Geology topics

Research about Illinois, Iowa, Missouri

Source-linked reports with geographic coverage including Illinois, Iowa, Missouri.

3 recordsLinked to original sources

USGS2025

Off-channel habitat use by silver carp (Hypophthalmichthys molitrix) and bighead carp (H. nobilis) in the upper Mississippi River

The spread of invasive carp in the Mississippi River Basin of the U.S. has caused substantial ecological and economic problems. Although there are a variety of strategies to manage invasive carp, removal remains a central part of many efforts. To be most effective, large-scale removal of invasive carp should target fish when they are densely aggregated in locations with favorable conditions for deploying fishing gear. We used acoustic telemetry to track off-channel habitat use by silver carp Hypophthalmichthys molitrix and bighead carp H. nobilis in backwaters and impounded areas across three navigation pools of the upper Mississippi River to identify factors associated with high densities. Backwater areas generally had high use when temperatures were warm and river discharge was high, and impounded areas generally had high use when temperatures were cooler and discharge was lower. Models of habitat use suggest silver carp and bighead carp show predictable habitat relationships in off-channel areas that could improve removal efficiency.

Illinois, Iowa, Missouri↗

USGS2021

Age-0 Silver Carp otolith microchemistry and microstructure reveal multiple early life environments and protracted spawning in the upper Mississippi River

Silver Carp Hypophthalmichthys molitrix are highly mobile and fecund planktivorous cyprinids that have invaded much of the Mississippi River and are known to alter food webs and compete with native planktivores. In 2016, for the first time, an abundance of age-0 Silver Carp ( n = 12,208; 16–231 mm) were captured at many ( n = 11) sites upstream of Lock and Dam 19 on the upper Mississippi River. Previous reports were of a few individuals at a few locations; however, effort to capture juveniles of this size was likely less in previous years. Determining the origin, frequency, and timing of the reproductive events that led to this large year-class is important for determining control strategies. We used otolith microstructure and microchemistry from age-0 Silver Carp to estimate timing and frequency of spawning and early life environments of these fish. Hatch dates were determined from the lapillus otoliths of 190 age-0 Silver Carp (16–231 mm), and early life environments were identified from otolith microchemistry for 124 of these fish (64–231 mm). Age-0 Silver Carp were collected from Pools 18 and 19 during July–October 2016 by using a variety of sampling gears. We identified 10 cohorts with hatch dates ranging from May to August 2016 and with main-stem Mississippi River (75%) and tributary (23%) early life signatures. Tributary otolith chemistry signatures were present in all cohorts between May and July ( n = 8) but were absent from the August cohorts ( n = 2). Our results indicate that tributaries and small tributary streams, in addition to the main-stem river, play an important role in Silver Carp recruitment in areas near the reproductive front, where management actions (e.g., contract removal and deterrents) are often targeted.

Illinois, Iowa, Missouri↗

USGS1998

Physical and chemical data on sediments deposited in the Missouri and the Mississippi River flood plains during the July through August 1993 flood

In July and August 1993, Missouri and Mississippi River floodwaters overtopped or breached levees and inundated agricultural and urban areas in the flood plains. To assess the regional variability of quality of silt and clay sediments transported and deposited during inundation, sediment samples were collected in September 1993 at 25 sites in the Missouri and the Mississippi River flood plains. The samples were analyzed for physical properties and chemical constituents that included particle-size distribution, water content, volatile solids, nutrients, carbon, selected trace elements, pesticides, and semi volatile organic compounds for post flood sediment samples, and particle-size distribution for preflood soil samples. Pesticides were detected in samples from many of the sites, with alachlor detected in one sample at a concentration of 54 micrograms per kilogram. Many semi volatile organic compounds were detected in samples at several sites, with the concentration of fluoranthene in one sample at 270 milligrams per kilogram. Procedures for selecting sites, techniques developed for sampling, laboratory analytical methods, and quality-assurance sampling methods also are described.

Illinois, Iowa, Missouri↗