Effects of thermal history on the responses to thermal stress of a large benthic foraminifera, Calcarina gaudichaudii
Effects of thermal history on the responses to thermal stress of a large benthic foraminifera, Calcarina gaudichaudii
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热史对大型底栖有孔虫 Calcarina gaudichaudii 热应激反应的影响
DOI：
10.1007/s00338-021-02186-8
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发表时间：
2021
期刊：
影响因子：
3.5
通讯作者：
S. Doo
中科院分区：
文献类型：
--
作者：
Gaby E. Carpenter;V. Denis;T. Fan;S. Doo
由于人类活动的影响，海洋生态系统，特别是沿海环境，正在迅速发生变化，导致全球气候变化加剧（海洋变暖）、海洋酸化、缺氧和富营养化。在珊瑚礁上，共生的大型底栖有孔虫（LBFs）可以作为珊瑚礁成分和碳酸盐生产者发挥关键作用，贡献了高达5%的珊瑚礁规模碳酸盐预算。然而，预测的气候变化，特别是海洋变暖，有可能显著改变海洋生物生存的条件。虽然lbf对高热应激的反应在实验室研究中有很好的记录，但通过先前的环境热历史适应或驯化对这种反应的潜在影响在很大程度上仍然未知。本研究以台湾澎湖群岛的Calcarina gaudichaudii， an LBF为研究对象，采集了热变化的潮间带和热稳定的潮下（~ 6 m深度）环境的标本。然后将LBFs适应环境温度（25°C）和升高温度（28°C）的实验室条件三周，随后再进行对照和热应激处理（25°C, 28°C, 30°C, 33°C）一周。与在28°C驯化的标本相比，在25°C驯化的潮下深度采集的gaudichadii的光合速率（通过氧通量测量确定）显著降低，而热历史对呼吸没有影响，这表明共生体和全息生物的响应可能在LBFs中有所不同。此外，由于热胁迫，最大光化学效率（Fv/Fm）显著下降，尽管一周后没有视觉上观察到漂白。这些结果突出了藻微生物组的可塑性响应，表明热历史、驯化温度和热胁迫相互作用影响了高笛藻的生理状态。这项研究增加了越来越多的文献，这些文献强调了理解热历史作为一个重要因素的更大含义，以更好地理解生态系统过程（例如，碳酸盐生产）如何在现代珊瑚礁上改变。
Marine ecosystems, particularly coastal environments, are rapidly changing due to anthropogenic impacts resulting in increased global climate change (ocean warming), ocean acidification, hypoxia, and eutrophication. On coral reefs, symbiont-bearing large benthic foraminifera (LBFs) can play a key role as reef constituents and carbonate producers, contributing up to 5% of reef-scale carbonate budgets. However, projected climate change, particularly ocean warming, has the potential to significantly alter the conditions in which marine organisms persist. While the response of LBFs to elevated thermal stress is well documented in laboratory studies, the potential influence of adaptation or acclimatization through prior environmental thermal history on this response remains largely unknown. In this study, specimens of Calcarina gaudichaudii, an LBF from the Penghu Islands, Taiwan, were collected from thermally variable intertidal and thermally stable subtidal (~ 6 m depth) environments representing thermal history. LBFs were then acclimated to laboratory conditions at ambient (25 °C) and elevated (28 °C) temperatures for three weeks, and subsequently exposed to control and heat stress treatments (25 °C, 28 °C, 30 °C, 33 °C) for an additional one week. Photosynthetic rates (determined through oxygen flux measurements) of C. gaudichaudii significantly decreased in specimens collected at subtidal depths acclimated at 25 °C when compared to those acclimated at 28 °C, whereas there was no effect of thermal history on respiration, indicating that symbiont and holobiont responses may differ in LBFs. Additionally, maximum photochemical efficiency (Fv/Fm) significantly decreased as a result of heat stress, although bleaching was not visually observed after one week. These results highlight the plastic responses of the algal microbiome and indicate that thermal history, acclimatization temperature, and heat stress interact to affect the physiological status of C. gaudichaudii. This study adds to the growing literature which highlights the larger implications of understanding thermal history as an important factor to consider to better understand how ecosystem processes (e.g., carbonate production) are altered on modern coral reefs.