Reconstructing Environmental Changes of a Coastal Lagoon with Coral Reefs in Southeastern Hainan Island

Coastal lagoons with small catchment basins are highly sensitive to natural processes and anthropogenic activities. To figure out the environmental changes of a coastal lagoon and its contribution to carbon burial, two sediment cores were collected in Xincun Lagoon, southeastern Hainan Island and (210) ~Pb activities, grain size parameters, total organic carbon(TOC), total nitrogen(TN), total inorganic carbon(TIC) and stable carbon isotopes(δ^(13)C) were measured. The results show that in 1770–1815, the decreasing water exchange capacity with outer open water, probably caused by the shifting and narrowing of the tidal inlet, not only diminished the currents and fined the sediments in the lagoon, but also reduced the organic matter of marine sources. From 1815 to 1950, the sedimentary environment of Xincun Lagoon was frequently influenced by storm events. These extreme events resulted in the high fluctuation of sediment grain size and sorting, as well as the great variation in contributions of terrestrial(higher plants, soils) and marine sources(phytoplankton, algae, seagrass). The extremely high content of TIC, compared to TOC before 1950 could be attributed to the large-scale coverage of coral reefs. However, with the boost of seawater aquaculture activities after 1970, the health growth of coral species was severely threatened, and corresponding production and inorganic carbon burial flux reduced. The apparent enhanced inorganic carbon burial rate after 1990 might result from the concomitant carbonate debris produced by seawater aquaculture. This result is important for local government long-term coastal management and environmental planning.

Recent Trends of Zostera marina (Eelgrass) in a Highly Eutrophic Coastal Lagoon in the Mid-Atlantic Region (USA)

Spatial and temporal characteristics of Zostera marina (eelgrass) in the Barnegat Bay-Little Egg Harbor Estuary are compared before (2004-2011) and after (2012-2013) major fertilizer legislation (Fertilizer Law A2290) was enacted in New Jersey (USA) to reduce nutrient inputs from fertilizers to water bodies in the state. A significant decrease of Z. marina biomass and areal cover occurred in this eutrophic estuary between 2004 and 2011 concomitantly with increasing nitrogen and phosphorus loading from the watershed. The rate of decline in aboveground and belowground biomass was significantly sharper during 2004-2006 than during 2008-2010. In 2010, Z. marina biomass dropped to a very low level (mean aboveground biomass = 7.7 g dry wt mDŽ;mean belowground biomass = 27.0 g dry wt mDŽ), persisting through the last sampling period (October-November) in 2013. Biomass and areal cover of Z. marina decreased even further after Fertilizer Law A2290 was enacted in January 2012, with the lowest values recorded from August to November each year. These low values are the result of ongoing eutrophication of the system. More seagrass monitoring and research are necessary in future years to determine if the fertilizer law will have a positive effect on Z. marina condition in the estuary over the long term.

Changes in the Composition and Abundance of Phytoplankton in a Coastal Lagoon of Baja California,Mexico,during 2011

A time series with weekly sampling was conducted from February 20, to December 16, 2011 at a station in the interior of the San Quintín Bay to estimate seasonal changes in the composition and abundance of phytoplankton. Water temperature was recorded and the upwelling index was calculated for the period. Phytoplankton abundance was estimated and phytoplankton were identified by using an inverted microscope and the CHEMTAX program. There were 16 positive phytoplankton anomalies during the year, but only three were considered to be blooms. The blooms were dominated by diatoms and were recorded in the winter, spring and summer. Different genera composed 80% of the total phytoplankton abundance of each of the blooms. The first bloom consisted of diatoms of the genera Pseudo-nitzschia sp. (15.7%), Skeletonema sp. (14.6%), Eucampia sp. (7%), and Navicula sp. (7%);a haptophyte of the genus Imantonia sp. (13.1%);and dinoflagellates of the genus Prorocentrum sp. (4.6%). The second bloom consisted mainly of diatoms of the genera Guinardia sp. (30.6%), Pseudo-nitzschia sp. (21.5%), Skeletonema sp. (14.5%), Chaetoceros sp. (8.4%) and Eucampia sp. (5.3%). The third bloom consisted of Chaetoceros sp. (46.3%), Pseudo-nitzschia sp. (22.6%), Skeletonema sp. (7.29%), and Imantonia sp. (6%). Dinoflagellates were observed in the winter, summer and autumn, but they contributed less biomass than diatoms. Prorocentrum sp., Gymnodinium sp., and Ceratium sp. were among the dinoflagellates that were observed. The differences in abundance and composition of phytoplankton groups in the blooms in San Quintín Bay during 2011 were due primarily to seasonal changes in the physical and chemical factors of the seawater and to upwelling events.

Changes in the Abundance and Composition of Phytoplankton in a Coastal Lagoon during Neap-Spring Tide Conditions

The objective of this work was to estimate the changes in abundance and composition of phytoplankton in a coastal lagoon in Baja California, México during neap-spring tide conditions. Sampling was conducted from the 7th to the 16th of October 2004. Surface water was collected at 18 stations distributed across the bay during day time at high tide. Also, a time series was collected at a fixed station;surface water was collected every two hours from 8:00 to 18:00. High temperatures, low salinities and low nutrient concentrations at the oceanic end indicated weak or non upwelling conditions during this period. The phytoplankton community was characterized using an inverted microscope and the chemical taxonomy program CHEMTAX, based on pigment concentration estimated by high performance liquid chromatography (HPLC). The phytoplankton concentration was two times lower during this period than during periods of upwelling in the same year. Cryptophytes and diatoms were the most abundant groups estimated by CHEMTAX. Statistical analyses of the effect of tidal conditions on phytoplankton composition indicate that Zone A is strongly affected by tides, and that tidal effects are lessened at the inner zones. Differences in phytoplankton abundance between zones and between tidal conditions indicate that phytoplankton distribution is patchy in the lagoon.

The Bird Community in a Threatened Coastal Lagoon in Southeastern Brazil

We provide a list of bird species for Ribeira lagoon, a protected area in Rio de Janeiro, southeastern Brazil. Data were obtained in monthly surveys in points along a continuous transect, between August 2008 and July 2009, and 21 ad libitum observations. In total, 174 species were listed, including 121 land birds and 53 waterbirds. Of these, 11 are considered threatened at regional level. Waterbird richness was significantly higher in the dry season (April to September) than in the rainy season (October to March), whereas land bird richness remained constant. However, land bird richness varied throughout the year, with the highest value in February 2009 (77 species) and the lowest in May 2009 (41 species). The species listed account for 23% of the total of 745 bird species listed for Rio de Janeiro, and for 49% of 108 waterbirds recorded for the state.

Organophosphate Pesticides in Coastal Lagoon of the Gulf of Mexico

The worldwide use of semi-persistent organophosphate pesticides has become increasingly frequent and notorious. Their presence is registered in both continental and coastal waters;the latter ones are known for their subtly balanced environmental richness, difficult to recover once lost. These xenobiotics compounds reach the coastal zone through rivers that have crossed human settlements, as well as through peripheral run-off water used to exterminate agricultural pests. In Mexico, a developing country, the use of pesticides for several decades has not been adequately regulated, which is why various coastal ecosystems are the accumulation areas of these agrochemicals used in the continent. In the Gulf of Mexico, one of the coastal systems of high fishing importance for many years is the lagoon of Alvarado and receives the discharges of two great rivers, Blanco, Limón and Papaloapan, which travel more than 200 km from its source to the sea, crossing large extensions of farmland where there are also livestock activities and the use of these pesticides. For this reason, the objective of this work was to determine the presence of organophosphate pesticides in the Alvarado lagoon at the Gulf of Mexico as a potential aspect of high impact contamination. Five pesticides have been identified in the lagoon sediments, of which the most important and highest concentrations are Dimethoate and Chlorpyrifos, with 75.65 - 79.0 ng/g and 0.17 - 0.23 ng/g respectively, both internationally classified as moderately toxic. These concentrations were comparable to levels in other world regions with intense agricultural activity and vector control like the Mediterranean Sea and the lagoon of Alvarado was evidenced as a hot spot for the accumulation of these organophosphates with the high risk for the benthic organisms and for the human health when consuming these fishery products.

Pesticides in a temperate coastal lagoon in southwest Europe (Ria de Aveiro, Portugal) – Risk assessment and acute assays with Artemia and Daphnia

The Ria de Aveiro lagoon has been considered one of the most important Southern European long-term monitoring sites(LTER-site)concerning climate change and anthropogenic pollution.Nevertheless,studies concerning pesticide contamination herein are few and mostly outdated.Here,56 pesticides dissolved in the aqueous phase(DAP)and suspended particulate matter(SPM)were examined to fill the knowledge gap,considering the hydrophobic nature of most evaluated compounds.Water samples were taken seasonally from eight sites,and both DAP and SPM fractions were analysed by gas-chromatography-mass spectrometry.The annual average concentrations of fungicides,herbicides and insecticides were≈57 ng/L,≈409 ng/L and≈1058 ng/L in DAP and≈7μg/g,≈28μg/g and≈67μg/g in SPM.These pesticides and the excessive phosphate concentrations suggest that the lagoon's water quality may be hazardous to biota and humans.Invertebrates were identified as the most threatened trophic level using deterministic risk assessment,with chlorpyriphos and chlorfenvinphos being the primary culprits.Acute experiments with Artemia and Daphnia supported the suppositions.

The fate of antibiotic resistance genes in the coastal lagoon with multiple functional zones

Coastal lagoons provide many important services to human society,but their year-round use for aquaculture introduces large amounts of sewage.The contamination of antibiotic resistance genes(ARGs)is therefore of great concern.In this study,50 ARGs subtypes,two integrase genes(intl1,intl2),and 16S rRNA genes were detected by high-throughput quantitative PCR,and standard curves of all target genes were prepared for quantification.The occurrence and distribution of ARGs in a typical coastal lagoon(XinCun lagoon,China)were comprehensively explored.We detected 44 and 38 subtypes of ARGs in the water and sediment,respectively,and discuss the various factors influencing the fate of ARGs in the coastal lagoon.Macrolides-lincosamides-streptogramins B was the primary ARG type,and macB was the predominant subtype.Antibiotic efflux and antibiotic inactivation were the main ARG resistance mechanisms.The XinCun lagoon was divided into eight functional zones.The ARGs showed a distinct spatial distribution owing to the influence of microbial biomass and anthropogenic activity in different functional zones.Fishing rafts,abandoned fish ponds,the town sewage zone,and mangrove wetlands provided a large quantity of ARGs to the XinCun lagoon.Nutrients and heavy metals also significantly correlated with the fate of the ARGs,especially NO_(2)^(−)-N and Cu,which cannot be ignored.It is noteworthy that lagoon-barrier systems coupled with persistent pollutant inputs result in coastal lagoons acting as a“buffer pool”for ARGs,which can then accumulate and threaten the offshore environment.

Comparing the biogeochemical functioning of two arid subtropical coastal lagoons:the effect of wastewater discharges

Nutrient flux,net metabolism,and N2 fixation and denitrification processes were estimated and compared in two semi-arid subtropical coastal lagoons in the Gulf of California:El Soldado(ES),where no wastewater is discharged,and El Rancho(ER),where shrimp farm effluents are regularly discharged.Biogeochemical processes were evaluated with the LOICZ model.Flushing time was<2 days in both systems.Nutrient fluxes were higher in ER than in ES and both systems acted as nutrient sinks for most of the year.ER showed a larger nutrient flow rate in the summer and autumn due to the input of shrimp-farm effluents.Nitrogen fluxes increased in both ER and ES in the winter in response to the increased nutrient supply from coastal upwellings.ER and ES both showed autotrophic metabolism and N2 fixation in the spring,autumn,and winter,but heterotrophic metabolism and denitrification in the summer.Denitrification dominated in ER(−2.21 mmol m^(2)day^(−1))and values were higher than those estimated in ES(−0.45 mmol m^(2)day^(−1)).The comparative analysis between ES and ER evidenced the significant changes in its biogeochemical performance caused by the input of anthropogenic nutrients,and can orient the environmental management of coastal lagoons.

Estimating nutrient budgets in a coastal lagoon

To estimate nutrient budgets,water samples were collected at 16 sites in Tapong lagoon from January 2004 through April 2005 and the parameters of water quality were analyzed immediately after collection.These data were used to build a box model for calculating nutrient budgets of the lagoon.We estimated the net amount of nutrient fluxes into (coming from creeks) and out (from tidal inlet) of the lagoon and calculated the total amount of nutrient that deposits into the sediment in a full tidal cycle.During January and April,nutrients (including nitrate,nitrite and ammonia) accumulated in the lagoon,but phosphate,total phosphate and suspended solids were flushed out of the lagoon from the tidal inlet.In addition,a huge amount of suspended solids (13-15 tons per tidal cycle) flew from the lagoon to the adjacent ocean through the inlet-outlet channel.

The Influence of Land-Use on Water Quality in a Tropical Coastal Area: Case Study of the Keta Lagoon Complex, Ghana, West Africa

The Keta Lagoon and its catchment areas in Ghana are influenced by intensive agriculture and the use of agro-chemicals. It has therefore, become necessary to assess the quality of water in the lagoon and the surrounding fresh water aquifers. In this study, a water quality index (WQI), indicating the water quality has been adopted. The WQI was determined on a basis of various physico-chemical parameters like pH, conductivity, turbidity, dissolved oxygen, calcium, magnesium, chloride, nitrates, ammonium and sodium. The index was used both for tracking changes at one site over time, and for comparisons among sites. The WQI was also employed to wells used for irrigation on farms along the Keta Sand Spit as well as that of the Keta Lagoon Complex and its surrounding floodplains, in order to ascertain the quality of water for public and livestock consumption, irrigation, recreation and other purposes. The WQI of the wells, Keta lagoon and its floodplains showed various degrees of poor water quality and therefore considered unsuitable for drinking and recreation. By WHO standards, this calls for intensive physical and chemical treatment of the water for human consumption.

Structure of the Community of Dominant Fish Species Associated to Soft-Bottoms in the Lagoon of La Paz, B.C.S., México

The study of fish communities from coastal lagoons allows a better understanding of role of these organisms in these systems, and the effect of anthropogenic impact. The aim of the present study was to determine the community structure, in particular dominance of fish species associated to soft bottoms in the lagoon of La Paz. Six bimonthly samplings were carried out in seven localities from November 2016 to September 2017 and physicochemical parameters were recorded. Analysis of temperature showed differences between two marked seasons, warm and cold. Species richness showed differences between months and localities. Shannon-Weaver index and Pielou’s evenness showed significant differences only between months. Simpson’s index suggests a high diversity. According to the BVI, 15 species from the families Haemulidae, Sciaenidae and Gerreidae, were the most biologically important. Zoogeographic affinity analysis showed that 58% of the species prefer the Province of Cortez. Dominant species recorded in this study play a key role in soft-bottom systems like the lagoon of La Paz.

Functional Diversity of the Fish Community Associated to Soft-Bottoms in the Lagoon of La Paz B.C.S., México

There has been an increase of community studies that incorporate the use of functional diversity indices. The incorporation of these indices in the analysis of marine communities is recent, however, could contribute with relevant information about the health of those communities. The lagoon of La Paz is a body of water located in La Paz, B.C.S., México. Despite its regional importance, there are not recent studies about its fish communities. Therefore, the aim of the present study was to analyze the temporal and spatial structure of the functional diversity of fish communities associated to soft bottoms, from August 2016 to July 2017, as well as important environmental variables. Functional diversity indices showed significant differences between months. Spatial analysis did not show significant differences perhaps due to low variability of the type of substrate. Temperature showed temporal differences as well. Therefore, temperature may be a limiting environmental variable for many fish species inhabiting coastal lagoons.

A Biotic Index （∧） for Measuring the Ecological Quality of Mediterranean Lagoons

This study presents a biotic index （∧） for measuring environmental quality in the coastal lagoons of the Mediterranean. Index A considers combined anthropogenic （pollution） and natural factors （prohibitive salinity, anoxia, toxic blooms, isolation from sea, etc.） of deterioration. The method is based on the principle of indicator species and on the conceptual scheme developed by Frisoni et al. （1984） according to which there are six possible sub-assemblages （Zones） of benthic macrofauna, each indicating a different level of environmental quality. The procedure requires defining the relative extent of the Zones in the lagoon under study, and the number of species and the mean biomass of benthic macrofauna present in each. The three metrics are applied in the index formula and the resulting number from one to ten indicates increasing environmental quality. The authors have validated the index by applying it to two lagoons, Lesina and Varano （S.Adriatic, Italy）.

Dichloro-Diphenyl-Trichloroethane (DDT) and Endosulfan in Sediments of Sabancuy Lagoon, Campeche, Mexico

DDT and Endosulfan are persistent organic compounds which have been prohibited and their use has been limited in agricultural activities due to their toxicity, persistence and bioaccumulation potential. The use of DDT in fumigation campaigns against endemic diseases transmitted by vectors of malaria and dengue was prohibited in Carmen Island, Campeche, Mexico since 1995. In the surroundings of Sabancuy Lagoon, many and diverse agricultural activities are carried out and it is a common practice to use organ-chlorine pesticides as endosulfan. In order to know the levels of these compounds in this area, a sediment sampling campaign was carried out in ten sampling points randomly located within the Sabancuy Lagoon, Campeche and considering one reference sampling point located 2 km away from Sabancuy Lagoon within the Mexican Gulf. Three metabolites were identified in sediments samples belonging to DDT’s family: (4,4’-DDD;4,4’-DDE;4,4’- DDT) and Endosulfan’s family (Endosulfan I, Endosulfan II y Endosulfan sulfate). Higher concentrations in DDT’s family were found for 4,4’-DDD, followed by 4,4’-DDE and 4,4’-DDT. Endosulfan’s family, showed the following order for concentrations: Endosulfan II > Endosulfan I > Endosulfan sulfate. Mean concentration for S-DDT and S-Endosulfan in Sabancuy Lagoon sediments was twice higher than those found in other studies carried out in Términos Lagoon, Campeche, Mexico in 2002.

Geomorphology of the Boao coastal system and potential effects of human activities-Hainan Island,South China

The Boao coastal system along the eastern coast of Hainan Island is a dynamic delta-tidal inlet-barrier formed during the late Holocene. The delta developed inside a shallow lagoon barred by a sandy barrier with a narrow, shallow tidal inlet opening. Two major distributary channels separated by small islands characterize the delta. The lagoon is silting up receiving and trapping sediments from both the river and, in minor measure during storms, through the tidal inlet opening and barrier washovers. The barrier at the tidal inlet is highly dynamic and changes its form, accreting (migrating spit) against the inlet during fair-weather conditions and being eroded during storms and river floods. The delta has almost completely filled the lagoon and major concerns exist on the effect that ongoing large development plans may have on the environment. These concerns include the effect on floods and rate of siltation once banks of the islands have been stabilized and floodwater and sediment load are impeded from spreading over the lowlands, and the effect of increasing pollutant loads from the new facilities on the ecosystems of the increasingly restricting lagoon water and on the seashores.

Climate Change and Dynamics of the ITCZ on the Hydro-Climatic Regime of the Northern Ecosystems of the Gulf of Guinea: A Case of the Grand-Lahou Lagoon System

Atmospheric dynamics and climatology in West Africa are strongly dominated by the latitudinal migration of the ITCZ which imposes directly or indirectly determinism on coastal ecosystems. Thus, the Grand-Lahou lagoon system and its watershed are influenced by the ITCZ, whose seasonal study made it possible to understand its mode of action first on climatic factors, then hydroclimatic, and finally hydrological in the context of global changes. The study of these factors showed a differentiated impact of its migration on the hydrological regime defining a new configuration of the lagoon system and beyond;the coastal ecosystems of the northern coast of the Gulf of Guinea irrigated by numerous fluvial inputs. Salinity, a hydrological parameter of critical ecosystem importance, combined with transparency and depth, has enabled the spatio-temporal description of hydrology. To do this, a series of monthly measurements (in-situ) for spatial coverage of 25 stations was tested. Long before that, the climatic and hydroclimatic parameters were obtained respectively at SODEXAM, the meteorological site earth.nullschool.net and ONADE. This study brought together the dynamics of the ITCZ and the hydrological system of the lagoon.

Coastal geomorphic evolution at the Denglou Cape, the Leizhou Peninsula

The Denglou Cape, southwest of the Leizhou Peninsula, is the most typical tropical coast in the continent of China.The coastal geomorphic development basics of the geology and Quaternary environment change are discussed. Aerial photograph interpretation with fieldwork is applied to draw the outlines of geomorphic types. Based on the investigative data, the exogenic forces and marine organism conditions concerning tropical coast development in the area are expounded, and coastal dynamo-deposition geomorphic bodies are analysed, mainly with sea cliff-abrasion platform,barrier-lagoon system, modern beach, coral reef and mangrove tidal flat, and the general process of coastal evolution at this area, as well as coastline changes since middle Holocene transgression.

河北七里海外海岸沙丘群成因新探

七里海有中国第一大潟湖之称,多数学者认为七里海外的海岸沙丘群是在滨外沙坝的基础上发育形成的。研究认为,七里海外的海岸沙丘群是在末次冰期时期风成沙丘群的基础上演化形成的继承性沙丘综合体。七里海也不是科学意义上的潟湖,它没有形成海岸沙坝这一潟湖形成的过程,其前身是晚更新世末期由风暴活动形成的风蚀洼地。应加强七里海外海岸沙丘群的形成、发育类型及演化过程的研究,从多角度探究七里海外海岸沙丘群的演化机理和发育趋势。

我国海岸潟湖卫星遥感分类方法研究

参照Landsat-5TM和HJ-1CCD遥感影像,依据实地踏勘资料及解译经验,分析各种海岸潟湖地貌学成因和发育演变阶段,提出基于潟湖地貌学成因的遥感分类方法。并将我国海岸潟湖划分为滨外坝型、沙坝型、沙嘴型、湾顶坝型、连岛坝型和河口型共6种地貌类型。建立基于发育演变阶段的潟湖遥感分类标准,将海岸潟湖分为青壮年期、老年期和死亡期共3个发育演变过程;结合潟湖在影像中的特征,以近红外、红、绿波段组合后的假彩色影像为例,从色彩、纹理、地物邻接关系等方面建立不同潟湖类型的遥感解译标志;根据所建立的遥感解译标志,对山东省53个海岸潟湖进行遥感分类验证,结果吻合。