Countries with ties to Antarctica have adopted US proposals to limit tourism in the region, in a bid to protect the fragile ecosystem¹ of the continent.

南极洲周边各国采取了美国的建议，为了保护南极洲脆弱的生态系统而限制其周边地区的旅游。

 
The stricken M/S Explorer sank off the Antarctic coast in 2007

Parties to the Antarctic Treaty agreed to limit the size of cruise（巡航，漫游） ships and the number of tourists taken ashore² at a meeting in the US city of Baltimore.

Limiting tourism has taken on urgency due to a surge（汹涌，澎湃） in visits and a number of cruise ship accidents.

Antarctic visits have risen from 6,700 in 1992-93 to over 45,000 last season.

The agreed limits will only become legally binding³ once ratified⁴（批准） by each of the 28 nations who have signed the Antarctic Treaty, launched in Washington 50 years ago.

The restrictions⁵ do not set out an enforcement mechanism⁶（机械，机构，原理） or penalties, but require member countries to prevent ships with more than 500 passengers from landing in Antarctica and to allow a maximum of 100 passengers on shore at any given time.

Another resolution adopted at the meeting places a mandatory⁷（命令的，强制性的） safety code on vessels⁸ operating in the region, while a third enhances environmental protection for the entire Antarctic ecosystem.

Two cruise ships ran aground during the 2008-09 season, and officials documented several incidents which carried a risk of major contamination（污染）.

The most high-profile accident in the region was the sinking of the M/S Explorer cruise ship in November 2007.

Antarctica is the unique home to several varieties of penguin⁹, an important base for others such as seals, and a vital feeding ground for whales.