One of the challenges of impact studies in anthropized areas is
that, in most cases, the situation is not Manichean, with pristine
sites clearly identified and point source pollution characterizing
impacted sites. Reality is far less straightforward, often resulting
in mixed effects from multiple and diffused pollution sources. In
our study, we expected sewage outflow to have an indubitable effect;
however, we found a more subtle situation. Overall, our study
highlighted independent patterns based on the nature of the input,
dissolved or particulate. The results of our analysis of the P. oceanica
community, which reflects the nature of dissolved nitrogen,
suggest that (i) a 15N-enriched nutrient supply exists at the level
of the sewage outflow and the harbor entrance; (ii) there is a higher
seasonal variability at these sites compared to more pristine
sites; and (iii) there is a slight 15N-enrichment at the site near
the fish farm. Our analysis of transplanted mussels, with respect
to SPM, indicates that (i) there is less disparity in the bay during
autumn; (ii) there is a 15N-enrichment at the harbor entrance;
(iii) the 15N-depleted sewage SPM influences mussel growth near
the source of sewage outflow; and (iv) the rain input potentially
influences the SPM at the site close to the rain outflow. Thus, a
combined analysis of the isotopic signatures of diverse marine
organisms gave us clues about the spatial differences that exist
in nutrient supplies in a strongly anthropized bay. It is important
to note, however, that the information provided by our analysis
of stable isotopes was qualitative rather than quantitative. The spatial
design that we used did not allow us to map a clear pollution
gradient but rather highlighted the global and diffuse pollution
that occurs in the Golfe-Juan bay.
One of the challenges of impact studies in anthropized areas isthat, in most cases, the situation is not Manichean, with pristinesites clearly identified and point source pollution characterizingimpacted sites. Reality is far less straightforward, often resultingin mixed effects from multiple and diffused pollution sources. Inour study, we expected sewage outflow to have an indubitable effect;however, we found a more subtle situation. Overall, our studyhighlighted independent patterns based on the nature of the input,dissolved or particulate. The results of our analysis of the P. oceanicacommunity, which reflects the nature of dissolved nitrogen,suggest that (i) a 15N-enriched nutrient supply exists at the levelof the sewage outflow and the harbor entrance; (ii) there is a higherseasonal variability at these sites compared to more pristinesites; and (iii) there is a slight 15N-enrichment at the site nearthe fish farm. Our analysis of transplanted mussels, with respectto SPM, indicates that (i) there is less disparity in the bay duringautumn; (ii) there is a 15N-enrichment at the harbor entrance;(iii) the 15N-depleted sewage SPM influences mussel growth nearthe source of sewage outflow; and (iv) the rain input potentially influences the SPM at the site close to the rain outflow. Thus, acombined analysis of the isotopic signatures of diverse marineorganisms gave us clues about the spatial differences that existin nutrient supplies in a strongly anthropized bay. It is importantto note, however, that the information provided by our analysisof stable isotopes was qualitative rather than quantitative. The spatialdesign that we used did not allow us to map a clear pollutiongradient but rather highlighted the global and diffuse pollutionthat occurs in the Golfe-Juan bay.
การแปล กรุณารอสักครู่..