It is, of course, possible that God performed a supernatural miracle and literally turned the water of the Nile into blood—but does the biblical text support this conclusion? We believe that what happened in the Nile is better explained as a hypernatural miracle, which may have involved toxic red algae in a manner similar to Toledo’s trouble with blue-green algae.
Significant biblical problems challenge the interpretation that God turned the Nile into actual blood. For example, Exodus 7:22 tells us that the Egyptian magicians were able to repeat the miracle. It seems unlikely the magicians would be able to turn water into literal blood. Also, the Bible does not mention that God himself reversed the miracle, which would have been necessary if it were really blood.
Moreover, a similar event is described in the Ipuwer Papyrus, an ancient Egyptian document from the early second millennium.2 This account implies that the Egyptians had seen red water before, though never at the magnitude Exodus describes. The Bible’s portrayal of the Egyptian reaction to the Nile’s contamination suggests the same thing. For example, the Hebrew in Exodus 7:18b—“the Egyptians will find difficulty in drinking water from the Nile” (NASB)—can be literally translated as the Egyptians were “tired out” [la’ah], perhaps by digging for water (Exodus 7:24). If the river were really blood, their attitude would probably have been alarm and horror rather than exhaustion and frustration.
And like the people of Toledo, who knew what to do and fixed their problem in a few days, the Egyptians knew what to do to obtain potable water. Exodus 7:24 says they filtered water by digging into the riverbanks. If the river were literally blood, it could not have been filtered in this way.
Red Algae and Other Explanations
It seems more likely that what God did to the Nile was a hypernatural miracle. In a hypernatural miracle, God exercises extraordinary control over nature for a particular purpose. He uses natural law and natural phenomena in an extraordinary way to bring about His will (see Psalm 104:4; 148:8), rather than acting supernaturally and violating the laws of physics.3 Hypernatural miracles encompass extraordinary timing, an extraordinary selection of location, extraordinary magnitude, and/or extraordinary selectivity. We suggest that hypernaturalism explains many of God’s miracles as a combination of divine power and natural law, thereby demonstrating God’s total authority over creation.
Several scientific explanations have been offered to account for the Nile’s vivid red color, the death of fish, and the fouling of the river. In 1957, scholar Greta Hortsuggested it was due to silt from the river’s southern tributaries which carried flagellate protozoa.4 But in the 1990s, analysis by H. M. Duncan Hoyte5 and John S. Marr and Curtis D. Malloy6 suggested the miracle was due to an infestation of toxic red algae. Writing from an epidemiological point of view, Marr and Malloy offer evidence for their hypothesis: