International Journal of Molecular Ecology and Conservation, 2025, Vol.15, No.4, 163-174 http://ecoevopublisher.com/index.php/ijmec 1 71 depends on their density and oil content. For instance, the right whale (one of the large baleen whales) sometimes floats instead of sinking to the bottom after death because it is rich in fat. Even if these whales die, they do not form deep-sea whale falls, making it impossible to establish deep-sea communities that depend on them (Smith et al., 2019). Bone structure also has an impact. The skull of filter-feeding whales is huge and rich in oil, which can form large "skull colonies", and their chemogenic communities may occur separately from other parts of the body (Yin et al., 2023). There are also decomposition products: Some toothed whales (such as sperm whales) contain large amounts of waxy oil (whale wax), and its decomposition may release methane, which might form additional small methane nutrient communities similar to cold seep, but the current evidence is limited. 7 The Application Prospects and Challenges of Whale Fall Research 7.1 Deep-sea ecological protection and biodiversity awareness Whale fall research provides new perspectives and opportunities for deep-sea ecological protection and the understanding of biodiversity. Whale fall communities are highly specialized, containing a large number of novel species and unique adaptation mechanisms, expanding human understanding of life diversity (Souza et al., 2021). At the conservation level, whale fall reminds people to pay attention to the occasional habitats in the deep sea and their vulnerability. Restoring whale populations not only restores surface ecological functions but also may enhance deep-sea carbon sinks and biodiversity, which is part of the "natural solution" (Pearson et al., 2023). Therefore, strengthening the protection of cetaceans has a dual significance: it not only safeguards the macroscopic flagship species but also maintains the health of the hidden deep-sea ecosystem. Whale fall research also prompts us to re-examine the scope of deep-sea protection. At present, the establishment of most deep-sea protected areas focuses on hydrothermal, coral, fishery resources, etc. The intermittent small habitat of whale falls is often overlooked, but it is crucial for some organisms (Smith et al., 2019). 7.2 Assessment of contribution to the carbon cycle and material deposition Whale landing plays a unique role in the Marine carbon cycle and material deposition process, making certain contributions to global carbon sinks. As large creatures, whales store a large amount of carbon in the form of a "carbon pool" during their lifetime. When they die and sink, it is equivalent to rapidly transporting the carbon from the surface to the deep sea and storing it. On the other hand, the massive deposition of organic matter from whale falls has also promoted local carbon burial. The organic carbon enriched in whale bones and surrounding sediments is partially converted into inorganic carbon and enters the lithofacies cycle under the action of microorganisms, while the rest remains in the sedimentary layer in a form that is difficult to decompose. In addition, the biological communities attracted by whale falls also store carbon within the organisms. The bones and shells of a large number of organisms that are deposited after death also serve as carbon sinks. It should be pointed out that there is still controversy over the efficiency of whale fall carbon sinks. The role of whale fall in the carbon cycle requires a comprehensive assessment: It is significant in terms of local deep-sea carbon sequestration and sediment carbon burial, but has a limited overall impact on the global carbon cycle (Pearson et al., 2023). 7.3 Development and limitations of research methods The methodology of whale fall research has made significant progress in recent years, but it still faces many challenges and limitations. The advancement of deep-sea exploration technology. Modern remotely operated vehicles (ROVs) and autonomous underwater vehicles (AUVs) are equipped with high-definition cameras, enabling scientists to actively search and closely observe whale landing sites (Yin et al., 2023). The application of novel analytical methods, such as molecular biology and environmental DNA (eDNA) technology, is helping to discover whale fall species and potential whale fall locations. Through metagenomics, researchers can detect the succession of whale fall microbial communities in sediments and discover bacterial changes that cannot be captured by traditional cultures (Li et al., 2022). Despite this, the study of whale falls remains fraught with difficulties. The biggest challenge lies in the randomness and rarity of whale falls - natural whale falls are hard to come by. At present, there are less than 50 cases of natural whale landings reported in the literature (Zhou et al., 2020). There is also the issue of time scale.
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