摘要:

Physicochemical and botanical limnological characteristics were determined for Boomer Lake, Oklahoma, a recently reexcavated 70 year old urban impoundment. The lake is alkaline (median pH 8.1, range 6.9—8.8) and extremely turbid with suspended clay (median Secchi depths 0.35 m at the shallow upper reach and 0.6 m near the dam, with vertical attenuation coefficients of 1.4—4.7 m−1), although it is slightly clearer than before reexcavation. Boomer Lake is polymictic, with only weak intermittent stratification (median and maximum surface—bottom temperature differentials of 2.0 and 7.6°C at the deepest site) and no evidence of bottom hypoxia. Soluble reactive phosphorus was vertically homogeneous on average, whereas nitrate + nitrite and ammonium tended to be slightly higher at the surface and bottom, respectively. Chlorophyll biomass was very low (~1 mg · m−3), probably because of poor light penetration and possibly low bioavailability of phosphate due to scavenging by suspended clay. Phytoplankton genera (>10 μm) and macrophyte species were documented for the first time in this lake. APotamogeton nodosusgrowth experiment indicated that the fine, anaerobic sediments may slightly depress macrophyte growth rate, and growth was enhanced by sediment ammonium phosphate enrichment. Nevertheless, essentially the entire littoral zone <1 m depth has been colonized by rooted macrophytes, mainlyP. nodosus, Najas guadalupensis, Chara globularisand, more locally,Ludwigia peploides.

ISSN:0270-5060    

DOI:10.1080/02705060.1998.9663612

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Eighteen species of native unionid mussels (Unionidae) were recovered from sediments dredged from behind a coffer dam built during the construction of the Melvin Price Lock and Dam on the Upper Mississippi River. For three species (Amblema plicata, Anodonta grandis, and Obliquaria reflexa), shells in the dredged material were significantly smaller than those of the same species collected at about the same time from other sites in Pool 26 of the Illinois and Mississippi Rivers. The concentration of juvenile specimens in the dredged material is thought to represent a de novo development associated with silt accumulation behind the coffer dam.

ISSN:0270-5060    

DOI:10.1080/02705060.1998.9663613

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Six golden topminnow (Fundulus chrysotus) specimens were collected in Mississippi County, Missouri in 1997. This is the most northern location on record for the species.F. chrysotusis currently listed as extirpated in Missouri, but it should now be reconsidered for endangered status in the state. Because of a planned flood control project in the area of these collections the future of this species in Missouri is uncertain.

ISSN:0270-5060    

DOI:10.1080/02705060.1998.9663614

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:0270-5060    

DOI:10.1080/02705060.1998.9663615

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:0270-5060    

DOI:10.1080/02705060.1998.9663601

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor