Red Tides In the Gulf of Mexico: Where, When, and Why?

Independent data from the Gulf of Mexico are used to develop and test the hypothesis that the same sequence of physical and ecological events each year allows the toxic dinoflagellate Karenia brevis to become dominant. A phosphorus-rich nutrient supply initiates phytoplankton succession, once deposition events of Saharan iron-rich dust allow Trichodesmium blooms to utilize ubiquitous dissolved nitrogen gas within otherwise nitrogen-poor sea water. They and the co-occurring K. brevis are positioned within the bottom Ekman layers, as a consequence of their similar diel vertical migration patterns on the middle shelf. Upon onshore upwelling of these near-bottom seed populations to CDOM-rich surface waters of coastal regions, light-inhibition of the small red tide of similar to 1 ug chl l(-1) of ichthytoxic K. brevis is alleviated. Thence, dead fish serve as a supplementary nutrient source, yielding large, self-shaded red tides of similar to 10 ug chl l(-1). The source of phosphorus is mainly of fossil origin off west Florida, where past nutrient additions from the eutrophied Lake Okeechobee had minimal impact. In contrast, the P-sources are of mainly anthropogenic origin off Texas, since both the nutrient loadings of Mississippi River and the spatial extent of the downstream red tides have increased over the last 100 years. During the past century and particularly within the last decade, previously cryptic Karenia spp. have caused toxic red tides in similar coastal habitats of other western boundary currents off Japan, China, New Zealand, Australia, and South Africa, downstream of the Gobi, Simpson, Great Western, and Kalahari Deserts, in a global response to both desertification and eutrophication

How much did you actually drink last night? An evaluation of standard drink labels as an aid to monitoring personal consumption

Background: Barriers exist for drinkers who wish to comply with low-risk guidelines when these are expressed in terms of numbers of “standard drinks” of alcohol. The increasing variability of container sizes and alcoholic strengths mean that percent alcohol by volume (%ABV) labels alone may be insufficient. Aims: To investigate whether standard drink (SD) labels would improve drinkers’ accuracy when estimating personal alcohol consumption. Setting: Private liquor stores near the University of Victoria, BC. Design: A 2 × 3 × 3 experimental design was employed with two labels (%ABV and SD), three beverages (beer, wine, and spirits) and three beverage strengths in balanced order. Subjects estimated the number of standard drinks that would be consumed in scenarios involving containers of their preferred beverages presented with different labels. Participants: A convenience sample of 301 liquor store patrons, aged 19 years and over. Measurements: Participants’ accuracy was determined by the relative and absolute percent errors in their estimations in comparison with correct answers. Results: Estimates were significantly more accurate with SD than %ABV labels in almost all the scenarios. Significantly more underestimation errors were made with %ABV labels. Mixed model regression analysis indicated younger respondents, beer drinkers and those with higher education made significantly fewer errors. Most (82.7%) supported SD labelling and believed SD labels would help them to comply with low-risk drinking guidelines (68.3%). Conclusions: The addition of clear SD labels helps consumers to make more accurate estimates of the SD content of their usual beverages than %ABV labels alone and would be more likely to help them comply with drinking guidelines