Li-Qing Jiang - Academia.edu (original) (raw)

Papers by Li-Qing Jiang

Progress in Oceanography, 2016

Global Biogeochemical Cycles, 2015

Limnology and Oceanography, 2010

To assess the impact of ocean acidification on the carbonate chemistry of the shelf waters off th... more To assess the impact of ocean acidification on the carbonate chemistry of the shelf waters off the southeastern United States (South Atlantic Bight [SAB]), we measured carbonate mineral saturation states from January 2005 to May 2006. The findings reveal that aragonite (V arag : 2.6-4.0) and calcite (V cal : 4.1-6.0) saturation states were considerably higher than those recently reported along the West Coast of North America. Different water mass age between the Atlantic and Pacific Oceans during global ocean circulation is the primary reason for the higher carbonate mineral saturation states in the SAB than along the West Coast. The contrasting water temperatures in the two coasts contribute to such differences. Both upwelling and freshwater discharge also play important roles in controlling saturation state. Carbonate mineral saturation in the surface water of the West Coast is strongly controlled by the upwelling of high-salinity, low-temperature, low-oxygen, and low-pH deep water. In comparison, saturation states in the surface water of the SAB coast are rarely affected by upwelling. Instead, they are strongly influenced by the input of low-saturation-state water from rivers. Continued increases of atmospheric CO 2 under the Intergovernmental Panel on Climate Change B1 emission scenario will decrease the carbonate mineral saturation states by up to 40% by the end of this century, and aragonite will approach undersaturation near the coast.

Earth System Science Data Discussions, 2015

This paper defines the best practices for documenting ocean acidification (OA) data and presents ... more This paper defines the best practices for documenting ocean acidification (OA) data and presents a framework for an OA metadata template. Metadata is structured information that describes and locates an information resource. It is the key to ensuring that a data set will be accessible into the future. With the rapid expansion of studies on biological responses to OA, the lack of a common metadata template to document the resulting data poses a significant hindrance to effective OA data management efforts. In this paper, we present a metadata template that can be applied to a broad spectrum of OA studies, including those studying the biological responses to OA. The "variable metadata section", which includes the variable name, observation type, whether the variable is a manipulation condition or response variable, and the biological subject on which the variable is studied, forms the core of this metadata template. Additional metadata elements, such as investigators, temporal and spatial coverage, and data citation, are essential components to complete the template. We explain the structure of the template, and define many metadata elements that may be unfamiliar to researchers.

Limnology and Oceanography, 2012

Dissolved inorganic carbon (DIC), total alkalinity (TAlk), pH, and dissolved oxygen (DO) were det... more Dissolved inorganic carbon (DIC), total alkalinity (TAlk), pH, and dissolved oxygen (DO) were determined in the Mississippi River plume during five cruises conducted in the spring, summer, and fall. In contrast to many other large rivers, both DIC and TAlk were higher in river water than in seawater. Substantial losses of DIC, relative to TAlk, occurred within the plume, particularly at intermediate salinities. DIC removal was accompanied by high DO, high pH, and nutrient depletion, and was attributed to high phytoplankton production. As a result, the carbonate saturation in the plume became much higher than in ocean and river waters. A mixing model was used to determine DIC removal. We provide evidence that the use of a two-end-member (river and ocean) mixing model was valid during late summer and fall (low discharge period). However, for other periods we used salinity and TAlk to delineate a mixing model that included two river end members and an ocean end member. Net community production rates in the plume, estimated using a box model, peaked in the summer and were among the highest reported to date for large river plumes. In the summer and fall, biological production in the river plume consumed a majority of the available nutrients, whereas during the spring only a small fraction of the available nutrients were consumed in the plume. Biological production was the dominant process influencing pH and carbonate saturation state along the river-ocean gradient, whereas physicochemical dynamics of mixing played an important role in controlling the TAlk and DIC distributions of this large river plume.

Limnology and Oceanography, 2008

The partial pressure of carbon dioxide (pCO 2 ), concentration of total dissolved inorganic carbo... more The partial pressure of carbon dioxide (pCO 2 ), concentration of total dissolved inorganic carbon, and total alkalinity were measured at both high tide and low tide in the surface water of three Georgia estuaries from September 2002 to May 2004. Of the three estuaries, Sapelo and Doboy Sounds are marine-dominated estuaries, while Altamaha Sound is a river-dominated estuary. During all sampling months, the three estuaries were supersaturated in CO 2 with respect to the atmosphere (39.5-342.5 Pa, or 390-3380 matm) because of CO 2 inputs from within the estuarine zone (mainly intertidal marshes) and the river. Overall, pCO 2 in the river-dominated estuary is much higher than that in the marine-dominated estuaries. The calculated annual air-water CO 2 flux in Altamaha Sound (69.3 mmol m 22 d 21 ) is 2.4 times those of Sapelo and Doboy Sounds (28.7-29.4 mmol m 22 d 21 ). The higher CO 2 degassing in the river-dominated estuary is fueled largely by CO 2 loading from the river. Because of the substantial differences between river-and marine-dominated estuaries, current estimates of air-water CO 2 fluxes in global estuaries (which are based almost entirely on river-dominated estuaries) could be overestimated.

Journal of Geophysical Research, 2008

1] The partial pressure of carbon dioxide (pCO 2 ) in surface seawater on the South Atlantic Bigh... more 1] The partial pressure of carbon dioxide (pCO 2 ) in surface seawater on the South Atlantic Bight (SAB) of the United States was measured during six cruises from January 2005 to May 2006. The high-resolution pCO 2 data allow us to create the first maps of the sea surface pCO 2 over the SAB for all seasons. Contrary to an earlier study that was based on limited spatial and seasonal coverage, this study shows that the SAB is a net sink of atmospheric CO 2 on an annual basis (À0.48 ± 0.21 mol m À2 a À1 ). The inner shelf is a source of +1.20 ± 0.24 mol m À2 a À1 , while the middle and outer shelves are sinks of À1.23 ± 0.19 and À1.37 ± 0.21 mol m À2 a À1 , respectively. Seasonally, the SAB shifts from a sink for atmospheric CO 2 in winter to a source in summer. The annual cycle of sea surface temperature plays a dominant role in controlling the seasonal variation of the pCO 2 . Wind speeds are seasonally anti-correlated with the air-sea pCO 2 differences, and this is an important factor in contributing to the net annual air-sea CO 2 exchange. Factors related to the estimates of CO 2 fluxes in the coast ocean, such as the choice of wind speeds, the correction of gas transfer equations with nonlinearity coefficients, the effect of diel variations of pCO 2 , the spatial extrapolation of the pCO 2 to the nearshore area, and the seasonal interpolation are also discussed.

Journal of Geophysical Research, 2010

Continental Shelf Research, 2011

The southern Yellow Sea (SYS), located to the north of the East China Sea (ECS), was considered p... more The southern Yellow Sea (SYS), located to the north of the East China Sea (ECS), was considered part of the ECS when proposed the ''continental shelf pump'' (CSP) hypothesis. However, the original CSP carbon dioxide (CO 2 ) uptake flux (2.9 mol C m À 2 yr À 1 ) appears to have been overestimated, primarily due to the differences between the SYS and the ECS in terms of their CO 2 system. In this paper, we estimated air-sea CO 2 fluxes in the SYS using the surface water partial pressure of CO 2 (pCO 2 ) measured in winter, spring, and summer, as well as that estimated in fall via the relationship of pCO 2 with salinity, temperature, and chlorophyll a. The results indicate that overall, the entire investigated area was a net source of atmospheric CO 2 during summer, winter, and fall, whereas it was a net sink during spring. Spatially, the nearshore area was almost a permanent CO 2 source, while the central SYS shifted from being a CO 2 sink in spring to a source in the other seasons of the year. Overall, the SYS is a net source of atmospheric CO 2 on an annual scale, releasing $ 7.38 Tg C (1 Tg¼10 12 g) to the atmosphere annually. Thus, the updated CO 2 uptake flux in the combined SYS and ECS is reduced to $ 0.86 mol C m À 2 yr À 1 . If this value is extrapolated globally following , the global continental shelf would be a sink of $ 0.29 Pg C yr À 1 , instead of 1 Pg C yr À 1 (1 Pg¼ 10 15 g).

$Research paper thumbnail of The stoichiometry of inorganic carbon and nutrient removal in \newline the Mississippi River plume and adjacent continental shelf$

Biogeosciences, 2012

ABSTRACT The stoichiometry of dissolved inorganic carbon (DIC) and nutrients during biological up... more ABSTRACT The stoichiometry of dissolved inorganic carbon (DIC) and nutrients during biological uptake is widely assumed to follow the Redfield ratios (especially the C / N ratio) in large river plume ecosystems. However, this assumption has not been systematically examined and documented, because DIC and nutrients are rarely studied simultaneously in river plume areas and interpretation of ratios can be confounded by strong river–ocean mixing as well as intense biological activity. We examined stoichiometric ratios of DIC and nutrients (NO3-, PO43- and Si[OH]4) in the Mississippi River plume and adjacent continental shelf in June 2003 and August 2004 and calculated biological removal as the difference between observed concentrations and those predicted from conservative mixing, as determined from a multi-end-member mixing model and observed salinity and total alkalinity. Despite complex physical and biogeochemical influences, relationships between DIC and nutrients were strongly dependent on salinity range and geographic location, and influenced by biological removal. Lower C / Si and N / Si ratios in one nearshore area were likely due to localized input of high Si and low NO3- water from adjacent wetlands or preferential removal of nitrogen in the area. When net biological uptake was separated from river–ocean mixing and corrected for preferential N removal, the stoichiometric ratio of C / N / Si was similar to the Redfield ratio, thus supporting the applicability of the Redfield-type C / N / Si ratios in river-plume biogeochemical models.

Biogeochemistry, 2010

The South Atlantic Bight (SAB) has been a focus for the study of continental shelf ecosystem resp... more The South Atlantic Bight (SAB) has been a focus for the study of continental shelf ecosystem respiration during the past two decades. However, two questions concerning respiration in this area have yet to be answered. First, why do previous estimates of respiration in the SAB exceed measured carbon fixation rates by almost an order of magnitude? Second, considering that bacteria are responsible for most of the pelagic community respiration in the SAB, why is respiration almost uniform from the coastline to the shelf break, while bacterial production estimates decrease offshore? This study addresses these critical questions by presenting new pelagic community respiration data that were collected across the entire width of the continental shelf off Georgia, USA from June 2003 to May 2006. The respiration was calculated as in vitro changes of dissolved oxygen and dissolved inorganic carbon concentrations during deck incubations. The measured respiration rates ranged from 0.3(±0.1) to 21.2(±1.4) mmol m -3 day -1 . They followed a clear seasonal pattern, being lowest over the entire shelf in winter and reaching maxima in summer. Summertime respiration rates were highest on the inner shelf and decreased with distance offshore. Consistent with this trend, bacterial abundance measurements taken during the sampling month of July 2005 followed a pattern of seaward decline. The SAB organic carbon fluxes calculated from the respiration data are close to the estimates for primary production, which resolves a long-standing mystery regarding perceived carbon imbalance in the SAB.

The stoichiometric ratios of dissolved inorganic carbon (DIC) and nutrients during biological rem... more The stoichiometric ratios of dissolved inorganic carbon (DIC) and nutrients during biological removal have been widely assumed to follow the Redfield ratios (especially the C/N ratio) in large river plume ecosystems. However, this assumption has not been systematically examined and documented because DIC and nutrients are rarely studied 5 simultaneously in a river plume area, a region in which they can be affected by strong river-ocean mixing as well as intense biological activity. We examined stoichiometric ratios of DIC, total alkalinity (TA), and nutrients (NO 3 , PO 3− 4 and Si(OH) 4 ) data during biological removal in the Mississippi River plume and adjacent continental shelf in June 2003 and August 2004 with biological removals defined as the difference between 10 measured values and values predicted on the basis of conservative mixing determined using a multi-endmember mixing model. Despite complex physical and biogeochemical influences, relationships between DIC and nutrients were strongly dependent on salinity range and geographic location, and influenced by biological removal. Lower C/Si and N/Si ratios in one nearshore area were attributed to a potential silicate source 15 induced by water exchange with coastal salt marshes. When net biological uptake was separated from river-ocean mixing and the impact of marshes and bays excluded, stoichiometric ratios of C/N/Si were similar to the Redfield ratios, thus supporting the applicability of the Redfield-type C/N/Si ratios as a principle in river-plume biogeochemical models. 20

Journal of Marine Systems, 2016