A short-term in situ CO2 enrichment experiment on Heron Island (GBR)

Ocean acidification poses multiple challenges for coral reefs on molecular to ecological scales, yet previous experimental studies of the impact of projected CO2 concentrations have mostly been done in aquarium systems with corals removed from their natural ecosystem and placed under artificial light and seawater conditions. The Coral–Proto Free Ocean Carbon Enrichment System (CP-FOCE) uses a network of sensors to monitor conditions within each flume and maintain experimental pH as an offset from environmental pH using feedback control on the injection of low pH seawater. Carbonate chemistry conditions maintained in the −0.06 and −0.22 pH offset treatments were significantly different than environmental conditions. The results from this short-term experiment suggest that the CP-FOCE is an important new experimental system to study in situ impacts of ocean acidification on coral reef ecosystems

Comparison of the pharmacokinetics of lamotrigine in patients with chronic renal failure and healthy volunteers

Aims. The aim of this study was to compare the pharmacokinetics of the antiepileptic agent, lamotrigine, in patients with chronic renal failure and healthy volunteers. Methods. Non-compartmental pharmacokinetics of a single oral dose (200 mg) of the anti-epileptic agent, lamotrigine, and its main metabolite, lamotrigine N-glucuronide, were determined for 10 patients with chronic renal failure of mean estimated creatinine clearance 18 ml min and a control group of 11 healthy volunteers, matched for age and gender. Results. For lamotrigine, there were no significant differences in C(max), t(max), AUC, t( 1/4 z), CL/F and amount excreted in urine although t( 1/4 z) tended to be longer for the renal failure group with a mean (± s.d.) of 35.9 ± 10.7 h vs 27.8 ± 4.3 h for the control group. For the renal failure group, V(Z)/F was 18% higher (95% Cl 1% to 39%) compared with controls and CL(R) was reduced to 61% (95% Cl 46% to 80%) of the control group value. For lamotrigine glucuronide, C(max) was increased 4-fold (95% Cl 3.1 to 5.3) and AUC 7.8-fold (95% Cl 6.0 to 10.1) in the renal failure group compared with controls. CL(R) was approximately 9-fold lower and apparent t( 1/4 ) was increased by 53% (95% Cl 27% to 84%). Concentrations of an N-methylated cardio-active metabolite, previously observed in dogs, were below the limit of detection (2 ng ml) of the ASTED/h.p.l.c. assay in the renal failure group as well as controls. Conclusions. These results indicate that impaired renal function will have little effect on the plasma concentrations of lamotrigine achieved for a given dosing regimen

Variable climatic conditions dominate recent phytoplankton dynamics in Chesapeake Bay

Variable climatic conditions strongly influence phytoplankton dynamics in estuaries globally. Our study area is Chesapeake Bay, a highly productive ecosystem providing natural resources, transportation, and recreation for nearly 16 million people inhabiting a 165,000-km(2) watershed. Since World War II, nutrient over-enrichment has led to multiple ecosystem impairments caused by increased phytoplankton biomass as chlorophyll-a (chl-a). Doubled nitrogen (N) loadings from 1945–1980 led to increased chl-a, reduced water clarity, and low dissolved oxygen (DO), while decreased N loadings from 1981–2012 suggest modest improvement. The recent 30+ years are characterized by high inter-annual variability of chl-a, coinciding with irregular dry and wet periods, complicating the detection of long-term trends. Here, we synthesize time-series data for historical and recent N loadings (TN, NO(2) + NO(3)), chl-a, floral composition, and net primary productivity (NPP) to distinguish secular changes caused by nutrient over-enrichment from spatio-temporal variability imposed by climatic conditions. Wet years showed higher chl-a, higher diatom abundance, and increased NPP, while dry years showed lower chl-a, lower diatom abundance, and decreased NPP. Our findings support a conceptual model wherein variable climatic conditions dominate recent phytoplankton dynamics against a backdrop of nutrient over-enrichment, emphasizing the need to separate these effects to gauge progress toward improving water quality in estuaries