The Internet of Underwater Things (IoUT) is an emerging research area that extends the concept of IoT to aquatic environments, enabling smart sensing, monitoring, and communication in oceans, rivers, and lakes. Research papers in this domain focus on underwater sensor networks, acoustic and optical communication protocols, energy-efficient data collection, and autonomous underwater vehicles (AUVs) for exploration, environmental monitoring, disaster prevention, and marine resource management. Key contributions include localization and routing techniques, data fusion and aggregation methods, security and privacy mechanisms, and integration with edge/fog computing for real-time decision-making. Recent studies also address challenges such as high latency, limited bandwidth, harsh underwater conditions, and energy constraints, while exploring AI-driven analytics and blockchain-based trust management for reliable underwater networks. IoUT research plays a vital role in enabling intelligent, resilient, and sustainable aquatic monitoring systems for environmental, industrial, and scientific applications.