Geology topics

Matthew J. Solensky

Publications and source records attributed to Matthew J. Solensky.

6 recordsLinked to original sources

USGS2022

Lessons learned from wetlands research at the Cottonwood Lake Study Area, Stutsman County, North Dakota, 1967–2021

Depressional wetlands in the Prairie Pothole Region of North America have a long history of investigation owing to their importance in maintaining migratory-bird populations, especially waterfowl. One area of particularly intensive study is the Cottonwood Lake study area in Stutsman County, North Dakota. Studies at the Cottonwood Lake study area began in 1967 and continue through the present (2022). During this period of scientific discovery, meteorological conditions at the Cottonwood Lake study area varied greatly and included one of the most severe droughts of the 20th century and one of the wettest periods in the past 500 years. Persistent wet conditions that began in 1993 have contributed to state changes in many of the study area’s larger wetlands to lake-like conditions, whereas the smaller wetlands returned to seasonally ponded conditions during relatively dry years interspersed within the longer-term wet period. Additionally, some nonwetland areas of the study area developed wetland plant, hydrology, and soil characteristics during the 1993-to-present (2022) wet period. The persistently high stages of water in the larger wetlands since 1993 contributed to a buildup of dissolved solids and increases in salinity with time following an initial decrease in salinity caused by the dilution of dissolved solids within a larger volume of water. During 2021, drought conditions similar to the 1988 to 1992 period may develop if conditions persist. However, meteorological changes during the past 30 years have persisted long enough to be considered a change in climate conditions at the study area and, if such wet conditions continue, would represent a change from conditions that occurred in the past two millennia. During the period of study covered in this report (1967–2021), biotic communities responded in a variety of ways to subtle and marked changes in ponded-water depths, permanence, and salinity among the different wetland types in the study area. This report provides background information on the Cottonwood Lake study area and its context within the Prairie Pothole Region, documents techniques used to quantify environmental conditions and biotic communities, describes major trends that have been observed, presents significant findings as “lessons learned,” discusses recent modeling advances, and highlights key messages to managers. The Wetland Continuum concept was used as a framework to place research findings within an ecological context and to highlight the dynamic nature of prairie-pothole wetland ecosystems.

North Dakota↗

USGS2021

Chemical connectivity and multi-element composition of groundwater in depressional wetlands

Little is known about the element composition of groundwater along flow paths between wetlands. What is known is based on a few major elements, such as Na and Ca. We examined the spatial and temporal variation of elements in a depressional-wetland, groundwater-flow system in the Prairie Pothole Region of North Dakota, USA. Wetlands of the region are characterized by their occurrence in hydrologically connected complexes, where those at higher elevations in the groundwater flow system often recharge groundwater (recharge wetlands), while those at lower elevations receive groundwater (discharge wetlands). The aim of our study was to get a better understanding of factors affecting the distribution of more than 30 elements in groundwater along a flow path between recharge and discharge wetlands. We found that oxidation-reduction potential (ORP) decreased as electrical conductivity (EC) increased along the flow path. As EC increased, so did the concentrations of major ions, such as Na, Ca, and Mg. That was already well known. Less known, however, was that concentrations of Cs, Sn, U and Zr increased along the flow path as well. Not reported before was that concentrations of Sn increased strongly as ORP decreased. The concentrations of most elements in groundwater increased with lower relative elevation in the groundwater flow system, but notable exceptions were Ba and Zn, which both showed opposite patterns. Our results contribute to a better understanding of element cycling in groundwater between wetlands, which in turn is important for our understanding of resultant influences on associated biogeochemistry and ecosystem services.

North Dakota↗

USGS2019

Temporal gamma-diversity meets spatial alpha-diversity in dynamically varying ecosystems

Community measures collected at a single instance or over a short temporal period rarely provide a complete accounting of biological diversity. The gap between such “snapshot” measures of diversity and actual diversity can be especially large in systems that undergo great temporal variation in environmental conditions. To adequately quantify diversity in these temporally varying ecosystems, individual measures of diversity collected throughout the range of environmental variation, i.e., temporal alpha-diversity measures, must be combined to obtain temporal gamma-diversity. Such a time-integrated gamma-diversity measure will be a much closer approximation of a site’s true alpha-diversity and provide a measure better comparable to spatial alpha-diversity measures of sites with lower temporal variation for which a single or a few “snapshot” measures may suffice. We used aquatic-macroinvertebrate community-composition data collected over a 24-year period from a complex of 16 prairie-pothole wetlands to explore the rate that taxa accumulate over time at sites with differing degrees of temporal variation. Our results show that the rate of taxa accumulation over time, i.e., the slope of the species–time relationship, is steeper for wetlands with ponds that frequently dry compared to those with more-permanent ponds. Additionally, we found that a logarithmic function better fit species accumulation data for seasonally ponded wetlands whereas a power function better fit accumulations for permanently and semi-permanently ponded wetlands. Thus, interpretations of ecological diversity measures, and conservation decisions that rely on these interpretations, can be biased if temporal variations in community composition are not adequately represented.

North Dakota↗

USGS2017

Abundant carbon substrates drive extremely high sulfate reduction rates and methane fluxes in Prairie Pothole Wetlands

Inland waters are increasingly recognized as critical sites of methane emissions to the atmosphere, but the biogeochemical reactions driving such fluxes are less well understood. The Prairie Pothole Region (PPR) of North America is one of the largest wetland complexes in the world, containing millions of small, shallow wetlands. The sediment pore waters of PPR wetlands contain some of the highest concentrations of dissolved organic carbon (DOC) and sulfur species ever recorded in terrestrial aquatic environments. Using a suite of geochemical and microbiological analyses, we measured the impact of sedimentary carbon and sulfur transformations in these wetlands on methane fluxes to the atmosphere. This research represents the first study of coupled geochemistry and microbiology within the PPR and demonstrates how the conversion of abundant labile DOC pools into methane results in some of the highest fluxes of this greenhouse gas to the atmosphere ever reported. Abundant DOC and sulfate additionally supported some of the highest sulfate reduction rates ever measured in terrestrial aquatic environments, which we infer to account for a large fraction of carbon mineralization in this system. Methane accumulations in zones of active sulfate reduction may be due to either the transport of free methane gas from deeper locations or the co-occurrence of methanogenesis and sulfate reduction. If both respiratory processes are concurrent, any competitive inhibition of methanogenesis by sulfate-reducing bacteria may be lessened by the presence of large labile DOC pools that yield noncompetitive substrates such as methanol. Our results reveal some of the underlying mechanisms that make PPR wetlands biogeochemical hotspots, which ultimately leads to their critical, but poorly recognized role in regional greenhouse gas emissions.

North Dakota↗

USGS2001

Fall migration routes, timing, and wintering sites of North American ospreys as determined by satellite telemetry

Satellite telemetry was used to determine fall migratory movements of Ospreys (Pandion haliaetus) breeding in the United States. Study areas were established along the lower Columbia River between Oregon and Washington; in north-central Minnesota; on Shelter Island, New York; and in southern New Jersey. Seventy-four adults (25 males, 49 females) were tracked from 1995 through 1999. Migration routes differed among populations but not by sex. Western Ospreys migrated through California and to a lesser degree other western states and wintered in Mexico (88%), El Salvador (6%), and Honduras (6%) (25.9A?N to 13.0A?N and 108.3A?W to 87.3A?W). Minnesota Ospreys migrated along three routes: (1) through the Central U.S. and then along the east coast of Mexico, (2) along the Mississippi River Valley, then across the Gulf of Mexico, or (3) through the southeastern U.S., then across the Caribbean. East Coast birds migrated along the eastern seaboard of the U.S., through Florida, and across the Caribbean. Midwestern birds wintered from Mexico south to Bolivia (22.35A?N to 13.64A?S, and 91.75A?W to 61.76A?W), while East Coast birds wintered from Florida to as far south as Brazil (27.48A?N to 18.5A?S and 80.4A?W to 57.29A?W). Dates of departure from breeding areas differed significantly between sexes and geographic regions, with females leaving earlier than males. Western birds traveled a shorter distance than either midwestern or eastern Ospreys. Females traveled farther than males from the same population, which resulted in females typically wintering south of males.

The Condor↗

USGS2000

Migration strategies and wintering areas of North American ospreys as revealed by satellite telemetry

Since 1995 we have trapped and tagged 110 Ospreys ( Pandion haliaetus ) from 12 study sites in 8 states (Fig. 1). This total includes 71 females, 32 males and 7 juveniles. Our study areas encompass the major Osprey population concentrations found in the United States including the Western States, the Great Lakes region and the Eastern Seaboard. Tagging of nesting pairs along with three complete family groups revealed that departure times from nesting areas varied by gender; with females leaving before the juveniles and the males departing last. Neither nesting pairs, nor families, migrated or wintered together (Fig. 2). Departure dates from the breeding areas ranged from 12 July to 1 October. Migration routes differed between populations but not gender (Fig. 3). Western Ospreys migrated through California and to a lesser degree other western states and then into Mexico. Minnesota Ospreys migrated along three routes; 1) through the central U.S. and then along the east coast of Mexico, 2) along the Mississippi River then across the Gulf of Mexico, or 3) through the Southeastern U.S., then across the Caribbean. East Coast birds migrated along the Eastern Seaboard of the U.S. through Florida and across the Caribbean.

Arkansas, Illinois, Iowa, Louisiana, Minnesota, Mi↗