3.4 DISCUSSIONMy study shows that s

3.4 DISCUSSION
My study shows that short exposure to low concentrations of copper has complex latent impacts on E. chloroticus juvenile performance, visible only from 8 d postsettlement,and that it especially affects juvenile resistance to further copper exposure.
3.4.1 LATENT EFFECTS OF LARVAL EXPOSURE TO COPPER ON SETTLERS
Successful settlers were larger and had longer spines relative to body size when they had been exposed to the highest concentration of copper as larvae. However, this positive effect at settlement was cancelled by negative subsequent growth. Settlers that had been exposed to the highest copper concentration both early and late during larval development dramatically decreased in both body size and spine length between 8 d and 25 d post-settlement. As a result, at 25 d post-settlement, settlers that had been in the High copper level groups, were substantially smaller than controls.Juveniles were not individually followed during this experiment and thus a decrease in average size may be due to selective mortality of larger individuals. However, the reduction in average size was large (24%), with very little mortality (less than 5%,corresponding to an average of three individuals per container) suggesting that settlers had actually shrunk. Shrinkage in test diameter of adult sea urchins as the result of food limitation has been reported for some species, including E. chloroticus
(Dix 1972, Levitan 1988, Constable 1993). In the current study, food abundance in settlement containers was not directly measured, however a broad estimation of benthic diatom cover was recorded and no difference was noted between treatments.In addition, benthic coverage appeared more than sufficient for grazing pressure (i.e.well developed brown film with sparse grazing tracks) and almost all settlers had visibly full guts at 25 d post-settlement. Furthermore, growth was not related to settler density, as would be expected if food limitation was a factor. This study provides the first evidence that test shrinkage in urchins might occur as a result of environmental stressors other than food limitation. Furthermore, for these very young juveniles it is a latent effect of larval experience, not their current experience as is the case for food limitation. However, further experimental work following individual settlers would be needed to confirm this pattern.
While there was no difference in settler survival for those from different larval copper concentrations in my experimental setting, growth impairment is likely to result in higher subsequent mortality due to predation in the field. Indeed, young juveniles in many benthic species are thought to be the most at risk of predation (Hunt & Scheibling 1997). Predators of juvenile urchins typically include crabs, demersal fish and sea stars (Hunt & Scheibling 1997, Clemente et al. 2013). Although little is known about predation patterns on small juveniles due to inherent difficulties in studying highly cryptic early life stages, Clemente et al. (2013) showed that the smallest Strongylocentrotus purpuratus juveniles tested (5 - 14 mm) were more than three times more likely to be eaten by crabs than larger juveniles, regardless of predator size. It has been suggested that juvenile urchins may reach an threshold size at which the predation rate dramatically decreases (Menge & Sutherland 1976) or at which they may start feeding on macroalgae thus substantially increasing their growth rate (Rowley 1990). Any delay in reaching this escape size would therefore have a strong impact on a juvenile’s chance of survival or growth, thus affecting population dynamics and adult abundance (Ebert 1983, Underwood & Fairweather 1989).Furthermore, if the observed negative growth was due to shrinkage, then juveniles may also be in poorer body condition as was observed for shrinking Heliocidaris erythrogramma (Constable 1993), and thus be less likely to survive in the field. Very few studies have followed the impact of copper on long-lived benthic invertebrates for as long after settlement as in this study (6 weeks post-settlement). Indeed most studies on pollutants are typically either short-term assays (days) or end shortly after settlement. However, Ng & Keough (2003) reported a dramatic decrease in survival and growth following larval copper exposure in bryozoans visible only weeks to months post-settlement. In contrast, no carry-over effects were observed in growth or survival of juvenile sponges up to six months after larval copper exposure(Cebrian & Uriz 2007).

結果 (中文) 1:

3.4 讨论我的研究表明短期暴露于低浓度的铜上 E.chloroticus 少年的表现，可见只从 8 d postsettlement，具有复杂的潜在影响和它尤其是影响青少年抵抗进一步铜暴露。3.4.1 潜在暴露的影响幼虫到铜定居者成功定居者更大，有更长的脊椎，相对于身体大小时他们曾接触最集中的铜作为幼虫。然而，这个积极的效力于解决被取消随后的负增长。受到两个早期和晚期在幼体发育过程中显著下降的两个身体大小和脊柱长度 8 d 和 25 d 后结算之间的铜浓度最高的定居者。结果，在 25 d 安置后，一直在高铜级别的组的定居者大大小于控件。少年不单独跟随在这个实验中，因此平均大小减少可能是由于选择性死亡的较大的个人。然而，平均大小的减少是大 （24%)，与很少死亡率 （小于 5%，对应的每个集装箱的三个人平均) 暗示，定居者在实际上萎缩。一些物种，包括 E.chloroticus 据报在成人海胆作为食物限制结果的测试直径收缩(Dix 1972 年，1988 年，列维坦警员 1993年)。在当前的研究中，不直接测定沉降容器中的食物丰富了，但是底栖硅藻广泛估计涵盖录和无差异指出处理之间。另外，底栖覆盖出现更多比足够放牧压力 （i.e.well 开发棕膜与稀疏放牧轨道） 和几乎所有的定居者在 25 d 后解决了明显充满勇气。此外，经济增长不定居者与密度有关，可以想象如果食物限制是一个因素。这项研究提供试验收缩在海胆的第一个证据后可能会出现食物限制以外的环境压力。此外，对这些非常年轻的青少年亦是经验的幼虫，而不是经验的他们当前的潜在疗效食品限制的理由。然而，将需要进一步实验工作后个别定居者确认这种模式。While there was no difference in settler survival for those from different larval copper concentrations in my experimental setting, growth impairment is likely to result in higher subsequent mortality due to predation in the field. Indeed, young juveniles in many benthic species are thought to be the most at risk of predation (Hunt & Scheibling 1997). Predators of juvenile urchins typically include crabs, demersal fish and sea stars (Hunt & Scheibling 1997, Clemente et al. 2013). Although little is known about predation patterns on small juveniles due to inherent difficulties in studying highly cryptic early life stages, Clemente et al. (2013) showed that the smallest Strongylocentrotus purpuratus juveniles tested (5 - 14 mm) were more than three times more likely to be eaten by crabs than larger juveniles, regardless of predator size. It has been suggested that juvenile urchins may reach an threshold size at which the predation rate dramatically decreases (Menge & Sutherland 1976) or at which they may start feeding on macroalgae thus substantially increasing their growth rate (Rowley 1990). Any delay in reaching this escape size would therefore have a strong impact on a juvenile’s chance of survival or growth, thus affecting population dynamics and adult abundance (Ebert 1983, Underwood & Fairweather 1989).Furthermore, if the observed negative growth was due to shrinkage, then juveniles may also be in poorer body condition as was observed for shrinking Heliocidaris erythrogramma (Constable 1993), and thus be less likely to survive in the field. Very few studies have followed the impact of copper on long-lived benthic invertebrates for as long after settlement as in this study (6 weeks post-settlement). Indeed most studies on pollutants are typically either short-term assays (days) or end shortly after settlement. However, Ng & Keough (2003) reported a dramatic decrease in survival and growth following larval copper exposure in bryozoans visible only weeks to months post-settlement. In contrast, no carry-over effects were observed in growth or survival of juvenile sponges up to six months after larval copper exposure(Cebrian & Uriz 2007).

結果 (中文) 2:

3.4讨 ​​论
我的研究表明，短接触低浓度的铜的对大肠杆菌chloroticus少年性能复杂潜影响，只从8天postsettlement可见的，并且它尤其影响进一步铜曝光少年性。
幼体3.4.1潜在影响接触铜ON SETTLERS
成功定居者更大了，当他们已经暴露的铜幼虫的最高浓度相对于车身尺寸长刺。然而，在此定居的积极作用是通过后续的负增长取消。已被暴露在高浓度铜仔鱼期早期和晚期定居大幅两个车身尺寸和脊柱长度8 D和D 25后结算的下降。其结果是，在25 D后解决，即已经在高铜级组的定居，均基本上小于controls.Juveniles未单独这个实验中，随后，从而在平均尺寸的减小可能是由于选择性死亡率个体较大。然而，在平均尺寸的减少是大的（24％），用很少的死亡率（低于5％，相当于平均每个容器三个人），表明定居者实际上缩小了。收缩在作为食物限制的结果已经报道对一些物种，包括大肠杆菌chloroticus成人海胆试验直径
（迪克斯1972年，列维坦1988年，警员1993）。在目前的研究中，食物丰富结算容器没有直接测量，但是底栖硅藻覆盖了广泛的评估记录和无差异treatments.In之间。另外指出，底栖覆盖率出现绰绰有余放牧压力（iewell开发棕片稀疏放牧磁道），几乎所有的定居者在25 D后沉降明显充满胆量。此外，经济增长是不相关的定居者的密度，就好像食物限制是一个因素是可以预期的。这项研究提供了在海胆测试收缩可能发生的食品比其 ​​他的限制环境压力的结果的第一个证据。此外，对于这些非常年轻的少年是幼虫的经验，而不是他们的是食品限制的情况下目前的经验潜在影响。然而，随着个体的定居者进一步的实验工作将需要确认这种模式。
虽然是来自于我的实验设置不同的幼虫铜浓度定居者生存率没有差异，生长障碍很可能会导致更高随后的死亡率是由于捕食场。事实上，在许多海底物种年轻少年被认为是最捕食时（亨特1997年Scheibling）的风险。少年海胆的掠食性动物通常包括蟹，底层鱼类和海星（亨特1997年Scheibling，克莱门特等人2013年）。尽管很少有人在研究高度神秘的早期生命阶段知道关于小少年，由于固有的困难捕食形态，克莱门特等人。（2013年）表明，最小的紫色球海胆稚测试（5 - 14 MM）均超过三倍更容易被蟹大于幼鱼被吃掉，无论捕食的大小。它已被提出，少年海胆可能达到在该捕食率显着降低（猛恶＆萨瑟兰1976）的阈值的大小，或在其可以开始于海藻从而大大地增加它们的生长速率（劳利1990）喂养。因此在达成这种逃避大小的任何延迟都会对生存或生长，从而影响种群动态和成人丰富青少年的机会有很大的影响（艾伯特1983年，安德伍德和嘉航1989年）。再者，如果观察到的负增长是由于收缩，那么青少年也可能是较差的身体条件为观察到萎缩Heliocidaris erythrogramma（1993年警员），因此不太可能在野外生存。很少有研究遵循铜对长寿命底栖无脊椎动物，只要结汇后在这项研究中（6周后，结算）的影响。事实上，污染物多数研究都是通常是短期的试验（天）或和解后不久结束。然而，吴和基奥（2003）报道了生存和发展按照苔藓虫可见只有周铜幼虫暴露在月结算后急剧下降。相反，在生长或少年海绵生存观察长达半年没有结转影响幼虫铜曝光（Cebrian与2007 Uriz）之后。

結果 (中文) 3:

3.4讨论我的研究表明，短期暴露于低浓度的铜对大肠chloroticus少年表现复杂的潜在影响，仅从8 D postsettlement可见，这尤其影响到青少年抵抗进一步的铜暴露。3.4.1潜在影响幼虫暴露于铜对移民成功的移民较大，并有较长的棘相对身体的大小，当他们被暴露于铜的最高浓度的幼虫。然而，这种积极的效果在结算被取消了负随后的增长。已经暴露于最高的铜浓度的定居者，在幼虫发育的早期和晚期，显着减少在车身尺寸和脊柱长度在8天和25天之间的结算。其结果是，在25天的结算，定居者已经在高铜水平组，基本上小于对照组，未成年人在本实验中，从而减少平均规模可能是由于选择性死亡的较大的个人。然而，平均规模的减少是大的（24%），非常小的死亡率（小于5%，对应的平均三个人的容器），这表明定居者实际上已经缩小。在成年海胆测试直径收缩食品限制的结果已报道的一些物种，包括大肠chloroticus（DIX 1972、列维坦1988，警察1993）。在目前的研究中，在沉降容器食物丰富度不能直接测量，但底栖硅藻覆盖广泛的估计被记录和无差异的治疗。此外，底栖覆盖足够多的放牧压力（即出现了稀疏放牧轨道棕片）和几乎所有的移民有明显的全胆25 d后沉降。此外，生长不到移民密度相关，将食品的限制是一个因素，预计。本研究在海胆测试收缩可能是由于环境压力比其他食物限制的发生提供了第一手的证据。此外，对于这些非常年轻的青少年，它是一个潜在的影响，幼虫的经验，而不是他们目前的经验，作为食品限制的情况下。然而，进一步的实验工作，个别移民后，将需要确认这种模式。虽然没有差异，移民生存那些来自我的实验设置不同的幼虫铜浓度存在，生长障碍可能会导致更高的死亡率由于捕食的场。事实上，在许多底栖生物的年轻少年被捕食的风险最大（Hunt & scheibling 1997）。幼海胆掠食者通常包括蟹类、底栖鱼类和海星（Hunt & scheibling 1997，克莱门特等人。2013）。虽然鲜为人知的捕食模式由于学习非常神秘的生命早期阶段固有的困难的小少年，克莱门特等人。（2013）表明，最小的紫色球海胆幼体测试（5 - 14毫米）超过三倍更有可能吃螃蟹比较大的青少年，无论捕食者的大小。它已经表明，幼年的海胆可能达到一个阈值大小，捕食率显著降低（门格&萨瑟兰1976）或他们可能开始摄食海藻大大增加他们的增长率（罗利1990）。因此，在达到这种逃避大小的任何延误都会对青少年的生存机会或生长影响很大，从而影响种群动态和成人的丰度（埃伯特1983，安德伍德和晴天1989）。此外，如果观察到的负增长是由于收缩，然后少年也可能是身体状况较差的是收缩Heliocidaris erythrogramma观察（警察1993），因此不太可能在野外生存。极少数的研究已经遵循的影响，铜对长寿命的底栖无脊椎动物，在这项研究中（6周后结算）结算后的长期底栖无脊椎动物。事实上，大多数污染物的研究通常是短期试验（天）或结束后不久结算。然而，吴王（2003）报道，在生存和发展的显著降低铜暴露在苔藓虫幼虫只有几周或几个月后结算后。相反，生长或青少年海绵幼虫铜暴露后长达六个月的生存期均无延续效应（Cebrian和uriz 2007）。