Article continues below advertisementMaria Shriver shared a beautiful tribute to mourn the death of Tatiana Schlossberg.The former first lady of California - who is the cousin of Schlossberg's mother, Caroline Kennedy - took to Instagram on Tuesday, December 30, to pay her respects to the late environmental journalist, who was just 35.News broke of Schlossberg's death on Tuesday afternoon, and it took Shriver just a few hours to write a social media post.Article continues below advertisementMaria Shriver Mourns Tatiana Schlossberg's DeathSource: MEGATatiana Schlossberg passed away at age 35.