Northwest Florida beaches are beginning to come alive once again as spring breakers, lifeguards and marine life migrate back to the shoreline. 

Fort Walton Beach and Destin will begin posting lifeguards this weekend, while South Walton and Navarre lifeguards have already begun manning their posts. Beach flags, which identify the conditions of the Gulf of Mexico, will also all fly again by Saturday.

The warmer weather isn't attracting just spring breakers, according to Christopher Pomory, biology professor at the University of West Florida. Jellyfish, algae and sea hares will also start showing up in the shallows.

Swimmers in Okaloosa County could spot sea nettle jellyfish in the Gulf of Mexico on Sunday and Monday. Portuguese man o' war, a cousin of the jellyfish, also were scattered along the beach on Okaloosa Island in the last few days.

Pomory said Northwest Florida's most common types of jellyfish are moon, sea nettle, cannonball and mushroom. He said the cannonball, moon and mushroom jellyfish are not common stingers because they don't have long tentacles.

"The Portuguese man o' war is one you should definitely stay away from," Pomory said. "Their tentacles can be 50 to 100 feet long. So, you don't even see it by you. The sea nettles will also give people a pretty good sting."

Brown algae — a long, leaf-like organism — is also a common sight as the Gulf begins to warm up. Pomory said he encourages beachgoers to take a closer look at the algae this season.

"It's really interesting to see all of the creatures attached," Pomory said.

He added that sea hares, which look like water slugs, are also common at this time of year.

"They naturally live in the area, but have a tendency to show up in large numbers during this time of year," Pomeroy said.

A change of shape

As summertime nears, the beach itself will also begin to change shape. Winter storms and currents can impact the slope of the beach, according to Pomory, and create a wall of sand. Warmer weather, he said, creates a flatter surface for folks walking along the waterline.

"Sand bars also migrate further offshore during the wintertime," Pomory said. "So during summer you'll see them closer to the shore. That all changes when a tropical storm or hurricane comes through."

Although beachgoers love to see the emerald green water, Pomory said there are two events that can change the color of the water.

"The most important one is phytoplankton blooming in the water," Pomory siad. "When you have a very large growth it clouds up the water. The water also becomes cloudy from storms that stir up sand and small debris."

Let nesting birds lie

Spring is also the time of year when shorebirds start nesting locally.

According to a press release from the Gulf Islands National Seashore, the first nest was discovered this week.

Beginning in late February and ending in late summer, the seashore provides a habitat for several species of ground nesting birds, the release said. The birds include least terns, snowy plovers, Wilson's plovers and black skimmers.

Least terns come from as far away as Central and South America to raise their young on local beaches, the release said.

Intrusion into the nesting areas will cause the birds to take flight and leave their nests vulnerable to heat and predators. The adult birds will often dive at intruders to drive them away from the colony. 

Alarmed birds may then fly low across the road and into the paths of oncoming vehicles. Bicyclists, walkers and joggers are encouraged to be aware of bird behaviors along roads.

"If visitors find themselves besieged by birds, it means that you are near an unmarked nesting area or young chicks," Dan Brown, superintendent of Gulf Island National Seashore, said in the release.  "Please leave the area by back-tracking your steps. The eggs are very small, well camouflaged and hard to see."