1 Introduction

Tintinnid ciliate is an important component of microzooplankton which had lorica as taxonomic characters.At the genera level, tintinnids were divided into different biogeographical types according to their occurrence in different water masses (Dolan et al., 2012; Pierce and Turner, 1993). According to the strong water mass affiliation with neritic waters, warm-waters, boreal and austral cold waters, they were classified as neritic, warmwater, boreal and austral biogeographical types, respectively. Occurring in all water masses, cosmopolitan tintinnids do not have water mass affiliation. Different biogeographical types converged and mixed in the sea areas where different water masses converged and mixed.

Although Yellow Sea (YS) is influenced by YS warm currents (Hsueh, 1988; Teague and Jacobs, 2000; Yu et al.,2010), no warm-water tintinnids was found in previous studies (Li et al., 2014; Yu et al., 2014; Zhang et al.,2009, 2008; Zhang and Wang, 2000a, b; Zhang et al.,2002) in YS and Bohai Sea (BS). Because warm-water zooplankton and phytoplankton intruded into YS (Wang et al., 2013), we hypothesized that warm- water tintinnid should occur in YS.

YS was the southmost distribution area of boreal tintinnid in the west Pacific. The boreal genera, Parafavella and Ptychocylis, were found in YS in spring (Zhang et al., 2018), early summer (Zhang et al., 2008) and winter (Zhang et al., 2009). But there was no report of its connection with its nearest distribution area in the north of Japan Sea (Dolan et al., 2012; Gómez, 2007; Kato and Taniguchi, 1993; Li et al., 2016a; Taniguchi, 1984). They were not found in the biweekly, monthly or year round monitoring in Tsushima Strait (Kim et al., 2012), indicating that there was no transport of boreal tintinnid to YS from Japan Sea. Because high temperature was the limit of boreal tintinnid, we needed to find these tintinnids in high summer in order to understand their oversummer mechanism.

Neritic tintinnids occurred in waters from seashore to deep waters. In such a vast area, we still did not know where its high abundances area (core area) lied. Neritic tintinnids abundance and species richness in the surface decreased with the increase of water depth (Li et al.,2016b). Because neritic tintinnids had higher abundance in bottom waters than in surface waters (Yu et al., 2016),neritic tintinnid abundance core area should be determined by bottom abundance.

The aim of the present study were to find out: i)whether there was warm-water tintinnids in YS and BS; ii)whether there was boreal tintinnids in high summer; iii)the position of core area of neritic tintinnids and iv) how these different biogeographical tintinnids mixed.

2 Materials and Methods

2.1 Studying Area and Sampling Strategy

Neritic tintinnids mixed with warm-water and boreal tintinnids in both summer and winter. However, the location of highest abundance of neritic tintinnids rarely overlapped with that of warm-water or boreal tintinnids(Figs.3–6).

Fig.1 Map of sampled stations in the Yellow Sea and Bohai Sea.

The vertical profiles of temperature and salinity from surface to 2 m above bottom were obtained using a conductivity-temperature-pressure (CTD) sensor (Sea-Bird 911, USA). Water masses were defined based on temperature and salinity (Su and Weng, 1994; Pan and Pang,1997; Chen, 2009). In this study, the temperature and salinity characteristics matched the standards of different water masses in the previous studies, thus water masses in this study were identified according to their temperature and salinity characteristics. The fronts were identified where oceanographic parameters, such as temperature and salinity, change rapidly. They were usually the boundaries separating two different water masses (Chen,2009; Hickox et al., 2000).

Seawater samples (10 L) for tintinnids were collected by Niskin bottles attached to the rosette CTD system in different depths (sampling points) at each station. Each seawater sample was concentrated into about 200 mL by gently filtering through a net (mesh pore size 10 μm). The concentrated sample was fixed with Lugol’s solution (1%final concentration) and kept in cool and dark place until analysis.

2.2 Tintinnid Analysis

In laboratory, the fixed seawater sample was concentrated into 20 mL by serial settling (for at least 24 h) and siphoning out the supernatant. The whole concentrated sample was counted in an Utermöhl counting chamber using an Olympus IX71 inverted microscope (100× or 400×) (Utermöhl, 1958). So the limit of the examination was 0.1 ind L−1 for tintinnids. At least 20 individuals of each species were photographed for morphological measurements as taxonomic determination criteria. Tintinnid species were determined based on lorica morphology according to taxonomic references (Kofoid, 1929; Kofoid and Campbell, 1939; Zhang et al., 2012). Tintinnids were divided into different biogeographical types at genera level according to Dolan et al. (2012) and Li et al.(2016b). The occurrence frequency of each tintinnid species was calculated by dividing the total number of sampling points by the number of sampling points where this species occurred.

3 Results

3.1 Environmental Factors

3.1.1 Environmental factors in summer

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The ranges of temperature and salinity in water column were 6.26–27.91℃ (on average 17.08 ± 7.00℃) and 28.66–33.28 (on average 31.74 ± 0.83), respectively. Four water masses were defined (Table 1). Waters with salinity<31 were defined as coastal waters, including Bohai Sea Coastal Water (BSCoW) and Yellow Sea Coastal Water(YSCoW). Vertically, there were thermocline and halo-cline in 20 m depth in YS. Above the thermocline and halocline were Yellow Sea Surface Warm Water (YSSWW)with temperature >25℃ and salinity <32. Below the thermocline and halocline were Yellow Sea Bottom Cold Water (YSBCW), which was cold (< 13℃) and salty (S >32) (Figs.2–7). They were observed in the central deep area (bottom depth > 50 m) of YS (Fig.2A). In BS, temperature decreased while salinity increased with depth.However, there were no clear thermocline and halocline in BS (Figs.8, 9).

Fig.2 Surface and bottom horizontal distribution of temperature (T, ℃) and salinity (S) in summer (A) and winter (B).

Fig.3 Vertical distribution of temperature (℃), salinity and different biogeographical tintinnid abundance (ind L−1)along Transect 1 in the northern Yellow Sea in summer (A) and winter (B).

Fig.4 Vertical distribution of temperature (℃), salinity and different biogeographical tintinnid abundance (ind L−1)along Transect 2 in the northern Yellow Sea in summer (A) and winter (B).

Fig.5 Vertical distribution of temperature (℃), salinity and different biogeographical tintinnid abundance (ind L−1)along Transect 3 in the southern Yellow Sea in summer (A) and winter (B).

Fig.6 Vertical distribution of temperature (℃), salinity and different biogeographical tintinnid abundance (ind L−1)along Transect 4 in the southern Yellow Sea in summer (A) and winter (B).

Fig.7 Vertical distribution of temperature (℃), salinity and different biogeographical tintinnid abundance (ind L−1)along Transect 5 in the southern Yellow Sea in summer.

Fig.8 Vertical distribution of temperature (℃), salinity and different biogeographical tintinnid abundance (ind L−1)along Transect 6 in the Bohai Sea in summer.

Table 1 Temperature and salinity of water masses in summer and winter

Notes: YSCoW, Yellow Sea Coastal Water; BSCoW, Bohai Sea Coastal Water; YSBCW, Yellow Sea Bottom Cold Water;YSSWW, Yellow Sea Surface Warm Water; YSWW, Yellow Sea Warm Water. T, temperature (℃); S, salinity.

Fronts formed surrounding the YSBCW, which were boundaries separating two different water masses, e.g.,YSSWW vs. YSBCW and YSCoW vs. YSBCW.

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Our results confirmed the occurrence of warm-water tintinnids in YS and BS for the first time. Since our investigations were in the coldest and hottest extremes of one year, we proposed that warm-water tintinnids might exist in YS and BS all year round. The distribution area of warm-water tintinnids in winter was similar with warmwater copepod in Wang et al. (2013).

The ranges of temperature and salinity in water column were −0.48–11.80℃ (on average 7.20 ± 2.92℃) and 16.47–33.03 (on average 32.08 ± 1.14), respectively. Three water masses were defined (Table 1). Yellow Sea Warm Water (YSWW, 8–12℃, S > 32) was well developed in YS in both surface and bottom. Temperature and salinity decreased from southeast of YS to Bohai Strait in the northwest. Temperature in BS was lower than 5℃ (on average 1.32 ± 1.23℃, Fig.2B). Vertically, the thermocline and halocline in YS disappeared. However, coastal waters (BSCoW and YSCoW) with salinity < 32 were identified. Salinity was homogeneous except lower salinity (S < 30) near the Changjiang Estuary (Figs.3–9). The fronts were found between coastal waters and YSWW.

Fig.9 Vertical distribution of temperature (℃), salinity and different biogeographical tintinnid abundance (ind L−1)along Transect 7 in the Bohai Sea in summer (A) and winter (B).

3.2 Tintinnid Species Richness and Biogeographical Types

Warm-water tintinnids had different seasonal cycle:Ascampbelliella and Dadayiella distributed in larger area and more northward in summer than in winter while Acanthostomella showed opposite cycle. In summer,warm-water tintinnids were found in both YSSWW and YSBCW, while they were rarely found in coastal waters(Fig.12A). In winter, they mainly concentrated in YSWW(Fig.12B).

Fig.10 Photos of warm-water (a, b, c) and boreal (d, e, f) tintinnid species occurred in this study. (a. Acanthostomella minutissima, b. Ascampbelliella armilla, c. Dadayiella ganymedes, d. Ptychocylis obtusa, e. Parafavella jorgenseni, f.Parafavella gigantean).

Table 2 List of tintinnid species and their maximum (Max.) abundance in Yellow Sea and Bohai Sea

Max. abundance (ind L−1) Max. abundance (ind L−1)Species Species Summer Winter Summer Winter Neritic T. rapa 0.6 8.8 Codonellopsis lusitanica 11.6 0.3 T. schotti 1.8 0.5 C. mobilis 12.6 1.6 T. tenuis 1029.1 C. morchella 3.2 T. tocantinensis 18.2 C. ostenfeldi 1.6 T. tubulosoides 38.7 10.8 Favella ehrenbergii 95.8 T. urnula 1.1 Helicostomella longa 169.5 Warm-water Leprotintinnus nordqvisti 30.5 Acanthostomella minutissima 19.0 8.4 L. simplex 5.0 12.9 Ascampbelliella armilla 30.0 0.5 Stenosemella nivalis 221.9 51.3 Dadayiella ganymedes 0.6 S. parvicollis 123.6 25.8 Boreal S. ventricosa 0.4 Parafavella gigantea 0.4 Tintinnidium mucicola 0.8 40.1 P. jorgenseni 0.7 T. primitivum 81.7 9.1 Ptychocylis obtusa 28.5 0.7 Tintinnidium sp. 19.0 0.6 Cosmopolitan Tintinnopsis estuariensis 1.5 Amphorellopsis acuta 1623.3 1.7 T. angusta 4.0 1.5 Amphorides amphora 60.2 0.5 T. baltica 0.8 1.9 Eutintinnus lusus-undae 80.2 T. beroidea 148.8 10.1 E. stramentus 0.3 T. brasiliensis 4.6 Eutintinnus sp. 11.6 0.2 T. butschlii 1.2 E. tubiformis 41.5 T. chinglanensis 16.6 Metacylis corbula 1.8 T. corniger 31.2 M. Jorgensenii 17.9 T. directa 0.7 M. oviformis 33.6 T. japonica 0.4 Others T. lohmanni 5.9 Sp.1 0.4 0.7 T. mayeri 0.5 Sp.2 1.7 T. minuta 1.4 0.6 Sp.3 0.8 T. radix 22.3 1.4

3.3 Distribution Pattern of Different Biogeographical Tintinnids

water tintinnids mainly distributed in the east edge of each transect and were found in the whole depth (Figs.5B,6B).

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Warm-water tintinnids had low occurrence frequencies in summer (11.91%) and winter (9.05%). Their abundances were higher in summer (0.2–30 ind L−1, on average 3.2 ± 5.8 ind L−1) than that in winter (0.2–8.4 ind L−1,on average 1.6 ± 2.3 ind L−1). Horizontally, warm-water tintinnids were limited in deep waters of southern YS in winter, but intruded into northern part of YS and BS as well as into the shallow waters in summer (Fig.11).

A total of 16 genera, 52 species (including 3 undefined)were observed in two cruises. Those species belong to 4 biogeographical types (as shown in Table 2): neritic (7 genera 34 species), warm-water (3 genera 3 species),boreal (2 genera 3 species) and cosmopolitan (4 genera 9 species). Warm-water species (Acanthostomella minutissima, Ascampbelliella armilla, Dadayiellaganymedes)were all hyaline tintinnids with small size (shown in Fig.10). Boreal species (Parafavella gigantean, P. jorgenseni, Ptychocylis obtusa) were all hyaline tintinnids with larger size (Fig.10). The total number of species in summer (50 species) were higher than that in winter (28 species).

Vertically, in summer, the highest abundance of warmwater tintinnids in most transects (e.g., Transects 1, 2, 3)were observed in the upper 20 m (Figs.3A, 4A, 5A). In some transects (e.g., Transect 4), the highest abundance occurred in bottom layers (Fig.6A). In winter, warm-

3.3.2 Boreal tintinnids

Boreal tintinnids were not found in BS during the two cruises. In summer, boreal tintinnid had higher occurrence frequency (12.90%) and abundance (0.1–28.5 ind L−1, on average 2.8 ± 5.4 ind L−1) than those in winter(0.82% and < 1 ind L−1, respectively).

In winter, the intrusion of relatively warmer and saltier YSWW in the central deep region (bottom depth > 50 m)of YS made the distribution of boreal tintinnids moving northward. They were found in the north of 37˚N, which was consistent with the previous results showing boreal tintinnids distribution in the north of 36.5˚N during win-tertime (Zhang et al., 2009). The abundance of boreal tintinnids in YS was higher in summer (Max. 28.5 ind L−1)than that in winter (Max. < 1 ind L−1) in our study. However, they were much lower than in spring (2895 ind L−1,Zhang et al., 2017).

3.3.1 Warm-water tintinnids

Vertically, in summer, the highest abundance of boreal tintinnids occurred in the bottom layers (Figs.4A, 5A,6A). In the T-S plots, most boreal tintinnids occurred in YSBCW and they rarely appeared in coastal waters in summer (Fig.12A). In winter, boreal tintinnids occurred outside of YSWW and coastal waters (Fig.12B).

Fig.11 Horizontal projection of the maximum abundance (Max., ind L−1) in water column of different warm-water genera in summer (A) and winter (B). The purple lines were 50 m isobaths (+, sampling stations without certain tintinnid).

Fig.12 Tintinnid abundances (ind L−1) demenstrated in the T-S (temperature-salinity) plots in summer (A) and winter(B). YSBCW, Yellow Sea Bottom Cold Water; YSSWW, Yellow Sea Surface Warm Water; YSWW, Yellow Sea Warm Water. Black points showed the stations without certain tintinnid.

Fig.13 Horizontal projection of warm-water, boreal and neritic tintinnid maximum abundance (Max., ind L−1) in water column in summer (A) and winter (B). The purple lines were 50 m isobaths (+, sampling stations without tintinnid).

Fig.14 Horizontal distribution of the maximum abundance (Max., ind L−1) in water column of all boreal genera in summer. The purple lines were 50 m isobaths (+, sampling stations without certain tintinnid).

3.3.3 Neritic tintinnids

Neritic tintinnids were dominant in YS and BS with high occurrence frequencies (93.80% in summer and 95.88% in winter) and abundances (0.2–1209.5 ind L−1,on average 30.3 ± 75.3 ind L−1 in summer and 0.3–52.1 ind L−1, on average 9.5 ± 8.5 ind L−1 in winter).

Vertically, neritic tintinnids distributed in near bottom areas in most transects in summer (Figs.3A, 4A, 6A, 7A,8A, 9A). In winter, although neritic tintinnids tended to distribute in the upper layers in more transects (Figs.3B,4B, 6B, 9B), there were always a high abundance area of neritic tintinnids near the bottom areas. High abundance of neritic tintinnids in bottom layers occurred along the 50 m isobath in both summer and winter (Fig.15), which were the core area of neritic tintinnids.

3.3.4 Mixing of different biogeographical tintinnids

（1）碾压设备必须在双层摊铺机的后面，并保持一定的距离，当道路摊铺长度达到100～150m/h，碾压设备才可以进行工作。碾压设备的施工方式为4t重小型压路机往复静压。

Fig.15 Horizontal distribution of neritic tintinnid abundance (ind L−1) in bottom layers in summer (A) and winter (B).The pink lines were 50 m isobaths.

In summer, both warm-water and boreal tintinnids appeared in the central deep region (bottom depth > 50 m)of YS (Fig.13A), but the high abundance areas were separated vertically: warm-water tintinnids mainly distributed in the upper 20 m and boreal tintinnids mainly occurred in YSBCW deeper than 20 m (Figs.4A, 5A). They mixed in the south of 36˚N because of the intrusion of warm-water tintinnids into YSBCW and the intrusion of boreal tintinnids into YSSWW (Fig.6A).

In winter, warm-water and boreal tintinnids were separated horizontally. Warm-water tintinnids were limited in the warm water tongue in the southern YS. Boreal tintinnids occurred in front of the warm water tongue in the northern YS (Fig.13B).

高职院校实训基地建设是动态的过程，不是建成后就永久不变。实训基地建设过程中应坚持动态发展，根据经济发展和人才的需求变化，随着专业技术不断的更新，实训基地建设也要做到与时俱进。实训基地的设备更新与专业技术结合，专业技术的发展，设备的配套采购要相适应。让实训基地建设具有可持续性，高职院校的教育教学才能做到持续发展。

Two cruises were conducted in BS and YS (32˚–40˚N,119˚–124˚E, Fig.1) in summer (16 August–6 September 2015) and winter (13–31 January 2016) on board R/V Dongfanghong-2. One hundred and eighteen stations were investigated in summer, while 73 stations were investigated in winter. Water depths ranged in 12 m (St.B68 in BS) and 81 m (St. SY03 in YS).

4 Discussion

4.1 Warm-Water Tintinnids Transported into YS and BS by Warm Water Masses

3.1.2 Environmental factors in winter

Previous studies did not find warm-water tintinnids in YS and BS might because of limitation of sampling methods and sampling effort which is important for the finding of rare tintinnid species (Dolan et al., 2017): i)because the abundances of warm-water tintinnids were low (0.2 to 30 ind L−1, on average 3.2 ± 5.8 ind L−1) in YS and BS, 1 L water sample (Yu et al., 2014; Zhang and Wang, 2000a; Zhang et al., 2002; Zhang et al., 2018) was not enough to collect them; ii) warm-water tintinnids found in YS and BS in our study had small size (lorica oral diameter: 23–26 μm). Sampling by vertical tow net(mesh size 76 μm) would lose the small size species(Zhang et al., 2009, 2008). In our research, large volume water sample in each depth concentrated by gently filtering through a small pore size net was able to avoid the two problems.

不好有诈！他一念既出，撑在地上的六只节足，已猛地曲弹而起，带着他的身体飞快地离开了地面。罡风擦着他的双脚刮过，将他的鞋底削去了一大块，然后，在一声尖锐的金属擦击声中，将那只插在天葬师胸前的节足斩断。

Warm-water tintinnids occurred in YS and BS would be the most adaptable species of the pioneer warm-water species. Similarly, these species were found in Korea Strait and Japan Sea (Kim et al., 2012; Li et al., 2016a).Since they were in an expatriate state (Pierrot-Bults and Angel, 2012), their abundance in our study (< 30 ind L−1 in summer and < 8.4 ind L−1 in winter) were lower than those in East China Sea where in summer the maximum abundance of Acanthostonmella, Ascampbelliella and Dadayiella were 29.9, 77.5 and 68.6 ind L−1, respectively(Li et al., 2016b).

4.2 Distribution of Boreal Tintinnids in YS

Among three boreal species (P. gigantean, P. jorgenseni, P. obtusa) found in YS, P. gigantean and P. jorgenseni were reported in YS for the first time. The endemic species (P. elongate) in YS (Yu et al., 2013) and BS(Wang, 1936) were not observed in our study.

Our results confirmed the occurrence of boreal tintinnids in YS in high summer (August) as well as in winter, which supported the prediction that boreal tintinnids might be an indigenous species in previous studies(Zhang et al., 2018). In summer, the vertical distribution of boreal tintinnids mainly concentrated in YSBCW, indicating the presence of an oversummering stock of boreal tintinnids. YSBCW turned out to be the shelter for boreal tintinnids during the summer time. Actually,YSBCW served as an oversummering site for many temperate species, like Calanus sinicus and Euphausia pacifica (Wang and Zuo, 2004; Wang et al., 2003). To our knowledge, YS is the southernmost habitat for boreal tintinnids compared with the previous studies (Dolan et al.,2012; Li et al., 2016a).

Horizontally, boreal tintinnids concentrated in the central deep waters (bottom depth >50 m) in YS in summer,while they appeared at only two stations in the northern YS in winter (Fig.13). In summer, the two genera were distributed in different areas: Parafavella was mainly distributed along the 50 m isobath, while Ptychocylis concentrated in the central deep region (bottom depth>50 m) of YS (Fig.14). In winter, only Ptychocylis was found.

The abundance of boreal tintinnids might be influenced by two factors: temperature and food. Previous study investigating tintinnid assemblages along a transect from East China Sea to Chukchi Sea showed that when temperature maintained about 10℃ in North Pacific and Bering Sea, the abundance of boreal tintinnids was high(nearly 100 ind L−1) (Li et al., 2016a). When temperature dropped rapidly to below 0℃ in Chukchi Sea, the abundance of boreal tintinnids decreased sharply to <1 ind L−1(Li et al., 2016a). Thus, we thought that the most proper temperature for boreal tintinnids was 5–10℃. When temperature was higher or lower than the proper range,the abundance of boreal tintinnids would decrease. In YS,spring had the most proper environmental factors, including proper temperature (6.7–14.4℃) and enough food, which made the rapid increasing of boreal tintinnids abundance (Zhang et al., 2018). In summer, temperature in surface water became high which was not suitable for boreal tintinnids. However, they survived in YSBCW where temperature (8–12℃) was suitable for them. Previous studies showed that the biomasses of Synechococcus, heterotrophic bacteria and flagellates in YSBCW were much lower than those in the upper layers(Li et al., 2006; Zhu et al., 2009). Thus, food became a limitation factor and the abundance of boreal tintinnids in YSBCW was low during summertime. In winter, the limitation factor for boreal tintinnids was not only food but also temperature because the local water became lower than 5℃.

4.3 The Effects of the Front Systems on Neritic Tintinnids

In our study, high abundance of neritic tintinnids (most of them were agglutinated tintinnid) mainly distributed in the near bottom areas in most transects. This result was consistent with that in the East China Sea (Yu et al.,2016). Generally, agglutinated tintinnids tended to distribute near bottom when turbulence was low, because their heavy agglutinated particles added extra weight and reduced their mobility (Yu et al., 2016).

Similarly, core area of neritic tintinnids occurred at 50 m isobath because this is the position of front system(Belkin and Cornillon, 2003; Hickox et al., 2000) with high turbulence. There were two reasons for the core area of neritic tintinnids in the front system. Firstly, the high turbulence in the front system provide enough nutrients for tintinnid. Front system have been recognized to have high plankton biomass for a long time (Acha et al., 2004;Le Fèvre, 1986). They constitute a suitable environment for plankton such as bacteria (Riou et al., 2016) and phytoplankton (Taylor et al., 2012). Secondly, the high turbulence provided the mineral particle for most of agglutinated tintinnids, which was necessary for the shaping of agglutinated lorica (Zhang et al., 2012). Because neritic tintinnid would stay near bottom when turbulence low, they occurred in the water column only when turbulence became high. That was the reason why there were high neritic tintinnid abundances in the upper layers of core area. Our study was the first one to reveal the influence of the front system on neritic tintinnids.

◎夜间咳嗽加剧、喉鸣、犬吠样咳嗽应警惕喉炎,喉部充血肿胀有窒息危险，并即刻呼吸冷空气缓解充血肿胀，立即到医院就诊。

4.4 Mixing Distribution of Different Biogeographical Tintinnids

Because the mixing of different biogeographical tintinnids happened in edges of their distribution area.These edges were very narrow compared with their vast distribution area. Therefore, studies on the mixing distribution of different biogeographical tintinnids were very limited (Dolan et al., 2007; Li et al., 2016a, b; Modigh et al., 2003; Santoferrara and Alder, 2009). All of them were the mixing of two biogeographical types. Our study was very special in that there were mixing of three biogeographical types.

1986年，我在山东师范大学教育系读研究生时，就系统地研究了捷克教育家乔治·洛扎诺夫（Georgi Lozanov）的暗示教学法及苏联教育家沙塔洛夫的纲要信号图示教学法。1990年下半年，我与山东省邹平县教研室和淄博市临淄区教研室合作，首先在初中生物、历史、地理、数学教学中推广纲要信号图示教学法，在中小学的语文、英语、数学教学中推广暗示教学法，简称“两种愉快教学法实验”。

从中国经济演化升级的历程来看，旧动能曾经在规模和数量追赶过程中发挥了重要作用，但在新时代背景下难以承担起提高经济发展质量的重任。因此，寻求战略创新，必须加快新旧动能转换，培育符合高质量要求的新动能，构建现代产业体系，从而提高中国的经济质量、产业效率和国际竞争力。

The warm-water and boreal tintinnids in YS were the pioneer species according to Li et al. (2016a, b). Normally, boreal tintinnid would be in the north of warmwater tintinnid when they met as in winter in our study and in Li et al. (2016a). However, in YS, the boreal tintinnid occurred south of warm-water tintinnid because of YSBCW in our study.

(1)斜板浓缩通道的集成模式。每个沉降通道具有相同的进料、分级浓缩、排砂和溢流功能，结构尺寸相同，保证各分级浓缩通道作业的稳定性和同一性。

因此，坚持课内文言文教学，尽最大可能挖掘好每一篇文言文的内在价值及拓展外延，则学生不仅在课内文言本身学习方面，而且在课外文言文学习层面也会开枝散叶。

5 Conclusion

In conclusion, our results confirmed occurrence of warmwater tintinnids in YS and BS. Boreal tintinnids occurred in YSBCW in summer indicating the presence of an oversummering stock. Core distribution areas of neritic tintinnids occurred in front area. High abundance of warm-water and boreal tintinnids were well separated vertically in summer and horizontally in winter. The high abundance of neritic tintinnids rarely overlapped with that of warm-water or boreal tintinnids.

Acknowledgements

This work was supported by the National Natural Science Foundation of China (No. 41576164), the ‘Strategic Priority Research Program-Western Pacific Ocean System: Structure, Dynamics and Consequences’ of the Chinese Academy of Sciences (No. XDA11020103.1), and NSFC-Shandong Joint Fund for Marine Ecology and Environmental Sciences (No. U1606404). The authors thank the captain and crews of R/VDongfanghong-2,Chen Liang, Zhaojie Teng, Cong Xu, and Shan Zhang for their assistance in the field and laboratory work.

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