Nutrient Dynamics in Jiaozhou Bay

Abstract

Three cruises were carried out in Jiaozhou Bay (JZB) in the neap tide in October 2002 (fall) and in both neap and spring tides in May 2003 (spring) to understand the relative importance of external nutrient inputs versus physical transport and internal biogeochemical processes. Nutrients (NO À 3 , NO À 2 , NH þ 4 , PO 3À 4 , silicic acid, total dissolved nitrogen (TDN) and phosphorus (TDP), dissolved organic nitrogen (DON) and phosphorus (DOP)) were measured. The concentrations of nutrients were higher in the northern part than in the southern part. High concentrations of NH þ 4 and DON in JZB demonstrated the anthropogenic input. Ambient nutrient ratios indicated that the potential limiting nutrients for phytoplankton growth were silicon, and then phosphorus. Nutrients showed an obvious tidal effect with low values at flood tide and high values at ebb tide. Nutrient elements were transported into JZB in the north and output in the south (i.e., into the Yellow Sea), which varied with season, tidal cycle and investigation sites. Water exchange between JZB and the Yellow Sea exports NO À 3 , NH þ 4 and DON out of JZB, while it inputs PO 3À 4 , silicic acid and DOP into JZB. Nutrient budgets demonstrate that riverine input and wastewater discharge are major sources of nutrients, while residual flow is of minor importance in JZB ecosystem. JZB is a sink for the nutrient elements we studied except for DON. Stoichiometric calculations demonstrate that JZB is a net autotrophic system.

Nutrients Seasonal Variation and Budget in Jiaozhou Bay, China: A 3-Dimensional Physical–Biological Coupled Model Study

“…The foremost limiting element for phytoplankton growth is silicate, followed by phosphate, whereas nitrogen does not serve as limiting factor over the whole year. These findings are in agreement with observation analysis of the nutrients' structure (Shen 2001;Liu et al 2007). The phytoplankton growth in the JZB surface water is mainly limited by nutrients with significant spatiotemporal variability.…”

“…3d-f). The modeled nutrients horizontal distribution reveals the JZB eutrophication processes and confirms the deduction by Liu et al (2007) that nutrients are transported from land sources. The model output of zooplankton is in good agreement with observation data (Fig.…”

“…Several small seasonal rivers empty into the bay serving as canals of industrial and domestic water discharge along with economic innovation and increase of population. Among these rivers, Daguhe, Moshuihe, Licunhe, and Haibohe contribute over 90% nutrients supply from land sources (Liu et al 2007). Like many other coastal areas, JZB is under growing stress caused by human activities, especially excessive nutrients loads (Zhang 2007).…”

Reactive iron and its buffering capacity towards dissolved sulfide in sediments of Jiaozhou Bay, China

“…Nutrient dynamics and budget (Liu et al, 2005(Liu et al, , 2007Shen et al, 2006), phytoplankton biomass (Shen, 2001;Wu et al, 2005), and contaminant chemistry (Dai et al, 2007;Ye et al, 2011) have been studied. Studies on sulfide (including pyrite) in the bay have been reported only in selected estuarine (Pu et al, 2009), intertidal , and mariculture sediments (Huo et al, 2001).…”

Modeling of non-point source nitrogen pollution from 1979 to 2008 in Jiaodong Peninsula, China

“…As a result, nutrient over‐enrichment and serious environmental problems caused by increased point source and NPS pollution have been found in inland and coastal waters of Jiaodong Peninsula (Wei et al ., ), such as repeated red tide outbreaks offshore of Yantai city from 2004 to 2009 (Hao et al ., ). However, present studies in this region mainly put emphasis on estuary nutrient flux and its environmental impacts on a number of critical areas of coastal water for short time periods (Liu et al ., ; Zhang, ; Liu et al ., ; Han et al ., ). Long‐term characteristics of NPS pollution and its impacts on coastal water are scarcely talked about, which restricted our deep understanding of the land‐ocean interactions in coastal zone (LOICZ) and the effective implementation of the integrated coastal zone management (ICZM) in Jiaodong Peninsula.…”