Successive Summers Research Articles

Intercropping Pattern and N Fertilizer Schedule Affect the Performance of Additively Intercropped Maize and Forage Cowpea in the Mediterranean Region

Intercropping maize and forage cowpea is a widely proposed strategy to improve land use efficiency, and maximize the economic value of the farming system, especially in developing countries with restricted resources. The current study was carried out during the successive summers of 2020 and 2021 in Northern Egypt. The main objective was to evaluate the effect of three N schedules (NS1, NS2, NS3), when three different maize–cowpea intercropping patterns (IP1, IP2, IP3) were applied, on the grain yield of maize, forage yield and quality of forage cowpea. In addition, yield gain and land use efficiency were evaluated using the land equivalent ratio (LER) and dry matter equivalent ratio (DMER) indices. Results revealed that the intercropping patterns that provided wider spacings for the component crops and reduced the competition between them, mainly IP3, resulted in the best performances for the two crops. This was clear for maize ear and grain yields, 100-grain weight and harvest index, in addition to cowpea fresh and dry forage yields, crude protein and non-fiber carbohydrates of the three cuts. Regarding the applied N schedules, NS1 which included the application of a N starter dose with sowing proved to be the most efficient schedule that led to the best performance for both crops. Maize produced 9.07 t ha−1 grain yield under IP3 and NS1. In addition, the application of IP3 resulted in the highest significant cowpea dry forage yield (DFY), with the highest crude protein (CP) content. The DFY of cuts 1, 2, and 3 amounted to 1.27, 0.45, and 0.24 t ha−1, while the CP content for the three respective cuts reached 159.49, 157.96, and 148.91 g kg−1. Nonetheless, NS1 produced a reasonable amount of DFY with high CP content. It is recommended to follow the third proposed intercropping pattern (IP3) and to include a nitrogen starter dose (NS1) in the fertilization scheme to ensure highest productivity from the intercropped maize and forage cowpea.

Automated Mosaicking of Sentinel-2 Satellite Imagery

Repeat frequencies of optical remote sensing satellites have been increasing over the last 40 years, but there is still dependence on clear skies to acquire usable imagery. To increase the quality of data, composited mosaics of satellite imagery can be used. In this paper, we develop an automated method for clearing clouds and producing different types of composited mosaics suitable for use in cloud-affected countries, such as New Zealand. We improve the Tmask algorithm for cloud detection by using a parallax method to produce an initial cloud layer and by using an object-based cloud and shadow approach to remove false cloud detections. We develop several parametric scoring approaches for choosing best-pixel composites with minimal remaining cloud. The automated mosaicking approach produced Sentinel-2 mosaics of New Zealand for five successive summers, 2015/16 through 2019/20, with remaining cloud being less than 0.1%. Contributing satellite overpasses were typically of the order of 100. In comparison, manual methods for cloud clearing produced mosaics with 5% remaining cloud and from satellite overpasses typically of the order of 20. The improvements to cloud clearing enable the use of all possible Sentinel-2 imagery to produce automatic mosaics capable of regular land monitoring, at a reasonable cost.

Drivers of Marine Heatwaves in the East China Sea and the South Yellow Sea in Three Consecutive Summers During 2016–2018

AbstractIn 3 consecutive years from 2016 to 2018, extreme ocean warming events, or marine heatwaves (MHWs), occurred during boreal summers in the East China Sea (ECS) and South Yellow Sea (SYS), which is unprecedented in the past four decades based on the satellite record. In this study, we used a high‐resolution hydrodynamic model based on Finite Volume Community Ocean Model (FVCOM) to simulate the evolution of these warming events. An upper ocean temperature budget (0–20 m) analysis based on the model results shows that the shortwave radiation and the ocean advection anomalies jointly contributed to the anomalous warming in the three successive summers (June–August) in the SYS and the north part of the ECS. In addition, the reduction of surface wind speeds during the 2016 and 2017 summers further weakened the vertical mixing, thereby enhancing the anomalous warming in the north part of the ECS adjacent to the SYS. During the three summers, the increases of shortwave radiation were closely related to the East Asian Summer Monsoon (EASM) variability, which reduced the cloud cover in the ECS and SYS, whereas the advection anomalies were mostly associated with regional wind anomalies. In summer 2018, upper ocean heat was transported into the central trough of the SYS, accumulated in an anticyclonic eddy generated by the anomalous wind stress curls. Therefore, despite the primary driver of the MHWs is the EASM variation, regional processes are critical to driving the spatial pattern of the MHW intensity in the ECS and SYS.

Planktonic Protists of the Eastern Nordic Seas and the Fram Strait: Spatial Changes Related to Hydrography During Early Summer

The European Arctic is rapidly changing where increasing water temperatures and rapid loss of sea-ice will likely influence the structure and functioning of the entire ecosystem. This study aimed to describe the taxonomic composition and spatial distribution of early summer (2015-2016) nano- and microplanktonic protists in the Nordic (Norwegian, Greenland) Seas and the Fram Strait (70.99°N to 78.84°N; 1.52°E to 19.90°E) and to determine the distribution patterns of the communities from the aspect of hydrography, as deduced from in situ measurements. Here we identify some generalized regularity in the protistan distribution, indicating the two separated domains at the 6 °C threshold. While Phaeocystis seemed to be a fairly conservative representative of the colder area ( 6 °C) may vary significantly between successive summers: from mostly Bacillariophyceae-dominated communities in 2015 to flagellate-dominated in 2016. Based on our results, we hypothesised that the more intense phototrophs development in the area, as deduced from higher remotely sensed chlorophyll a concentrations in 2016, i.e., record warm year in the observational period, could lead to faster depletion of nutrients, and thus, an earlier shift into the post-bloom community stage. Taking into account the possible phenological shift towards early summer domination of flagellates in a warmer year, as well as a higher number of heterotrophic protists associated with the warmer domain in two evaluated summers, it is highly likely that climatic warming of this region will have an impact on energy transfer to higher trophic levels. Although generalized patterns could be elucidated, more information is needed to predict and understand how the changing Arctic will alter protistan communities, and thus, higher-order consumers.

Variability of A Subterranean Prey-Predator Community in Space and Time

Subterranean habitats are characterized by buffered climatic conditions in comparison to contiguous surface environments and, in general, subterranean biological communities are considered to be relatively constant. However, although several studies have described the seasonal variation of subterranean communities, few analyzed their variability over successive years. The present research was conducted inside an artificial cave during seven successive summers, from 2013 to 2019. The parietal faunal community was sampled at regular intervals from outside to 21 m deep inside the cave. The community top predator is the cave salamander Speleomantes strinatii, while invertebrates, mainly adult flies, make up the rest of the faunal assemblage. Our findings indicate that the taxonomic composition and the spatial distribution of this community remained relatively constant over the seven-year study period, supporting previous findings. However, different environmental factors were shaping the distribution of predators and prey along the cave. Invertebrates were mainly affected by the illuminance, while salamanders were influenced by both illuminance and distance from the cave’s entrance. The inter-annual spatial distribution of the salamander population was highly repeatable and age specific, confirming a gradual shift towards the deeper parts of the cave with an increasing age. In general, the spatial distribution along the cave of this prey-predator system remained relatively constant during the seven-year study, suggesting that strong selective constraints were in action, even in this relatively recent subterranean ecosystem.

David Wingate.

David Wingate.

Finding your inner modeler: An NSF-sponsored workshop to introduce cell biologists to modeling/computational approaches.

In classical Cell Biology, fundamental cellular processes are revealed empirically, one experiment at a time. While this approach has been enormously fruitful, our understanding of cells is far from complete. In fact, the more we know, the more keenly we perceive our ignorance of the profoundly complex and dynamic molecular systems that underlie cell structure and function. Thus, it has become apparent to many cell biologists that experimentation alone is unlikely to yield major new paradigms, and that empiricism must be combined with theory and computational approaches to yield major new discoveries. To facilitate those discoveries, three workshops will convene annually for one day in three successive summers (2017-2019) to promote the use of computational modeling by cell biologists currently unconvinced of its utility or unsure how to apply it. The first of these workshops was held at the University of Illinois, Chicago in July 2017. Organized to facilitate interactions between traditional cell biologists and computational modelers, it provided a unique educational opportunity: a primer on how cell biologists with little or no relevant experience can incorporate computational modeling into their research. Here, we report on the workshop and describe how it addressed key issues that cell biologists face when considering modeling including: (1) Is my project appropriate for modeling? (2) What kind of data do I need to model my process? (3) How do I find a modeler to help me in integrating modeling approaches into my work? And, perhaps most importantly, (4) why should I bother?

Food Web Responses to Artificial Mixing in a Small Boreal Lake

In order to simulate food web responses of small boreal lakes to changes in thermal stratification due to global warming, a 4 year whole-lake manipulation experiment was performed. Within that time, period lake mixing was intensified artificially during two successive summers. Complementary data from a nearby lake of similar size and basic water chemistry were used as a reference. Phytoplankton biomass and chlorophyll a did not respond to the greater mixing depth but an increase was observed in the proportional abundance of diatoms, and the proportional abundance of cryptophytes also increased immediately after the onset of mixing. Obligate anoxic green sulphur bacteria vanished at the onset of mixing but gradually recovered after re-establishment of hypolimnetic anoxic conditions. No major effect on crustacean zooplankton was found, but their diversity increased in the metalimnion. During the mixing, the density of rotifers declined but protozoan density increased in the hypolimnion. Littoral benthic invertebrate density increased during the mixing due to Ephemeroptera, Asellus aquaticus and Chironomidae, whereas the density of Chaoborus larvae declined during mixing and lower densities were still recorded one year after the treatment. No structural changes in fish community were found although gillnet catches increased after the onset of the study. The early growth of perch (Perca fluviatilis) increased compared to the years before the mixing and in comparison to the reference lake, suggesting improved food availability in the experimental lake. Although several food web responses to the greater mixing depth were found, their persistence and ecological significance were strongly dependent on the extent of the disturbance. To better understand the impacts of wind stress on small lakes, long term whole-lake experiments are needed.

Microbial Community Structure and Interannual Change in the Last Epishelf Lake Ecosystem in the North Polar Region

Climate warming is proceeding rapidly in the polar regions, posing a threat to ice-dependent ecosystems. Among the most vulnerable are microbial-dominated epishelf lakes, in which surface ice-damming of an embayment causes a freshwater layer to overlie the sea, creating an interface between distinct habitats. We characterized the physicochemical and biotic environment of Milne Fiord epishelf lake (82° N, Canada) in three successive summers (2010–2012), and on one date of profiling (5 July 2011) we collected samples for high through-put amplicon sequencing of variable regions of small subunit rRNA to characterize the microbial community (Eukarya, Bacteria and Archaea). Potentially active water column communities were investigated using reverse-transcribed rRNA, and phytoplankton were further characterized by accessory pigment analysis. Cluster analysis of pigment data showed a demarcation between freshwater and marine communities, which was also evident in the sequence data. The halocline community of Eukarya was more similar to the deeper marine sample than to the freshwater surface community, while the Archaea and Bacteria communities at this interface clustered more with surface communities. In 2012, conductivity-depth profiles indicated shallowing of the freshwater layer and mixing across the halocline, accompanied by lower picocyanobacteria and higher picoeukaryote concentrations. Picocyanobacteria cells were more evenly distributed throughout the water column in 2012, implying partial deep mixing. Several mixotrophic taxa of Eukarya were more abundant in the freshwater layer, where low nutrient concentrations may favor this lifestyle. Unusual features of Milne Fiord microbial communities included benthic taxa not previously reported in marine water columns (notably, the archaeon Halobacteriales), and dominance by taxa that are typically present in sparse concentrations elsewhere; for example, the Chlorophyte group Radicarteria and the betaproteobacterium Rhodoferax. Milne Fiord epishelf lake is the last known lake of this kind remaining in the Arctic, and the fate of this distinct microbial ecosystem may ultimately depend on the stability of the Milne Fiord ice shelf, which has experienced a negative mass balance over the past half century.

Improvement of bait sprays for the control of Bactrocera oleae (Diptera: Tephritidae)

The control of the olive fruit fly Bactrocera oleae (Gmelin) is based on insecticides that are usually applied as bait sprays. Large-scale field experiments were conducted in the Kolymvari region of Crete (Greece) to evaluate the efficacy of several bait spray solutions against the fly that were applied at the recommended spraying volume per hectare (or 300 ml per treated tree), compared applications at volumes reduced by two and three fold (150 and 100 ml, respectively). The trophical attractant (hydrolysed protein at 75% w/w) that was used was mixed with alpha-cypermethrin, thiacloprid, thiacloprid + deltamethrin or dimethoate, and these formulations were tested during three successive summers (2012–2014) according to European Plant Protection Organisation (EPPO) standards. The products were alternated with one another over time in the experimental plots. The results indicated that all of the bait spraying solutions of the tested products were effective against B. oleae at all of the doses tested and resulted in significantly lower olive fly populations compared with the standard recommended dose, which was indicated by the fly catches in the nets of McPhail traps within the experimental plots. The percentages of live infestations of B. oleae were very low (<2%, except in 2013 due to a very low olive fruit yield), as was the number of applications each year, which was 6–7 and did not differ among treatments. The benefits of this concept in the management of the pest and potential future improvements of the method are discussed.

Residual attractiveness of various bait spray solutions to Bactrocera oleae

Effective insecticidal bait formulations ought to induce high levels of attraction and stimulate flies to ingest a lethal dose of the toxicant upon feeding or contact. The key to the effectiveness of such baits is the amount of time that the bait remains attractive to adult flies after spray application. Solutions of trophical attractants of Bactrocera oleae (two formulations of hydrolysed proteins at 55% and 75% w/w) mixed with various insecticides (alpha-cypermethrin, lambda-cyhalothrin and dimethoate) and a spinosad solution, applied either in McPhail traps or sprayed in olive foliage (except lambda-cyhalothrin), were tested for their attractiveness over time during two periods in successive summers. The results indicated that among all bait spraying solutions tested against B. oleae, the highest catches were recorded with both protein solutions of alpha-cypermethrin; its capture rate ranged from 7.6 to 10.5 olive fruit flies/trap/solution age (seven measurements were made when the trap solution was changed at 3, 7, 10, 14, 17, 20 and 24 days after its preparation). A three-day-old solution of any protein mixed with alpha-cypermethrin was significantly more attractive to olive fruit flies (at least three times) compared with the solutions at other ages, as indicated by the capture of flies in the McPhail traps. No differences were observed among solution ages for dimethoate solutions or spinosad solutions (less than 6 olive fruit flies/trap/week). When olive foliage was sprayed with the solutions under field conditions, they attracted approximately 0.3–1.5 adults per day for a 10-day period. The highest number of flies was recorded on both proteins combined with or without alpha-cypermethrin solution, as indicated by the catches on sticky transparent panels. Finally, changes in the pH values of the aforementioned solutions over time were associated with increased fly catches.

Phosphorus Removal from Lake Water Using Basic Oxygen Furnace Slag: System Performance and Characterization of Reaction Products

Effectiveness of basic oxygen furnace slag (BOFS) for removing dissolved phosphorus (P) was evaluated in a hypolimnetic withdrawal system. Lake water collected from the hypolimnion, with phosphate (PO4-P) concentrations of 0.25 to 0.49 mg/L, was passed through a pilot-scale (pore volume, ∼0.87 m3) treatment system over two successive summers. In year 1, the hydraulic retention time (HRT) varied from 0.58 to 1.64 days and 96.1–98.1% PO4-P was removed. The HRT in year 2 was 0.31 to 0.48 days and PO4-P removal was 97.4–99.9%. Effluent pH was 11.37±0.17 and 11.96±0.17 in years 1 and 2, respectively, with the increase attributed to dissolution of CaO and Ca(OH)2 from the BOFS. The effluent was neutralized by addition of CO2(g) before the water was discharged. Vanadium and aluminum were released from the BOFS, and were subsequently removed through addition of a filter containing 5 wt.% granular zero valent iron with a balance of silica sand and by neutralizing pH. Solid phase analyses conducted on the spent media, including FESEM-EDX, XPS, FTIR, and XANES spectroscopy, confirmed the presence of calcium carbonate and calcium phosphate minerals. Diminished hydraulic performance was observed in year 1, which was attributed to CaCO3 accumulation on the spent BOFS media. Restricting ingress of atmospheric CO2 into the system in year 2 minimized the extent of CaCO3 accumulation on the treatment media and led to improved hydraulic characteristics. Results show potential for long-term removal of phosphorus.

Comparative field studies of Bactrocera oleae baits in olive orchards in Crete

Protein-based food attractants are used in Bactrocera oleae (Gmelin) (Diptera: Tephritidae) management for monitoring populations, estimating the time of bait sprays and for Mass Trapping. McPhail traps loaded with two trophical attractant solutions (two formulations of hydrolysed proteins equal to 55% and 75% w/w) at 0.5, 1, 2, 4 and 8% concentrations were tested for their attractiveness, which was indicated by the captures of flies in McPhail traps during two periods in successive summers. The results indicated that lower concentrations than the 2% concentration recommended for both tested proteins (highest captures of 31.4 olive fruit flies/trap/week were recorded at 1% for protein equal to 55% and 28.5 at 0.5% for protein equal to 75%) were also attractive to olive fruit flies, whereas 8% was the least attractive concentration for both attractants (18.7 and 9.9 olive fruit fly/trap/week respectively). In addition, the 2% attractant concentration for both proteins was evaluated for attractiveness over time compared with ammonium sulphate; three-day-old solution of the protein equal to 75% was significantly more attractive to flies (at least twice) than 7-, 10-, 14-, 17-, 20- or 24-day-old solutions while the 7-day-old solution of the protein equal to 55% did not display differences compared with other solution ages. The attractiveness of ammonium sulphate weakened as time passed (below 5 olive fruit flies/trap/week). On the other hand, olive stems sprayed with the tested proteins under field conditions attracted approximately 0.6–1.0 adults per day, as indicated by captures in yellow sticky panels, with the highest number of flies recorded on the first day (0.9–1.4 adults). Finally, changes of pH values of these trophical attractants after dilution to the water are also reported.

Seasonal variation in the metratranscriptomes of a Thaumarchaeota population from SE USA coastal waters

We used a combination of metatranscriptomic analyses and quantitative PCR (qPCR) to study seasonal changes in Thaumarchaeota populations from a salt marsh-dominated estuary. Surface waters (0.5 m depth) were sampled quarterly at Marsh Landing, Sapelo Island, GA, USA over a 3-year period. We found a mid-summer peak in Thaumarchaeota abundance measured by qPCR of either 16S rRNA or amoA genes in each of the 3 years. Thaumarchaeota were 100-1000-fold more abundant during the peak than at other times of the year, whereas the abundance of ammonia- and nitrite-oxidizing Bacteria varied <10-fold over the same period. Analysis of the microdiversity of several highly transcribed genes in 20 metatranscriptomes from a 1-year subset of these samples showed that the transcriptionally active population consisted of 2 or 3 dominant phylotypes that differed between successive summers. This shift appeared to have begun during the preceding winter and spring. Transcripts from the same genes dominated the Thaumarchaeota mRNA pool throughout the year, with genes encoding proteins believed to be involved in nitrogen uptake and oxidation, and two hypothetical proteins being the most abundant transcripts in all libraries. Analysis of individual genes over the seasonal cycle suggested that transcription was tied more closely to variation in growth rates than to seasonal changes in environmental conditions. Day-night differences in the relative abundance of transcripts for ribosomal proteins suggested diurnal variation in Thaumarchaeota growth.

Greenhouse production of Impatiens wallerana using a controlled-release fertiliser produces quality finished plants with enhanced garden performance

SummaryThe use of controlled-release fertiliser (CRF) has been identified as a best-management practice because CRFs supply localised nutrients to the surrounding substrate over a period of time, and so can reduce the amount of nutrient that is leached from the pot. However, no information is available regarding the application of CRF during plant production, and how that can affect the subsequent garden performance of a crop. The objective of this research was to evaluate the effect of CRF, applied at the time of plug planting, on the finished quality and garden performance (post-production) of impatiens (Impatiens wallerana Hook. f. ‘Xtreme Scarlet’) plants. Plants were fertilised with a water-soluble 20:4.4:16.6 (w/w/w) N:P:K fertiliser (WSF), applied at each irrigation event at a rate of 150 mg l–1 N, or with a 16:3.9:10 (w/w/w) N:P:K CRF with either of two longevities (5 – 6 or 8 – 9 months) at a rate of 6.8 kg m–3. Impatiens plants were grown in a greenhouse and transplanted to the field, where no fertiliser was applied. Shoot dry weights (DW), flower numbers, leaf greenness, and consumer ratings were determined for plants grown over two successive Summers in Columbus, Ohio, USA. In Experiment I, plants grown with CRF had similar DWs to those grown with WSF during the greenhouse phase; however, in Experiment II, plants grown with CRF during the greenhouse phase had at least 52% more flowers than WSF-grown plants.At the end of the field phase, CRF-treated plants were less chlorotic, had 33 – 45% higher shoot DWs, produced 25% more flowers, and had 82% higher consumer ratings than plants grown with WSF. Growers can therefore use CRF to produce a high-quality impatiens crop, and can promote the use of CRF as a value-added practice that benefits consumers through enhanced garden performance.

A previously undescribed ostreid herpes virus 1 (OsHV-1) genotype detected in the pacific oyster, Crassostrea gigas, in Ireland

Significant mortalities of the Pacific oyster, Crassostrea gigas, have been reported worldwide since the 1950s. The impact these re-occurring mortality events have had on the C. gigas industry has highlighted the necessity to determine the factors that may be causing these mortalities. This study investigated the possible role of ostreid herpes virus (OsHV-1) in C. gigas mortalities over 2 successive summers at 2 study areas in Ireland. A single sample of adult C. gigas, which had been experiencing mortalities at one of the sites was screened. Successive cohorts of C. gigas spat obtained from a hatchery outside Ireland was relayed to both sites in 2003 and in 2004. Spat were screened each year prior to relaying. Samples were collected every 2 weeks and mortality counts were recorded and observed at both sites. Polymerase chain reaction (PCR) analysis and subsequent sequencing indicated that a previously undocumented variant genotype of OsHV-1 was present in the single cohort of adult C. gigas and in seed and juveniles at both sites, in both years. Analysis suggests that the Irish OsHV-1 μvar variant genotype is closely related to OsHV-1 μvar, first described in France in 2008.

Terrain of Memory: A Japanese Canadian Memorial Project (review)

Reviewed by: Terrain of Memory: A Japanese Canadian Memorial Project Glenn Deer (bio) Kirsten Emiko McAllister. Terrain of Memory: A Japanese Canadian Memorial Project. UBC Press. xiv, 296. $34.95 Terrain of Memory is a powerful contribution to cultural studies and memory work, specifically focusing on the Nikkei Internment Memorial Centre (NIMC) at New Denver, British Columbia, built in 1994. A sansei – third-generation Japanese Canadian – Kirsten Emiko McAllister has written an ethically grounded exploration of the Memorial Centre which honours the community and the elders of New Denver. As she demonstrates, the NIMC is ‘a public site of mourning and remembrance that contributes to the formation and reconfiguration of contemporary communities.’ McAllister reconstructs the conflicting investments that the community, the government, and the external contractors represented in the development of the Internment Memorial, the site of ‘a struggle over the interpretation of history’ that is captured in the euphemizing of the trauma of the ‘internment’ through the previously favoured government term, ‘the evacuation.’ McAllister has had a long history of participation in the Japanese Canadian community, beginning with her work for the Japanese Canadian Citizens Association in 1989. Inspired by human rights activism and by the settlement for redress negotiated by the National Association of Japanese Canadians, she has ‘defiantly argued against “the end of the community.”’ Fundamentally grounded in the pioneering work of the Asian Canadian activist scholarship of Roy Miki, Cassandra Kobayashi, Ann Sunahara, and Audrey Kobayashi, her new book conjoins the disciplinary critique of Michel Foucault, memory studies by Annette Kuhn, the hermeneutic meta-ethnography of Renato Rosaldo, and the discursive and temporal theorizing of Bakhtin. McAllister represents the cultural studies practitioner who organically evolves a disciplinary intervention, and she dramatically articulates the fraught self-fashioning of [End Page 702] the participant observer whose research process is as much the subject of study as is the New Denver community that forms the heart of the Memorial Centre. She provides a candid and illuminating narrative of the process of transforming her academic writing self, a radical revising of her disciplinary identity and research methodologies. Employing an approach that scrutinizes with exacting honesty her moments of crisis, blockages, and breakthroughs, McAllister unfolds a scholarly activist praxis that is ethical, inventive, inimitable, and suffused with dramatic emotional struggle. She is especially conscious of distinguishing her work from ‘positivist’ historians who ‘do not critically reflect on their own investments in producing knowledge that reifies the past as facts waiting to be discovered.’ We learn that she is so self-critical of her ‘sociological gaze’ that she has anxiously petrified herself at one stage of her research. It is the elders who rescue her from this anxious immobility by cheerily initiating interviews and encouraging her to ‘get going with your project!’ Oscillating between a sense of being an outsider in New Denver and profound moments of shared emotional connection with new friends, her two successive summers of fieldwork in 1995 and 1996 permit her to accumulate a wealth of interviews, field notes, maps, photographs, documents, and new social bonds. Another blockage occurs when she returns to Ottawa with boxes of research and then diverts the built-up emotional effects of her experience into intensive martial arts training. This ‘immersion in aikido was a way to work through traumatic post-memories,’ her means of ‘searching for a narrative form, a way of moving, a rhythm with the principal of mutual engagement that could bear, while transforming, what I had experienced.’ The second chapter, ‘Mapping the Spaces of Internment,’ provides a critical reading of the placement of the Nikkei Internment Memorial Centre. Crisply reproduced photographs supplement the visually evoked tour of the streets with accompanying descriptions of retail stores, grocers, and gas stations that provide contexts for the site of the memorial. Maps are read as organizers of social memory, as guides to the visible, but also as mechanisms that can ‘threaten to drain the site of potency, to reduce the site to easily consumable evidence for the tourist.’ The penultimate sixth chapter, ‘In Memory of Others,’ presents fascinating observations on the impact of the memorial on visitors, with selective elements from McAllister’s ethnographic field notes that are critically reframed with the...

Population dynamics of Salpa thompsoni near the Antarctic Peninsula: Growth rates and interannual variations in reproductive activity (1993–2009)

The salp Salpa thompsoni has exhibited increased abundance in high latitude portions of the Southern Ocean in recent decades and is now frequently the numerically dominant zooplankton taxon in the Antarctic Peninsula region. The abundance increase of this species in high latitude waters is believed related to ocean warming. Due to its continuous filter feeding and production of dense rapidly sinking fecal pellets S. thompsoni is considered to be an important link in the export of particulate carbon from the surface waters. Hence basic information on the life history of this component of the Antarctic marine ecosystem is essential for assessing its impact given continued climate warming. Here we cover various aspects of the life history of S. thompsoni collected in the north Antarctic Peninsula during annual austral summer surveys of the US Antarctic Marine Living Resources (AMLR) Program between 1993 and 2009. We focus on seasonal and interannual variations in the size composition and abundance of the aggregate (sexual) and solitary (asexual) stages. This information is valuable for refining components of Southern Ocean food web models that explicitly deal with size-structured and life history information on zooplankton. Intraseasonal changes in length–frequency distribution of both stages are used to estimate their growth rates. These average 0.40mmday−1 for aggregates and 0.23mmday−1 for solitaries; together these represent ∼7week and ∼7.5month generation times, respectively, and a 9month life cycle (i.e., onset of aggregate production year 1 to aggregate production year 2). Based on the maximum lengths typically found during January–March, the life spans of the aggregate and solitary stages can reach at least ∼5 and ∼15months, respectively. Length–frequency distributions each year reflect interannual differences in timing of the initiation and peak reproductive output. Interannual differences in the abundance of total salps and proportions of the overwintering solitary stage are significantly correlated with El Niño Southern Oscillation indices (SOI and Nino3.4) prevailing over the previous 2years. Massive salp blooms result from two successive summers of elevated solitary production following a reversal from La Niña to El Niño conditions. These results indicate the role of basin-scale atmospheric–oceanic processes in establishing optimal conditions that support aggregate and solitary stage reproduction, development and growth.

Tetracycline Resistance Genes Persist at Aquaculture Farms in the Absence of Selection Pressure

The prophylactic and therapeutic use of tetracyclines in aquaculture has been shown to contribute to the spread of tetracycline resistance in the environment. In this work, the prevalence of four different tetracycline-resistance genes, tetA, tetC, tetH, and tetM, in sediments from four aquaculture farms and their surroundings in the Baltic Sea was monitored by quantitative polymerase chain reaction (qPCR). The presence of three additional tetracycline-resistance genes (tetE, tetG, and tetW) was studied qualitatively by standard PCR, and the amount of bioavailable tetracyclines and total amounts of tetracycline and oxytetracycline in samples were also measured. None of the farms were using tetracycline at the time of the sampling and one of the farms had stopped all antibiotic use six years prior to the first sampling. Two of the farms were sampled over four successive summers and two were sampled once. Our results showed greater copy numbers of tetA, tetC, tetH, and tetM at the farms compared to pristine sites and demonstrated the presence of tetE, tetG, and tetW genes in the sediments under aquaculture farms at most sampling times. However, no resistance genes were found in samples collected 200 m from any of the farms. None of the samples contained therapeutically active concentrations of tetracyclines at any of the sampling times, suggesting that the increase in the prevalence of tetracycline resistance genes is caused by the persistence of these genes in the absence of selection pressure.

Effect of reduced summer indoor temperature on symptoms, perceived work environment and productivity in office work

The effects of reduced summer indoor temperature, through renovation of an HVAC system, on symptoms, perceived environment and productivity in an office building are investigated. Measurements of indoor parameters, perceived environment and productivity were conducted over two successive summers. Two floors of the office building were renovated during the wintertime. The renovation mainly consisted of cooling the supply air, installation of cooling ceilings in about half of the office rooms, and distributing supply air to all office rooms. An indoor air questionnaire assessing current symptom intensity, including questions on self-estimated work efficiency, was presented to employees on five days each summer. The measurements taken during the summer before the renovation showed that indoor temperatures rose above thermal comfort levels (maximum temperature 31.4°C). When the temperature rose above 25°C, neurobehavioural symptoms and the percentage of those dissatisfied with the indoor air quality increased, and self-estimated work efficiency decreased statistically significantly. After the renovation, thermal indoor comfort was achieved, and the percentage dissatisfied with the temperature and indoor air quality remained at a low level, i.e. 2–4 per cent. Objective productivity measurements conducted with a few employees performing solo work showed a 4.4 per cent improvement of work efficiency in the summertime.