Direct Ocean Capture (DOC) has emerged as a promising Carbon Dioxide Removal (CDR) strategy, yet its structural and dynamic properties remain underexplored compared to the more established Direct Air Capture (DAC). To address this, we construct and analyze a kinetic system for DOC using Chemical Reaction Network Theory (CRNT). Our analysis identifies the necessary conditions for the existence of positive steady states and highlights the potential for multistationarity, emphasizing critical tipping points within the carbon cycle. Furthermore, we characterize the conditions under which specific carbon pools exhibit Absolute Concentration Robustness (ACR) and determine the system's carbon reduction capability. Finally, we present a comparative analysis of the DOC model against an established DAC model and an integrated DOC-DAC framework, providing insights into their roles in climate mitigation.