There is no consensus over the factors responsible for dune stabilization in arid regions, with some scholars maintaining that dust (i.e., silt and clay) plays a major role in dune stabilization. Aiming to explore the principal driving factor responsible for dune stabilization in the Negev, we compared various biocrusts having different biomass and compressive strength, and performed surface degradation and illuviation experiments with dust in the presence or absence of biocrusts in order to assess the crust role in impeding wind erosion and dust illuviation. We show that dust cannot be regarded as the primary driving factor for crust strength and subsequently for dune stabilization in the Negev, as suggested in some publications. This function is however fulfilled by extracellular polymeric substances (EPS, mostly polysaccharides), which are excreted by the biocrust (mainly cyanobacteria), and serve as a cementing agent for the establishing crust and therefore for the dust. Exhibiting high water absorption and strong adhering properties, EPS is responsible for granting strength to the crust, impeding wind erosion and dust illuviation, thus providing the necessary cementing agent, which facilitates dune stabilization in the Negev. Global warming which may result in frequent droughts and high input of dust may not contribute to dune stabilization as suggested by some scholars, but rather will negatively affect dune stabilization, as it may result in EPS degradation and subsequently in dune mobilization.

中文翻译：

---

生物结皮诱导的细胞外聚合物是内盖夫沙丘稳定的原因

干旱地区沙丘稳定的因素尚未达成共识，一些学者认为尘埃（即淤泥和粘土）在沙丘稳定中起主要作用。为了探索内盖夫沙丘稳定的主要驱动因素，我们比较了具有不同生物量和抗压强度的各种生物结皮，并在存在或不存在生物结皮的情况下对灰尘进行了表面降解和光照实验，以评估结壳在土壤中的作用。防止风蚀和沙尘。正如一些出版物所建议的那样，我们表明尘埃不能被视为内盖夫地壳强度和随后沙丘稳定的主要驱动因素。然而，这一功能是由细胞外聚合物（EPS，主要是多糖）实现的，它们由生物结皮（主要是蓝细菌）排出，并作为形成结皮的胶结剂，因此也用于灰尘。EPS 具有高吸水性和强粘附性，负责赋予地壳强度，阻止风蚀和尘埃冲刷，从而提供必要的胶结剂，促进内盖夫沙丘的稳定。可能导致频繁干旱和大量沙尘输入的全球变暖可能不会像一些学者所建议的那样有助于沙丘稳定，而是会对沙丘稳定产生负面影响，因为它可能导致EPS降解并随后导致沙丘动员。EPS 具有高吸水性和强粘附性，负责赋予地壳强度，阻止风蚀和尘埃冲刷，从而提供必要的胶结剂，促进内盖夫沙丘的稳定。可能导致频繁干旱和大量沙尘输入的全球变暖可能不会像一些学者所建议的那样有助于沙丘稳定，而是会对沙丘稳定产生负面影响，因为它可能导致EPS降解并随后导致沙丘动员。EPS 具有高吸水性和强粘附性，负责赋予地壳强度，阻止风蚀和尘埃冲刷，从而提供必要的胶结剂，促进内盖夫沙丘的稳定。可能导致频繁干旱和大量沙尘输入的全球变暖可能不会像一些学者所建议的那样有助于沙丘稳定，而是会对沙丘稳定产生负面影响，因为它可能导致EPS降解并随后导致沙丘动员。