Angeles Alvariño: 1916—: Marine Biologist, Oceanographer - Became Zooplankton Expert

The following year Alvariño was awarded a British Council Fellowship to study zooplankton at the Marine Biological Laboratory in Plymouth, England. There she worked with the prominent English marine biologist, Dr. Sir Frederick Stratten Russell, an expert on zooplankton, particularly the medusae or jellyfish. Thus Alvariño began her lifelong study of the Chaetognatha, Siphonophora, medusae, and fish larvae. Very little was known about these animals in the 1950s. Chaetognaths, a phylum of about 50 species of marine plankton, also called arrowworms, are abundant, tiny carnivores that feed on other zooplankton. Their responses to small chemical and physical characteristics of sea water make them important biological indicators of water type. Siphonophores and other hydrozoans are colonial, swimming or floating animals of the phylum Cnidaria (coelenterates), including Physalia, the Portuguese man-of-war. These organisms are made up of zooids, colonial cells that are specialized for floating, sensing, feeding, or reproduction. The gastrovascular canals of all of the zooids in a colony are contiguous. New colonies bud from the stem of the siphonophore.

Siphonophores, like the chaetognaths, are predators that feed on other plankton, including fish larvae and krill (small shrimp-like crustaceans). Medusae are the free-swimming forms of the hydrozoan cnidarians.

Alvariño studied all of the zooplankton groups that were found in collections from the Bay of Viscay and the English Channel. She discovered Sagitta friderici in plankton samples of the chaetognatha. This is a species normally found in the shallow, warm or temperate waters of the eastern Atlantic coast. She also found abundant eggs and larvae of Sardina pilchardus in samples from herring fishery areas. Her discovery of these organisms off the British coast indicated the abnormal northward movement of warm water that was displacing the herring fisheries.

Returning to Spain in 1954, Alvariño began designing and manufacturing plankton nets, which she gave to Spanish fishing boats and research ships for collecting samples. This enabled her to study zooplankton collected from the Iberian Atlantic, the Mediterranean Sea, and the Grand Banks of Newfoundland. In 1956 Alvariño was awarded a Fulbright Fellowship to work with Dr. Mary Sears at the Woods Hole Oceanographic Institute in Massachusetts. Sears, a well-known expert on zooplankton, especially the Siphonophora, and chair of the First International Congress on Oceanography, was so impressed with Alvariño's research and the breadth of her knowledge, that she recommended her to Dr. Roger Revelle, director of the Scripps Institution of Oceanography at the University of California in La Jolla. From 1958 until the end of 1969, Alvariño worked as a biologist at Scripps, examining the chaetognaths, siphonophores, and medusae in plankton collected off the coast of California and from the Atlantic, Pacific, and Indian Oceans. During those years she was a grantee of the U. S. Office of the Navy and the California Cooperative Oceanic Fisheries Investigations. Between 1961 and 1969 she also held grants from the U. S. National Science Foundation. Alvariño also became a United States citizen in 1966.

An expert on taxonomy and zoogeography, Alvariño's discoveries included 12 new species of Chaetognatha, nine new species of Siphonophora, and a new medusa. She also established the worldwide three-dimensional distribution of various species of chaetognaths and siphonophores. Alvariño's research at Scripps earned her a doctor of sciences degree summa cum laude in 1967 from the University of Madrid.