Many people donât realize that chest pain and shortness of breath can be symptoms of RA. In fact, heart and lung problems can be a serious complication of the disease. People with RA have an increased incidence of blocked and hardened arteries, which could lead to heart attack or stroke, especially if they also smoke.
Calcium carbonate spicules of calcareous sponges have been found in Early Cambrian rocks from about 530 to 523 million years ago in Australia. Other probable demosponges have been found in the Early Cambrian Chengjiang fauna, from 525 to 520 million years ago. Freshwater sponges appear to be much younger, as the earliest known fossils date from the Mid-Eocene period about 48 to 40 million years ago.
Growth models for X. muta have been formulated from digital photographs of the same sponges over a period of 4.5 years. Sponge growth rates ranged from over 400% per year to only 2% per year. The largest sponges on Conch Reef, about the size of a oil barrel, were estimated to be about 130 years old.t is typically brownish-red to brownish-gray in color, with a hard or stony texture. The giant barrel sponge has been called the  redwood of the reef  because of its size and estimated lifespan of hundreds to a thousand or more years.