Rubinoff’s 1968 article opened the floodgates of critique from fellow biologists.
The major intellectual disputes encompassed conflicting interpretations of the limited empirical research on transisthmian evolution, biological diversity, and biotic mixing, and of the validity of the Suez and Panama Canals as models for predicting how the sea- level waterway might affect ecological and evolutionary processes. Some participants also questioned Rubinoff’s more explicitly political assumptions and framing choices. At a time when the negative environmental consequences of modern technoscience were gaining more and more attention, but when marine biodiversity and bioinvasions barely registered as issues of con-cern, the debates reveal how biologists of different disciplinary backgrounds and levels of conservationist concern struggled to communicate the political relevance and fund- worthiness of a topic for which they lacked a common vo-cabulary and conceptual understanding.
The first published scientific response to Rubinoff’s essay came from the ich-thyologist and marine zoogeographer John C. Briggs.86 While appreciating the redirection of scientific attention away from radiation damage, Briggs took issue with Rubinoff’s sense of opportunism and inevitability. The breaching of the isthmian zoogeographic barrier would, he predicted, allow animals of the appar-ently more species- rich western Atlantic ecosystem to dominate their relatives in the eastern Pacific, eventually wreaking havoc on the latter: “Let us not be con-cerned about preparation for a great biological experiment. The important ques-tion is: Should the sea- level canal project be undertaken at all? Are we prepared to assume the responsibility for the irrevocable destruction of several thousand unique species in the Eastern Pacific?” For Briggs, the sea- level canal proposal posed “a conservation problem of an entirely new order of magnitude.”87
The absurdity of conducting routine baseline research in the face of an extinc-tion crisis led Briggs to publish a much longer article in the January 1969 issue of BioScience with the striking subtitle “Potential Biological Catastrophe.” He argued that the Suez offered disturbing empirical evidence of how organisms from a richer marine ecosystem might outcompete the natives of a less stable one, as shown by the aggressive migration of Red Sea fishes, crustaceans, mollusks, and tunicates into the empty niches of the nutrient- poor eastern Mediterranean.
Briggs calculated that 6,720 Caribbean species would migrate westward through a Central America sea- level canal and 4,480 less robust Pacific species would move eastward, resulting in massive extinctions among the latter. While sug-gesting that a sea- level waterway could be designed to kill migrating animals with chemicals or hot water, Briggs deemed such methods “risky and distasteful”
and instead called for improving the existing canal to meet the needs of world shipping.88
Briggs’s analysis provoked strong reactions from fellow members of the scien-tific community. Rubinoff and other scientists questioned his statistical meth-ods and assumptions.89 Biological oceanographer Gilbert Voss later implicitly called Briggs and Mayr “two of the most outspoken alarmists [who] have had no personal experience in the areas and have not engaged in research relating to the problem.”90 And the eminent ichthyologist Carl Hubbs, whose research on the native and nonnative fishes of both the Great Lakes and Suez Canal dated to the 1920s, probably had Briggs in mind when he urged the president of the National Academy of Sciences in February 1969 to appoint a committee to ad-dress the questions raised by the sea- level canal. In contrast to “the irresponsible nature of some of the published discussions,” Hubbs emphasized, “I am deeply impressed with the potential biological consequences, for better or for worse,
and with the fantastic opportunities for research that are presented,” points he reiterated at oceanographic and zoological meetings in Curaçao and Caracas.91 Hubbs’s points underscored the failure of biological oceanography and marine biology to keep pace with the advances in physical oceanography made possible by Cold War military patronage of the earth sciences.92
Hubbs also drew on emerging research by the Smithsonian- Israeli collabora-tion to support his assessment of the Suez as “an imperfect model” for estimating the biotic effects of the proposed Central American canal.93 The two isthmuses differed in terms of not only salinity levels but also geological histories. The more recently separated coastal Caribbean and Pacific biotas contained many closely related pairs of species, whereas the Mediterranean and Red Sea biotas contained almost no such sister species, differences which presented “extremely urgent, and at the same time very promising” opportunities for systematic, eco-logical, and evolutionary studies.94
A stark rejection of the Suez situation as a valid precedent came from a STRI predoctoral visitor, Robert Topp. It was no surprise, he argued, that Red Sea ich-thyofauna had occupied the vacant niches of the impoverished Mediterranean.
By contrast, because most of the ecological niches on either side of the Central American isthmus were already filled, species introgression through a sea- level canal would likely not cause widespread extinction. “Faunal enrichment” might even occur, especially in the Caribbean.95
In support of his prediction that the proposed waterway would not cause widespread extinctions, Topp mobilized new evidence made possible by other visiting researchers to Panama and the Smithsonian’s internal funding. After towing cheesecloth- wrapped marine animals through the canal, Robert Men-zies concluded that genetic exchange was probably already occurring on a large scale due to the ability of fouling organisms attached to the bottoms of ships to survive the full fifty- mile transit.96 Another visiting biologist studying marine plankton transport, Richard Chesher, confirmed via interviews with Panama Canal Company officials that tankers and freighters had been required since 1956 to ballast down prior to the transit to ensure maneuverability.97 “Much biotic transfer” was thus probably already occurring as ships made the eight- hour journey and then emptied their ballast tanks on the other side, to no ill effect.98
Topp’s paper provided vindication for Sheffey, who was upset by a CBS tele-vision report on the proposed canal that, in his view, minimized the fouling and ballasting means of marine species transport that had been occurring since the Panama Canal’s opening in 1914.99 But Rubinoff countered that such modes of dispersal rarely contained enough individuals of any given species to allow
colonization. He also questioned the scanty empirical evidence for ballast- mediated carriage, arguing that Menzies used intertidal organisms preadapted to survival in fresh water and that Chesher overlooked the toxic anticorrosion coatings lining ballast tanks. He did concede that modern tankers with stainless steel tanks—most of which were too large to use the existing canal—might en-able plankton to survive passage from ocean to ocean. “The actual role of ballast transport through the present Canal is a subject that could be properly evaluated, and a thorough study should remove this area from speculation,” he argued, as did other sea- level canal authors.100
Of course, such research could be conducted only if funding came through, and to that end, the CSC and Smithsonian brokered a strategy to try to resolve the problem that had occupied Smithsonian naturalists for the past half decade.
The commission scrounged up enough funds to elicit the National Academy of Sciences to lend its authority to the quest for external federal support of a com-prehensive tropical marine biological inventory.
Conclusion
The CSC conveyed its fifth annual report to the new president, Richard M.
Nixon, in the summer of 1969. The report acknowledged the Route 17 clay shale problem, as well as the expanded efforts to address marine biotic exchange.
However, like his predecessor Nixon neglected these points in his public message when he forwarded the report to Congress, focusing instead on the good news:
the engineering feasibility team had completed data collection efforts and closed down all field operations; the diplomatic, economic, and military subgroups were wrapping up their evaluations; and the Plowshare scientists had conducted the third 1968 cratering experiment, Project Schooner, at the Nevada Test Site.
While conceding that all six planned shots would not be completed prior to the December 1970 deadline, the commission still expected to render its conclusion by then on the feasibility of nuclear explosives for canal excavation.101
Neither the CSC report nor the president, however, mentioned another set-back, the uncontrolled release of radioactivity by the 35- kiloton Schooner ex-plosion. Five days after creating a crater of 725 feet wide and 250 feet deep on December 8, 1968, the experiment caused radiation levels at sampling stations as far away as Ontario and Quebec, Canada, to rise to ten to twenty times above normal background levels.102 The fifth annual report also glossed over Panama’s revolutionary events of October 1968—the military coup staged by Omar Tor-rijos and other officers of the Guardia Nacional. Soon after taking control of the
government, Torrijos established his own Office of Interoceanic Canal Studies and ordered an investigation into a Panamanian- built seaway using nonnuclear methods along the Route 10 site west of the existing canal. While hinting at the recent political changes, the international relations section of the CSC docu-ment praised the U.S., Panamanian, and Colombian officials whose cooperation made the field surveys possible. “A large quantity of environmental information has been acquired in areas of the isthmus that previously had been little ex-plored,” valuable data that would soon be made public.103
Yet from a high- modernist standpoint, new scientific knowledge of the mythic Darién landscape failed to counterbalance the increasingly bad news about PNEs. Reported a Panama American journalist in the spring of 1969,
“an atomic engineers’ dream . . . is fading into a ditch diggers’ pick and shovel nightmare.”104 That history could move backward, from the space age to the olden days, seemed incredible to the friends of Plowshare. So did the insistence of biologists that the canal engineering feasibility studies address issues that had nothing to do with radioactivity, just so they could resuscitate the old- fashioned study of natural history.
Today, fifty years on, it is clear that those demanding realistic, comprehensive assessments of the megaproject’s environmental effects were as forward- thinking as the other sea- level canal stakeholders. The Plowshare physicists and allied engineers sought to advance the unproven field of nuclear excavation, and U.S.
officials aimed to update the isthmian transportation system and relations with Panama. Likewise, the marine evolutionary and ichthyological scientists sought to revitalize relevant naturalist disciplines to analyze the enormous ecological changes a wide channel at the level of the seas would induce. The sea- level canal proposal served as a modernization strategy for a wide range of stakeholders, and it facilitated many kinds of work with far- reaching political and intellec-tual effects.
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