信息分化与数字鸿沟的比较分析

针对众多相关资料将数字鸿沟作为信息分化的代名词或者将二者交替使用这一现象,从基本概念作为切入点,阐述了它们各自的由来、含义,比较分析了它们的异同,最后指出了二者的密切关系.     

The Southern Ocean biogeochemical divide

Modelling studies have demonstrated that the nutrient and carbon cycles in the Southern Ocean play a central role in setting the air-sea balance of CO(2) and global biological production. Box model studies first pointed out that an increase in nutrient utilization in the high latitudes results in a strong decrease in the atmospheric carbon dioxide partial pressure (pCO2). This early research led to two important ideas: high latitude regions are more important in determining atmospheric pCO2 than low latitudes, despite their much smaller area, and nutrient utilization and atmospheric pCO2 are tightly linked. Subsequent general circulation model simulations show that the Southern Ocean is the most important high latitude region in controlling pre-industrial atmospheric CO(2) because it serves as a lid to a larger volume of the deep ocean. Other studies point out the crucial role of the Southern Ocean in the uptake and storage of anthropogenic carbon dioxide and in controlling global biological production. Here we probe the system to determine whether certain regions of the Southern Ocean are more critical than others for air-sea CO(2) balance and the biological export production, by increasing surface nutrient drawdown in an ocean general circulation model. We demonstrate that atmospheric CO(2) and global biological export production are controlled by different regions of the Southern Ocean. The air-sea balance of carbon dioxide is controlled mainly by the biological pump and circulation in the Antarctic deep-water formation region, whereas global export production is controlled mainly by the biological pump and circulation in the Subantarctic intermediate and mode water formation region. The existence of this biogeochemical divide separating the Antarctic from the Subantarctic suggests that it may be possible for climate change or human intervention to modify one of these without greatly altering the other.     

On the great plume debate

1、Introductory note Geological processes are ultimately consequences of Earth＇s thermal evolution. Plate tectonic theory, which explains geological phenomena along plate boundaries, elegantly illustrates this concept. For example, the origin of oceanic plates at ocean ridges, the movement and growth of these plates, and their ultimate consumption back into the Earth＇s deep interior through subduction zones provide an efficient mechanism to cool the earth＇s mantle, leading to large-scale mantle convection. Mantle plumes, which explain another set of global geological phenomena such as within-plate volcanism, cool the earth＇s deep interior （probably the Earth＇s core） and represent another mode of Earth＇s thermal convection. Plate tectonic theory and mantle plume hypothesis thus complement each other to explain much of the whole picture of Earth processes and phenomena.