ABSTRACT:

An ecological footprint accounting of the prototype ocean nutrient enhancer TAKUMI was performed to assess the sustainability of this type of artificial upwelling technology. The results indicate that the dominant component of the ecological footprint is CO2 emissions from the combustion of fuel to provide system power. The ecological footprint per unit biomass of fish production by TAKUMI was determined to be about 30% of the value associated with commercial chicken production. The analysis also suggests that renewable energy sources should be employed to operate the system in order to realize sustainable artificial upwelling.

INTRODUCTION

World population has increased rapidly following the industrial revolution, reaching 6.5 billion in 2006. Several forecasts estimate that this number will rise to about 8 billion in 2020. The statistical database (http://faostat.fao.org) of the Food and Agriculture Organization (FAO) of the United Nations (UN) reveals serious problems concerning global food supply meeting the needs of this growing population. 800 million people currently suffer hunger, and it is not unreasonable to expect worldwide food shortages in the future. For example, over the past 30 years, world cereal production has approximately doubled; however, since around 1996, production has remained essentially constant at about 2,100 Mt y-1. In the U.S., per capita cereal consumption stands at 800 kg-cereal y-1 per person. On the other hand, 10 billion people could be sustained at the African level of 200 kg-cereal y-1 per person, although this may negatively impact health and longevity; the average life expectancy in Africa is about 50 years, due in part to compromised nutrition. Growth in food production has been accomplished through tremendous use of fresh water, chemical fertilizer and fossil fuels. This, in turn, has resulted in depletion of water resources, expanding areas of infertile land, climate change, and so forth.

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