About Jordan Dale Covin and his research
|
| Jordan Dale Covin |
Jordan's M.S. thesis was interrupted by a year of cancer therapy. He surveyed soil nitrogen throughout the cordgrass marsh at Tijuana Estuary in 1981. Then, cancer struck. He returned in 1983, hopeful that his disease was in remission. He carried out an ambitious experimental study that tested the importance of nitrogen additions to salt marsh vegetation. His work was a landmark for Pacific coastal marsh science. His experiment was of a kind that had never been done before--he simultaneously tested the importance of nutrients to plant growth and to competitive interactions between the two marsh dominants, cordgrass and pickleweed.
Jordan's study earned him an M.S. degree in 1984. His work forms the basis of our understanding of the role of nitrogen in coastal marshes. Through his work, we know that nitrogen is limiting to cordgrass growth, that nitrogen is highly variable in the marsh soils, and that concentration levels in the soil can not predict cordgrass growth--it's the addition rate that needs to be known.
From Jordan's work, we also know that adding nitrogen won't necessarily increase the biomass of cordgrass, because pickleweed is a better competitor for nitrogen. His study demonstrates how important it is to examine more than one factor at a time. Cordgrass benefited from nitrogen fertilization only when pickleweed was absent. Even without competitors, it appeared that increased nitrogen in the leaves of cordgrass fostered attack by an herbivorous fly.
The fly proved to be a new species of the genus Incertella. Jordan later set up experiments to determine the importance of the herbivore to cordgrass growth. Through NOAA's National Estuarine Research Reserve program, he carried out an innovative experiment--the first attempt to rear our Pacific species of cordgrass in mesocosms. This taught us more about the plant's requirements for growth. He fertilized the cordgrass soils and used insecticide to eliminate flies from half the plots. The fly had its own agenda, however; it didn't persist on the transplanted cordgrass. That suggested more questions about what it takes to construct salt marsh mesocosms that are suitable representatives of the real system.
Jordan maintained our salt marsh vegetation monitoring program for several years. His persistence and consistency of sampling produced a long-term data set all that has benefited all of us who work on southern California salt marshes--it is the backbone for our knowledge of vegetation dynamics.
Through his research and monitoring activities, Jordan played an integral role in establishing the Pacific Estuarine Research Laboratory, including the experimental facilities at Tijuana Estuary and the research group at SDSU.
Jordan died of Hodgkins Disease on October 22, 1988, at the age of 32. He will always be remembered for his courage, determination, and optimism. His impact on wetland science was significant. His brief career serves as a model, not only for the contributions he made to our knowledge, but also for his approach to his work. I have never known a more dedicated and persistent individual who was simultaneously such an enjoyable colleague.
--Joy B. Zedler Pacific Estuarine Research Laboratory San Diego State University
