Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4397750 | Journal of Experimental Marine Biology and Ecology | 2007 | 12 Pages |
Abstract
The porcelain crab Petrolisthes elongatus is a particulate suspension feeding species common to coastal areas of New Zealand (NZ). Consistent with the responses of other suspension feeding species, it is likely to be negatively influenced by elevated suspended sediment concentrations. Laboratory experiments were conducted to quantify the effect of temperature (12 °C, 15 °C and 18 °C) and suspended sediment concentration (total particulate matter (TPM): low < 100 mg Lâ 1; medium 100-1000 mg Lâ 1; high > 1000 mg Lâ 1) on the clearance rate (CR in L hâ 1), oxygen uptake rate (VO2 in mL hâ1), net absorption efficiency (AE), and net energy budget (NEB in J hâ 1) of P. elongatus across a range of sizes. Variation in CR and AE was independent of temperature and of body size, but were significantly different (P < 0.05) at low and medium suspended sediment concentrations compared with high suspended sediment concentrations. CR responded in a non-linear manner to changes in TPM, increasing with TPM up to a maximum value at medium-low concentrations (approximately 250 mg Lâ 1) and then decreasing thereafter. CR had almost completely shut down at TPM concentrations of > 1000 mg Lâ 1 and at particulate organic matter (POM) concentrations of > 250 mg Lâ 1. AE was zero at approximate TPM and POM values of 1200 mg Lâ 1 and 300 mg Lâ 1, respectively. VO2 was positively correlated with body size and with temperature, but was independent of TPM. NEB values for P. elongatus were low (approx 110 J gâ 1 hâ 1) at low sediment concentrations, were high (approx 320 J gâ 1 hâ 1) at medium sediment concentrations, and were negative (approx â 114 J gâ 1 hâ 1) at high sediment concentrations. These findings indicate that P. elongatus is likely to be food-limited at sediment concentrations of < 100 mg Lâ 1, and severely negatively affected at sediment concentrations of > 1000 mg Lâ 1, at least for the duration of such events which may persist for 2-3 days in coastal environments where this crab occurs.
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Authors
Kate K. Steger, Jonathan P.A. Gardner,