Between Miami and Miami Beach there are several long causeways over the water with bridges that are opened to let boats through. Traffic comes to a temporary halt when a bridge is up.
Between the Cuban-American, black, and white populations in this area there are some causeway-like links, too, such as joint civic committees and cultral events drawing all ethnic groups.
As the Cuban-Americans have become more active in local politics and more assimilated into the American culture, their links with the rest of the community have been increasing. But two recent events have temporarily raised some of the bridges between the black, Cuba-American, and white communities again:
1. The firing Oct. 25 of black City Manager Howard Gary by vote of the three Hispanic members of the five-member City Council has stirred blacks' anger against Hispanics.
2. The October passage by the Dade County Commission of an ordinance making English the official language of the county has left some Hispanic leaders disappointed with whites, who supported the one-language concept.
Some community leaders interviewed say the bridges will come down again soon. Others are paying less attention to the gradual assimilation of Cubans and are focusing more on the recent events.
And it is difficult to tell the extent to which any divisions caused by such events are the result of outspoken community leaders fanning the coals.
''Some politicians use this (such events) to their advantage,'' says Alvah Chapman Jr., chairman and chief executive officer of Knight-Ridder Newspapers Inc., which owns the Miami Herald.
''There's a lot less of a gap (between ethnic groups here) than may be perceived from the outside,'' says Mr. Chapman, who has worked on numerous multiracial civic committees. ''I have the feeling it is closing.''
Cuban-born Guarione Diaz agrees. ''I'm very optimistic about Miami. It's got a lot going for it,'' says Mr. Diaz, who heads the Cuban National Planning Council, a private research and service organization.
There are a growing number of civic activities in which Cuban-Americans and whites cooperate, he says. He cites the city's new annual film festival, the United Way, and the Chamber of Commerce. The yearly Calle Ocho (Eighth Street) festival in Miami's Little Havana draws huge crowds from all parts of the city, Diaz notes.
White flight - whites leaving the area as the Hispanic population grows - has leveled off and may have stopped, Diaz says. He suggests that the community has survived the test presented by ''the suddenness'' of population change here.
About 1 million Cubans have migrated into the United States, most since 1959. About half have settled in Dade County, which includes Miami and Miami Beach. The portion of the county population which is Hispanic went from 5 percent in 1960 to about 42 percent in 1983. Cuban-Americans account for the bulk of that. But relations between whites and Cuban-Americans are getting worse, according to Manuel Diaz, chairman of the Spanish-American League Against Discrimination. He cites the language ordinance adopted by the county as an example.
''The big institutions, such as banks, the police department, are still top heavy with Anglos,'' he says.
Much of the antagonism on the part of whites toward Hispanics is based on misperceptions, Manuel Diaz suggests. For example, he says, the idea that you have to speak Spanish to get a job is wrong. Studies have shown that only about 10 percent of the ads in local papers require bilingual skills, and that's mostly for sales or secretarial jobs, he points out.
Regarding ties between blacks and Hispanics here, the firing of City Manager Gary ''could tear apart any relations that exist,'' says T. Willard Fair, president of the Urban League chapter here. Mr. Fair is leading a black effort to have Puerto Rican born Mayor Maurice Ferre recalled from office.
The official reasons cited for the firing were ''unacceptable management style'' and being difficult to communicate with. Mayor Ferre complained that Mr. Gary failed to attend two key meetings and that the city missed an opporutnity to qualify for federal funds for a hospital project because Gary did not complete the application in time.
Gary has indicated he may request a public hearing. Fair says blacks feel ''outraged'' and see the dismissal as racially motivated.