Nutrient Enrichment Drives Gulf of Mexico Hypoxia

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95312/1/eost16763.pd

Discrete bands of petroleum hydrocarbons and molecular organic markers identified within massive coral skeletons

The tissues of corals deposit an aragonite exoskeleton beneath their outer living film at a rate dependent on growth and hence on environmental conditions. This typically results in annual (seasonal) bands being formed within colonies. By analysing molecular organic markers within these bands, our research suggests that coral skeletons record contamination from oil and potentially could be used to investigate other anthropogenic and biogenic organic inputs. Our analyses of sections from within corals (Porites lutea) sampled from the Gulf coasts of Kuwait and Saudi Arabia demonstrate discrete bands of oil contamination which, using selected terpenoid biomarkers, can be source-indexed to specific oil fields (i.e. Kuwait, Iranian or Arabian crude oils). Together with dating using microscopic and X-ray inspection, this offers the potential to investigate contamination during recent years. Further research is, however, necessary to elucidate degradation mechanisms during, and following, the occlusion process of organics within coral skeletons

The application of calculation models for estimating primary productivity in two topical Mexican coastal lagoons

Se hizo un estudio detallado de la fijación de carbón radiactivo en dos lagunas costeras tropicales de la costa del Pacífico mexicano, con el propósito de estimar la tasa diurna de productividad primaria (∑p), Los datos así obtenidos fueron utilizados para evaluar y adaptar modelos de cálculo para la integración de las curvas de p/I (Productividad/Intensidad luminosa), Las integrales comúnmente empleadas en estudios oceanográficos requieren datos precisos de p en la región de baja iluminación y no contemplan los efectos de la fotoinhibición y, por lo tanto, no son aplicables al caso actual. Se desarrolló un modelo que solamente requiere conocimiento de la altura y posición del máximo sub superficial de p y que permite el cálculo preciso de ∑p.Data from detailed radiocarbon uptake studies of two turbid and highly productive Mexican tropical coastal lagoons with distinct ecological environments were used to evaluate and adapt calculation models for the integration of total daily 14C productivity (∑p). For such environments, the precision of the conventional methodology does not permit reliable estimates of Ik from the low light regions of p/I curves. Since the widely used "Talling integral" was thus not directly applicable, alternative solutions which only require knowledge of the position and height of the subsurface productivity maximum were evaluated. One of these models was found to predict ∑p to within 10% of planimetric measurements in all cases. Suggestions are given for practical application of this model and for its future development in association with the assimilation number concept

The effect of Holstein-Friesian genotype and feeding system on selected performance parameters of dairy cows on grass-based systems of milk production in Ireland.

End of Project ReportThe overall objective of this project was to assess, the effect of strain of Holstein-Friesian dairy cow, pasture-based feed system (FS) and their interaction on animal performance in terms of milk productivity and lactation profile, body weight (BW), body condition score (BCS), feed intake and energy balance (EB), reproductive performance and overall economic profitability