Variation pattern of particulate organic carbon and nitrogen in oceans and inland waters

Abstract

We examined the relationship between, and variations in, particulate organic carbon (POC) and particulate organic nitrogen (PON) based on previously acquired ocean and inland water data. The latitudinal dependency of POCg PON is significant between 20 and 90N but weak in low-latitude areas and in the Southern Hemisphere. The mean values of POCgPON in the Southern Hemisphere and Northern Hemisphere were 7.40g3.83 and 7.80g3.92, respectively. High values of POCgPON appeared between 80-90 (12.2g7.5) and 70-80N (9.4g6.4), while relatively low POCgPON was found from 20 (6.6g2.8) to 40N (6.7g2.7). The latitudinal variation of POCgPON in the Northern Hemisphere is much stronger than in the Southern Hemisphere due to the influence of more terrestrial organic matter. Higher POC and PON could be expected in coastal waters. POCgPON growth ranged from 6.89g2.38 to 7.59g4.22 in the Northern Hemisphere, with an increasing rate of 0.0024gkm from the coastal to open ocean. Variations of POCgPON in lake water also showed a similar latitude-variation tendency of POCgPON with ocean water but were significantly regulated by the lakes' morphology, trophic state and climate. Small lakes and high-latitude lakes prefer relatively high POCgPON, and large lakes and low-latitude lakes tend to prefer low POCgPON. The coupling relationship between POC and PON in oceans is much stronger than in inland waters. Variations in POC, PON and POCgPON in inland waters should receive more attention due to the implications of these values for the global carbon and nitrogen cycles and the indeterminacy of the relationship between POC and PON.