Life histories of the copepods Pseudocalanus minutus, P. acuspes (Calanoida) and Oithona similis (Cyclopoida) in the Arctic Kongsfjorden (Svalbard)

The year-round variation in abundance and stage-specific (vertical) distribution of Pseudocalanus minutus and Oithona similis was studied in the Arctic Kongsfjorden, Svalbard. Maxima of vertically integrated abundance were found in November with 111,297 ind m−2 for P. minutus and 704,633 ind m−2 for O. similis. Minimum abundances comprised 1,088 ind m−2 and 4,483 ind m−2 in June for P. minutus and O. similis, respectively. The congener P. acuspes only occurred in low numbers (15–213 ind m−2), and successful reproduction was debatable. Reproduction of P. minutus took place in May/June, and stage distribution revealed a 1-year life cycle with copepodids CIII, CIV, and CV as the overwintering stages. Oithona similis exhibited two main reproductive peaks in June and August/September, respectively. Moreover, it reproduced more or less continuously throughout the whole year with all stages occurring during the entire sampling period, suggesting two generations per year. Both species migrated towards greater depth in November, but O. similis preferred to stay longer in the upper 100 m as compared to Pseudocalanus. The reproduction of the two species in Kongsfjorden seemed to be linked to phytoplankton dynamics

Large deep-sea zooplankton biomass mirrors primary production in the global ocean

The biological pump transports organic carbon produced by photosynthesis to the meso- and bathypelagic zones, the latter removing carbon from exchanging with the atmosphere over centennial time scales. Organisms living in both zones are supported by a passive flux of particles, and carbon transported to the deep-sea through vertical zooplankton migrations. Here we report globally-coherent positive relationships between zooplankton biomass in the epi-, meso-, and bathypelagic layers and average net primary production (NPP). We do so based on a global assessment of available deep-sea zooplankton biomass data and large-scale estimates of average NPP. The relationships obtained imply that increased NPP leads to enhanced transference of organic carbon to the deep ocean. Estimated remineralization from respiration rates by deep-sea zooplankton requires a minimum supply of 0.44 Pg C y(-1) transported into the bathypelagic ocean, comparable to the passive carbon sequestration. We suggest that the global coupling between NPP and bathypelagic zooplankton biomass must be also supported by an active transport mechanism associated to vertical zooplankton migration

Weight-loss and exercise for communities with arthritis in North Carolina (we-can): design and rationale of a pragmatic, assessor-blinded, randomized controlled trial

Background: Recently, we determined that in a rigorously monitored environment an intensive diet-induced weight loss of 10% combined with exercise was significantly more effective at reducing pain in men and women with symptomatic knee osteoarthritis (OA) than either intervention alone. Compared to previous long-term weight loss and exercise trials of knee OA, our intensive diet-induced weight loss and exercise intervention was twice as effective at reducing pain intensity. Whether these results can be generalized to less intensively monitored cohorts is unknown. Thus, the policy relevant and clinically important question is: Can we adapt this successful solution to a pervasive public health problem in real-world clinical and community settings? This study aims to develop a systematic, practical, cost-effective diet-induced weight loss and exercise intervention implemented in community settings and to determine its effectiveness in reducing pain and improving other clinical outcomes in persons with knee OA. Methods/Design: This is a Phase III, pragmatic, assessor-blinded, randomized controlled trial. Participants will include 820 ambulatory, community-dwelling, overweight and obese (BMI ≥ 27 kg/m2) men and women aged ≥ 50 years who meet the American College of Rheumatology clinical criteria for knee OA. The primary aim is to determine whether a community-based 18-month diet-induced weight loss and exercise intervention based on social cognitive theory and implemented in three North Carolina counties with diverse residential (from urban to rural) and socioeconomic composition significantly decreases knee pain in overweight and obese adults with knee OA relative to a nutrition and health attention control group. Secondary aims will determine whether this intervention improves self-reported function, health-related quality of life, mobility, and is cost-effective. Discussion: Many physicians who treat people with knee OA have no practical means to implement weight loss and exercise treatments as recommended by numerous OA treatment guidelines. This study will establish the effectiveness of a community program that will serve as a blueprint and exemplar for clinicians and public health officials in urban and rural communities to implement a diet-induced weight loss and exercise program designed to reduce knee pain and improve other clinical outcomes in overweight and obese adults with knee OA