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首页> 外文期刊>Marine Chemistry >The oceanic gel phase: a bridge in the DOM-POM continuum
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The oceanic gel phase: a bridge in the DOM-POM continuum

机译：海洋凝胶相：DOM-POM连续体中的桥梁

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Recent discoveries reveal that polymer gel particles are abundant and important in the microbial loop, sedimentation processes, biogeochemical cycling, marine carbohydrate chemistry, and particle dynamics in the ocean. The novelty of these discoveries elicited an interdisciplinary discussion among investigators working in marine geochemistry, microbiology, and polymer physics on the significance of gels in the functioning of marine ecosystems. Marine gels are three-dimensional networks of biopolymers imbedded in seawater. They range in size from single macromolecules entwined, forming single-chain colloidal networks, to assembled polymer networks several hundreds of microns or larger. Gels can form in minutes to hours from dissolved organic matter or polymer chains released by phytoplankton or bacteria. They enclose nanoscale microenvironments that exhibit emerging physical, chemical, and biological properties that are drastically different from those of the DOM polymers that make them. Previous studies show that ～10% of surface DOM could,be assembled as gels, yielding estimates of ～70 x 10~(15) g of organic carbon. This figure exceeds the global biomass of marine organisms by a factor of 50. The potential huge magnitude of the oceanic gel organic matter (GOM) pool suggests a need to develop reliable quantitative methods to systematically investigate the budget of marine gels and their role in biogeochemical cycling. Gels are particularly important for carbon cycling in that they provide an abiotic mechanism to move organic molecules up the particle size spectrum to sizes capable of sedimentation and eventual sequestration in the deep sea. Macrogels such as transparent exopolymer particles (TEP) are especially significant in sedimentation processes because they appear to be critical for the formation of marine snow and the aggregation of diatom blooms. The discovery of highly abundant gels in seawater also fundamentally changes how we think about the physical nature and microscale structure of the fluid and organic matter field encountered by bacteria, protists, and viruses in the sea. Gels may serve as nutrients and/or attachment surfaces for microbes, as refuges from predation, and as hot spots of high substrate concentration. Investigation of gels in the ocean represents an important new area of research ripe for exciting discovery. Areas where future research should be focused include the following: (1) determination of the budgets and pool sizes of gels, (2) investigation of the role of gels in biogeochemical cycling, (3) reconciliation of polymer physics and aggregation theory as explanations for macrogel formation, (4) quantification of the role of gels in sedimentation processes and particle dynamics and, (5) assessment of the role of gels as microhabitats, food sources, and attachment surfaces for marine organisms.
机译：最近的发现表明，聚合物凝胶颗粒在微生物回路，沉积过程，生物地球化学循环，海洋碳水化合物化学以及海洋中的颗粒动力学中非常丰富且重要。这些发现的新颖性引发了从事海洋地球化学，微生物学和高分子物理学的研究人员之间关于凝胶在海洋生态系统功能中的重要性的跨学科讨论。海洋凝胶是嵌入海水中的生物聚合物的三维网络。它们的大小从缠结在一起的单个大分子（形成单链胶体网络）到组装的聚合物网络（数百微米或更大）不等。数分钟至数小时内，浮游植物或细菌释放的溶解有机物或聚合物链就会形成凝胶。它们封装了纳米级微环境，这些环境展现出新兴的物理，化学和生物学特性，这些特性与制造它们的DOM聚合物完全不同。先前的研究表明，约10％的表面DOM可以组装成凝胶，估计产生约70 x 10〜（15）g的有机碳。这个数字比海洋生物的全球生物量高出50倍。潜在的巨大数量的海洋凝胶有机物（GOM）池表明需要开发可靠的定量方法来系统地研究海洋凝胶的预算及其在生物地球化学中的作用循环。凝胶对于碳循环特别重要，因为它们提供了一种非生物机制，可以将有机分子沿粒径谱向上移动到能够沉降并最终在深海中隔离的尺寸。诸如透明外聚合物颗粒（TEP）之类的大凝胶在沉积过程中尤为重要，因为它们对于海洋积雪的形成和硅藻水华的聚集至关重要。海水中高度丰富的凝胶的发现也从根本上改变了我们对海洋细菌，原生生物和病毒遇到的流体和有机物领域的物理性质和微观结构的看法。凝胶可以用作微生物的营养和/或附着表面，捕食的避难所和高底物浓度的热点。海洋中凝胶的研究代表了重要的新研究领域，现在已经可以令人兴奋地发现。未来研究应重点关注的领域包括：（1）确定凝胶的预算和池大小；（2）研究凝胶在生物地球化学循环中的作用；（3）调和高分子物理和聚集理论作为解释大凝胶的形成，（4）凝胶在沉降过程和颗粒动力学中的作用的量化，（5）凝胶作为海洋生物的微生境，食物来源和附着面的作用的评估。

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