琼东海域营养盐与叶绿素a季节变化及日变化

发布时间：2018-02-03 12:23

本文关键词： 琼东海域营养盐叶绿素a 季节变化周日变化　出处：《广东海洋大学》2015年硕士论文　论文类型：学位论文

【摘要】：琼东海域位于南海北部大陆架西南缘,处于南海暖流的最西端,是我国著名的上升流海区,营养盐含量高,出现了清澜和七州列岛等渔场。同时,琼东海域属于亚热带季风区,气候变化主要受东亚季风控制,夏季盛行暖湿的西南季风,冬季盛行干冷的东北季风。另外,琼东海域位于海南岛东部,受到海南人类活动以及东部沿岸断续相间的o_湖水体的影响明显。这些独特的地理环境和气候以及物理水文条件等对琼东海域营养盐与叶绿素a的时空分布具有重要影响。本文依托2012年12月南海开放航次和2013年8月广东海洋大学开放航次,以琼东海域为研究区域,通过对海水中营养盐与叶绿素a分布的分析,探讨琼东海域营养盐与叶绿素a的时空分布特征及其季节变化和日变化的影响因素。本文研究结论如下:1.通过对2012年冬季和2013年夏季营养盐时空分布特征进行研究,发现2012年冬季,调查海域除了北部站位DIN,SiO32-浓度和DIN/P、Si/P比值较高之外,其余站位营养盐浓度和比值整体比较低且分布比较均匀。这是由于北部站位受到了具有高浓度DIN、SiO32-和低浓度PO43-的广东沿岸流的影响。2013年夏季,调查海域DIN和PO43-浓度与冬季分布相似,分布比较均匀,SiO32-浓度和Si/DIN、Si/P比值则呈近岸高离岸低的分布趋势。这主要是由于夏季河流径流量大,琼东近岸海域受到具有低浓度DIN、PO43-和高浓度SiO32-特征的河流影响,同时夏季近岸生物量增大和层化作用增强,因此DIN和PO43-浓度由于近岸生物利用和层化作用影响分布比较均匀,SiO32-浓度和Si/DIN、Si/P比值由于河流量增大的影响呈近岸高离岸低的分布特点。2.通过对2012年冬季和2013年夏季叶绿素a时空分布特征进行研究,发现2012年冬季,叶绿素a浓度除了琼东海域东北部几个站位浓度比较高之外,整体分布比较均匀。这是由于琼东海域东北部受到广东沿岸流影响,沿岸流带来丰富的营养盐,促进浮游植物生长。2013年夏季,叶绿素a浓度大体呈现近岸海域高于外海域的分布特征。这可能是由于夏季河流径流量增大,河流输入带来了丰富的营养盐,促进浮游植物的生长,因此叶绿素a浓度在近岸站位出现高值。夏季叶绿素a浓度明显大于冬季,这主要是由于夏季河径流量增大,河径流影响的范围大于广东沿岸流的影响区域,河流输入带来丰富的营养盐,且夏季光强度增大,光照时间也变长,浮游植物光合作用增强,促进了浮游植物生长,因此夏季叶绿素a浓度高于冬季。3.分析该调查海域营养盐对浮游植物生长的可能限制因子发现,冬季表层水体呈现明显的硅限制,其限制因子几率为58.83%,夏季呈现氮-硅协同限制的可能性。这主要是由于生物利用、季节性的河径流量、广东沿岸流以及层化作用的影响,使得营养盐限制因子由冬季的硅限制转变为夏季的氮和硅共同限制。4.通过对2013年夏季近岸站位S1与陆架区站位S2营养盐与叶绿素a浓度周日变化进行研究,分析发现在垂直分布上,近岸站位S1与陆架区站位S2温跃层之上的层位(表中层)营养盐浓度接近,温跃层之下的层位(底层)营养盐浓度较高,说明温跃层可能减弱了营养盐的向上输运。在时间变化上,S1站位底层硅酸盐、硝酸盐和磷酸盐浓度具有半日波动的特点,而S2站位的营养盐则不具有周日波动的现象,这说明近岸站位的营养盐受到潮汐作用的影响更显著。S1站位的叶绿素a分层不明显,夜间的低值体现浮游动物的摄食作用,S2站位的叶绿素a分层明显,夜间没体现浮游动物的摄食作用。总体上,琼东海域近岸站位S1和陆架区站位S2叶绿素a和营养盐周日波动都受到温跃层、潮汐、生物作用和光照的影响,但S1站位受潮汐作用影响更显著,且S1站位叶绿素a浓度还受到浮游动物摄食作用影响。正是由于叶绿素a和营养盐受到多种环境要素的影响,使得两者没有显著相关。
[Abstract]:East coast of Hainan Island is located in the northern continental shelf of South China Sea southwest margin, in the west of South China Sea warm current, upwelling area is famous in China, the nutrient content is high, the Qing Lan and seven state islands and other fisheries. At the same time, east coast of Hainan Island belongs to subtropical monsoon zone, climate change is mainly affected by the East Asian monsoon, warm and humid in the summer the southwest monsoon, the winter prevailing dry northeast monsoon. In addition, east coast of Hainan Island is located in the east of Hainan Island, by human activities in Hainan and the o_ lake along the east coast and the intermittent impact is obvious. The unique geographical environment and climate as well as physical and hydrological conditions have significant influence on nutrient and chlorophyll a of the east coast of Hainan Island based on the temporal and spatial distribution. The South China Sea in December 2012 and August 2013 Guangdong Ocean University open open voyage voyage, on the East Coast of Hainan Island as the study area, based on water nutrients and chlorophyll a distribution Analysis of the influence factors on the temporal and spatial distribution characteristics and seasonal variation of nutrients and chlorophyll a and diurnal variation in the east coast of Hainan Island. The conclusions of this paper are as follows: 1. through the winter of 2012 and 2013 summer spatio temporal distribution of nutrients were investigated, found in the winter of 2012, in addition to the North Sea survey stations DIN, SiO32- concentration and DIN/P, outside the ratio of Si/P is higher, the nutrient concentration and the ratio of the overall position is relatively low and uniform distribution. This is because the northern stations are having a high concentration of DIN, SiO32- and PO43- of low concentration of Guangdong coastal current impact.2013 summer, similar DIN investigation area and PO43- concentration and distribution in winter, more evenly distributed, the concentration of SiO32- and Si/DIN, Si/P ratio is high inshore and low offshore distribution trend. This is mainly due to the summer runoff of rivers, coastal waters Qiongdong is affected by the low concentration of DIN, PO43- and high The influence of the concentration of SiO32- characteristics of the river, while summer coastal biomass increases and the stratification is enhanced, so the DIN and PO43- concentration due to affect coastal bioavailability and stratification is more evenly distributed, the concentration of SiO32- and Si/DIN, the ratio of Si/P was increased due to the effect of river flow distribution characteristics of.2. in high and low offshore offshore through the study of 2012 the winter and summer of 2013 chlorophyll a space-time distribution characteristics found in the winter of 2012, the concentration of chlorophyll a in addition to the northeast east coast of Hainan Island in several sites of concentration is relatively high, the overall distribution is more uniform. This is due to the northeast by the east coast of Hainan Island Guangdong coastal current, the coastal current has rich nutrients, promote the growth of phytoplankton in the summer of.2013, distribution characteristics chlorophyll a concentrations generally present in coastal waters is higher than that of the outer sea. This may be due to the summer runoff increases, the river input brings The rich in nutrients, promote the growth of phytoplankton, the chlorophyll a concentration had a high value in inshore station. Chlorophyll a concentration in summer was significantly higher than that in winter, which is mainly due to the summer river runoff range of river runoff effect is greater than the effect area of Guangdong coastal current, the river input brings abundant nutrients, and summer light the light intensity increases, time is long, phytoplankton photosynthesis, promote the growth of phytoplankton, the chlorophyll a concentration in summer than in winter and.3. analysis of the investigation area of nutrients on phytoplankton growth may be limiting factor that winter surface water has obvious limitation of silicon and its limited factors, the probability is 58.83%, showing the possibility of nitrogen in summer silicon synergistic restrictions. This is mainly due to the biological utilization, seasonal river runoff and Guangdong coastal current and the influence of stratification, the nutrient limitation Factor change from silicon limitation in winter for nitrogen and silicon in summer limited.4. through the study of the 2013 summer inshore station and continental shelf area at S2 S1 nutrient and chlorophyll a concentration Sunday change, analysis found in the vertical distribution, and the continental shelf inshore station S1 station S2 thermocline layer above the horizon (table middle) the nutrient concentration near the thermocline below the horizon (bottom) nutrient concentration is higher, indicating the thermocline may nutrients to transport the weakened. In the change of time, the underlying S1 station has the characteristics of semi diurnal fluctuations of silicate, nitrate and phosphate concentration, and nutrient S2 stations are not Sunday has fluctuation, which indicates that nutrients in coastal stations affected by the tidal effect is more significant in site.S1 chlorophyll a layer is not obvious, feeding effects of planktonic animal low value at night, leaves green site S2 a layered Obviously, the night did not reflect the effect of feeding planktonic animal. Overall, Qiongdong offshore stations S1 and S2 stations in the continental shelf area of chlorophyll a and nutrients on Sunday by thermocline fluctuations, tides, bio effect and light, but the station S1 by the tidal effect is more significant, and the chlorophyll a concentration also S1 station affected by planktonic animal feeding. It is due to the impact effect of chlorophyll a and nutrients is affected by many environmental factors, which both have no significant correlation.

【学位授予单位】：广东海洋大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P734

【参考文献】