Buried Effects Of Dredged Material On Ruditapes Philippinarum And Perinereis Aibuhitensis

Dredged material is a kind of aiming to protect ports, wharf, navigation channel,anchorage to use smoothly, and to meet the needs of port construction， marineengineering which is digged from the water. Maritime activities have becomeincreasingly prominent, marine waste-dumping activities become strengthenedgradually, and dumping of dredged material become the main elements of marinewaste-dumping. It’s not only polluted the Marine ecological environment, but alsokilled Marine life etc, especially the effects on the benthos. This research has alsobecome a hot-button issue. In this paper we study affectes of dredged material buried onRuditapes philippinarum and Perinereis aibuhitensis survival, and Ruditapesphilippinarum defense system of antioxidative enzymes (SOD, and CAT) under twokinds of granularity, to discuss benthos survive and physiological effect. The results areas following:1. The short-term effects of clean dredged material buried for ruditapesphilippinarum, nereis survival suggestsDuring the experimental period, there is a highly significant positive correlationbetween burial depth and Ruditapes philippinarum mortality, however there is nosignificant correlation between Perinereis aibuhitensis mortality and burial depth; whendredged material granularity is125~63μ m, the4d-LC50for R. philippinarum was6.8cm. When the burial depth is12cm, ruditapes philippinarum can not move out ofdredged material. This means that when the dumping of this particle size dredgedmaterial thickness is more than12cm, it is fatal to the populations of ruditapesphilippinarum,but the nereis have a strong adaptation capacity, when the depth is12cm,it caused no impact; when dredged material granularity is under63μm, the4d-LC50for R. philippinarum was11.1cm. On the experiment, when it is4th day,12cm grouphas caused only53.3%deaths. It suggest that the ruditapes philippinarum has a strongability to adapt in this granularity, the damage caused by buried is limited. During the most of the experiment, the experimental group of ruditapes philippinarum can notmigrate out of the surface of dredged material. Although the bio is still alive, but as thetime go on, dredged material are more and more dense, This may be affected themigrations of bio capable in some time, it can be unfavorable for the bio survival.2. The long-term effects of clean dredged material buried for ruditapesphilippinarum survival suggestsWhen dredged material granularity is125~63μm, the8d-LC50for R.philippinarum was8.4cm. When the burial depth is12cm, the mortality rates ofruditapes philippinarum is100%. When we are drumping dredged material, we cancontrol the depth under12cm. When dredged material granularity is under63μm, the8d-LC50for R. philippinarum was7.1cm. As the burial depth increases, the number ofruditapes philippinarum moved out reduced significantly. The migrating capacitybecame weaker, when the burial depth was increasing. Because this granularity of thedredged material has a deposition process, so there will be a large spaces and smallviscosity between particles. Ruditapes philippinarum remains to be buried largely and ithave no vertical migration amostly. Although the largest depth experimental group stillhas survival, but we can predicte that if the bio can not migrate to the suface, it will leadto his death eventually.3. Effects of clean dredged material buried for ruditapes philippinarum antioxidantenzymes suggestsWhen dredged material granularity is125~63μm, under low buried depth (2cm),SOD activity in viscera of the ruditapes philippinarum was performed restrained-induced cycle, SOD activity significantly induced after96h; under high buried depth(10cm,12cm), SOD activity in viscera was basically in a state of inhibition, they alldead in96h. Under low buried depth (2cm), SOD activity in gills of the ruditapesphilippinarum has been in a state of inhibition, it has returned to normal levels in96h;under middle-low buried depth (4cm,6cm), the SOD activity was firstly restrained andthen induced; under middle-high buried depth (8cm), SOD activity were basically in astate of significant inhibition; in the process of burying stress, dose-effect is notobvious. Under low buried depth, CAT activity in viscera of the ruditapes philippinarumwas performed restrained-induced cycle; under middle-low buried depth, the activityof enzyme was induced in the whole process, but it returned to normal levels after96h;under middle-high buried depth, the activity of enzyme was firstly restrained and then induced obviously; high buried group was in a state of significant inhibition basically.CAT activity in gill of the ruditapes philippinarum was restrained obviously after6h,under low and middle-low buried depth, CAT activity was restrained firstly and theninduced; under middle-high buried depth, it was performed restrained–induced beforemoved out, it was in a state of restrained after moved out, it showed that gill filamentshad damaged and had not repaired effectively; under high biried depth, CAT activitywas higher than the control group in sometime, it was restrained obviously in the wholetime.When dredged material granularity is under63μm, under the stress of burying,SOD activity in viscera of the ruditapes philippinarum mainly induced rise first, it wasrestrained under the continue stress then. Under low buried depth, SOD activity in gillof the ruditapes philippinarum was in a state of induction of most of the time, it wascalled the "poison excited effect"; under middle-low buried depth, SOD activity wasback to normal level after induced as a whole; under middle-high buried depth, SODactivity was gradually returned to normal after restrained and induced; under highburied depth, SOD activity was induced firstly and then restrained. Under the stress ofburying, the induction and inhibition of CAT activity in viscera of the ruditapesphilippinarum were more significant, the CAT of each group was restrained afterinduced, it explained the viscera may be damaged. CAT activity in gill of the ruditapesphilippinarum was induced firstly, then it was restrained; the enzyme activity of thegroups which had lower barried depth had return to nomal levels at96h, but theenzyme activity of the groups which had higher barried depth was significantlyrestrained after96h.When dredged material granularity is125~63μm, it is more harmful to livingbodys in a short time.