70 



Table 8. Santa Barbara hydrocarbon seep microbes and meiofauna parameters means by year and station 

 (Montagna et al. 1987, 1989). 



Year Station Chi BAC 2nd NEM HAR OTH 



Chi = chlorophyll a (mg/m 2 ). 



BAC = bacterial biomass (ug C/m 3 ). 



2nd = bacterial secondary production (mg C/m 2 /d ). 



NEMatoda, 



HARpacticoida, 



OTHer (29 taxa) = meiofauna density (103/m 2 ). 



Sampled: Dec 84, Apr 85, Jul 85, and Apr 86, Jul 86, Dec 86. 



Gradient of seepage at stations = A>B, and no seepage at C. 



As well as organic enrichment by the petroleum, we also studied potential sublethal toxic effects on benlhic 

 recruitment. Harpacticoid copepods were used for the reproductive study. They undergo six naupliar and six 

 copepodite stages, the adults are sexually dimorphic, and females brood their eggs. Thus a number of 

 reproductive parameters can easily be counted and measured for size differences. We found that life history 

 strategies were different in the three sites. Species which were restricted to the heavy hydrocarbon seepage site 

 had very high rates of egg production relative to the number of surviving juveniles (10:1). Species away from 

 the seep had ratios of eggs to juveniles approaching 2 or 5:1 (Spies et al. 1988). Similar life history responses 

 of harpacticoids to the AMOCO CADIZ spill in France have been reported by Bodin (1989). 



The SEEP study demonstrates the usefulness of measuring benthic tropho-dynamic processes to determine the 

 long-term cumulative impacts of petroleum on benthic communities. Harpacticoid copepods were especially 

 useful to elucidate sublethal effects on population recruitment. 



Conclusions and recommendations based on CAMP, GEEP and SEEP studies: All three studies point out the 

 importance of studying both macrofauna and meiofauna to detect short- and long-term impacts on soft bottom 

 ecosystems. Regardless of whether the goal is to design a monitoring study, chronic impact study, or an 

 ecosystem study one should: 



• develop a prior null hypotheses; 



• use community structure to determine effects on habitat structural degradations; 



• use rates of processes to determine effects on habitat functioning degradation; 



• use life history and reproductive data to indicate sublethal or chronic impacts; 



• design work so natural influences can be easily segregated from man's impact on both local and regional 

 scales; 



• choose the target group with the best attribute for the question; this may generally require knowledge 

 about bacteria, meiofauna, and macrofauna; 



• explore the use of higher taxonomic levels to detect impacts, rather than identifying everything to the 

 species level; 



• measure trophic dynamic structure and processes to indicate impacts which might result in organic 

 enrichment. 



