Distribution and trophic links of gelatinous zooplankton on Dogger Bank,North Sea

The ecology of small, gelatinous zooplankton is not integrated into management of Dogger Bank (54° 00′ N, 3° 25′ E to 55° 35′ N, 2° 20′ E). In pursuit of this goal, gelatinous zooplankton and their potential prey were sampled along a transect across the bank on June 10–16, 2007. Eleven species of small medusae and ctenophores were collected, with six abundant taxa occurring in greater numbers below the thermocline and in the shallower, southeastern portion of the bank. There were no statistically significant diel changes in distribution. In contrast, potential prey were distributed more evenly across the bank and throughout the water column. Isotopic analyses revealed that gelatinous zooplankton fed on both smaller (100–300 μm) and larger (>300 μm) mesozooplankton, but also potentially on each other. These ecological insights suggest that small medusae and ctenophores should be integrated into sustainable management of Dogger Bank.     

Post-disaster agricultural transitions in Nepal

In Spring 2015, a series of earthquakes and aftershocks struck Nepal. The earthquakes caused significant changes in labor and land availability, cash income needs, and land quality. We examine how these post-earthquake impacts converged with ongoing agricultural shifts. Earthquake-related socio-economic and landscape changes specifically motivate the adoption of cardamom, Amomum subulatum, a high-value ecologically beneficial, and low labor commercial crop. We investigate reasons for the increased interest in cardamom post-earthquake, and challenges associated with it. We find that adopting cardamom serves as an important post-disaster adaptation. However, more broadly, unevenly distributed interventions coupled with the high capital costs of agricultural transition exacerbate social differentiation in communities after the disaster. Adoption is often limited to economically better off smallholder farmers. This paper extends previous research on disasters and smallholder farming by highlighting the specific potential of disasters to accelerate agricultural transitions and resulting inequality from the changes.     

Comparison of two fatal occupational injury surveillance systems in the United States

INTRODUCTION: Using different methods, two national systems compile fatal occupational injury data in the United States: the National Institute for Occupational Safety and Health (NIOSH) National Traumatic Occupational Fatalities (NTOF) surveillance system, and the Bureau of Labor Statistics (BLS) Census of Fatal Occupational Injuries (CFOI). The NTOF uses only death certificates, while CFOI uses multiple sources for case ascertainment. METHODS: Through overall and case-by-case comparisons, this study compares these systems and evaluates counts for the nation and by state for worker and case characteristics. RESULTS: From 1992 through 1994, NTOF reported an average of 84% of the number of traumatic occupational fatalities reported in CFOI. This percentage changed somewhat when a case-by-case comparison was conducted--88% of the NTOF cases were matched directly to the CFOI cases. Although CFOI captured a larger number of fatalities annually, the additional fatalities did not follow a discernable pattern. IMPACT ON INDUSTRY: By understanding the distribution of fatalities, targeted efforts to reduce them will benefit all industries.     

Effect of phosphate and ammonium levels on photosynthetic and respiratory responses of the red alga Gracilaria verrucosa

Gracilaria verrucosa (Hudson) Papenfuss exposed to nutrient enriched media (0.1 mM PO₄; 1.0 mM NH ₄ ⁺ ) by pulse feeding 2 h every third day for a period of 5 wk at 20°C and 25–30 salinity showed significantly higher rates of photosynthesis regardless of photon flux density correlated with increased pigment levels. Algae in nonenriched media showed significantly higher levels of soluble carbohydrates and decreased levels of phycoerythrin and chlorophyll a. Photosynthetic and respiratory responses to temperature 15°, 25°, 30°C and salinity (15, 25, 30 S) combinations indicate broad tolerances by both nutrient enriched and non-nutrient enriched algae. Photosynthetic and respiratory rates were highest at the high temperatures. Pulse-fed algae had significantly higher photosynthetic rates than non-nutrient enriched plants at all temperature and salinity combinations. Non-nutrient enriched algae had significantly higher respiratory rates than nutrient enriched algae at only 30°C and 15. The respiratory rates of both nutrient enriched and non-nutrient algae decreased under combinations of higher temperatures and salinities. G. verrucosa, grown without nutrients, has lower tolerances to environmental stresses.     

Enhancement of reproductive success through mate choice in a social rock-wallaby, Petrogale assimilis (Macropodidae) as revealed by microsatellite markers

The reason why a female who is socially paired to one particular male seeks extra-pair copulations (EPCs) with others has important implications in life history models and to the study of behaviour. The Allied rock-wallaby, Petrogale assimilis, lives in spatially isolated colonies in tropical north Queensland, Australia. Extensive observations of a colony at Black Rock showed that intense behavioural bonding occurs between pairs of adult males and females; about two-thirds of males paired with one female, the remainder paired with two females simultaneously. Single-locus microsatellite profiling determined the paternity of 63 offspring from 21 females for which long-term behavioural data were available. One-third of the young were fathered by males which were not paired socially with the mother. The mating system was heterogeneous: (1) all offspring of 11 females were fathered by the mother's partner, (2) all young of 5 females were fathered by extra-pair males, and (3) only some of the young of 5 females were fathered by their regular consort. Analysis of individual longitudinal demographic records showed that females whose young were always fathered by their consort had higher reproductive success than those whose young were always fathered as a result of (EPCs). However, females with some offspring fathered by their regular consort and others via EPCs had the highest probability of raising young to independence. These females were significantly more likely to have an offspring fathered as a result of an EPC if their previous young had failed to survive to pouch emergence. These results are consistent with the hypothesis that females choose mates for their genetic quality. Comparison of the males with which these females sought EPCs and the regular consorts suggested that arm length rather than body weight or testes size was used as the index of genetic quality. Results from a second colony of rock-wallabies in which the reproductive rate was accelerated were also consistent with the genetic-quality hypothesis. These results imply that by choosing better-quality fathers irrespective of social pairing, females are able to maximise their overall lifetime reproductive success, and presumably, those of their offspring. Received: 8 June 1997 / Accepted after revision: 28 February 1998