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Hakodate, Japan

Respiration, ammonia excretion and chemical composition data [water content, ash, carbon (C), nitrogen (N) and C:N ratios] of 16-43 pelagic decapods from epipelagic through abyssopelagic zones of the world's oceans were compiled. For respiration, the independent variables including body dry mass, habitat temperature and sampling depth were all significant predictors of the empirical regression model, whereas the former two variables were significant predictors of the theoretical regression model. For ammonia excretion, body dry mass and habitat temperature were significant predictors of both regression models. Overall, these variables accounted for 68-87 % of the variance in the data. Atomic O:N ratios (respiration:ammonia excretion) ranged from 9.1 to 91 (median 16.4), and no appreciable effects of the three variables were detected. Body composition components were not significantly affected by the three variables, except positive effects of habitat temperature on ash and negative effects of sampling depth on N composition. As judged by C:N ratios, protein was considered to be the major organic component of most pelagic decapods. Some pelagic decapods from >500 m depth exhibited high C:N ratios (8.6-10.2), suggesting a deposition of lipids in the body. Comparison of the present results with global bathymetric models of euphausiids and mysids revealed great similarities among these pelagic crustacean taxa characterized by common behavioral and morphological features such as active swimming, developed compound eyes and respiratory gill organ. © 2013 The Oceanographic Society of Japan and Springer Japan. Source


Respiration and ammonia excretion rates of 19-24 euphausiids from the epipelagic through bathypelagic zones of the world's oceans were compiled. Body mass (expressed in terms of dry mass, carbon or nitrogen), habitat temperature and sampling depth were designated as parameters in multiple regression analysis. Results suggested that the three parameters were highly significant, contributing 71-89 % of the variance in respiration rates and 69-81 % of the variance in ammonia excretion rates. Atomic O:N ratios derived from simultaneous measurements of respiration and ammonia excretion rates ranged from 11 to 90 (median: 27), and no appreciable effects of the three parameters on O:N ratios were detected. If global-bathymetric models for the metabolism and chemical composition of copepods and chaetognaths are compared with those of euphausiids, it becomes evident that euphausiids are unique in that they maintain high metabolic rates and accumulate moderate amounts of energy reserves (lipids). © 2012 Springer-Verlag Berlin Heidelberg. Source


Respiration and ammonia excretion data and chemical composition data [water content, ash, carbon (C), nitrogen (N) and C:N ratios] of 18-32 amphipods (hyperiids and gammarids) from the epipelagic through bathypelagic zones of the world's oceans were compiled. The independent variables including body mass, habitat temperature and mid-sampling depth were all significant predictors of respiration, accounting for 65-83 % of the variance in the data, while the former two variables were significant predictors of ammonia excretion, accounting for 64-77 % of the variance. Atomic O:N ratios (respiration:ammonia excretion) ranged from 11 to 74 (median 21.5). C composition was negatively correlated with habitat temperature, but water contents, ash, N, and the C:N ratio were uncorrelated with the three independent variables. As judged by C:N ratios, protein was considered to be the major organic component of most pelagic amphipods. However, some amphipods from >500 m depth exhibited high C:N ratios (>10) suggesting a large deposition of lipids in the body. Comparison of the present results with global bathymetric models of euphausiids and pelagic copepods revealed that respiration rates of the pelagic amphipods were near-equal to the rates of euphausiids but greater than the rates of pelagic copepods, reflecting taxon-specific body morphology and swimming behavior among the three taxa. As a marked feature of body chemical composition, the pelagic amphipods exhibited extremely high ash content (mean 25 % of DM) due to their possession of a robust exoskeleton. © 2013 The Oceanographic Society of Japan and Springer Japan. Source


Ikeda T.,16 3 1001 Toyokawa cho
Journal of Experimental Marine Biology and Ecology | Year: 2013

Respiration and ammonia excretion data and chemical composition data [water content, ash, carbon (C), nitrogen (N) and C:N ratios] of 13-32 mysids from freshwater, coastal littoral, epipelagic and abyssopelagic zones of the world's oceans were compiled. The independent variables including body mass, habitat temperature and sampling depth were all significant predictors of respiration, accounting for 74-85% of the variance in the data, while body mass and habitat temperature were significant predictors of ammonia excretion, accounting for 85-86% of the variance. Atomic O:N ratios (respiration: ammonia excretion) ranged from 7.9 to 44.8 (median: 18.7), indicating protein-oriented metabolism. Body water content and ash were not correlated with body mass, habitat temperature and sampling depth, but C composition and N composition increased and decreased, respectively, with the increase of sampling depth. As judged by C:N ratios, protein was considered to be the major organic component of most mysids. However, some deep-sea mysids exhibited high C:N ratios (8.6-10.6), suggesting a predominance of lipids in the body. © 2013 Elsevier B.V. Source


Ikeda T.,16 3 1001 Toyokawa cho
Journal of Oceanography | Year: 2014

Metabolism (respiration and ammonia excretion rates) and chemical composition data [water content, ash, carbon (C), nitrogen (N) and C:N ratios] of a total of between 6-32 species of pteropods (thecosomes and gymnosomes) and heteropods from ≤500 m depth of the world's oceans were compiled. Among the independent variables designated (body mass, habitat temperature, sampling depth, taxon), body mass and habitat temperature were significant predictors of metabolism, attributing to 85 % of the variance in respiration rates and 69 % of the variance in ammonia excretion rates. Atomic O:N ratios (respiration:ammonia excretion) ranged from 7.0 to 100 (median 14.5), and no appreciable effects of the variables were detected. A significant negative correlation of C and N compositions and habitat temperature was seen only in the thecosomes. As judged by the concomitant increase in C:N ratios with increasing habitat temperature, a greater deposition of inorganic C (as CaCO3-C) in the shell of the warmer-living species was suggested. Compared with other zooplankton (copepods, chaetognaths, and euphausiids), the thecosomes were characterized by higher respiration rates per unit body N and larger ash content by having possession of calcareous shells. Because of the shells, C and N composition expressed as % of dry mass of the thecosomes were lower than those of the other zooplankton taxa. © 2014 The Oceanographic Society of Japan and Springer Japan. Source

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