Benthic Macroinvertebrate Community Changes Following Zebra Mussel Colonization of Southwestern Lake Ontario

Changes in abundance and diversity of benthic macroinvertebrates inhabiting a natural cobble and artificial reef substrate in southwestern Lake Ontario were quantified following invasion of the zebra mussel, Dreissena polymorpha. Post-zebra mussel invasion data (1991-92) were statistically compared with pre-invasion data (1983) from the same sites. By 1991-92 zebra mussels comprised 73% and 90% of cobble and artificial reef macroinvertebrates, respectively, replacing the amphipod Gammarus fasciatus as the numerically dominant taxon at both sites. Overall abundance of non-zebra mussel taxa was significantly greater (p \u3c 0.05) at cobble and artificial reef sites in 1991-92, than in 1983 before zebra mussels were present. Taxa exhibiting significant population increases at the cobble site during the time period separating the two studies were the annelids Manayunkia speciosa, Spirosperma ferox and unidentified tubificids; the gastropods Helisoma anceps,Physa heterostropha, Stagnicola catascopium, Valvata tricarinata, Goniobasis livescens and Amnicola limosa; and the arthropods Gammarus fasciatus and Orconectes propinquis. Significant population increases of Physa heterostropha, Goniobasis livescens, Amnicola limosa, Gammarus fasciatus and the trichopteran Polycentropus were observed at the artificial reef site. Although a few taxa sampled infrequently in 1983 were not collected in 1991-92, no taxa have decreased significantly since 1983. Comparisons of community composition in 1983 and 1991-92 suggest the cobble community has changed more than the artificial reef community. These changes are likely positive, as species richness was greater at cobble and artificial reef sites in 1991-92 relative to 1983, and Simpson\u27s Diversity showed no decline. Though other factors may have contributed to observed native macroinvertebrate community changes, my results support theories that zebra mussels are facilitating energy transfer to the benthos by filter-feeding, and that mussel shoals are providing additional habitat for native invertebrate taxa

Benthic Algae of Lake Erie (1865-2006): A Review of Assemblage Composition, Ecology, and Causes and Consequences of Changing Abundance

Author Institution: Department of Natural Resource Ecology and Management, Iowa State UniversityAuthor Institution: Department of Biological Sciences, Bowling Green State UniversityPeer-reviewed literature and published reports were used to summarize knowledge of benthic algal assemblage composition and ecology in Lake Erie, and causes and consequences of temporal variation in algal abundance. Macroalgal assemblages in rocky littoral and soft substrate habitats have been reasonably well described and studied, as has the epiphyte/metaphyte assemblage associated with rocky littoral macroalgae. In contrast, little information exists for non-epiphytic microalgae in littoral habitat. During the period when algal records were reported (1865-2006), the rocky littoral macroalgal assemblage was often dominated by the chlorophyte genera Cladophora and Ulothrix and the rhodophyte Bangia, whereas the charophytes Chara and Nitella were most abundant in littoral soft substrate. In addition to substrate effects, assemblage composition varied as a function of depth, temperature, light levels, and nutrient concentrations. Under certain conditions, macroalgal taxa appeared to outcompete and exclude other taxa from littoral habitat. However, these organisms have also facilitated increased algal diversity by supporting epiphytes/metaphytes. In Lake Erie, significant temporal change in benthic algal abundance has been associated with: 1) eutrophication (prior to 1972), 2) oligotrophication following the Great Lakes Water Quality Agreement (1972-1985), and 3) invasion by Dreissena mussels (1986-2006). Increasingly eutrophic conditions were reflected by high abundance and frequent shoreline fouling by Cladophora, declining charophyte (such as Chara, Nitella) abundance, and invasion of rocky littoral habitat by euryhaline Bangia. Subsequent indicators of oligotrophication included declining Cladophora abundance, and increased diatom abundance in deepwater habitat. Effects of filter-feeding Dreissena (such as increased water clarity, phosphorus excretion) were likely causes for Cladophora resurgence in the 1990s, and likely contributed to return of Chara and Nitella to formerly occupied habitat. Algal assemblages clearly reflect environmental conditions in aquatic ecosystems. To accurately assess present and future conditions in Lake Erie, continued study of all benthic assemblages is recommended, with greater attention directed toward microalgae in littoral habitat than has occurred in the past

Benthic Algae of Lake Erie (1865-2006): A Review of Assemblage Composition, Ecology, and Causes and Consequences of Changing Abundance

Peer-reviewed literature and published reports were used to summarize knowledge of benthic algal assemblage composition and ecology in Lake Erie, and causes and consequences of temporal variation in algal abundance. Macroalgal assemblages in rocky littoral and soft substrate habitats have been reasonably well described and studied, as has the epiphyte/metaphyte assemblage associated with rocky littoral macroalgae. In contrast, little information exists for non-epiphytic microalgae in littoral habitat. During the period when algal records were reported (1865-2006), the rocky littoral macroalgal assemblage was often dominated by the chlorophyte genera Cladophora and Ulothrix and the rhodophyte Bangia, whereas the charophytes Chara and Nitella were most abundant in littoral soft substrate. In addition to substrate effects, assemblage composition varied as a function of depth, temperature, light levels, and nutrient concentrations. Under certain conditions, macroalgal taxa appeared to outcompete and exclude other taxa from littoral habitat. However, these organisms have also facilitated increased algal diversity by supporting epiphytes/metaphytes. In Lake Erie, significant temporal change in benthic algal abundance has been associated with: 1) eutrophication (prior to 1972), 2) oligotrophication following the Great Lakes Water Quality Agreement (1972-1985), and 3) invasion by Dreissena mussels (1986-2006). Increasingly eutrophic conditions were reflected by high abundance and frequent shoreline fouling by Cladophora, declining charophyte (such as Chara, Nitella) abundance, and invasion of rocky littoral habitat by euryhaline Bangia. Subsequent indicators of oligotrophication included declining Cladophora abundance, and increased diatom abundance in deepwater habitat. Effects of filter-feeding Dreissena (such as increased water clarity, phosphorus excretion) were likely causes for Cladophora resurgence in the 1990s, and likely contributed to return of Chara and Nitella to formerly occupied habitat. Algal assemblages clearly reflect environmental conditions in aquatic ecosystems. To accurately assess present and future conditions in Lake Erie, continued study of all benthic assemblages is recommended, with greater attention directed toward microalgae in littoral habitat than has occurred in the past

Resummed Photon Spectra for WIMP Annihilation

We construct an effective field theory (EFT) description of the hard photon spectrum for heavy WIMP annihilation. This facilitates precision predictions relevant for line searches, and allows the incorporation of non-trivial energy resolution effects. Our framework combines techniques from non-relativistic EFTs and soft-collinear effective theory (SCET), as well as its multi-scale extensions that have been recently introduced for studying jet substructure. We find a number of interesting features, including the simultaneous presence of SCET$_{\text{I}}$ and SCET$_{\text{II}}$ modes, as well as collinear-soft modes at the electroweak scale. We derive a factorization formula that enables both the resummation of the leading large Sudakov double logarithms that appear in the perturbative spectrum, and the inclusion of Sommerfeld enhancement effects. Consistency of this factorization is demonstrated to leading logarithmic order through explicit calculation. Our final result contains both the exclusive and the inclusive limits, thereby providing a unifying description of these two previously-considered approximations. We estimate the impact on experimental sensitivity, focusing for concreteness on an SU(2)$_{W}$ triplet fermion dark matter - the pure wino - where the strongest constraints are due to a search for gamma-ray lines from the Galactic Center. We find numerically significant corrections compared to previous results, thereby highlighting the importance of accounting for the photon spectrum when interpreting data from current and future indirect detection experiments.Comment: 55+25 pages, 11+2 figures; v3, updated an expression in the appendix to make it applicable at higher order - no impact on the results in this wor

708-4 Can the Results of SPECT Scintigraphy Safely Guide Clinical Management of Patients with Active CAD?

Myocardial perfusion scintigraphy is increasingly used to categorize risk in pts with known or a high likelihood of CAD. This strategy will only be cost-effective if: 1) cardiologists will largely reserve further testing such as angiography (angio) to high-risk subsets; and 2) it is shown that less severe patterns of abnormality can be safely managed medically. We previously reported angio rates after all 4, 162 SPECT studies (excluding those with angio within 90 days beforeSPECT) at our cardiology practice-based nuclear lab: 4% (69/1663) in pts with fixed defects only and/or no ischemia; 60% (682/1141) in pts with high-risk ischemia (2 of multivessel or LAD distribution ischemia and abnormal lung uptake); and 9% (123/1352) for pts with mild-moderate ischemia. In this study, we determined outcome of the 1229 pts with mild-moderate ischemia who did not have referral for angio. Patient characteristics: mean age 65 yrs; known CAD=1061 (86%); prior CABG=344; prior MI=575; prior PTCA=674; angina=592. Twenty-eight (2%) pts were lost to follow-up. The remainder were followed for a mean of 18 months. There were 22 hard events (MI=15; cardiac death=71) (1.8%) and 54 pts required PTCA or CABG (total event rate 6.3%). Mean time to any event was 13.2 months from SPECT. Freedom from hard events at 1 yr was 99% and at 2 yrs 97%. Freedom from any event was 97% at 1 yr and 91% at 2 yrs.Conclusions1) SPECT can be a highly effective strategy for selecting pts for angio; 2) Even in a self-referral setting angio is largely reserved for pts with high-risk scans; and 3) Pts with mildly-moderately abnormal scans can be treated safely with medical therapy and close follow-u

Using the Storm Water Management Model to predict urban headwater stream hydrological response to climate and land cover change

Streams are natural features in urban landscapes that can provide ecosystem services for urban residents. However, urban streams are under increasing pressure caused by multiple anthropogenic impacts, including increases in human population and associated impervious surface area, and accelerated climate change. The ability to anticipate these changes and better understand their effects on streams is important for developing and implementing strategies to mitigate potentially negative effects. In this study, stream flow was monitored during April-November (2011 and 2012), and the data were used to apply the Storm Water Management Model (SWMM) for five urban watersheds in central Iowa, USA, representing a gradient of percent impervious surface (IS, ranging from 5.3 to 37.1%). A set of three scenarios was designed to quantify hydrological responses to independent and combined effects of climate change (18% increase in precipitation), and land cover change (absolute increases between 5.2 and 17.1%, based on separate projections of impervious surfaces for the five watersheds) for the year 2040 compared to a current condition simulation. An additional set of three scenarios examined stream response to different distributions of land cover change within a single watershed. Hydrological responses were quantified using three indices: unit-area peak discharge, flashiness (R-B Index; Richards-Baker Index), and runoff ratio. Stream hydrology was strongly affected by watershed percent IS. For the current condition simulation, values for all three indices were five to seven times greater in the most developed watershed compared to the least developed watershed. The climate change scenario caused a 20.8% increase in unit-area peak discharge on average across the five watersheds compared to the current condition simulation. The land cover change scenario resulted in large increases for all three indices: 49.5% for unit-area peak discharge, 39.3% for R-B Index, and 73.9% for runoff ratio, on average, for the five watersheds. The combined climate and land cover change scenario resulted in slight increases on average for R-B Index (43.7%) and runoff ratio (74.5%) compared to the land cover change scenario, and a substantial increase, on average, in unit area peak discharge (80.1%). The scenarios for different distributions of land cover change within one watershed resulted in changes for all three indices, with an 18.4% increase in unit-area peak discharge for the midstream scenario, and 17.5% (downstream) and 18.1% (midstream) increases in R-B Index, indicating sensitivity to the location of potential additions of IS within a watershed. Given the likelihood of increased precipitation in the future, land use planning and policy tools that limit expansion of impervious surfaces (e.g. by substituting pervious surfaces) or mitigate against their impacts (e.g. by installing bioswales) could be used to minimize negative effects on streams