Winter condition, physiology, and growth potential of juvenile Antarctic krill
Winter condition, physiology, and growth potential of juvenile Antarctic krill
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DOI：
10.3389/fmars.2022.990853
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发表时间：
2022-09-23
影响因子：
3.7
通讯作者：
Fontana, Julia M.
中科院分区：
文献类型：
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作者：
Bernard, Kim S.;Steinke, Kirsten B.;Fontana, Julia M.
近年来，由于南极磷虾在南大洋食物网和海洋地球化学循环中的关键作用，人们做出了大量努力来了解气候变化对南极磷虾的影响。冬季是南极洲研究最少的季节之一，我们对南极磷虾过冬的策略了解有限。特别是，严重缺乏关于南极磷虾幼虾冬季生理和状况的数据。从2019年5月到9月（南方秋冬），我们在南极洲帕尔默站的大型（1，330 L）水族箱中饲养了幼年南极磷虾，并每月测量它们的生理和状况。每一个水槽作为一个“食物环境情景”，代表磷虾可能遇到的食物环境在冬季沿着南极西部半岛。我们发现，与成年磷虾，少年保持相对较高的呼吸速率，通过冬季和积极响应增加食物浓度，增加他们的摄食率。与幼虾不同，幼虾利用夏季和秋季积累的脂质储存来维持自己在冬季的饥饿期。我们用我们的经验得出的生理和条件的测量，估计能量预算和生长潜力的少年磷虾在冬季。我们发现，由于其相对较高的呼吸速率，小的幼年磷虾（20毫克干重）将需要遇到的食物浓度类似于0.15毫克C L-1每天，以避免损失的身体碳。如果没有足够的脂质储备，该值增加到接近0.54 mg C L-1，每天。幼磷虾在冬季的健康取决于它们在夏季和秋季积累脂质储存的能力，以及在冬季找到足够食物的能力。南极磷虾全年食物供应的变化可能会在未来对幼磷虾造成问题。了解南极磷虾幼虾冬季能量收支的变化将使我们能够改进对季节性生长模式做出假设的种群模型。
In recent years, substantial efforts have been made to understand the implications of climate change on Antarctic krill, Euphausia superba, because of their pivotal role in the Southern Ocean food web and in biogeochemical cycling. Winter is one of the least studied seasons in Antarctica and we have limited understanding about the strategies Antarctic krill use to survive the winter. In particular, data on the winter physiology and condition of juvenile Antarctic krill are severely lacking. From May to September (the austral autumn-winter) of 2019, we maintained juvenile Antarctic krill in large (1,330 L) aquarium tanks at Palmer Station, Antarctica and, at monthly time intervals, measured their physiology and condition. Each tank served as a "food environment scenario", representing possible food environments the krill may encounter during winter along the Western Antarctic Peninsula. We found that, unlike adults, juvenile krill maintain relatively high respiration rates through the winter and respond positively to increased food concentrations by increasing their ingestion rates. Unlike larval krill, juveniles use lipid stores accumulated during the summer and autumn to sustain themselves through periods of starvation in the winter. We used our empirically derived measurements of physiology and condition to estimate the energy budget and growth potential of juvenile krill during the winter. We found that, given their comparatively high respiration rates, small juvenile krill (20 mg dry weight) would need to encounter food at concentrations of similar to 0.15 mg C L-1 daily to avoid loss of body carbon. Without sufficient lipid reserves, this value increases to similar to 0.54 mg C L-1, daily. The health of juvenile krill in the wintertime is dependent on their ability to accumulate lipid stores in the summer and autumn and to find sufficient food during the winter. Changes in food availability to Antarctic krill throughout the year may become problematic to juvenile krill in the future. Understanding the variability in the winter energy budget of juvenile Antarctic krill will allow us to improve population models that make assumptions on seasonal growth patterns.