scholarly journals In situ measurements of righting behavior in the common sea urchin Lytechinus variegatus: the importance of body size, substrate type, and covering material

2017 ◽  
Vol 26 ◽  
pp. 33-40 ◽  
Author(s):  
RC Challener ◽  
JB McClintock
Keyword(s):  
Body Size ◽  
Sea Urchin ◽  
In Situ Measurements ◽  
Lytechinus Variegatus ◽  
Substrate Type ◽  
Covering Material ◽  
The Common ◽  
Righting Behavior

Comparative study of the covering reaction of the purple sea urchin, Paracentrotus lividus, under laboratory and field conditions

1999 ◽  
Vol 79 (6) ◽  
pp. 1117-1121 ◽  
Author(s):  
Anne C. Crook ◽  
Emma Verling ◽  
David K.A. Barnes
Keyword(s):  
Comparative Study ◽  
Sea Urchin ◽  
Age Groups ◽  
Paracentrotus Lividus ◽  
Field Conditions ◽  
Population Differences ◽  
Purple Sea Urchin ◽  
Covering Material

Abiotic and biotic aspects of the covering behaviour of the purple sea urchin, Paracentrotus lividus (Echinodermata: Echinoidea) were systematically examined in situ and in the laboratory to analyse potential intra-population differences in the nature of this behaviour. In the field, significant differences in the occurrence of covering behaviour were found between age groups. Smaller P. lividus covered at higher frequencies than larger individuals. Higher proportions of individuals were also observed to cover during afternoon sampling periods. Significant differences in the types of covering material used were found between P. lividus observed in the laboratory and in the field. These findings suggest that the benefits and/or opportunities of covering behaviour may change with size and habitat.

The Carbon:²³⁴Thorium ratios of sinking particles in the California Current Ecosystem 2: Examination of a thorium sorption, desorption, and particle transport model

2019 ◽  
Author(s):  
Michael Stukel ◽  
Thomas Kelly
Keyword(s):  
Organic Carbon ◽  
Water Column ◽  
Particulate Organic Carbon ◽  
Transport Model ◽  
California Current ◽  
In Situ Measurements ◽  
Power Law Distribution ◽  
Sinking Particles ◽  
Organic Carbon Concentration

Thorium-234 (234Th) is a powerful tracer of particle dynamics and the biological pump in the surface ocean; however, variability in carbon:thorium ratios of sinking particles adds substantial uncertainty to estimates of organic carbon export. We coupled a mechanistic thorium sorption and desorption model to a one-dimensional particle sinking model that uses realistic particle settling velocity spectra. The model generates estimates of 238U-234Th disequilibrium, particulate organic carbon concentration, and the C:234Th ratio of sinking particles, which are then compared to in situ measurements from quasi-Lagrangian studies conducted on six cruises in the California Current Ecosystem. Broad patterns observed in in situ measurements, including decreasing C:234Th ratios with depth and a strong correlation between sinking C:234Th and the ratio of vertically-integrated particulate organic carbon (POC) to vertically-integrated total water column 234Th, were accurately recovered by models assuming either a power law distribution of sinking speeds or a double log normal distribution of sinking speeds. Simulations suggested that the observed decrease in C:234Th with depth may be driven by preferential remineralization of carbon by particle-attached microbes. However, an alternate model structure featuring complete consumption and/or disaggregation of particles by mesozooplankton (e.g. no preferential remineralization of carbon) was also able to simulate decreasing C:234Th with depth (although the decrease was weaker), driven by 234Th adsorption onto slowly sinking particles. Model results also suggest that during bloom decays C:234Th ratios of sinking particles should be higher than expected (based on contemporaneous water column POC), because high settling velocities minimize carbon remineralization during sinking.

Evaluation of reanalysis and satellite-based sea surface winds using in situ measurements from Chinese Antarctic Expeditions

2013 ◽  
Vol 24 (3) ◽  
pp. 147
Author(s):  
Ming LI ◽  
Qinghua YANG ◽  
Jiechen ZHAO ◽  
Lin ZHANG ◽  
Chunhua LI ◽  
...  
Keyword(s):  
In Situ Measurements ◽  
Sea Surface ◽  
Surface Winds ◽  
Sea Surface Winds
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