218 * Marine Minerals: Exploring Our New Ocean Frontier 



mm.) and clays (finer than .06 mm.) remain in the 

 water column for a much longer time. 



It is not scientifically or economically possible to 

 develop very detailed baseline information on the 

 ecology of all offshore environments in the near fu- 

 ture; the consequences of a variety of mining sce- 

 narios cannot be precisely predicted. However, pre- 

 sumably environmental impact statements (EIS) 

 will be prepared to identify site-specific problems 

 prior to the commencement of mining operations. 

 Environmental impacts should also be monitored 

 during an actual mining operation. Areas where 

 offshore mining is most likely to pose an environ- 

 mental risk can be identified now or in the near 

 future using existing data, (e.g., see figure 6-4 

 showing areas of high biological productivity su- 

 perimposed on a map, produced by the Strategic 

 Assessment Branch of NOAA, depicting areas of 

 high mining potential.) For shallow water environ- 

 ments, areas considered sensitive because of unique 

 plant or animal species, spawning or nursery areas, 

 migration pathways, fragile coastline, etc., should 

 be prohibited from mining activities (see figure 6- 

 3); this approach is being pursued in the United 

 Kingdom and Canada and is one of the prime rec- 

 ommendations of the International Council for Ex- 

 ploration of the Seas (ICES) Working Group. 



Analogues in natural environments that simu- 

 late disturbances on the scale of a mining effort 

 should be investigated. For example, insight into 

 the response of the deep-sea to a mining operation 

 can be gained from studying deep-sea areas exposed 

 to natural periodic perturbations such as the 

 HEBBLE3 (High Energy Benthic Boundary Layer 

 Experiment) area. 



In addition, when mining does proceed in either 

 shallow or deep water, at least two reference areas 

 should be maintained for samipling during the oper- 

 ation: one sufficiently removed from the impact 

 area to serve as a control, and one adjacent to the 

 mining area. 



'D. Thistle 1981, "Natural Physical Disturbances and Communi- 

 ties of Marine Soft Bottoms," Mar. Ecol. Prog. Ser. 6: 223-228, and 

 B. Hccker, "Possible Benthic Fauna and Slope Instability Relation- 

 ships," Marine Slides and Other Mass Movements, S. Saxov and 

 J. K. Nicuwcnhuis (eds.), Plenum Publishing Corp., 1982. 



Shallow water effects are better understood than 

 deep water effects because nearshore areas have 

 been studied in detail for a longer time. A great 

 deal is known about the environment and plant and 

 animal communities in shallow water areas. But 

 there has been no commercial mining and much 

 less is known about ecology in deep-sea areas where 

 manganese-cobalt crusts, manganese nodules, and 

 polymetallic sulfides occur. However, there appears 

 to be remarkable uniformity in the mechanisms that 

 control deep-sea environments, so that information 

 gleaned from one area in the deep-sea can be used 

 to make predictions about others; shallow water 

 environments on the other hand, differ significandy 

 from site to site. 



One area of shallow water research that requires 

 attention is coastline alteration. Sand, gravel, and 

 placer mining in nearshore areas may aggravate 

 shore erosion by altering waves and tides. A site- 

 specific study would have to be done for each shal- 

 low water mining operation to ensure wave climates 

 are not changed. New theories about wave action 

 suggest that, contrary to previous scientific opin- 

 ion, water depth may be a poor indicator of subse- 

 quent erosion. The relative importance of differ- 

 ent kinds of seafloor alterations on coastline 

 evolution needs to be clarified. For example, what 

 is the effect of a one-time, very large-scale sediment 

 removal (e.g., at Grand Isle, Louisiana, for beach 

 replenishment over a several mile area) versus 

 cumulative scraping of a small amount over a very 

 long period (such as decades). 



The information most needed to advance under- 

 standing of the deep-sea is even more basic. The 

 research community needs more and better sub- 

 mersibles to adequately study the deepsea benthos. 

 Currently, there is a 2-year time-lag between re- 

 search grant approval and available time on one 

 of the two U.S. -owned deepsea submersibles avail- 

 able to the scientific community. Deep-sea biota 

 need to be identified and scientifcaUy classified. Up 

 to 80 percent of the animals obtained from the few 

 samples recovered have never been seen before.* 

 It will be impossible to monitor change in animal 

 communities without systematic survey of these 

 populations. Research funding is needed to develop 



'B, Hccker, Lamonl-Doherty Geological Observatory, OTA Work- 

 shop on Environmental Concerns, Washington, D.C., Oct. 29, 1986. 



