Final answer:
DOM stands for Dissolved Organic Matter, which is organic material dissolved in ocean water. It consists of high molecular weight substances and is vital for understanding the composition of seawater.
Step-by-step explanation:
The term DOM stands for Dissolved Organic Matter, which refers to organic material that is dissolved in ocean water. Organic carbon in seawater is predominantly present as dissolved material, with only a small percentage in particulates. The composition of dissolved organic matter is still not fully understood, but it is believed to consist of high molecular weight substances, such as humic acids found in soils.