کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4396888 | 1305850 | 2009 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Density dependent effects of an infaunal suspension-feeding bivalve (Austrovenus stutchburyi) on sandflat nutrient fluxes and microphytobenthic productivity
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علوم کشاورزی و بیولوژیک
علوم آبزیان
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Density dependent effects of an infaunal suspension-feeding bivalve (Austrovenus stutchburyi) on sandflat nutrient fluxes and microphytobenthic productivity Density dependent effects of an infaunal suspension-feeding bivalve (Austrovenus stutchburyi) on sandflat nutrient fluxes and microphytobenthic productivity](/preview/png/4396888.png)
چکیده انگلیسی
We examined in situ the density dependent effects of an infaunal suspension-feeding bivalve, Austrovenus stutchburyi (hereafter Austrovenus) on sandflat nutrient fluxes and microphytobenthic (MPB) production. Nine experimental plots (0.64 mâ 2) were established at two locations separated by 300 m. Ambient fauna was left intact and Austrovenus added to plots creating a density range from 20 to 2000 ind. mâ 2. Three weeks later, light and dark benthic chambers (area = 0.114 mâ 2) were deployed to measure MPB production and nutrient fluxes. Austrovenus density was positively correlated with organic content and porosity but did not affect other sediment properties (grain size, pigment content) or resident macrofauna. In dark chambers there was a net influx of oxygen (O2) into the sediments which increased with Austrovenus density (from â 0.45 to â 1.21 mmol mâ 2 hâ 1) whereas in light chambers there was a net efflux from the sediments which decreased with density (from 0.90 to 0.31 mmol mâ 2 hâ 1). Significant (p < 0.01) multiple linear regression models explained respectively 42% and 72% of the variability in the dark and light chamber O2 fluxes with Austrovenus density as the most important predictor variable. When the effects of significant co-variables (light intensity, grain size) were accounted for, the negative relationship between O2 flux and Austrovenus density was less steep in light chambers (ANCOVA p < 0.001) suggesting a stimulation of MPB production at higher densities. Estimates of gross MPB primary production indicated a 30% increase in rates of carbon fixation with Austrovenus density (from 36 to 48 mg C mâ 2 hâ 1). Ammonium (NH4+) was released from the sediments in both light and dark chambers and increased with Austrovenus density by a factor of 5.9-6.9Ã. Multiple linear regression models were significant for light and dark chambers (p < 0.001; r2 86-87%) with Austrovenus again as the most important variable influencing fluxes. ANCOVA results (p < 0.001) indicated that in dark chambers NH4+ efflux increased with Austrovenus density at a rate 1.76à greater than in light chambers. These results indicate that the greater efflux of NH4+ at high densities was being trapped by photosynthesising MPB at the sediment-water interface supporting higher rates of primary production. Our results suggest that a reduction in Austrovenus density will lower nutrient fluxes potentially influencing system productivity by reducing MPB production.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Experimental Marine Biology and Ecology - Volume 373, Issue 1, 15 May 2009, Pages 16-25
Journal: Journal of Experimental Marine Biology and Ecology - Volume 373, Issue 1, 15 May 2009, Pages 16-25
نویسندگان
Dean R. Sandwell, Conrad A. Pilditch, Andrew M. Lohrer,