ISSN:
1573-5117
Keywords:
macroinvertebrates
;
DDT
;
benthos
;
herpobenthos
;
haptobenthos
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Quarterly measurements were conducted of the structure, abundance, and diversity of macroinvertebrates comprising two distinct, but overlapping zoobenthic communities in backwaters to Wheeler Reservoir Alabama. The study area included portions of Huntsville Spring Branch (HSB) and Indian Creek (IC) which contain massive quantities of DDT residues (DDTR = DDT, DDD, DDE). Additionally, sewage effluents entering HSB just upstream from the study area have resulted in nutrient enrichment, especially at the two uppermost stations. Herpobenthos (burrowed in bottom sediments) and haptobenthos (attached to substrates) were collected at seven stations along an east-west gradient including a control site above the DDT contamination, and sites with mean sediment residues ranging from 2,730 ppm DDTR in HSB down to 12 ppm DDTR at the mouth of IC. Fifty taxa were collected from dredge samples of the herpobenthos; Tubificid oligochaetes and chironomid larvae comprised 97% of the herpobenthos. At the two uppermost stations in HSB, the control site and the site with the highest sediment DDTR, oligochaete density averaged twice that of chironomids. Downstream, densities of both groups were similar. Mean density at the upper two stations was 9431 and 10 644 organisms m−2, respectively, significantly (P 〈 0.05) higher than downstream stations. Herpobenthos was dominated by detrital-algal feeders in HSB while in IC, predaceous chironomids were more numerous. Taxa diversity was also lowest (P 〈 0.05) at the two upper sites. Forty-five taxa were collected from artificial substrate (Hester-Dendy multiplate samplers) samples of the haptobenthos. Naidid oligochaetes and chironomids dominated the haptobenthos, although nematodes were occasionaly abundant. Chironomids were more abundant than oligochaetes at all sites except the control station, which received the greatest nutrient enrichment from sewage effluents. Mean haptobenthic density in the middle portion of the study area ranged from 31 163 to 37 310 organisms m−2 and was diferent (P 〈 0.05) from upper and lower stations. Taxa diversity was lowest at the upper-most station, but no trends were evident among stations. Nutrient enrichment from sewage effluents apparently had greater impact on zoobenthic communities in the HSB-IC System than did DDT contamination. However, the presence of DDTR undoubtedly contributed, in part, to the few Ephemeroptera, Plecoptera, and Trichoptera collected at contaminated stations. Based on the density of oligochaetes and chironomid larvae at station 2 (highest DDTR), macroinvertebrates in this system are resistant to DDTR.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00018719
Permalink
