If you’re looking to mark the 45th annual Earth Day this Wednesday, two local institutions are inviting the public to join in special events to foster appreciation for the natural world.

A third local event will take place the day after the official Earth Day, on Thursday.

The Denison Pequotsepos Nature Center in Mystic is hosting two “Bioblitz” sessions Wednesday, one from 9 a.m. to noon and the other from 2 to 5 p.m.

“We thought this would be a fun and different way to celebrate Earth Day,” Elissa Bass, director of marketing & communications for the nature center, said Friday.

For $5 each, groups of all ages can sign up to search for and catalogue all the plants and animals that live at the nature center. Bass said this is the first year for the event.

People are urged to dress for the outdoor and to bring cameras, binoculars and field guides, although the nature center will also have equipment for participants to use. Staff will also be on hand to help participants identify wildlife.

At Lawrence + Memorial Hospital in New London, the day will be marked with “Patient Earth,” an environmental fair from 11 a.m. to 3 p.m. Wednesday in Baker Auditorium at the main hospital.

The focus of the event, said Mike O’Farrell, spokesman for L+M, is about “taking care of our most important patient.”

Hospital employees and the public are invited to the free event. Local vendors with earth-friendly products will have displays, as well as a small farmers market where plants, jams, honey and juice supplements will be offered for sale. There will be demonstrations of natural landscaping techniques and composting, monarch butterfly and bee displays and information about Long Island Sound conservation, invasive species and “Bike to Work” day May 15. O’Farrell said the event, now in its second year, is sponsored by the hospital’s “Go Green Committee,” which focuses on in-house conservation initiatives.

During the event, donations of eyeglasses, eyeglass cases and used hearing aids for a Lions club recycling program will be accepted. Empty computer ink cartridges can also be brought for recycling.

On Thursday, the public is invited to join the Ecohusky Club at the University of Connecticut’s Avery Point campus in Groton for its annual Earth Day celebration. The event will take place from 11:30 a.m. to 1:30 p.m. on the campus green. It will include live music, live animals from the nature center and Rankin Lab, recycling games, and displays from the state Department of Energy and Environmental Protection and local environmentally friendly businesses.

Clam chowder and pizza will be served. Participants are asked to bring a nonperishable food item to be eligible for a contest to win a solar lantern.

Admission is free. In case of rain, the event will take place in the student center.

j.benson@theday.com

Twitter: @BensonJudy