Final answer:
The correct answer is B. Causes pollution in marine ecosystems. Ballast water can introduce invasive species into new environments, negatively impacting local ecosystems, native species, and economies.
Step-by-step explanation:
The question pertains to the effect of ballast water on ships and aquatic species that adhere to boats on marine ecosystems. The correct answer is B. Causes pollution in marine ecosystems. Ballast water is used for ship stability when the vessel is not carrying a full load of cargo and is often taken from one port and discharged at another. This process can introduce non-native species, or invasive species, into new environments. Such introductions have significant ecological impacts, including the alteration of local ecosystems, threats to native species, and economic repercussions due to the need for management and control of these invasive species.
Examples of invasive species spread by ballast water include the zebra mussel in the Great Lakes and the European green crab along the Pacific coast of the United States. The zebra mussels have caused extensive damage to water intake structures and have dramatically changed the ecology of the Great Lakes, while green crabs have reduced the abundance of native clam and crab populations.
Shipping and ballast water management strategies, such as mid-ocean ballast water exchange and treatment, are crucial to reduce the spread of these invasive species and protect marine ecosystems. The International Maritime Organization (IMO) has also established the Ballast Water Management Convention to address these environmental challenges.