Ecological impacts of fluridone and copper sulphate in catfish aquaculture ponds
Annie P. Jacob, David A. Culver, Roman P. Lanno and Astrid Voigt. 2015. Environmental Toxicology and Chemistry. DOI: 10.1002/etc.3258.
Fluridone and copper sulphate are often used for controlling macrophytes and algae in aquaculture ponds. The present study examined the ecological effects of these chemicals on macrophyte, phytoplankton, and zooplankton biomass, plankton community structure, water quality parameters, and fish survival and yield in catfish culture ponds using a randomized complete block design. The estimated half-life of fluridone in the individual ponds ranged from 1.6 to 10.8 d. Free copper ion activity in ponds treated with copper sulphate was dynamic, ranging from pCu of 7.7 to 8.9 after each application and decreasing to ∼12 (1 × 10−12M) within a week after each application, approaching observed values in control ponds (pCu = 12.3 to 13.4). No difference in macrophyte biomass was observed among treatments. Fluridone and copper treatments elicited different responses within the phytoplankton community. Copper treatments reduced Cyanophyta biomass, but increased biomass of more tolerant taxa among the Chlorophyta and Chrysophyta. Fluridone treatments reduced total phytoplankton biomass including Cyanophyta and increased the sensitivity of Chlorophyta and Chrysophyta to copper. Copper also affected zooplankton community composition due to direct toxic effects on sensitive zooplankton taxa (e.g., Cladocera), whereas Copepoda biomass in copper-treated ponds exceeded that in controls. Catfish survival and yield were not significantly different among treatments. The results of the present study suggest that fluridone and copper interact at realistic application rates, increasing the ability to control algae compared to treatments where they are applied alone. This article is protected by copyright. All rights reserved.
Larval dispersal underlies demographically important inter-system connectivity in a Great Lakes yellow perch (Perca flavescens) population
Reed M Brodnik, Michael E. Fraker, Eric J Anderson, Lucia Carreon-Martinez, Kristen M. DeVanna, Daniel D Heath, Julie M Reichert, Edward F Roseman, Stuart A. Ludsin. 2015. Canadian Journal of Fisheries and Aquatic Sciences. 10.1139/cjfas-2015-0161.
Ability to quantify connectivity among spawning subpopulations and their relative contribution of recruits to the broader population is a critical fisheries management need. By combining microsatellite and age information from larval yellow perch (Perca flavescens) collected in the Lake St. Clair – Detroit River system (SC-DRS) and western Lake Erie with a hydrodynamic backtracking approach, we quantified subpopulation structure, connectivity, and contributions of recruits to the juvenile stage in western Lake Erie during 2006-2007. After finding weak (yet stable) genetic structure between the SC-DRS and two western Lake Erie subpopulations, microsatellites also revealed measurable recruitment of SC-DRS larvae to the juvenile stage in western Lake Erie (17-21% during 2006-2007). Consideration of pre-collection larval dispersal trajectories, using hydrodynamic backtracking, increased estimated contributions to 65% in 2006 and 57% in 2007. Our findings highlight the value of complementing subpopulation discrimination methods with hydrodynamic predictions of larval dispersal by revealing the SC-DRS as a source of recruits to western Lake Erie and also showing that connectivity through larval dispersal can affect the structure and dynamics of large-lake fish populations.
Restoring Ecosystem Function in Degraded Urban Soil Using Biosolids, Biosolids Blend, and Compost
N. T. Basta, D. M. Busalacchi, L. S. Hundal, K. Kumar, R. P. Dick, R. P. Lanno, J. Carlson, A. E. Cox and T. C. Granato. 2015. Journal of Environmental Quality. DOI: 10.2134/jeq2015.01.0009.
Many soils at former industrial sites are degraded. The objective of this research was to determine the ability of compost, biosolids, and biosolids blends to improve soil ecosystem function with minimal potential impact to surface water. Treatments rototilled into the top 12.5 cm of soil were biosolids at 202 Mg ha−1; biosolids at 404 Mg ha−1; compost at 137 Mg ha−1; or a blend consisting of biosolids applied at 202 Mg ha−1, drinking water treatment residual, and biochar. Rainfall runoff from experimental plots was collected for 3 yr. One year after soil amendments were incorporated, a native seed mix containing grasses, legumes, and forbs was planted. Soil amendments improved soil quality and nutrient pools, established a dense and high-quality vegetative cover, and improved earthworm reproductive measures. Amendments increased soil enzymatic activities that support soil function. Biosolids treatments increased the Shannon–Weaver Diversity Index for grasses. For the forbs group, control plots had the lowest diversity index and the biosolids blend had the highest diversity index. Biosolids and compost increased the number of earthworm juveniles. In general, biosolids outperformed compost. Biosolids increased N and P in rainfall runoff more than compost before vegetation was established. Several microconstituents (i.e., pharmaceutical and personal care products) were detected in runoff water but at concentrations below the probable no-effect levels and therefore should pose little impact to the aquatic environment. Future restoration design should ensure that runoff control measures are used to control sediment loss from the restored sites at least until vegetation is established.
Disrupted seasonal biology impacts health, food security and ecosystems
Stevenson, T.J., Visser, M.E., Arnold, W., Barrett, P., Biello, S., Dawson, A., Denlinger, D.L., Dominoni, D., Ebling, F.J., Elton, S., Evans, N., Ferguson, H.M., Foster, R.G., Hau, M., Haydon, D.T., Hazlerigg, D.G., Heideman, P., Hopcraft, J.C.C., Jonsson, N.N., Kronfeld-Schor, N., Kumar, V., Lincoln, G.A., MacLeod, R., Martin, S.A.M., Martinez-Bakker, M., Nelson, R.J., Reed, T., Robinson, J.E., Rock, D., Schwartz, W.J., Steffan-Dewenter, I., Tauber, E., Thackeray, S.J., Umstatter, C., Yoshimura, T., and Helm, B. 2015. Disrupted seasonal biology impacts health, food security and ecosystems. Proceedings of the Royal Society of London Series B: Biological Sciences.
The rhythm of life on earth is shaped by seasonal changes in the environment. Plants and animals show profound annual cycles in physiology, health, morphology, behaviour and demography in response to environmental cues. Seasonal biology impacts ecosystems and agriculture, with consequences for humans and biodiversity. Human populations show robust annual rhythms in health and well-being, and the birth month can have lasting effects that persist throughout life. This review emphasizes the need for a better understanding of seasonal biology against the backdrop of its rapidly progressing disruption through climate change, human lifestyles and other anthropogenic impact. Climate change is modifying annual rhythms to which numerous organisms have adapted, with potential consequences for industries relating to health, ecosystems and food security. Disconcertingly, human lifestyles under artificial conditions of eternal summer provide the most extreme example for disconnect from natural seasons, making humans vulnerable to increased morbidity and mortality. In this review, we introduce scenarios of seasonal disruption, highlight key aspects of seasonal biology and summarize from biomedical, anthropological, veterinary, agricultural and environmental perspectives the recent evidence for seasonal desynchronization between environmental factors and internal rhythms. Because annual rhythms are pervasive across biological systems, they provide a common framework for trans-disciplinary research.
Origin and genetic structure of a recovering bobcat (Lynx rufus) population
Genetic analyses can provide important insights into the demographic processes that underlie recovering populations of mammals of conservation concern such as felid species. To better understand the recent and rapid recovery of bobcats (Lynx rufus [Schreber, 1777]) in Ohio, we analyzed samples from 4 states in the lower Great Lakes Region using 12 microsatellite DNA loci and a portion of the mtDNA control region. Our results showed that a newly-established population of bobcats in the eastern part of Ohio was genetically distinct from a multi-state population distributed across Kentucky, southern Ohio, West Virginia, and western Pennsylvania. There was no direct genetic evidence of a bottleneck or inbreeding in this population. A lack of private alleles and only slightly lower levels of allelic richness and heterozygosity compared to its neighbors suggest that the eastern Ohio population likely originated from the migration of relatively large numbers of individuals from a source population rather than re-emerging from an undetected residual population. We recommend that a management plan should define the areas occupied by the two populations in Ohio as separate management units at least for the near future.
Suppression of net transpiration by multiple mechanisms conserves water resources during pupal diapause in the corn earworm Helicoverpa zea
Joshua B. Benoit, Qirui Zhang, Emily C. Jennings, Andrew J. Rosendale and David L. Denlinger. 2015. Physiological Entomology, 40: 336–342. DOI: 10.1111/phen.12119.
One critical aspect of an insect's ability to overwinter successfully is the effective management of its water resources. Maintenance of adequate water levels during winter is challenging because of the prevailing low relative humidity at that time of year and the short supply of environmental water that is not in the form of ice. These issues are further exacerbated for insects overwintering as pupae, comprising an immobile stage that is unable to move to new microhabitats if conditions deteriorate. The present study compares the water balance attributes of diapausing and nondiapausing pupae of the corn earworm Helicoverpa zea Boddie, aiming to identify the mechanisms used by diapausing pupae to maintain water balance during winter. Diapausing pupae are 10% larger than nondiapausing individuals. Water loss rates for nondiapausing pupae are low (0.21 mg h−1) and are suppressed (0.01 mg h−1) in diapausing pupae. Cuticular lipids, which serve to waterproof the cuticle and thus suppress cuticular water loss, are more than two-fold more abundant on the surface of diapausing pupae, and oxygen consumption rates during diapause drop to almost one-third the rate observed in nondiapausing pupae. Water gain can be accomplished only when atmospheric water content is near saturation or during contact with free water. At moderate relative humidities (20–40%), water loss rates are very low for diapausing pupae, suggesting that these moth pupae have robust mechanisms for combating water loss. The exceptional ability of H. zea to suppress water loss during diapause is probably a result of the combined effects of increased size, more abundant cuticular lipids and decreased metabolic rates.
Multi-copy venom genes hidden in de novo transcriptome assemblies, a cautionary tale with the snakelocks sea anemone Anemonia sulcata (Pennant, 1977)
Using a partial transcriptome of the snakelocks anemone (Anemonia sulcata) we identify toxin gene candidates that were incorrectly assembled into several Trinity components. Our approach recovers hidden diversity found within some toxin gene families that would otherwise go undetected when using Trinity, a widely used program for venom-focused transcriptome reconstructions. Unidentified hidden transcripts may significantly impact conclusions made regarding venom composition (or other multi-copy conserved genes) when using Trinity or other de novo assembly programs.