Answer to Question 1Maricultureis the farming of marine organisms, usually in estuaries, bays, or nearshore
environments or in specially designed structures using circulated seawater. Mariculture
facilities are sometimes placed near power plants to take advantage of the warm seawater
flowing from their cooling condensers. Worldwide mariculture production is thought to be
about one-eighth that of freshwater aquaculture. Several species of fish, including plaice and
salmon, have been grown commercially, and marine and brackish-water fish account for twothirds
of the total production. Shrimp mariculture is the fastest-growing and most profitable
segment, accounting for about 15 of the total international trade in fish products in 2011.
The value of the white-leg shrimp alone was estimated at more than US12 billion that same
year. In the United States, annual revenue from mariculture now exceeds US210 million,
with most of the revenue generated from salmon, kampichi (a tuna), and oyster mariculture.
More than half of the oysters consumed in North America are cultured.
Answer to Question 2The prospect of widespread methane hydrate mining worries environmentalists. The escape
of methane from marine sediments may have played a role in ancient climate change.
Methane is a powerful greenhouse gas, and changes in ocean circulation that result in deepocean
warming could release large quantities of methane. About 55 million years ago, the
deep ocean warmed by at least 4C. The large-scale escape of methane from the seabed may
have raised surface temperatures abruptly, melted surface ice, decreased the pH, and lowered
oxygen levels in the deep sea. Environmentalists are concerned that methane freed from deep
sediments may exacerbate the problem of climate change.In addition, it may provide a new
source of available energy and increase our dependency on carbon-based fossil fuels