generate vortex ring structures during propulsive cycle. Owing inherent physical coupling between locomotor and feeding in these animals, dynamics formation must be robustly tuned facilitate effective functioning both systems. To understand how this is achieved, we employed dye visualization techniques on...

Significance Jellyfish have the ability to bloom and take over perturbed ecosystems, but this is counterintuitive because jellyfish are described as inefficient swimmers rely on direct contact with prey feed. To understand how can outcompete effective visual hunters, such fish, we investigate energetics of propulsion. We find that exhibit a unique mechanism passive energy recapture, which reduce metabolic demand by swimming muscles. Contrary prevailing views, contributes being one most...

Abstract. Medusae were the earliest animals to evolve muscle‐powered swimming in seas. Although medusae have achieved diverse and prominent ecological roles throughout world's oceans, we argue that primitive organization of cnidarian muscle tissue limits force production and, hence, mechanical alternatives for bell function. We use a recently developed model comparing potential with hydrodynamic requirements jet propulsion, conclude is possible only at relatively small diameters. In...

Abstract A central and long-standing tenet in the conceptualization of animal swimming is idea that propulsive thrust generated by pushing surrounding water rearward. Inherent this perspective assumption locomotion involves generation locally elevated pressures fluid to achieve expected downstream push mass. Here we show rather than against fluid, efficient animals primarily pull themselves through via suction. This distinction manifested dominant low-pressure regions body, which are...

Animal propulsors such as wings and fins bend during motion these bending patterns are believed to contribute the high efficiency of animal movements compared with those man-made designs. However, efforts implement flexible designs have been met contradictory performance results. Consequently, there is no clear understanding role played by propulsor flexibility or, more fundamentally, how should be designed for optimal performance. Here we demonstrate that steady-state a wide range animals,...

Summary We describe and characterize a method for estimating the pressure field corresponding to velocity measurements, such as those obtained by using particle image velocimetry. The gradient is estimated from time series of fields unsteady calculations or single quasi-steady calculations. determined based on median polling several integration paths through in order reduce effect measurement errors that accumulate along individual paths. Integration are restricted nodes measured field,...

Simple mechanical models emulating fish have been used recently to enable targeted study of individual factors contributing swimming locomotion without the confounding complexity whole body. Yet, unlike these uniform models, body is notable for its non-uniform material properties. In particular, flexural stiffness decreases along fish's anterior-posterior axis. To identify role bending during fish-like propulsion, we studied four foil model configurations made by adhering layers plastic...

SUMMARY Jet propulsion, based on examples from the Hydrozoa, has served as a valuable model for swimming by medusae. However, cnidarian medusae span several taxonomic classes (collectively known Medusazoa) and represent diverse array of morphologies styles. Does one mode propulsion appropriately describe all medusae? This study examined group co-occurring hydromedusae collected waters Friday Harbor, WA, USA, to investigate relationships between performance underlying mechanisms thrust...

The creation of feeding currents by calanoid copepods increases encounter rates with their food and provides advantage in dilute nutritional environments. Small-scale turbulence has also been hypothesized to increase the rate between planktonic predators food. Centropages hamatus was exposed turbulent nonturbulent environments at two prey concentrations quantify influence on current efficacy. Turbulent energy dissipation used experiment were range 0.05-0.15 cm2. sec-3. In environments,...

SUMMARY Fast-swimming hydromedusan jellyfish possess a characteristic funnel-shaped velum at the exit of their oral cavity that interacts with pulsed jets water ejected during swimming motions. It has been previously assumed primarily serves to augment thrust by constricting flow in order produce higher jet velocities. This paper presents high-speed video and dye-flow visualizations free-swimming Nemopsis bachei hydromedusae, which instead indicate time-dependent velar kinematics observed...

SUMMARY It is generally accepted that animal–fluid interactions have shaped the evolution of animals swim and fly. However, functional ecological advantages associated with those adaptations are currently difficult to predict on basis measurements interactions. We report identification a robust, fluid dynamic correlate distinct functions in seven jellyfish species represent broad range morphologies foraging modes. Since comparative study based properties vortex wake – specifically, dynamical...

The lobate ctenophore Mnemiopsis leidyi occurs throughout Narragansett Bay, Rhode Island, during warm summer months but is often undetectable in the central portion of bay winter months. During 2 yr weekly sampling, we found that M. populations a shallow embayment, Greenwich Cove, either overwintered or were only briefly absent winter. Cove population reproduced weeks earlier and reached higher average peak concentrations than open‐bay populations. Shallow embayment such as probably serve...

In contrast to higher metazoans such as copepods and fish, ctenophores are a basal metazoan lineage possessing relatively narrow set of sensory-motor capabilities. Yet lobate can capture prey at rates comparable sophisticated predatory they capable altering the composition coastal planktonic communities. Here, we demonstrate that success ctenophore Mnemiopsis leidyi lies in its use cilia generate feeding current continuously entrains large volumes fluid, yet is virtually undetectable prey....

Models of marine ecosystem productivity rely on estimates small-scale interactions, particularly those between copepods and their algal food sources. Rothschild Osborn [Rothschild, B. J. & Osborn, T. R. (1988) Plankton Res. 10, 465-474], hypothesized that turbulence in aquatic systems increases the perceived abundance prey to predators. We tested this hypothesis by exposing planktonic copepod Centropages hamatus turbulent nonturbulent environments at different concentrations. Our results...

Manoeuvrability is critical to the success of many species. Selective forces acting over millions years have resulted in a range capabilities currently unmatched by machines. Thus, understanding animal control fluids for manoeuvring has both biological and engineering applications. Within inertial fluid regimes, propulsion involves formation interaction vortices generate thrust. We use volumetric planar imaging techniques quantify how jellyfish ( Aurelia aurita ) modulate vortex rings during...

ABSTRACT Swimming animals commonly bend their bodies to generate thrust. For undulating such as eels and lampreys, in the form of waves that travel from head tail. These kinematics accelerate flow adjacent fluids, which alters pressure field a manner generates We used comparative approach evaluate cause-and-effect relationships this process by quantifying hydrodynamic effects body at body–fluid interface lamprey, Petromyzon marinus, during steady-state swimming. compared hydrodynamics...

Ciliated microorganisms near the base of aquatic food chain either swim to encounter prey or attach at a substrate and generate feeding currents capture passing particles. Here, we represent attached swimming ciliates using popular spherical model in viscous fluid with slip surface velocity that affords analytical expressions ciliary flows. We solve an advection–diffusion equation for concentration dissolved nutrients, where Péclet number ( $Pe$ ) reflects ratio diffusive advective time...

Salps are marine pelagic tunicates with a complex life cycle including solitary and colonial stage. Salp colonies composed of asexually budded individuals that coordinate their swimming by multi-jet propulsion. Colonies develop into species-specific architectures distinct zooid orientations. These vary in how frontal area scales the number zooids colony. Here, we address differences drive speed relationship between cost transport salps. We (1) compare across salp species architectures, (2)...