Marine ecosystems are considered among the most complex and rich natural systems on Earth. Oceans and seas cover more than 70% of the planet’s surface and serve as a habitat for millions of living species. These ecosystems are characterized by their diversity of biotic and abiotic components, making them a fundamental pillar of global environmental balance. First: Components of Marine Ecosystems 1. Biotic Components: Phytoplankton and zooplankton Fish and invertebrates Marine mammals such as whales and dolphins Algae and coral reefs 2. Abiotic Components: Temperature Salinity Light Ocean currents These factors collectively determine the nature of life in each region of the seas and oceans. Second: The Importance of Marine Ecosystems Marine ecosystems play a crucial role in maintaining global ecological balance. They support vast biodiversity, regulate the Earth’s climate, and provide essential natural resources such as food, minerals, and energy. Moreover, these ecosystems contribute significantly to the global economy through fisheries, maritime transport, and coastal tourism. 1. Regulating Global Climate The oceans play a vital role in absorbing carbon dioxide and regulating the Earth’s temperature, which helps reduce the impacts of climate change. 2. Supporting Biodiversity Seas and oceans host many rare species, some of which exist only in marine habitats, making them a natural treasure that must be protected. 3. Providing Natural Resources Such as: Fish and seafood Minerals and salts Energy (such as wave energy) 4. Enhancing Global Economy Through: Marine fishing Maritime transport Coastal tourism Third: Threats Facing Marine Ecosystems — Marine Ecosystem Threats Plastic pollution Rising temperatures Overfishing Coral reef destruction Oil spills These threats weaken the ability of the oceans to maintain their ecological balance. Fourth: Methods for Protecting Marine Ecosystems — Marine Conservation Methods Reducing carbon emissions Establishing marine protected areas Regulating fishing Restoring coral reefs Increasing environmental awareness among communities Al-Mustaqbal University is the first university in Iraq.