Biology, Georgia Southern University, Statesboro, Georgia, United States.
Geology and Geography, Georgia Southern University, Statesboro, Georgia, United States.
PeerJ. 2023 Aug 4;11:e15837. doi: 10.7717/peerj.15837. eCollection 2023.
Eastern oysters, , are commercially important coastal species that provide many ecosystem services for coastal communities. Unfortunately, 85% of oyster reefs have been lost globally, prompting investments in restoration efforts to rebuild populations. Managers often consider several well-studied environmental and water quality parameters when making restoration site decisions. However, recent research suggests that submarine groundwater discharge (SGD) may play a role in driving the distribution of oysters in some estuaries. Specifically, SGD may result in localized areas of low dissolved oxygen and low pH that could inhibit oyster recruitment and survival. However, SGD may interact with other potential oyster stressors, including creek geomorphology. On point bars, sediment accumulation could alter growth rates of oysters and physiology, and it is possible that the two factors, SGD and creek geomorphology, could interact to impact oyster growth. We conducted a field experiment to examine the effects of SGD and creek geomorphology on oyster growth rates in a marsh-lined tidal creek in Georgia, USA. High and low SGD sites were paired within point bars and cut banks. Oysters were deployed in cages for 72 days and growth rates were determined. We found a significant interaction between SGD and creek geomorphology on oyster growth rates. Oysters grew at significantly faster rates at locations on accretionary point bars regardless of SGD flux, whereas, on erosional cut banks, high SGD flux significantly reduced oyster growth rate relative to low SGD flux. It appears that SGD may negatively influence oyster growth at specific creek locations, likely due to the presence of other stressors. Therefore, it is important to consider potential interacting and confounding stressors when managing oyster populations. As SGD is still a relatively understudied potential stressor for oysters, it is critical to continue to examine how groundwater might influence oysters in other locations and in combination with other stressors. Regardless, this study provides further evidence that SGD should be considered in future management efforts.
东方牡蛎是具有商业价值的沿海物种，为沿海社区提供了许多生态系统服务。不幸的是，全球范围内有 85%的牡蛎礁已经消失，这促使人们投资于恢复工作，以重建种群。管理者在做出恢复地点决策时，通常会考虑几个经过充分研究的环境和水质参数。然而，最近的研究表明，海底地下水排泄（SGD）可能在一些河口地区牡蛎分布中起作用。具体来说，SGD 可能导致局部地区溶解氧和 pH 值低，从而抑制牡蛎的繁殖和生存。然而，SGD 可能与其他潜在的牡蛎胁迫因素相互作用，包括溪沟地貌。在点滩上，沉积物的积累可能会改变牡蛎的生长速度和生理机能，而且这两个因素，SGD 和溪沟地貌，可能会相互作用，影响牡蛎的生长。我们在美国佐治亚州的一个滨海潮汐溪进行了一项实地实验，以研究 SGD 和溪沟地貌对牡蛎生长速度的影响。在点滩和切滩内配对高和低 SGD 地点。牡蛎被放置在笼子中 72 天，然后确定生长速度。我们发现 SGD 和溪沟地貌对牡蛎生长速度有显著的相互作用。无论 SGD 通量如何，在 accretionary 点滩上的位置，牡蛎的生长速度都明显更快，而在 erosional 切滩上，高 SGD 通量会显著降低牡蛎的生长速度，而低 SGD 通量则不会。似乎 SGD 可能会在特定的溪沟位置对牡蛎的生长产生负面影响，这可能是由于存在其他胁迫因素。因此，在管理牡蛎种群时，考虑潜在的相互作用和混杂的胁迫因素非常重要。由于 SGD 仍然是牡蛎的一个相对研究不足的潜在胁迫因素，因此必须继续研究地下水在其他地点以及与其他胁迫因素结合时如何影响牡蛎。无论如何，这项研究提供了进一步的证据，表明在未来的管理工作中应该考虑 SGD。
