Geology topics

Gerald Matisoff

Publications and source records attributed to Gerald Matisoff.

4 recordsLinked to original sources

USGS2016

Internal loading of phosphorus in western Lake Erie

This study applied eight techniques to obtain estimates of the diffusive flux of phosphorus (P) from bottom sediments throughout the western basin of Lake Erie. The flux was quantified from both aerobic and anaerobic incubations of whole cores; by monitoring the water encapsulated in bottom chambers; from pore water concentration profiles measured with a phosphate microelectrode, a diffusive equilibrium in thin films (DET) hydrogel, and expressed pore waters; and from mass balance and biogeochemical diagenetic models. Fluxes under aerobic conditions at summertime temperatures averaged 1.35 mg P/m 2 /day and displayed spatial variability on scales as small as a centimeter. Using two different temperature correction factors, the flux was adjusted to mean annual temperature yielding average annual fluxes of 0.43–0.91 mg P/m 2 /day and a western basin-wide total of 378–808 Mg P/year as the diffusive flux from sediments. This is 3–7% of the 11,000 Mg P/year International Joint Commission (IJC) target load for phosphorus delivery to Lake Erie from external sources. Using these average aerobic fluxes, the sediment contributes 3.0–6.3 μg P/L as a background internal contribution that represents 20–42% of the IJC Target Concentration of 15 μg P/L for the western basin. The implication is that this internal diffusive recycling of P is unlikely to trigger cyanobacterial blooms by itself but is sufficiently large to cause blooms when combined with external loads. This background flux may be also responsible for delayed response of the lake to any decrease in the external loading.

Lake Erie↗

USGS2015

Potential impact of Chironomus plumosus larvae on hypolimnetic oxygen in the central basin of Lake Erie

Previous studies have indicated that burrow-irrigating infauna can increase sediment oxygen demand (SOD) and impact hypolimnetic oxygen in stratified lakes. We conducted laboratory microcosm experiments and computer simulations with larvae of the burrowing benthic midge Chironomus plumosus to quantify burrow oxygen uptake rates and subsequent contribution to sediment oxygen demand in central Lake Erie. Burrow oxygen uptake and water flow velocities through burrows were measured using oxygen microelectrodes and hot film anemometry, respectively. Burrow oxygen consumption averaged 2.66 × 10 − 10 (SE = ± 7.82 × 10 − 11 ) mol O 2 /burrow/s at 24 °C and 9.64 × 10 − 10 (SE = ± 4.86 × 10 − 10 ) mol O 2 /burrow/s at 15 °C. In sealed microcosm experiments, larvae increased SOD 500% at 24 °C (density = 1508/m 2 ) and 375% at 15 °C (density = 864/m 2 ). To further evaluate effects of densities of C. plumosus burrows on SOD we developed a 3-D transport reaction model of the process. Using experimental data and chironomid abundance data in faunal surveys in 2009 and 2010, we estimated that bioirrigation by a population of 140 larvae/m 2 could account for between 2.54 × 10 − 11 mol/L/s (model results) and 5.58 × 10 − 11 mol/L/s (experimental results) of the average 4.22 × 10 − 11 mol/L/s oxygen depletion rate between 1970 and 2003, which could have accounted for 60–132% of the oxygen decline. At present, it appears that the population density of this species may be an important factor in development of hypoxic or anoxic conditions in central Lake Erie.

Ohio↗

USGS2014

A 200 year chronology of burrowing mayflies ( Hexagenia spp.) in Saginaw Bay

After an absence of 50 years, burrowing mayflies ( Hexagenia spp.) colonized western Lake Erie which led to interest in whether this fauna can be used to measure recovery in nearshore waters throughout the Great Lakes. However, in many areas we do not know if mayflies were native/endemic and thus, whether recovery is a logical measure to assess progress of recovery. In the present study, we construct a chronologic record of relative abundance of burrowing mayflies in Saginaw Bay by the use of mayfly tusks and radionuclides in sediments (i.e., a paleoecologic record) and historic records of mayfly nymphs in the bay. These records reveal that mayflies: (1) were few before 1799, which indicates that nymphs were probably native/endemic in the bay, (2) increased between 1799 and 1807 and remained at relatively high levels between 1807 and 1965, probably in response to increased nutrient run-off from the watershed, (3) declined dramatically between 1965 and 1973, probably as a result of excessive eutrophication in the mid-1950s; and, (4) were few and highly variable between 1973 and 2001, probably as a result of low and unstable abundances of mayfly nymphs. Historic records verify that nymphs disappeared in the bay in the late-1950s to early-1960s which is in agreement with the paleoecologic record. Reoccurrence of low abundances of nymphs in the bay between 1991 and 2008 and comparison of chronologic records of nymphs in Saginaw Bay and western Lake Erie suggest that mayflies may return to Saginaw Bay in the early-21st century. Undoubtedly, watershed conservation and three decades of pollution abatement have set the stage for a recovery of burrowing mayflies in Saginaw Bay, and possibly in other areas of the Great Lakes.

Michigan↗

USGS2009

The effect of mayfly (Hexagenia spp.) burrowing activity on sediment oxygen demand in western Lake Erie

Previous studies support the hypothesis that large numbers of infaunal burrow-irrigating organisms in the western basin of Lake Erie may increase significantly the sediment oxygen demand, thus enhancing the rate of hypolimnetic oxygen depletion. We conducted laboratory experiments to quantify burrow oxygen dynamics and increased oxygen demand resulting from burrow irrigation using two different year classes of Hexagenia spp. nymphs from western Lake Erie during summer, 2006. Using oxygen microelectrodes and hot film anemometry, we simultaneously determined oxygen concentrations and burrow water flow velocities. Burrow oxygen depletion rates ranged from 21.7 mg/nymph/mo for 15 mm nymphs at 23 °C to 240.7 mg/nymph/mo for 23 mm nymphs at 13 °C. Sealed microcosm experiments demonstrated that mayflies increase the rate of oxygen depletion by 2-5 times that of controls, depending on size of nymph and water temperature, with colder waters having greater impact. At natural population densities, nymph pumping activity increased total sediment oxygen demand 0.3-2.5 times compared to sediments with no mayflies and accounted for 22-71% of the total sediment oxygen demand. Extrapolating laboratory results to the natural system suggest that Hexagenia spp. populations may exert a significant control on oxygen depletion during intermittent stratification. This finding may help explain some of the fluctuations in Hexagenia spp. population densities in western Lake Erie and suggests that mayflies, by causing their own population collapse irrespective of other environmental conditions, may need longer term averages when used as a bio-indicator of the success of pollution-abatement programs in western Lake Erie and possibly throughout the Great Lakes.

Journal of Great Lakes Research↗