Laoshan Bay Artificial Reef Area Large Benthic Algae Community Of Seasonal And Regional Changes

The21st century is oceanic epoch. The sustainable development has become theleading tune of ocean exploitation. But with the rapid progress of world fishery, theunending supply of Marine fishery resources faces many problems. On one hand, withthe growing demand for fishery resources, fishing intensity is excessive; on one hand,with the industrial production, offshore aquaculture and sewage, the sea water ofoffshore is more serious polluted; on the other hand, fishery management work of ourcountry relatively falls behind. These question leads to the marine resources of ourcountry declined sharply, to the structure of marine biological resources deteriorated,to habitats degenerated or disappeared, biological populations and the number ofspecies reduced increasingly, to the ocean desertification. The sustainabledevelopment of the marine resources of our country had be seriously challenged. Inorder to restore the declined fishery resources and to repaired the deteriorated marineecological environment, the related departments of our country have made manymanagement policy and taken many measures, such as prohibition of fishing insummer, proliferation and discharge etc. But the destruction of offshore habitat andpollution of ocean have not been resolved radically. Constructions of artificial reefsare considered as an effective approach to improve water environment and to restorefishery resources by the most of fishery developed countries.This thesis mainly investigated the ecological factors and benthic algae of theartificial reefs in Laoshan Bay. It includes six chapters. Chapter1summarizes thestock enhancement of artificial reefs. Chapter2summarizes the advances in marinealgae of the benthic community at home and abroad. Chapter3analyses theecological factors of Laoshan bay. Chapter4summarizes the benthic algaecommunity seasonal changes rule of the artificial reefs in Laoshan Bay. Chapter5summarizes the algae community differences of three artificial reefs in Laoshan Bay.Chapter6sums up all the text and looks ahead. Our study concludes the annual change rule of artificial reefs marineenvironmental factors of Laoshan Bay in chapter3. Annual variation in oceantemperature is3.1-25.9℃; salinity is31.69-34.75‰; the rate of clarity is1.05-3.20m;pH is7.82-8.22. The chlorophyll content changed seasonally (summer> spring>autumn> winter). DO, PO4-P, IN and SiO3-Si are lower in summer and higher inwinter than other seasons. According to the Sea Water Quality Standard, pH, DO andPO4-P had reached Grade I water quality standards, while BOD and COD hadreached Grade II water quality standards. From what has discussed above, we candraw the conclusion that this area was of little pollution and was adapted to put intoartificial reefs and to develop aquaculture.Chapter4introduces the seasonal variation of the benthic algae community ofthe artificial reefs in Laoshan Bay.(1)By classifying and identifying the algaesamples, we collect altogether22species of benthic algae. The Rhodophyta has13genus and17species and takes up77.27%of the total; the Chlorophyta has2genusand3species and takes up13.64%of the total; the Phaeophyta has only2genus and2species and only takes up9.09%of the total. Structure of algae communities is thesame as other Qingdao area by our surveys.(2)In all of the algae species,66.67%isthe warm temperate zone species, and27.28%is the cold temperate species, and16.66%is subtropical temperate species. So the nature of artificial reef areas inLaoshan Bay is obviously warm temperate water.(3) In winter, the dominant algaeare Plocamium telfairiae and Gelidium amansii. In summer, it is Gelidiumdivaricatum. And in spring, they are Corallina pilulifera and Gelidium amansii. Inautumn they are Corallina pilulifera and Gelidium divaricatum.(4)The changes ofalgae community’s biomass is that spring> summer> autumn> winter.(5) Theinterannual variability of algae diversity index is spring> summer> autumn> winter.(6)The chlorophyll content algae community is spring> summer> autumn> winter.(7)Environmental factors of correlation analysis show that the temperature is the most important environmental factors to algal communities, while nutrient is the second.Chapter5reveals the algae community differences of three artificial reefs inLaoshan Bay.(a) The results of algae population shows that Fengshan> Gangdong>Yangkou.(b)The dominant species is coincident in winter and summer, but it isdifferent when spring.(c) Biomass is Fengshan> Gangdong> Yangkou, but Fengshanand Gangdong do not have a big difference.(d) In the diversity index, the changetrend of these three areas is basically similar. In each season, the diversity index ofGangdong is higher than it in Yangkou, and the change of Fengshan is different.(e)The chlorophyll of Gangdong area is higher than Yangkou. Yet the chlorophyll ofFengshan area is the highest in autumn and winter. Presumably, current and sedimentof ocean are the most important factors of influence to make reefs different in threeareas.According to the current researches and experiment results, we look forward tothe future of artificial reefs in chapter6.