Climate Change In Aquatic Systems

Complex effects of winter warming on the physicochemical characteristics of a deep lake

by Klaus Joehnk

Straile, D., Jöhnk, K.D., Rossknecht, H., 2003. Complex effects of winter-warming on the physico-chemical characteristics of a deep lake. Limnology & Oceanography 48: 1432-1438.

Summer heatwaves promote blooms of harmful cyanobacteria

by Klaus Joehnk

Jöhnk, K.D., Huisman, J., Sommeijer, B., Sharples, J, Visser, P.M., Stroom, J., 2008. Summer heatwaves promote blooms of harmful cyanobacteria. Global Change Biology 14, 495-512.

Auswirkungen des globalen Klimawandels auf den Bodensee

by Klaus Joehnk

Ostendorp, W., Brem, H., Dienst, M., Jöhnk, K.D., Mainberger, M., Peintinger, M., Rey, P., Rossknecht, H., Schlichtherle, H., Straile, D., Strang, I., 2007. Auswirkungen des globalen Klimawandels auf den Bodensee. Schriften des Vereins für die Geschichte des Bodensees und seiner Umgebung 125: 199-244.

1-D-hydrodynamische Modelle in der Limnophysik: Turbulenz-Meromixis-Sauerstoff

by Klaus Joehnk

Jöhnk, K.D., 2000. 1D hydrodynamische Modelle in der Limnophysik – Turbulenz, Meromixis, Sauerstoff. Habilitationsschrift, TU Darmstadt, 235 p.

Competitiveness of invasive and native cyanobacteria from temperate freshwaters under various light and temperature conditions

by Klaus Joehnk

Mehnert, G., Leunert, F., Cires, S., Jöhnk, K.D., Rücker, J., Nixdorf, B., Wiedner, C., 2010. Competitiveness of alien and native cyanobacteria from temperate freshwaters under various light and temperature conditions, Journal of Plankton Research 32, 1009-1021.

Modeling lakes and reservoirs in the climate system

by Klaus Joehnk

MacKay, M.D., P.J. Neale, C.D. Arp, L.N. De Senerpont Domis, X. Fang, G. Gal, K.D. Jöhnk, G. Kirillin, J.D. Lenters, E. Litchman, S. MacIntyre, P. Marsh, J. Melack, W.M. Mooij, F. Peeters, A. Quesada, S.G. Schladow, M. Schmid, C. Spence, and S.L. Stokes, 2009. Modeling lakes and reservoirs in the climate system. Limnology & Oceanography 54, 2315-2329.

Modelling life cycle and population dynamics of Nostocales (cyanobacteria)

by Klaus Joehnk

Jöhnk, K.D., Brüggemann, R., Rücker, J., Luther, B., Simon, U., Nixdorf, B., Wiedner, C., 2011. Modelling life cycle and population dynamics of Nostocales (cyanobacteria). Environmental Modelling and Software 26, 669-677.

Harmful cyanobacteria: Favored by global warming but suppressed by rising CO2

by Klaus Joehnk

Huisman, J., Paerl, H. W., Jöhnk, K.D., van de Waal, D.MB, Visser, P.M., Verspagen, J.M.H., 2011. Harmful cyanobacteria: Favored by global warming but suppressed by rising CO2? 8th APGC Symposium - Plant Functioning in a Changing Global and Polluted Environment. University of Groningen, ISBN 9789036749824, p. 81-82.

Summer heat waves promote blooms of harmful cyanobacteria

by Klaus Joehnk

Jöhnk, K.D., 2008. Summer heat waves promote blooms of harmful cyanobacteria. In: Schauser, I., Strube, T., Perspectives of lake modelling towards predicting reaction to trophic change, Kompetenzzentrum Wasser Berlin, ISBN 978-3-9811684-3-3, 74-76.

Chaos in a long-term experiment with a plankton community - Supplementary information

by Klaus Joehnk

Benincà, E., Huisman, J., Heerkloss, R., Jöhnk, K.D, Branco, P., Van Nes, E.H., Scheffer, M. & Ellner, S., 2008. Chaos in a long-term experiment with a plankton community. Nature 451: 822-825.

Sensitivity of a prairie wetland to increased temperature and seasonal precipitation changes

by Timothy Kittel

Poiani, K.A., W.C. Johnson, and T.G.F. Kittel. 1995. Sensitivity of a prairie wetland to increased temperature and seasonal precipitation changes. Water Resources Bulletin 31:283-294.

DOI: 10.1111/j.1752-1688.1995.tb03380.x

Water Resources Bulletin, now "Journal of the American Water Resources Association"

We assessed the potential effects of increased temperature and changes in amount and seasonal timing of precipitation... more We assessed the potential effects of increased temperature and changes in amount and seasonal timing of precipitation on the hydrology and vegetation of a semi-permanent prairie wetland in North Dakota using a spatially-defined, rule-based simulation model. Simulations were run with increased temperatures of 2°C combined with a 10 percent increase or decrease in total growing season precipitation. Changes in precipitation were applied either evenly across all months or to individual seasons (spring, summer, or fall).

The response of semi-permanent wetland P1 was relatively similar under most of the seasonal scenarios. A 10 percent increase in total growing season precipitation applied to summer months only, to fall months only, and over all months produced lower water levels compared to those resulting from the current climate due to increased evapotranspiration. Wetland hydrology was most affected by changes in spring precipitation and runoff. Vegetation response was relatively consistent across scenarios. Seven of the eight seasonal scenarios produced drier conditions with no open water and greater vegetation cover compared to those resulting from the current climate. Only when spring precipitation increased did the wetland maintain an extensive open water area (49 percent).

Potential changes in climate that affect spring runoff, such as changes to spring precipitation and snow melt, may have the greatest impact on prairie wetland hydrology and vegetation. In addition, relatively small changes in water level during dry years may affect the period of time the wetland contains open water. Emergent vegetation, once it is established, can survive under drier conditions due to its ability to persist in shallow water with fluctuating levels. The model's sensitivity to changes in temperature and seasonal precipitation patterns accentuates the need for accurate regional climate change projections from general circulation models.

Keywords:

prairie wetlands;
hydrology and vegetation dynamics;
simulation model;
climate change;
GIS;
waterfowl habitat;
global warming

Description of the Female of Capnia arapahoe (Plecoptera: Capniidae)

by Brian Heinold

Prior to collections in 2009, this species had not been reported since 1987. I collected and described the female from 2 specimens from the male type locality of Elkhorn Creek, a tributary to the Cache la Poudre River.

The previously unknown female of the rare Arapahoe Snowfly, Capnia arapahoe, is described and illustrated for the... more The previously unknown female of the rare Arapahoe Snowfly, Capnia arapahoe, is described and illustrated for the first time from two specimens collected from the Front Range of
Colorado. The female terminalia is unique among sympatric species of Capnia and is compared to similar species.

KEY WORDS: Plecoptera, Capniidae, Capnia arapahoe, Colorado, snowfly

Diversity and Distribution of Mayflies (Ephemeroptera), Stoneflies (Plecoptera), and Caddisflies (Trichoptera) of the South Platte River Basin, Colorado, Nebraska, and Wyoming, 1873–2010

by Brian Heinold

This is my Master's Thesis completed in 2010. It should be available through USGS website in late 2011 or early 2012.

Nearly 5,000 mayfly (Ephemeroptera), stonefly (Plecoptera), and caddisfly (Trichoptera) (EPT) species records... more Nearly 5,000 mayfly (Ephemeroptera), stonefly (Plecoptera), and caddisfly (Trichoptera) (EPT) species records collected from the South Platte River Basin (SPRB) were compiled from literature, field surveys, and institutional and personal collections. From this effort, a total of 291 species (69 mayflies, 66 stoneflies, 156 caddisflies) representing 35 families and 134 genera are reported from 1,208 unique collection locations. The EPT fauna of the foothills transition zone appears to be the most diverse and best characterized physiographic province of the SPRB. Four caddisflies are reported from Colorado for the first time; Asynarchus circopa (Ross and Merkley), Orthotrichia cristata Morton, Leptocerus americanus Banks, and Helicopsyche n. sp. The mayflies Ephemera compar (Hagen) and Ephemerella apopsis McCafferty are apparently endemic to the South Platte River Basin; however, both species have not been reported since their original collections in 1873 and 1974, respectively. The microcaddisfly Ochrotrichia susanae Flint and Herrmann and the winter stonefly, Capnia arapahoe Nelson and Kondratieff are currently under emergency petition in Colorado under the U.S. Endangered Species Act. Many other species were represented by few records and require further investigation to better understand their distributions.

Evidence for bias in C/N, δ13C and δ15N values of bulk organic matter, and on environmental interpretation, from a lake sedimentary sequence by pre-analysis acid treatment methods.

by Chris Brodie

In Press - Quaternary Science Reviews

Lead Author: Dr. Chris Brodie (Hong Kong University, Hong Kong)

Co-Authors: Dr. James Casford (Durham University); Dr. Jeremy Lloyd (Durham University, UK); Prof. Melanie Leng (NIGL, UK); Dr. Timothy Heaton (NIGL, UK); Christopher Kendrick (NIGL, UK); Dr. Zong Yongqiang (Hong Kong University, Hong Kong).

ABSTRACT:
There is a known bias in C/N, d13C and d15N values of organic matter (OM) due to pre-analysis acid... more ABSTRACT:
There is a known bias in C/N, d13C and d15N values of organic matter (OM) due to pre-analysis acid treatment methods. We report here, for the first time, the results of a pre-analysis acid treatment method comparison of measured C/N, d13C and d15N values in bulk OM from a sedimentary sequence of samples to illustrate this bias. Here we show that acid treatment significantly reduces the accuracy (between method biases) and precision (within method bias) of C/N, d13C and d15N values of OM, suggesting a differential response of sample OM between methods and sample horizons, and in some cases inefficient removal of inorganic carbon. We show that different methods can significantly influence environmental interpretation in some of our sample horizons (i.e. interpretation of aquatic vs. terrestrial OM source; C3 vs. C4 vegetation). Specifically, there are unpredictable and non-linear differences between methods for C/N values in the range of ~ 1 – 100; d13C values in the range of 0.2 – 6.8 ‰ and; d15Nvalues in the range of 0.3 – 0.7 ‰. Importantly, these ranges are mostly much greater than the instrument precision (defined as the standard deviation of replicate analysis of standard reference materials; for this study, ± 0.5 for C/N values, ± 0.1 ‰ for d13C values and; ± 0.1 ‰ for d15N). The accuracy and precision of measured C/N, d13C and d15N values of bulk OM is not just dependent upon environmental variability, but on acid pre-treatment, residual inorganic carbon and organic matter state and composition. Collectively, this makes the correlation between samples prepared in different ways, including those from down core reconstructions, highly questionable.

Keywords: C/N ratios, δ13C, δ15N, organic matter; pre-analysis acid treatment methods, environmental interpretation, palaeoclimate.

Multiscale influence of climate on estuarine populations of forage fish: the role of coastal upwelling, freshwater flow and temperature

by Jon Reum

published in 'Marine Ecology Progress Series', 2011