scholarly journals The first observations ofIschnochiton(Mollusca, Polyplacophora) movement behaviour, with comparison between habitats differing in complexity

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4180 ◽  
Author(s):  
Kiran Liversage ◽  
Kirsten Benkendorff
Keyword(s):  
Small Proportion ◽  
South Australia ◽  
Time Lapse ◽  
Habitat Types ◽  
Coastal Species ◽  
Active Dispersal ◽  
Large Populations ◽  
Adult Dispersal ◽  
Time Lapse Photography ◽  
Hard Substrata

Most species ofIschnochitonare habitat specialists and are almost always found underneath unstable marine hard-substrata such as boulders. The difficulty of experimenting on these chitons without causing disturbance means little is known about their ecology despite their importance as a group that often contributes greatly to coastal species diversity. In the present study we measured among-boulder distributional patterns ofIschnochiton smaragdinus, and used time-lapse photography to quantify movement behaviours within different habitat types (pebble substrata and rock-platform). In intertidal rock-pools in South Australia,I. smaragdinuswere significantly overdispersed among boulders, as most boulders had few individuals but a small proportion harboured large populations.I. smaragdinusindividuals emerge from underneath boulders during nocturnal low-tides and move amongst the inter-boulder matrix (pebbles or rock-platform). Seventy-two percent of chitons in the pebble matrix did not move from one pebble to another within the periods of observation (55–130 min) but a small proportion moved across as many as five pebbles per hour, indicating a capacity for adults to migrate among disconnected habitat patches. Chitons moved faster and movement paths were less tortuous across rock-platform compared to pebble substrata, which included more discontinuities among substratum patches. Overall, we show that patterns of distribution at the boulder-scale, such as the observed overdispersion, must be set largely by active dispersal of adults across the substratum, and that differing substratum-types may affect the degree of adult dispersal for this and possibly other under-boulder chiton species.

Relationship between elemental concentration and age from otoliths of adult snapper (Pagrus auratus, Sparidae): implications for movement and stock structure

2005 ◽  
Vol 56 (5) ◽  
pp. 661 ◽  
Author(s):  
A. J. Fowler ◽  
B. M. Gillanders ◽  
K. C. Hall
Keyword(s):  
Mass Spectrometry ◽  
Inductively Coupled Plasma ◽  
Elemental Concentration ◽  
South Australia ◽  
Stock Structure ◽  
Habitat Types ◽  
Inductively Coupled ◽  
Age Related ◽  
Pagrus Auratus ◽  
Plasma Mass Spectrometry

The present study investigated the stock structure of snapper (Pagrus auratus) in South Australia, and the extent to which this is influenced by adult movement. Fish from the 9+ age class were sampled from six different regions, encompassing >2000 km of coastline and different habitat types. The chemistry of transverse sections of otoliths was sampled using laser ablation inductively coupled plasma-mass spectrometry, providing elemental profiles that were related to age for the first nine years of the fish’s lives. The age-related annual averages for both 88Sr and 138Ba differed significantly between regions. They were, however, similar for the first three years, then diverged considerably between the ages of three to five years, and then remained consistently different through to the age of nine years. This suggests that all fish, regardless of where captured, originated from only one or two nursery areas, but dispersed throughout the different regions between the ages of three to five years, before becoming resident to their new regions of occupancy. Thus, this population of snapper represents a single, large, stock where the individuals have a common origin, but through age-related emigration ultimately disperse and supplement the low abundance populations in regional State waters.

The Mechanism of Cell-division

1953 ◽  
Vol s3-94 (28) ◽  
pp. 369-379
Author(s):  
M. M. SWANN
Keyword(s):  
Carbon Monoxide ◽  
Cell Division ◽  
Sea Urchin ◽  
White Light ◽  
Time Lapse ◽  
Psammechinus Miliaris ◽  
Energy Store ◽  
Time Lapse Photography

1. Developing eggs of the sea-urchin Psammechinus miliaris were subjected to carbon monoxide inhibition, which was controlled by changing from green to white light. The behaviour of the eggs was recorded by time-lapse photography. 2. If inhibition is applied before the eggs enter mitosis, their first cleavage is delayed by a time which is roughly equal to the period of the inhibition. 3. If the inhibition is applied when the cells have already entered mitosis, they complete mitosis and cleave with little or no delay, but their second cleavage is delayed by a time which is roughly equal to the period of the inhibition. 4. It is suggested that the necessary energy for the second mitosis and cleavage is being stored up during the first mitosis and cleavage, and that this energy store operates like a reservoir which is continually being filled but siphons out when it is full. Once the energy has siphoned out, it carries mitosis and cleavage through, even though the reservoir is not filling up because of carbon monoxide inhibition.

scholarly journals The determination of glacier speed by time-lapse photography under unfavorable conditions

1992 ◽  
Vol 38 (129) ◽  
pp. 257-265 ◽  
Author(s):  
W.D. Harrison ◽  
K.A. Echelmeyer ◽  
D.M. Cosgrove ◽  
C. F. Raymond
Keyword(s):  
Time Lapse ◽  
Systematic Errors ◽  
Horizontal Motion ◽  
Limited Information ◽  
Glacier Surface ◽  
Alaska Range ◽  
Use Of Time ◽  
West Fork ◽  
Time Lapse Photography

AbstractTwo practical problems in the use of time-lapse photography for the measurement of speed were encountered during the recent surge of West Fork Glacier in the central Alaska Range, Alaska, U.S.A. The first is severe rotational camera instability; we show how natural, unsurveyed features on the valley wall can be used to make the necessary corrections. The second problem is the computation of absolute speed when many different, unsurveyed glacier-surface features are used as targets. We give a method for connecting the data obtained from different targets, and for determining the scale using limited information obtained by surveying. Severe systematic errors can occur unless the angle between the axis of the lens and the direction of horizontal motion is determined.

scholarly journals Dynamin-related Protein Drp1 Is Required for Mitochondrial Division in Mammalian Cells

2001 ◽  
Vol 12 (8) ◽  
pp. 2245-2256 ◽  
Author(s):  
Elena Smirnova ◽  
Lorena Griparic ◽  
Dixie-Lee Shurland ◽  
Alexander M. van der Bliek
Keyword(s):  
Mammalian Cells ◽  
Fluorescent Protein ◽  
Time Lapse ◽  
Subcellular Fractionation ◽  
Related Protein ◽  
Direct Role ◽  
Mitochondrial Division ◽  
Transfected Cells ◽  
Green Fluorescent ◽  
Time Lapse Photography

Mutations in the human dynamin-related protein Drp1 cause mitochondria to form perinuclear clusters. We show here that these mitochondrial clusters consist of highly interconnected mitochondrial tubules. The increased connectivity between mitochondria indicates that the balance between mitochondrial division and fusion is shifted toward fusion. Such a shift is consistent with a block in mitochondrial division. Immunofluorescence and subcellular fractionation show that endogenous Drp1 is localized to mitochondria, which is also consistent with a role in mitochondrial division. A direct role in mitochondrial division is suggested by time-lapse photography of transfected cells, in which green fluorescent protein fused to Drp1 is concentrated in spots that mark actual mitochondrial division events. We find that purified human Drp1 can self-assemble into multimeric ring-like structures with dimensions similar to those of dynamin multimers. The structural and functional similarities between dynamin and Drp1 suggest that Drp1 wraps around the constriction points of dividing mitochondria, analogous to dynamin collars at the necks of budding vesicles. We conclude that Drp1 contributes to mitochondrial division in mammalian cells.

Variation in the naturally occurring rhythm of the estuarine amphipod, Corophium volutator (Pallas)

1983 ◽  
Vol 63 (4) ◽  
pp. 833-850 ◽  
Author(s):  
Walter F. Holmström ◽  
Elfed Morgan
Keyword(s):  
Activity Rhythm ◽  
Time Lapse ◽  
Early Summer ◽  
Corophium Volutator ◽  
Use Of Time ◽  
Recording Conditions ◽  
Free Running ◽  
Endogenous Activity ◽  
Free Running Period ◽  
Time Lapse Photography

The endogenous activity rhythm of the estuarine amphipod Corophium volutator has been studied by direct observation and with the use of time lapse photography. The rhythm persists under constant conditions having a free running period of between 12 and 13 h, and with activity maxima occurring during the early ebb. Freshly collected animals show a rhythm which is modulated on a semi-lunar basis, the activity maxima being attenuated during the neap tide periods, and the rhythm has also been found to vary in definition throughout the year. The activity pattern is most clearly denned in early summer and autumn, the population becoming arrhythmic during the winter months. The rhythm is relatively unaffected by the ambient light intensity and temperature of the recording conditions, and is evident in all post-natal stages of development. The possibility of mutual entrainment is discussed.

Observations of the deep-sea floor from 202 days of time-lapse photography

Nature ◽  
1978 ◽  
Vol 272 (5656) ◽  
pp. 812-814 ◽  
Author(s):  
ALLEN Z. PAUL ◽  
EDWARD M. THORNDIKE ◽  
LAWRENCE G. SULLIVAN ◽  
BRUCE C. HEEZEN ◽  
ROBERT D. GERARD
Keyword(s):  
Deep Sea ◽  
Time Lapse ◽  
Sea Floor ◽  
Time Lapse Photography
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