(Table 2) Production parameters of phytoplankton and some associated parameters in the area of the Titanic Polygon

Studies were carried out mostly in the area of RMS Titanic wreck site (41°44'N, 49°57'W) located above the continental slope and the south of the Grand Banks of Newfoundland. In a period from 18.06 to 24.09.2001 five surveys of production characteristics of surface phytoplankton were conducted over 5-9 days. Mean values of these characteristics obtained during the surveys were 9.2-11.7 mg C/m**3 per day for primary production (C_phs), 0.102-0.188 mg/m**3 for chlorophyll a (C_chls), and 4.44-7.42 mg C/mg chl. a per hour for assimilation number (AN). The main reason for low C_phs variability was a significant inverse relationship (R=-0.66) between AN and C_chls found over the research area. When cold shelf waters dominated in the area (27.07 to 19.08.2001), C_chls values for the slope region (0.125+/-0.031 µg/l) and for the outer shelf (0.130+/-0.040 µg/l) were similar. During strengthening of influence of warmer slope waters within area (from 29.08 to 13.09.2001), C_chls concentration within surface waters of the outer shelf was 0.152+/-0.039 µg/l and exceeded one for the slope region (0.094+/-0.004 µg/l) by factor 1.6. Against the background of low Cchls values, the High values of integral primary production in the water column (510-1010 mg C/m**2 per day) at low C_chls values measured within the area were determined both by high assimilation activity of phytoplankton and by the deep (30-40 m) maximum of primary production. Main reasons for formation of such a maximum were high chlorophyll concentration within the layer of the deep chlorophyll maximum (up to 0.5-2.5 µg/l) and in the relatively high solar irradiance within this layer varying from 1.4 to 8.6% of subsurface PAR.

本研究主要在地处大陆坡上方、纽芬兰大浅滩南部的皇家邮轮泰坦尼克号(RMS Titanic)失事海域（北纬41°44′，西经49°57′）开展。2001年6月18日至9月24日期间，研究团队先后5次针对该海域开展表层浮游植物生产特征调查，单次调查时长为5至9天。调查所得的各特征平均值如下：初级生产（primary production, C_phs）为9.2~11.7 mg C/(m³·d)，叶绿素a（chlorophyll a, C_chls）为0.102~0.188 mg/m³，同化数（assimilation number, AN）为4.44~7.42 mg C/(mg chl a·h)。导致初级生产波动幅度较低的主要原因，是研究区域内观测到的同化数与叶绿素a间存在显著负相关关系，相关系数R=-0.66。2001年7月27日至8月19日，该海域以寒冷陆架水为主导时，陆坡区叶绿素a浓度为(0.125±0.031) μg/L，外陆架区为(0.130±0.040) μg/L，二者数值相近。2001年8月29日至9月13日，随着暖性陆坡水影响增强，外陆架表层水体的叶绿素a浓度升至(0.152±0.039) μg/L，较陆坡区的(0.094±0.004) μg/L高出1.6倍。在研究区域内叶绿素a整体浓度偏低的背景下，水体柱积分初级生产仍可达510~1010 mg C/(m²·d)，这一高值既源于浮游植物的高同化活性，也得益于深度达30~40 m的初级生产次表层最大值。形成该次表层最大值的主要原因包括：深层叶绿素最大值层内叶绿素浓度较高（可达0.5~2.5 μg/L），且该层内太阳辐照度相对充足，约为表层下光合有效辐射(Photosynthetically Active Radiation, PAR)的1.4%~8.6%。