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Journal of Experimental Marine Biology and Ecology 249 2000 111–121
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Experimental examination of the effects of atmospheric wet deposition on primary production in the Yellow Sea
a , a
a,b
L. Zou , H.T. Chen , J. Zhang
a
College of Chemistry and Chemical Engineering , Ocean University of Qingdao, 5[ Yushan Road,
Qingdao , 266003, P.R. China
b
State Key Laboratory of Estuarine and Coastal Dynamics , East China Normal University,
3663[ Zhongshan North Road, Shanghai, 200062, P.R. China Received 11 February 1999; received in revised form 29 February 2000; accepted 2 March 2000
Abstract
The effects of atmospheric wet deposition on primary production in the coastal Yellow Sea were examined by in situ incubation experiments in August, 1997. Phytoplankton species flourished in
response to nutrient additions and chlorophyll-a Chl-a increased significantly when rainwater was added. Concentration of Chl-a increased 2.6 times with the addition of 10 v v rainwater.
In a coastal eutrophic region like Jiaozhou Bay, the impact of atmospheric wet deposition is negligible. However, the N P ratio ranged from 22:1 to 80:1, indicating P limitation of
photosynthesis in the Yellow Sea. During field observations, high N and low P rainwater was observed to be transported into the oligotrophic central Yellow Sea. Ammonium was used by
phytoplankton in preference to nitrate, and Fe stimulated nutrient uptake by phytoplankton. Rainwater increased the Chl-a growth more than a single nutrient owing to the abundance of both
plant and trace nutrients in the rainwater. A negative exponent relationship may exist between the impact of rainwater and total nutrient quality of the water in influencing phytoplankton growth.
2000 Elsevier Science B.V. All rights reserved.
Keywords : Rainwater; Chlorophyll a; Photosynthesis; Jiaozhou Bay; Yellow Sea
1. Introduction
The atmosphere is an important route for the transportation of nutrients into the marine environment, especially in those short of riverine, upwelling and oligotrophic
regions Menzel and Spaeth, 1962; Paerl, 1985, 1993; Duce, 1986; Loye-Pilot et al.,
Corresponding author. Tel.: 186-532-203-2005; fax: 186-532-296-3005. E-mail address
: zouliouqd.edu.cn L. Zou 0022-0981 00 – see front matter
2000 Elsevier Science B.V. All rights reserved.
P I I : S 0 0 2 2 - 0 9 8 1 0 0 0 0 1 8 6 - 6
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. Zou et al. J. Exp. Mar. Biol. Ecol. 249 2000 111 –121
1990. Studies in N-limited estuarine, coastal and oceanic waters show that the marine primary production is stimulated by N compounds of wet and dry forms from
atmospheric discharge Thayer, 1974; Pael et al., 1990, 1999; Willey and Cahoon, 1991; Willey and Paerl, 1993; Paerl and Fogel, 1994; Peierls and Paerl, 1997. Moreover,
rainfall produces a greater stimulation than either ammonium or nitrate when the amount of N is considered Pael et al., 1990; Paerl and Fogel, 1994. This may due to the other
elements in rainwater, which include P, Si, Al and Fe Martin et al., 1989; Duce and Tindale, 1991; Duce et al., 1991. Since Fe is a component of the enzymes responsible
for nitrate reduction to ammonium and N
fixation Stewart, 1974, the cooperation
2
between Fe and N in enhancing marine primary production has been affirmed Harrison et al., 1987; Martin et al., 1991; Ditullio et al., 1993; Pael et al., 1999.
The Yellow Sea is located in the northwestern Pacific Ocean, and has an oligotrophic character, which is somewhat similar to the central Pacific Ocean. Since input from
rivers and upwellings are small, atmospheric deposition plays an important role for nutrients. Previous studies indicate that 65 dissolved inorganic nitrogen DIN and
70 dissolved inorganic phosphorus DIP can be delivered to the surface of the Yellow Sea via the atmosphere Zhang and Liu, 1994. Rain-stimulated primary production is
considered as a category of ‘new production’ due to the nutrient input to the system by atmospheric deposition. It is estimated that nitrate in precipitation contributes about
4.3–9.2 of the nitrate requirement for the annual new production in the Yellow Sea. Three times higher production would be expected if dry nitrate deposition, and wet and
dry ammonium deposition are included Chung et al., 1998.
On an average, episodic deposition of nutrient elements accounts for only a small fraction of the concentration in seawater. However, individual rain events are directly
deposited on the sea surface and result in temporal eutrophication of surface waters. In this manner, chlorophyll a Chl-a and phytoplankton biomass in the surface water may
be greatly increased over short periods Owens et al., 1992; Mallin et al., 1993; Pearl, 1995, which may result in deleterious blooms Zhang, 1994; Paerl, 1997.
Very limited data are available in the literature on the relative production between phytoplankton and atmospheric deposition. However, in this study we provide data from
in situ observations on the effects of wet deposition on phytoplankton growth in the Yellow Sea during the summer, when stratification is dominant in the water column.
2. Materials and methods
