TRUE OR FALSE. (Marine Biology, FLVS) 22. Estuaries are partially enclosed bodies of water where salt water from the ocean mixes with fresh water from rivers and streams (brackish water). 23. Estuaries have some of the highest abundance of organisms of all of the ecosystems in the world. 24. Estuaries have very deep waters. 25. Estuaries provide food, shelter and nursery grounds for animals. 26. Estuaries tend to have low amounts of nutrients in their waters. 27. Estuaries are called the “cradle of the ocean.” 28. Estuaries are part of the intertidal zone. 29. Estuaries are stable environments in terms of tides, salinity and temperature.