Notes on the behaviour of Pectinaria koreni

1988 ◽  
Vol 68 (1) ◽  
pp. 55-59 ◽  
Author(s):  
Artemis Nicolaidou
Keyword(s):  
Diurnal Rhythm ◽  
Preliminary Data ◽  
Feeding Activity ◽  
Vertical Movement ◽  
Sediment Reworking ◽  
Effect Of Light

The paper presents preliminary data on the response of Pectinaria koreni to light and on the effect of light and temperature on its rate of sediment reworking. Pectinaria at the ‘settling in’ stage reacted to light by burying themselves completely under the sediment. There was indication that vertical movement of Pectinaria in the sediment followed a diurnal rhythm probably associated with feeding activity. Pectinaria was most active at higher temperatures and in the dark. At 7 °C the rate of sediment reworking was significantly less than that at 10 and 15 °C and was not affected by light. At 10 and 15 °C the amount of sediment reworked in the dark was significantly greater than that reworked in the light.

Studies in Diurnal Rhythms

1951 ◽  
Vol 28 (2) ◽  
pp. 165-172
Author(s):  
J. L. CLOUDSLEY-THOMPSON
Keyword(s):  
Diurnal Rhythm ◽  
Rhythmic Activity ◽  
Temperature Fluctuations ◽  
West African ◽  
Diurnal Rhythms ◽  
Locomotory Activity ◽  
Depressing Effect ◽  
African Species ◽  
Fluctuating Light ◽  
Effect Of Light

Visual experiments on two small British species of millipedes have demonstrated that the diurnal cycle of rhythmic activity as represented by the number of animals on the surface is primarily a response to light and darkness, but is also correlated with the stimulus of falling temperature in the evening. Aktograph experiments on two large West African species of millipedes have demonstrated an endogenous diurnal rhythm independent of fluctuating light and temperature, and persisting (in Ophistreptus) up to 19 days. Locomotory activity is stimulated both by increases and decreases of temperature; and it is probable that temperature fluctuations are of primary importance in the initiation of diurnal rhythms. The effect of light on activity is slight, but constant temperatures over long periods have, a depressing effect.

The effects of organic matter concentration on sediment reworking of Perinereis aibuhitensis : a mesocosm study

2020 ◽  
Author(s):  
Jaehwan Seo ◽  
Bon Joo Koo
Keyword(s):  
Organic Matter ◽  
Feeding Activity ◽  
Transport Rate ◽  
Benthic Organism ◽  
Mean Values ◽  
Sediment Reworking ◽  
Pellet Production ◽  
Organic Matter Concentration ◽  
Perinereis Aibuhitensis ◽  
The Mean

<p>The organic matter (OM) concentration is one of the most important factors influencing benthic organism sediment reworking during bioturbation. This study was designed to evaluate differences in sediment reworking rate of Perinereis aibuhitensis based on quantification of its pellet production (PP) and OM transport rate from ambient sediment to the surface due to its feeding. The mesocosm experiment was conducted in acrylic container (15×1×20 cm) with two treatments (high OM treatment and low OM treatment) and each treatment had ten replicates. The pellets in each container were removed 2h before the beginning of the pellet collection, and then newly produced pellets were collected every 2 h during 24 h at each treatment. The mean grain size of pellets (5.1 ∅) was smaller than that of ambient sediment particles (5.9 ∅), and the mean OM concentration was much higher in pellet (0.69% for C and 0.06% for N) than in ambient sediment (0.46% for C and 0.05% for N). Since an organism cannot produce more organic matter than it ingests, production of organically enriched pellets by this species indicates selective ingestion. The overall OM transport rate was 0.7 g C m<sup>-2</sup> day<sup>-1</sup> in carbon and 0.06 g N m<sup>-2</sup> day<sup>-1 </sup>in nitrogen, respectively. The daily PP was much higher in high OM treatment than that of low OM treatment with mean values of 0.007 and 0.002 g ind.<sup>-1</sup> h<sup>-1</sup>, respectively. It is expected that Perinereis feeding activity strongly depended on OM concentrations. The overall sediment reworking rate based on the pellet production was much higher in high OM concentration (0.005 mm day<sup>-1</sup>) than in low OM (0.001 mm day<sup>-1</sup>) concentration.</p>

scholarly journals The Effect of Light on the Buoyancy of the Cuttlefish

1961 ◽  
Vol 41 (2) ◽  
pp. 343-350 ◽  
Author(s):  
E. J. Denton ◽  
J. B. Gilpin-Brown
Keyword(s):  
Light Intensity ◽  
Diurnal Rhythm ◽  
Density Change ◽  
Artificial Light ◽  
Active Process ◽  
Complete Darkness ◽  
Gas Space ◽  
Effect Of Light

The behaviour of well fed cuttlefish is strikingly affected by light. When the light is bright they usually bury themselves in the gravel at the bottom of their tanks, whilst after twilight they come out of the gravel and swim around until dawn.Cuttlefish kept in complete darkness for one to two days usually become so buoyant that they are incapable of staying on the bottom and can only remain in mid-water with difficulty.Animals kept in artificial light and dark showed changes in density which could amount to 2%. These changes come from changes in the volume of the gas space within the cuttlebone.The density of the cuttlefish is largely governed by light intensity and there is little indication of an inherent diurnal rhythm of density change.The rate of uptake of liquid when the cuttlefish becomes denser is such that it is unnecessary to assume that any active process is used to pump liquid into the cuttlebone. The cuttlefish must, however, extract liquid actively from the cuttlebone to become less dense.

Diel Vertical Movements and Feeding Activity of Zooplankton in St. Georges Bay, N.S., Using Net Tows and a Newly Developed Passive Trap

1986 ◽  
Vol 43 (5) ◽  
pp. 952-967 ◽  
Author(s):  
G. C. Harding ◽  
W. P. Vass ◽  
B. T. Hargrave ◽  
S. Pearre Jr.
Keyword(s):  
Predator Avoidance ◽  
Feeding Activity ◽  
Vertical Movement ◽  
Avoidance Reaction ◽  
Trap Surface ◽  
Migration Patterns ◽  
Vertical Movements ◽  
Visual Predation ◽  
Competition For Food ◽  
Simultaneous Use

Newly developed plankton traps, designed to passively collect vertically mobile plankters, sampled ascending plankton but failed to collect many species during descent. This discrepancy may be behavioral with passively sinking organisms reacting to the trap surface with an upward avoidance reaction. Simultaneous use of conventional net tows and semiautomated traps allowed us to interpret the vertical movements of plankton more fully than by either method alone. Asynchronous vertical movement of the Pseudocalanus population is suspected because the percentage of trapped animals with food in their guts was usually higher in the downward moving fraction of the population. Migratory behaviors ranged from dusk and dawn ascent with midnight sinking to reverse migrations where the night level inhabited is deeper than the day depth. Noctural dispersal of herbivore and omnivore populations over depth probably reflects predator avoidance by presenting less dense aggregations to vertically mobile predators. Sightless predators reside in deeper waters than their prey during daylight presumably because they are larger and more vulnerable themselves to visual predation. Visual predators descend to greater depths than their prey at night. All the migration patterns observed can be explained in evolutionary terms simply by competition for food and avoidance of predators.

Sign in / Sign up

Export Citation Format

Share Document