Matter In Coastal Waters Research Articles

Mapping the Distribution of Organic Matter in Coastal Areas of Banyuwangi Regency

The Banyuwangi Regency Coastal Area is experiencing an increase in shrimp aquaculture and industrial business activities, which have the potential to cause environmental impacts. It is important to map the distribution of organic matter in coastal waters to address this problem. The main objective of this research is to map the distribution of organic matter in the waters of Banyuwangi Regency. The research method used is a descriptive. The study employed surveys and direct observation as data collection methods, and spatial analysis as the data analysis method. The results showed the mapping of the distribution of organic matter on the coast of Banyuwangi Regency, with the findings of the organic matter content on the Banyuwangi Coast with the lowest value ranging from 2,528 mg/L-9.00 mg/L located in the BL 2, KB 3, BL 3, and BWI 2 areas. The medium distribution value with a value range of 10.724 mg/L-39.18 mg/L is found in the BWI 1, WS 2, WS 1, WS 3, BWI 1, KB 2, KB 1, MC 2 areas. And the highest organic matter distribution value with a value range of 44.24-53.088 mg/L in the KL 2, KL 1, KL 3, BL 1, MC 1 and MC 3 areas. From the distribution results, a mapping picture of the organic matter content in the Banyuwangi Regency Coast is produced.

High-frequency and tidal period observations of suspended particulate matter in coastal waters by AHI/Himawari-8.

Driven by tidal forcing and terrestrial inputs, suspended particulate matter (SPM) in shallow coastal waters usually shows high-frequency dynamics. Although specific geostationary satellite ocean color sensors such as the geostationary ocean color imager (GOCI) can observe SPM hourly eight times in a day from morning to afternoon, it cannot cover the whole semi-diurnal tidal period (∼12 h), and an hourly frequency may be insufficient to witness rapid changes in SPM in highly dynamic coastal waters. In this study, taking the Yangtze River Estuary as an example, we examined the ability of the geostationary meteorological satellite sensor AHI/Himawari-8 to monitor tidal period SPM dynamics with 10-min frequency. Results showed that the normalized water-leaving radiance (Lwn) retrieved by the AHI was consistent with the in-situ data from both cruise- and tower-based measurements. Specifically, AHI-retrieved Lwn was consistent with the in-situ cruise values, with mean relative errors (MREs) of 19.58%, 16.43%, 18.74%, and 26.64% for the 460, 510, 640, and 860 nm bands, respectively, and determination coefficients (R2) larger than 0.89. Both AHI-retrieved and tower-measured Lwn also showed good agreement, with R2 values larger than 0.75 and MERs of 14.38%, 12.42%, 18.16%, and 18.89% for 460, 510, 640, and 860 nm, respectively. Moreover, AHI-retrieved Lwn values were consistent with the GOCI hourly results in both magnitude and spatial distribution patterns, indicating that the AHI can monitor ocean color in coastal waters, despite not being a dedicated ocean color sensor. Compared to the 8 h of SPM observations by the GOCI, the AHI was able to monitor SPM dynamics for up to 12 h from early morning to late afternoon covering the whole semi-diurnal tidal period. In addition, the high-frequency 10-min monitoring by the AHI revealed the minute-level dynamics of SPM in the Yangtze River Estuary (with SPM variation amplitude found to double over 1 h), which were impossible to capture based on the hourly GOCI observations.

Satellite and In Situ Monitoring of Chl-a, Turbidity, and Total Suspended Matter in Coastal Waters: Experience of the Year 2017 along the French Coasts

The consistency of satellite and in situ time series of Chlorophyll-a (Chl-a), Turbidity and Total Suspended Matters (TSM) was investigated at 17 coastal stations throughout the year 2017. These stations covered different water types, from relatively clear waters in the Mediterranean Sea to moderately turbid regions in the Bay of Biscay and the southern bight of the North-Sea. Satellite retrievals were derived from MODIS/AQUA, VIIRS/NPP and OLCI-A/Sentinel-3 spectral reflectance. In situ data were obtained from the coastal phytoplankton networks SOMLIT (CNRS), REPHY (Ifremer) and associated networks. Satellite and in situ retrievals of the year 2017 were compared to the historical seasonal cycles and percentiles, 10 and 90, observed in situ. Regarding the sampling frequency in the Mediterranean Sea, a weekly in situ sampling allowed all major peaks in Chl-a caught from space to be recorded at sea, and, conversely, all in situ peaks were observed from space in a frequently cloud-free atmosphere. In waters of the Eastern English Channel, lower levels of Chl-a were observed, both in situ and from space, compared to the historical averages. However, despite a good overall agreement for low to moderate biomass, the satellite method, based on blue and green wavelengths, tends to provide elevated and variable Chl-a in a high biomass environment. Satellite-derived TSM and Turbidity were quite consistent with in situ measurements. Moreover, satellite retrievals of the water clarity parameters often showed a lower range of variability than their in situ counterparts did, being less scattered above and under the seasonal curves of percentiles 10 and 90.

Influence of Algal Production and Decomposition on the Carbon Isotope Signature of Labile Particulate Organic Matter on a Productive Continental Shelf Under the Stress of Coastal Hypoxia

To better understand the sources and recycling of labile organic matter in coastal water, we studied the carbon isotope signature of particulate organic carbon (POC) and particulate amino acids, a major group of labile organic compounds, on the shelf of the northern South China Sea. In addition, we were able to compare effects of hypoxia on labile organic matter at one station on the shelf. We found that carbon-weighted average d13C values of particulate amino acids (wAAd13C) were generally higher at more productive offshore stations than nearshore stations. This amino acid d13C distribution suggests that the labile fraction of organic matter in coastal water originated primarily from local primary production. In contrast, bulk POC d13C values showed little spatial variation on the NSCS shelf. The different patterns of wAAd13C and PO13C distributions indicate a combined effect of POM lability and physical processes on the isotopic distribution of organic materials on this productive shelf. Moreover, the amino acid d13C in coastal hypoxic water suggests local primary production as the most likely source of labile organic matter that drives hypoxia on the NSCS shelf. No clear difference was observed in particulate amino acid d13C distribution between hypoxic and oxic waters,

Use of Geospatial, Hydrologic, and Geochemical Modeling to Determine the Influence of Wetland-Derived Organic Matter in Coastal Waters in Response to Extreme Weather Events

Flooding from extreme weather events (EWE), such as hurricanes, exports large amounts of dissolved organic matter (DOM) to both estuaries and coastal waters globally. Hydrologic connectivity of wetlands to adjacent river channels during flood events is potentially a major control on the DOM exported to coastal waters after EWEs. In this study, a geographic information system based flood model was used to: 1) determine the volume of flooded wetlands in a river corridor following Hurricane Matthew in 2016; 2) compute the resulting volume fluxes of DOM to the Neuse River Estuary-Pamlico Sound (NRE-PS), in eastern North Carolina and 3) use the flood model to quantify the wetland contribution to DOM export. The flood model-derived contributions were validated with a Bayesian Monte Carlo mixing model combining measurements of DOM quality: specific UV Absorbance at 254 nm (SUVA254), spectral slope ratio (SR), and stable isotope ratios of dissolved organic carbon (13C-DOC). Results indicated that 1) hydrologic connectivity of the freshwater riparian wetlands caused the wetlands to become the primary source of organic matter (OM) that was exported into the NRE-PS after Matthew and 2) this source lingered in these coastal waters in the months after the storm. Thus, in consideration of the pulse-shunt concept, EWE such as Hurricane Matthew cause pulses of DOM from wetlands, which were the primary source of the OM shunted from the terrestrial environment to the estuary and sound. Wetlands constituted ca. 48% of the annual loading of DOC into the NRE and 16% of DOC loading into the PS. Results were consistent with prior studies in this system, and other coastal ecosystems, that attributed a high reactivity of DOM as the underlying reason for large CO2 releases following EWE. Adapting pulse-shunt concept to estuaries requires the addition of a “processing” step to account for the DOM to CO2 dynamics, thus a new pulse-shunt process is proposed to incorporate coastal waters. Our results suggest that with increasing frequency and intensity of EWE, strengthening of the lateral transfer of DOM from land to ocean will occur and has the potential to greatly impact coastal carbon cycling.

Use of Geospatial, Hydrologic, and Geochemical Modeling to Determine the Influence of Wetland-Derived Organic Matter in Coastal Waters in Response to Extreme Weather Events

Use of Geospatial, Hydrologic, and Geochemical Modeling to Determine the Influence of Wetland-Derived Organic Matter in Coastal Waters in Response to Extreme Weather Events

Investigating suspended particulate matter in coastal waters using the fractal theory

Suspended particulate matters (SPM) in coastal waters were investigated with an approach combining suspended particulate matter concentrations (SPMCs) measured by an optical backscatter sensor (OBS), particle size distributions measured by a laser in situ scattering transmissometer (LISST), and the fractal theory. The aim was to investigate whether changes in the fractal dimension indicate variations in the SPM composition. The method relies on the fractal theory that relates the floc excess density ∆ρ to the ratio between floc size Df and primary particle size Dp as follows: Δρ = (ρp – ρw)[Df/Dp]nf − 3. The best-fit fractal dimension nf was determined by matching the OBS-derived SPMC and the SPMC calculated from the LISST assuming fixed primary particle size and density. This method was applied to measurements from four tidal cycles characterized by different organic matter (OM) contents. Spurious data caused by schlieren were identified and discarded. The fractal dimension was relatively homogeneous over each tidal cycle except one where a strong apparent decrease in the fractal dimension was related to an important episode of sediment resuspension. This apparent decrease could result from the limit of the LISST to measure valid data when SPMC is high enough to induce multiple scattering and/or a change in the SPM population in suspension. Results showed also strong differences between the tidal cycles such as an increase of the fractal dimension with increasing OM content. Sensitivity analyses of fractal dimension and settling velocity were performed on major parameters: primary particle size and density, slope of the OBS calibration relationship, and optical model of inversion of the LISST. Results showed that the assumed primary particle size and the OBS calibration relationship significantly affect fractal dimension and settling velocity calculations.

Tracing Different Freshwater Sources for Nutrients and Dissolved Organic Matter in Coastal Waters off Jeju Island Using Radon

In order to determine the origins of dissolved inorganic nutrients and dissolved organic matter in coastal waters off Jeju Island, Korea, we measured the concentrations of 222Rn, nutrients, fluorescent dissolved organic matter (FDOM), and dissolved organic carbon in coastal waters during September 2016 and October 2017. The lower salinity waters occurring in the southern coastal waters off Jeju (SCW) were characterized by higher nutrients and humic-like FDOM, while those in the western coastal waters off Jeju (WCW) showed no trend. A significant negative correlation between salinity and 222Rn in the SCW (r2 = 0.62, n = 7 for 2016; r2 = 0.56, n = 14 for 2017) indicates that freshwaters occurring in the SCW originate from fresh groundwater. However, depleted 222Rn activities in the fresh surface waters of the WCW indicate that those in the WCW originate mainly from the remote Changjiang diluted water. In general, the coastal ecosystem in the SCW is characterized by the dominance of brown seaweeds, and the WCW is by scleractinian corals. Our results imply that high nutrient concentrations in the SCW provide favorable conditions for the growth of seaweeds, while relatively low nutrient concentrations and high FDOM concentrations in the WCW provide favorable conditions for survival of corals.

Приветственное слово от издателя Института океанологии им. П.П. Ширшова РАН

Dear Colleagues! In early 2017, the Directorate and the Academic Council of the P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences (IO RAS) made a decision to revive the «Journal of Oceanological Research», which was published in the Institute from 1959 to 1993. As a rule, all issues of the Journal contained results of comprehensive studies of the World Ocean performed in international projects. The first issues of the Journal were devoted to the results of the International Geophysical Year of 1957 – 1958, in the early 1970s they were devoted to the «Polygon-70» experiment, then to the studies of the Western boundary currents in the Atlantic Ocean, and since 1979 – to the results of the Soviet-American experiment «POLIMODE». Unfortunately, in 1993, the last 44 th issue marked the end of the Journal’s publication. In your hands you have the new 45 th issue of the «Journal of Oceanological Research», which was born thanks to the efforts of the Editorial board and the Editorial staff. In a short time they managed to revive the Journal in its continuity, to obtain all the necessary permits for the publication of the Journal in an electronic and hard copy, to create a web-site of the Journal (http://www.jor.ocean.ru/), and also to collect engaging materials for publication in a new issue. In the Journal you will find the results of investigations of the thermohaline structure and vortex dynamics of waters in various regions of the World Ocean, modeling of the processes of distribution of suspended matter in coastal waters, modeling of oil spills, application of technical means to study the marine environment, the bottom and underwater objects, other physical and biological processes and phenomena in the ocean. In the same issue you will find the section “Personalities” about outstanding oceanographers who left a visible mark in science and worked with us for many years. Among them are L.M. Brekhovskikh and K.N. Fedorov; this year, Grigory Isaakovich Barenblatt has celebrated his 90 th anniversary, and Walter Munk (USA) – his 100 th anniversary! Surprisingly, the paths of these people repeatedly crossed in life, as evidenced by the photographs in the Journal. I wish the « Journal of Oceanological Research » success, impressive materials, publication activity of contributors, a reach “portfolio”, high citation, and international recognition. The Directorate of the Institute will support the development of the Journal, since we consider this to be one of the priority tasks in the Development Strategy of the IO RAS. Dr. A.V. Sokov Interim Director P.P. Shirshov Institute of Oceanology

Temporal and Spatial Distribution Characteristics of Colored Dissolved Organic Matter in Coastal Waters of Jiangsu Province

Temporal and Spatial Distribution Characteristics of Colored Dissolved Organic Matter in Coastal Waters of Jiangsu Province

Aggregation of organic matter in coastal waters: A dilemma of using a Couette flocculator

Aggregation of organic matter (OM) plays an important role in regulating the efficiency of biological pump. We investigated the effect of OM aggregation on bulk and compound-specific composition of particulate and dissolved samples from the coast of Avery Point, Connecticut, USA. Samples were incubated in a Couette device for 6h in the dark at 8rpm, which generated a mean shear of 3.4s−1. The shear induced a net aggregation (1.69µM-C, equivalent to 7.2% of initial particulate organic carbon; POC) and an even larger gross aggregation (7.43µM-C, equivalent to 31.5% of initial POC) in 6h. However, in a blank test, we found that Couette devices released a significant amount of uncharacterized dissolved organic matter (DOM) within 6h of the experiment. Blank tests have not been part of previous studies, but released DOM has to be taken into account when evaluating experimental data employing Couette devices. The relative abundance (as % of organic C and N) of labile POC components (i.e. amino acids and neutral aldoses in this study) decreased significantly in the treatment. There was no compound-specific selective degradation of amino acids or neutral aldoses in the particulate phase. The decrease of labile organic components and the increase of uncharacterized OM in the particulate phase, indicating that aggregation processes accumulate uncharacterized OM and lead to a more refractory POC. Further, our data indicate that aggregation processes may accumulate the element not essential for microbial growth under the specific environmental conditions. In this study, we found particulate C accumulates when microbial growth is N-limited.

Bacterial influence on chromophoric dissolved organic matter in coastal waters of the northern South China Sea

Bacterial influence on chromophoric dissolved organic matter in coastal waters of the northern South China Sea

Corrigendum to “Photochemical production of formaldehyde, acetaldehyde and acetone from chromophoric dissolved organic matter in coastal waters” [J. Photochem. Photobiol. A Chem. 226 (1) (2011) 16–22

Corrigendum to “Photochemical production of formaldehyde, acetaldehyde and acetone from chromophoric dissolved organic matter in coastal waters” [J. Photochem. Photobiol. A Chem. 226 (1) (2011) 16–22

Differentiating the role of different-sized microorganisms in peptide decomposition during incubations using size-fractioned coastal seawater

Peptide decomposition by different-sized microorganisms was compared by incubating tetrapeptide alanine–valine–phenylalanine–alanine (AVFA), a fragment of RuBisCO, in coastal seawater after size-fraction by filtration. The size-fractioned seawater included <0.8-μm filtered (free-living bacteria), <5-μm filtered (free-living bacteria+heterotrophic nanoflagellates), <20-μm filtered (free-living and particle-attached bacteria+heterotrophic nanoflagellates+other small protists), and unfiltered whole water collected from Texas coast in the western Gulf of Mexico. Decomposition rates of AVFA in the <20-μm and unfiltered seawater were significantly higher than those in the <0.8-μm and <5-μm seawater in the December 2011 incubation. The higher decomposition rate in the large size fractions can be attributed to activities of particle-attached bacteria and/or large-size microorganisms, such as osmotrophic protists. However, the role of particle-attached bacteria in explaining this decomposition difference might be limited, as bacterial abundance and community structure did not differ much among the 4 treatments. Consistently, the June 2013 incubation indicated that AVFA decomposed most rapidly in the unfiltered seawater with >20-μm microorganisms. This study provides insights into the relative role of different-sized microorganisms in regulating the recycling of labile organic matter in coastal waters.

Salp bloom and vertical fluxes of organic matter in coastal water

Salp bloom and vertical fluxes of organic matter in coastal water

Characterization and variability of particle size distributions in Hudson Bay, Canada

AbstractParticle size distribution (PSD) plays a significant role in many aspects of aquatic ecosystems, including phytoplankton dynamics, sediment fluxes, and optical scattering from particulates. As of yet, little is known on the variability of particle size distribution in marine ecosystems. In this study, we investigated the PSD properties and variability in Hudson Bay based on measurements from a laser diffractometer (LISST‐100X Type‐B) in concert with biogeochemical parameters collected during summer 2010. Results show that most power‐law fitted PSD slopes ranged from 2.5 to 4.5, covering nearly the entire range observed for natural waters. Offshore waters showed a predominance of smaller particles while near the coast, the effect of riverine inputs on PSD were apparent. Particulate inorganic matter contributed more to total suspended matter in coastal waters leading to lower PSD slopes than offshore. The depth distribution of PSD slopes shows that larger particles were associated with the pycnocline. Below the pycnocline, smaller particles dominated the spectra. A comparison between a PSD slope‐based method to derive phytoplankton size class (PSC) and pigment‐based derived PSC showed the two methods agreed relatively well. This study provides valuable baseline information on particle size properties and phytoplankton composition estimates in a sub‐arctic environment subject to rapid environmental change.

Assessment of the colored dissolved organic matter in coastal waters from ocean color remote sensing.

Knowledge on absorption by colored dissolved organic matter, a(cdom), spatio-temporal variability in coastal areas is of fundamental importance in many field of researches related to biogeochemical cycles studies, coastal areas management, as well as land and water interactions in the coastal domain. A new method, based on the theoretical link between the vertical attenuation coefficient, K(d), and the absorption coefficient, has been developed to assess a(cdom). This method, confirmed from radiative transfer simulations and in situ measurements, and tested on an independent in situ data set (N = 126), allows a(cdom) to be assessed with a Mean Relative Absolute Difference, MRAD, of 33% over two order of magnitude (from 0.01 to 1.16 m(-1)). In the frame of ocean color observation, K(d) is not directly measured but estimated from the remote sensing reflectance, R(rs). Based on 109 satellite (SeaWiFS) and in situ coincident (i.e. match-up) data points a(cdom) is retrieved with a MRAD value of 37%. This simple model generally presents slightly better performances than recently developed empirical or semi-analytical algorithms.

Monitoring spatio-temporal variability of the Adour River turbid plume (Bay of Biscay, France) with MODIS 250-m imagery

Increased loads of land-based pollutants through river plumes are a major threat to the coastal water quality, ecosystems and sanitary heath. Identifying the coastal areas impacted by potentially polluted freshwaters is necessary to inform management policies and prevent degradation of the coastal environment. This study presents the first monitoring of the Adour River turbid plume (south-eastern Bay of Biscay, France) using multi-annual MODIS data. Satellite data are processed using a regional algorithm that allows quantifying and mapping suspended matter in coastal waters. The results are used to investigate the spatial and temporal variability of the Adour River turbid plume and to identify the risk of exposure of coastal ecosystems to the turbid plume waters. Changes in river plume orientation and spatial extent as well as suspended matter discharged through the river are correlated to the main hydro-climatic forcings acting in the south-eastern Bay of Biscay. The Adour River turbid plume is shown to be a highly reactive system mainly controlled by the river discharge rates and modulated by the wind changes. Despite the relatively small size of the Adour River, the Adour River turbid plume can have a non-negligible impact on the water quality of the southern Bay of Biscay and the MSM and associated contaminants/nutrients transported within the Adour turbid river plume have the potential to be disseminated far away along the northern shoreline or offshore. The main areas of influence of the river plume are defined over multi-annual (3 years) and seasonal periods. The results presented in this study show the potential of 250-m MODIS images to monitor small river plumes systems and support management and assessment of the water quality in the south-eastern Bay of Biscay.

Influence of microorganism content in suspended particles on the particle–water partitioning of mercury in semi-enclosed coastal waters

It is known that particle scavenging of mercury (Hg) can be affected by the abundance of particulate organic matter in coastal waters. However, the role of living organic particles in Hg scavenging is not yet completely understood. In this study, we hypothesized that an abundance of living organic particles (i.e., phytoplankton and bacteria) would influence the particle–water partitioning of Hg in coastal waters. Surface seawater samples were collected from eight stations in Gwangyang Bay, Korea, in three seasons (November 2009, April 2010, and October 2010) for the determination of concentrations of suspended particulate matter (including chlorophyll-a and bacteria), and Hg in unfiltered and filtered waters. We found that more Hg partitioned toward particulate matter when phytoplankton biomass, indicated from the chlorophyll-a concentration in a particle, was higher. In the low algal season, when [chlorophyll-a]<0.6μgL−1, the bacterial number, instead of chlorophyll-a concentration in particle, showed a positive correlation with the particle–water partition coefficient of Hg. Overall, microbial abundance seems to play a critical role in particle scavenging of Hg in coastal water. Taking this result in light of Hg in pristine coastal zones, we predict that increases in algal biomass amplify the potential for algae to transfer Hg to marine food chains.

Using geostationary satellite ocean color data to map the diurnal dynamics of suspended particulate matter in coastal waters

Total suspended particulate matter (TSM) in coastal waters is often characterized by high concentration and significant diurnal dynamics. Insufficient spatial and temporal resolution limits both cruise sampling and polar-orbiting satellite remote sensing in the mapping of TSM diurnal dynamics in coastal regions. However, the in-orbit operation of the world's first geostationary satellite ocean color sensor, GOCI, provides hourly observations of the covered area. In this study, we proposed a practical atmospheric correction algorithm for GOCI data in turbid waters. The validation results showed that the GOCI-retrieved normalized water-leaving radiances matched the in situ values well in both quantity and spectral shapes. We also developed a regional empirical TSM algorithm for GOCI data that is applicable in extremely turbid waters. Based on these atmospheric correction and regional TSM algorithms, we generated hourly TSM maps from GOCI Level-1B data. The diurnal variations derived by GOCI were a good match to the buoy data. The hourly GOCI observations revealed that various regions and tidal phases had different diurnal variation magnitudes, with a maximum of up to 5000mg/l in central Hangzhou Bay. Strong wind events, such as typhoons, can significantly increase TSM in the bay; however, both the GOCI observations and buoy measurements indicated that this increase was episodic, had a short duration, and returned to normal within a day after the passage of a typhoon. Our results suggest that GOCI can successfully map the diurnal dynamics of TSM in turbid coastal waters. Moreover, the significant diurnal dynamics revealed in the hourly GOCI observations implied that caution should be taken in mapping TSM in coastal waters using cruise sampling and conventional polar-orbiting satellite data, as the temporal resolution is insufficient for catching diurnal variations.