Hon-Kit Lui

National Sun Yat-sen University | NSYSU · Department of Oceanography

We show that, statistically, the simple linear regression (SLR)-determined rate of temporal change in seawater pH (βpH), the so-called acidification rate, can be expressed as a linear combination of a constant (the estimated rate of temporal change in pH) and SLR-determined rates of temporal changes in other variables (deviation largely due to vari...

This study is the first to present observed acidification rates at the shelf break of the East China Sea (ECS) and in the Okinawa Trough between 1982 and 2007. The use of apparent oxygen utilization (AOU) data to quantify the change in pH due to physical changes and changes in biological activities is demonstrated. The results thus obtained reveal...

Oceans worldwide are undergoing acidification due to the penetration of anthropogenic CO2 from the atmosphere ¹⁻⁴ . The rate of acidification generally diminishes with increasing depth. Yet, slowing down of the thermohaline circulation due to global warming could reduce the pH in the deep oceans, as more organic material would decompose with a long...

Since half a century ago, the number and area of dead zones (dissolved oxygen (DO) < 2 mg L −1 or 30% saturation) in the coastal oceans has increased dramatically. As widely recognized, the increased terrestrial nutrient and organic matter inputs are the two main factors causing the eutrophication of many coastal oceans. Here we show with decadal o...

Submarine groundwater discharge (SGD) is an important source of nutrients in many coastal regions, yet little information is available on its carbonate chemistry and controlling factors. This study examined the processes and factors controlling the hydrogeochemistry and acidic property of the groundwaters and SGD waters of two isolated coral island...

Dissolved oxygen (DO) and partial pressure of CO2 (pCO2) were measured at half-hourly intervals from June 29 to September 9, 2019, in a seagrass meadow in the Southeast Asia archipelagos region. The open water mass balance of the O2 approach was used to calculate metabolic rates (i.e., gross primary production (GPP), community respiration (CR), and...

Like other high-latitude seas, the subpolar Bering and Okhotsk Seas in the northernmost Pacific Ocean changed rapidly from 1998 to 2018. The sea surface temperature (SST) increased by 0.62 and 0.41 °C/decade, respectively, much higher than the global rate of 0.108 °C/decade from 2000 until 2015. Despite this rapid warming, the chlorophyll content d...

Foraminifera play an important role in the organic and inorganic carbon pumps of the ocean. Understanding their responses in seasonal and interannual time scales to the climate and seawater chemistry changes is important for studying carbon cycles and paleoclimatology. This study examined about 5.1-year continuous mass fluxes in 2013/9-2019/8 and 1...

Seven cruises were carried out in a bay scallop (Argopecten irradians) farming area and its surrounding waters, North Yellow Sea, from March to November 2017 to study the dynamics of the carbonate system and its controlling factors. Results indicated that the studied parameters were highly variability over a range of spatiotemporal scales, comprehe...

Small rivers are complex ecosystems facing threats from human activities and climate change. Therefore, studying the sediment and water chemistry of several streams in the East Sepik Province of Papua New Guinea will enhance our understanding of the characteristics of remote aquatic systems. We found high total organic carbon (OC) and vanillic acid...

The Taiwan Strait is a conduit between East China Sea (ECS) and South China Sea (SCS). Seasonal monsoon winds drive the southbound Zhejiang-Fujian Coastal Current and northbound SCS Warm Current through the strait. Water masses carried by these major current systems also carry fluvial signals from two major rivers, the Changjiang (Yangtze) River in...

Based on the International Convention for the Control and Management of Ships’ Ballast Water and Sediments (the Ballast Water Management Convention, or BWM Convention) of the International Maritime Organization, from 8 September 2017, all ships must have an approved Ballast Water Management Treatment System (BWTS) to prevent the invasion of alien s...

In situ field investigations coupled with laboratory incubations were employed to explore the surface sedimentary phosphorus (P) cycle in a mariculture area adjacent to the Yangma Island suffering from summer hypoxia in the North Yellow Sea. Five forms of P were fractionated, namely exchangeable P (Ex-P), iron-bound P (FeP), authigenic apatite (CaP...

The Kuroshio is the most significant current in the western North Pacific Ocean and affects a wide area. This work shows that the intrusion of the oligotrophic upper-layer West Philippine Sea seawater into the South China Sea (SCS) as the branch of Kuroshio reduced the productivity and hence the fluxes of sinking particles in the SCS between 2013 a...

The tropical/subtropical South China Sea (SCS) is the largest marginal sea in the world. Like other warm bodies of water, its sea surface temperature (SST) is rising, albeit more slowly (0.012 °C/yr between 1998 and 2016) than that of cold-water regions at high latitudes. The chlorophyll concentration increased at 0.0012 μg/L/yr during that period,...

When fine particulates such as those with a diameter of approximate 1 μm (particulate matter, PM1) are released from fossil fuel combustion into the air, they warm the atmosphere and contribute to millions of premature death in humans each year. Considerable quantities of PM1 eventually enter the oceans as suspended particulates, yet subsequent rem...

The 30-day ongoing double-hull 2,629 GRT research vessel, Legend, was launched by Taiwan Ocean Research Institute. The main targets of Legend are to deploy the work-class deep-sea remotely operated vehicle (the so-called ROV), collect long core marine sediment with 20-meter long piston coring system, and collect high quality bathymetric mapping dat...

Submarine groundwater discharge (SGD) is the submarine seepage of all fluids from coastal sediments into the overlying coastal seas. It has been well documented that the SGD may contribute a great deal of allochthonous nutrients to the coastlines. It is, however, less known how much carbon enters the ocean via the SGD. Nutrients (NO3, NO2, NH4, PO4...

The sequestration of anthropogenic carbon dioxide in the form of organic carbon and its eventual deposition in the sediments is an important component of the marine carbon cycle. In the Sulu Sea, Philippines, organic carbon contents in the sediments have been relatively well studied, but the processes that describe the organic carbon distributions...

The inter-annual variations in the sea surface temperatures (SSTs) of the tropical and subtropical Pacific Ocean have been widely investigated, largely due to their importance in achieving the sustainable development of marine ecosystems under a changing climate. The El Niño-Southern Oscillation (ENSO) is a widely recognized variability. In the sub...

Understanding the driving forces of absorption of anthropogenic CO2 by the oceans is critical for a sustainable ocean carbon cycle. Decadal sinking particle flux data collected at 1000 m, 2000 m, and 3500 m at the South East Asia Time Series Study (SEATS) Station (18° N, 116° E), which was located in the northern South China Sea (nSCS), show that t...

Seawater pH is frequently measured at 25°C (pH25), and can be converted thermodynamically to pH at the in situ temperature (T), (pHinsitu) using an additional carbonate chemistry parameter, which is the total alkalinity (TA), dissolved inorganic carbon (DIC), or the partial pressure of CO2 (pCO2) of seawater. Although rates of temporal change of pH...

The concentration and geochemical fractionation of six trace metals related with environmental quality assessment, namely Cd, Cr, Cu, Ni, Pb, and Zn, in 30 surface sediments from both inshore and offshore areas of the Taiwan Strait were measured to investigate their distribution characteristics, evaluate their potential mobility, and assess their p...

The Penghu Channel is the main channel connecting the East and South China Seas, two of the largest marginal seas in the world. Located in the southeast of Taiwan Strait, the Penghu Channel is usually covered by the high salinity water from the South China Sea and the Kuroshio. However, we observed abnormal low-salinity water in the Penghu Channel...

Riverine N and P fluxes have increased rapidly in recent decades, resulting in increased eutrophication of adjacent coasts. Since N fluxes have been rising faster than P fluxes, many rivers are P-limited. Therefore, upper estuaries are commonly P-limited whereas lower estuaries are frequently N-limited, implying that nutrient management strategies...

Simple general equations are used to show that when riverine water mixes with seawater, the N : P ratio is a nonlinear function of salinity. Thus, a shift in the limiting-nutrient status at a particular salinity along a continuum is a mathematical certainty, albeit complicated by biological consumption and remineralization. The salinity where the s...

The Pearl River (Zhujiang) ranks as the 13th or the 14th largest river in the world and is the 2nd largest in China in terms of annual water discharge. It is also the second largest river entering into the South China Sea. The three major tributaries, namely, the Xijiang (West River), the Beijiang (North River) and the Dongjiang (East River) are hi...