Sources of macronutrients

The transfer of ocean properties into shelf waters is not straightforward. The observations discussed by Pingree etal. (1999) demonstrate the degree to 

The issue of atmospheric deposition as a transport mechanism for nutrients to coastal shelf seas is a relatively recent one. However, it has now emerged as being of great importance for the following reasons. Firstly, this method is very significant in a quantitative sense (Rendell etal., 1993 Asman etal., 1995). Secondly, the deposition of material frequently occurs some way out to sea (Jickells, 1995), where the impact of biological processes in the immediate coastal zone has already reduced nutrient concentrations to undetectable levels. Particular sources of nutrients include agricultural emissions from livestock and motor vehicle exhaust fumes. 

The flux of nutrients to coastal seas via groundwater discharge is a subject we know almost nothing about. 

In the last ten years, work has been done in the North Sea by a number of national and international projects. A key project was the UK Natural Environment Research Council s North Sea project (NSP). A unique feature of the NSP was that a consistent grid of stations was worked in the southern North Sea once a month for fifteen months (Howarth etal., 1993). From this, the winter standing stock of nitrate and silicate was calculated. The inputs to the system over an annual timescale were then calculated to determine whether they can account for this standing stock. 

In this budget, both estimates for dissolved inorganic nitrogen (DIN) and silicon fluxes are included. The silicon budget is included as a control. The processes involved in the silicon cycle are fewer than that of nitrogen, and so it might be expected that the budget can be closed more easily. The silicon cycle comprises essentially only river and ocean inputs, removal of dissolved silicon 

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General constituents and approximate energy values of common foods are given below. Apply Access to design a database such that the information can be retrieved according to sources of macronutrients for food types (e.g., protein sources or carbohydrate sources for cereal, fish, fruit, dairy, meat/poultry, vegetable). 

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