INVESTIGADORES
GONÇALVES Rodrigo Javier
artículos
Título:
Flow disturbances generated by feeding and swimming zooplankton
Autor/es:
KIØRBOE, THOMAS; JIANG, HOUSHUO; R. J. GONÇALVES; NIELSEN, LASSE TOR ; WADHWA, NAVISH
Revista:
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Editorial:
NATL ACAD SCIENCES
Referencias:
Lugar: Washington DC, USA; Año: 2014 vol. 111 p. 11738 - 11743
ISSN:
0027-8424
Resumen:
Interactions between
planktonic organisms, such as detection of prey, predators, and
mates, are often mediated by fluid signals. Consequently, many
plankton predators perceive their prey from the fluid disturbances
that it generates when it feeds and swims. Zooplankton should
therefore seek to minimize the fluid disturbance that they produce.
By means of particle image velocimetry, we describe the fluid
disturbances produced by feeding and swimming in zooplankton with
diverse propulsion mechanisms and ranging from 10-µm flagellates to
greater than millimeter-sized copepods. We show that zooplankton, in
which feeding and swimming are separate processes, produce flow
disturbances during swimming with a much faster spatial attenuation
(velocity u varies with distance r as u ∝
r−3 to r−4) than that
produced by zooplankton for which feeding and propulsion are the same
process (u ∝ r−1 to r−2).
As a result, the spatial extension of the fluid disturbance produced
by swimmers is an order of magnitude smaller than that produced by
feeders at similar Reynolds numbers. The ?quiet? propulsion of
swimmers is achieved either through swimming erratically by
short-lasting power strokes, generating viscous vortex rings, or by
?breast-stroke swimming.? Both produce rapidly attenuating flows.
The more ?noisy? swimming of those that are constrained by a need
to simultaneously feed is due to constantly beating flagella or
appendages that are positioned either anteriorly or posteriorly on
the (cell) body. These patterns transcend differences in size and
taxonomy and have thus evolved multiple times, suggesting a strong
selective pressure to minimize predation risk.