Occurrences of harmful algal blooms (HABs) associated with ocean environments in the South China Sea

Harmful algal blooms (HABs) occur frequently in the South China Sea (SCS), causing enormous economic losses in aquaculture. We analyzed historical HAB records during the period from 1980 to 2003 in SCS. We found that HABs-affected areas have expanded and the frequency of HABs varied during this period. The seasonal and annual variations, as well as causative algal species of HABs are different among the four regions. Areas with frequent HABs include the Pearl River Estuary (China), the Manila Bay (the Philippines), the Masinloc Bay (the Philippines), and the western coast of Sabah (Malaysia). HABs occurred frequently during March–May in the northern region of SCS, May–July in the eastern region, July in the western region, and year-round in the southern region. Among the species that cause HABs, Noctiluca scintillans dominated in the northern region, and Pyrodinium bahamense in the southern and eastern regions. Causative species also varied in different years for the entire SCS. Both P. bahamense and N. scintillans were the dominant species during 1980–2003. Some species not previously recorded formed blooms during 1991–2003, including Phaeocystis globosa, Scrippsiella trochoidea, Heterosigma akashiwo, and Mesodinium rubrum. Variations in HABs are related to various regional conditions, such as a reversed monsoon wind in the entire SCS, river discharges in the northern area, upwelling in Vietnam coastal waters during southwest winds and near Malaysia coastal waters during northeast winds, and eutrophication from coastal aquaculture in the Pearl River estuary, Manila Bay, and Masinloc Bay. Handling editor: D. Hamilton     

Fourteen FITC-conjugated lectins as a tool for the recognition and differentiation of some harmful algae in Chinese coastal waters

In order to test the use of lectins as a tool for the differentiation of harmful algal species, 13 species and 23 strains of algae were tested with 14 fluorescein isothiocyanate (FITC)-conjugated lectins, and the results examined using flow cytometry (FCM), epifluorescence microscopy (EFM) and spectrofluorometry (SFM). The lectin probes SBA, WGA, GSL I, DBA and PHA-E could distinguish between morphologically similar Gymnodinium-like species, such as Karenia mikimotoi (GMDH01), Takayama pulchellum (TPXM01) and Gymnodinium sp. (GspXM01), by their different binding activities. With the precise quantitative measurements of binding obtained using SFM and FCM, lectins appeared to be useful in distinguishing different strains of the same species. The results also showed that PHA-E could differentiate Alexandrium tamarense (ATDH04) from other strains of this species, and SJA could distinguish A. tamarense (ATMJ02) from other strains of this species (including ATMJ01). Similarly, PNA could identify A. tamarense (ATDH01, 02, 03); UEA I could recognize A. tamarense (ATCI01-JN, ATCI01); and RCA120 could differentiate Alexandrium sp (AspGX01) from strain AspGX02, which was shown to produce different levels of paralytic shellfish poisoning toxin. Lectin probes could also bind these target cells in mixed algal samples. Positive cells identified by FCM were clearer than negative cells thus, in EFM, both GspXM01 and TPXM01 labeled with a WGA lectin probe could be distinguished from target cells of K. mikimotoi, Prorocentrum donghaiense and P. minimum (PMDH01, PMXM01) in mixed algal samples. FCM, EFM and SFM analysis could clearly distinguish lectin-probe-bound cells from negative cells in culture.     

A guide to the pronunciation of the scientific names for harmful algae

A historical review of scientific nomenclature and ofthe pronunciation of classical languages suggests thatthere is no objectively correct way to enunciate thetechnical terms applied to harmful algae. Any guideto pronunciation is always relative to some group ofspeakers; scientific nomenclature is an artificialconstruct without a population of normative speakers,living or dead, to whom the bewildered enunciator canhave reference. Thus a key to the pronunciation ofthe Latin and Greek scientific terms in alldisciplines, and a fortiori to the pronunciation ofthose terms applied to harmful algae, must be based onrules of common sense, mutual forbearance, and generalintelligibility. This article includes a guide topronouncing the names of harmful algae based on theseprinciples.     

Renewal time and the impact of harmful algal blooms on the extensive mussel raft culture of the Iberian coastal upwelling system (SW Europe)

The extension and intensity of the upwelling season in the NW Iberian Peninsula (42°N–43°N) have decreased by 30 and 45% over the last 40 years, respectively. Accordingly, the renewal time (τ) of the Rías Baixas, four large coastal inlets where 15% of the World extraction of blue mussels occurs, has increased by 240%. We indirectly demonstrate here that the growing τ has caused the increasing occurrence of harmful microalgae in these embayments, dramatically affecting mussel raft cultivation. The equation D = 365(1 − exp(−τ/c₁)) explains 80% of the variability of the number of days per year that mussels cannot be extracted from the hanging ropes because of the occurrence of harmful microalgae (D). The coefficient c₁ = 37 ± 2 days indicates that an average τ over the upwelling season of >25 ± 1 or 50 ± 3 days reduce mussel extraction to only 50 or 25% of the year, respectively.     

Impacts of harmful algae on seafarming in the Asia-Pacific areas

Seafarming to produce human food has recently intensified, particularly in the Asia-Pacific region. Disastrous impacts of harmful phytoplankton blooms, however, have been experienced during the past 20 years. In extreme cases, these render shellfish and finfish toxic or cause massive fish and shrimp kills. Problems from marine algae in the region include paralytic shellfish poisoning, diarrhetic shellfish poisoning, ciguatera, tetrodotoxin poisoning, fish kills and tainting of fish and shellfish. An analysis of 72 incidents since 1934 showed that 57% were fish and shrimp kills; almost all the remainder were PSP events. By mid-1994 there had been 3164 recorded cases of human poisoning and 148 reported deaths from these events in Asia-Pacific. Economic losses may exceed one million US dollars per event, while monitoring costs may be up to $50000 annually for each affected area. Research needs, management strategies and international cooperation are discussed. National action plan considerations include shellfish sanitation programs, public awareness and education, coastal engineering and classification of waters to protect public health.     

Spatial, seasonal and species variations of harmful algal blooms in the South Yellow Sea and East China Sea

The occurrences of harmful algal blooms (HABs), in terms of frequency and area in the Chinese coastal waters, have been increasing since 1980s and caused considerable economic losses. In the present study, we have analyzed spatial and seasonal characteristics of HAB events in the southern Yellow Sea and East China Sea along Chinese coast from 1933 to 2004. With a total 435 HAB records, the most frequent HAB occurrence area (FHA) is off the Yangtze River mouth and another two FHA areas are located south of the Yangtze River estuary along about isobaths of 30–60 m coastal water in the East China Sea. The time of HAB occurrence shifted during our study period: from autumn (August–October) before 1980s to July–August in 1980s, during May–July in 1990s, and May–June for the period of 2000–2004. Causative species were found to be different: Noctiluca scintillans and Skeletonema costatum were dominant causative species prior to 2000; and Prorocentrum donghaiense Lu was dominant from 2000 to 2004 and also caused large blooms in May. Trichodesmium sp. caused many HABs in autumn (August–October) prior to 1980s with only one HAB between 1980 and 2004. The changes of the dominant HAB species may have affected the timings of HAB occurrence, as well as the increasing HAB-affected areas in recent years.     

A Code of Conduct for Human and Regional Security Around the South China Sea

In the past decade, there have been calls for a regional code of conduct for the South China Sea to ensure peace and stability in a region replete with conflicting territorial claims over offshore geographical features. This paper will distinguish between the process of codification of rules and principles in one document, on the one hand, and the process of implementing existing rules and principles, on the other hand. It will be argued that rules and principles governing conduct for human and regional security around the South China Sea already exist in many forms and that the South China Sea states are obligated by international law to implement them without waiting for their consolidation in one document.     

Metal concentrations in Sargassum algae from coastal waters of Nha Trang Bay (South China Sea)

The concentrations of metals, viz., Fe, Mn, Cu, Zn, Cd, Pb, and Ni, were investigated in brown algae of the genus Sargassum collected in the coastal waters of Nha Trang Bay (South China Sea). Metal concentrations in algae growing in the zone of influence of the city of Nha Trang were higher than those in macrophytes collected to the south and north of the city. Similar levels of Cu and Fe concentrations were observed in macrophytes from the urbanized coastal areas of Nha Trang Bay and in algae from the Peter the Great Bay (Sea of Japan). This is suggestive of comparable metal inputs from the anthropogenic sources of the cities of Nha Trang and Vladivostok (Peter the Great Bay). However, the concentrations of Pb, Ni, and Cd in algae from the coastal waters of Nha Trang Bay were lower than in macrophytes from the inshore zone of Vladivostok. The high level of pollution of sea water with Zn compounds near Nha Trang was local. The metal levels in macrophytes from background areas reflect the geochemical features of the environment. Sargassum algae from Nha Trang Bay had lower concentrations of Zn, Cd, and Ni and higher concentrations of Mn than algae from Peter the Great Bay. The background concentrations of Cu, Pb, and Fe in macrophytes from both bays were virtually the same.     

Screening and preliminary characterization of hemagglutinins in Vietnamese marine algae

Extracts from 44 species of Vietnamese marine algae, including 15 Chlorophyta, 18 Rhodophyta and 11 Phaeophyta species, were examined for hemagglutination activity with a variety of different animal and human erythrocytes that were untreated or treated with enzymes. Almost all extracts showed activity toward at least one type of erythrocytes, although those from three Chlorophyta and two Rhodophyta species showed no hemagglutination with any type of erythrocytes examined. Strong activity was detected in extracts from two Chlorophyta (Anadyomene plicata and Avrainvillea erecta) and four Rhodophyta species (Gracilaria eucheumatoides, Gracilaria salicornia, Kappaphycus alvarezii, and Kappaphycus striatum) with enzyme-treated rabbit and sheep erythrocytes. The hemagglutinins of seven Chlorophyta and eight Rhodophyta species were examined for sugar-binding specificity, pH- and temperature-stability, and divalent cation-independency of hemagglutination using ammonium sulfate-precipitates prepared from their extracts. In a hemagglutination-inhibition test with various monosaccharides and glycoproteins, none of the hemagglutinins had affinity for monosaccharides, except the Codium arabicum and Gracilaria euchematoides hemagglutinins, whose activities were inhibited by both N-acetyl-d-galactosamine and N-acetyl-d-glucosamine. On the other hand, all of the hemagglutinins activities were inhibited by some glycoproteins. The inhibition profiles with glycoproteins were different depending on hemagglutinin species, and suggest the presence of lectins specific for high mannose N-glycans, complex N-glycans, or O-glycans. The activities of these algal hemagglutinins were stable over a wide range of pH and temperature, and independent of the presence of divalent cations. These results indicate that Vietnamese marine algae are a good source of novel and useful lectins.     

Cochlodinium polykrikoides blooms and eco-physical conditions in the South Sea of Korea

Eco-physical conditions for the initiation and termination of Cochlodinium polykrikoides blooms in the South Sea of Korea are examined in this paper. The C. polykrikoides blooms generally occur in the sea near Naro-Do in late August every year. The submarine canyon near Naro-Do plays an important role in surface water intrusion from the open ocean driven by northeasterly winds. In late August, the monsoonal wind system in Korea changes from southwesterly to northeasterly winds, causing Ekman transport of warm, fresh Changjiang Diluted Water (CDW) into the sea near Naro-Do and creating a front between inland sea water and CDW. Along the front, aggregation of single C. polykrikoides cells in the CDW and downwelling yield favorable eco-physical conditions for development of C. polykrikoides blooms. When typhoons and strong northeasterly winds bring vertically well-mixed East China Sea water into the sea near Naro-Do again in September, the eco-physical conditions favor diatom growth and lead to the termination of C. polykrikoides blooms.     

Effects of natural and field-simulated blooms of the dinoflagellate Prorocentrum minimum upon hemocytes of eastern oysters, Crassostrea virginica, from two different populations

Oysters, Crassostrea virginica, from two populations, one from a coastal pond experiencing repeated dinoflagellate blooms (native), and the other from another site where blooms have not been observed (non-native), were analyzed for cellular immune system profiles before and during natural and simulated (by adding cultured algae to natural plankton) blooms of the dinoflagellate Prorocentrum minimum. Significant differences in hemocytes between the two oyster populations, before and after the blooms, were found with ANOVA, principal components analysis (PCA) and ANOVA applied to PCA components. Stress associated with blooms of P. minimum included an increase in hemocyte number, especially granulocytes and small granulocytes, and an increase in phagocytosis associated with a decrease in aggregation and mortality of the hemocytes, as compared with oysters in pre-bloom analyses. Non-native oysters constitutively had a hemocyte profile more similar to that induced by P. minimum than that of native oysters, but this profile did not impart increased resistance. The effect of P. minimum on respiratory burst was different according to the origin of the oysters, with the dinoflagellate causing a 35% increase in the respiratory burst of the native oysters but having no effect on that of the non-native oysters. Increased respiratory burst in hemocytes of native oysters exposed to P. minimum in both simulated and natural blooms may represent an adaptation to annual blooms whereby surviving native oysters protect themselves against tissue damage from ingested P. minimum.     

Morphological observations on some fleshy crustose algae of the Island of Gorgona (Tuscan Archipelago)

Abstract

Morphological and ecological observations on four fleshy crustose algae collected in the eulittoral and upper sublittoral zone of the Island of Gorgona: Myrionema liechtenstenii Hauck, Hildenbrandia canariensis B?rgesen, Peyssonnelia armorica (P. et H. Crouan) Weber-van Bosse in B?rgesen and Cruoria cruoriaeformis (P. et H. Crouan) Denizot are reported. For each species, information on some aspects of their ecology, geographical distribution and notes on their vegetative and reproductive morphology are given.     

Coastal States in the South China Sea and Submissions on the Outer Limits of the Continental Shelf

The purpose of this article is to examine the outer continental shelf submissions made by the coastal states of the South China Sea and their potential impact on legal and political developments in the South China Sea. In accordance with the United Nations Convention on the Law of the Sea of 1982 and the guidelines of the Commission on the Limits of the Continental Shelf, coastal states are to establish the outer limits of their continental shelf where it extends beyond 200 nautical miles. Meeting this obligation is complicated in enclosed or semienclosed seas where there are maritime disputes such as in the South China Sea.     

Use of the FlowCAM for semi-automated recognition and enumeration of red tide cells (Karenia brevis) in natural plankton samples

Early detection is the most effective way to mitigate the effects of harmful algal blooms (HAB). Cell counts based on examination of microplankton samples using settling chambers and visual inspection with an inverted microscope are tedious and time consuming, and counting precision is generally poor at low cell densities. The FlowCAM is a continuous imaging flow cytometer designed to characterize particles in the microplankton size range (20–200 μm diameter). In this study we examined the ability of the FlowCAM to improve routine monitoring protocols for HAB species by automatically recording information on size and fluorescence per cell. This will eliminate the need to examine cells outside the ranges of these measurements for our target species, Karenia brevis. We also tested the ability of image comparison software to match images of cells in mixed assemblages to images of the target species. For simple mixtures of cultured dinoflagellates, the ability of the image matching software to discriminate target cells varied greatly depending on how similar the two species were in size and shape. When target cells were added to natural plankton samples, the image recognition software correctly identified 80–90% of the target cells, but misidentified 20–50% of non-target cells in the size range of the target species. We conclude that the FlowCAM is less tedious and time-consuming than microscopy, allowing for examination of more cells for greater counting precision. The cell recognition software helps reduce the numbers of cells that must be screened, but images must still be examined by a trained operator to identify the HAB species of interest.     

A model for the prediction of Oncomelania hupensis in the lake and marshland regions, China

A model has been developed for predicting the density of Oncomelania hupensis, the intermediate host snail of Schistosoma japonicum. The model takes into account different environmental factors, including elevation, air and soil temperature, type of vegetation, mean height of preponderant vegetation and soil humidity. Deviance and Akaike information criteria were used to determine the best model fits. Model diagnostics and internal and external validations of model efficiency were also performed. From the final prediction model, two important results emerge. First, air temperature should be used with care to study the distribution of O. hupensis and to predict its potential survival because the impact is indirect, and it is weaker and more unstable than soil temperature. Second, the more important environmental factor for O. hupensis prediction at the microscale is soil humidity, but the more important macroscale environmental factor is soil temperature. This finding might help in selecting different environmental features for studying O. hupensis at different spatial scales. Our model is promising for predicting the density of O. hupensis, and hence can provide more objective information about snail dispersal, which might eventually replace the tedious and imprecise field work for annual surveillance of O. hupensis.     

Using quantitative real-time PCR to study competition and community dynamics among Delaware Inland Bays harmful algae in field and laboratory studies

The Delaware Inland Bays (DIB) have experienced harmful algal blooms of dinoflagellates and raphidophytes in recent years. We used quantitative polymerase chain reaction (QPCR) techniques to investigate the community dynamics of three DIB dinoflagellates (Karlodinium veneficum, Gyrodinium instriatum, and Prorocentrum minimum) and one raphidophyte (Heterosigma akashiwo) at a single site in the DIB (IR-32) in summer 2006 relative to salinity, temperature and nutrient concentrations. We also carried out complementary laboratory culture studies. New primers and probes were developed and validated for the 18S rRNA genes in the three dinoflagellates. K. veneficum, H. akashiwo, and G. instriatum were present in almost all samples throughout the summer of 2006. In contrast, P. minimum was undetectable in late June through September, when temperatures ranged from 20 to 30 °C (average 25.7 °C). Dissolved nutrients ranged from 0.1 to 2.8 μM PO₄³⁻ (median = 0.3 μM), 0.7–30.2 μM NO_x (median = 12.9 μM), and 0–19.4 μM NH₄⁺ (median = 0.7 μM). Dissolved N:P ratios covered a wide range from 2.6 to 177, with a median of 40. There was considerable variability in occurrence of the four species versus nutrients, but in general P. minimum and H. akashiwo were most abundant at higher (>40) N:P ratios and dissolved nitrogen concentrations, while K. veneficum and G. instriatum were most abundant at low dissolved N:P ratios (<20) and dissolved nitrogen concentrations < 10 μM. The semi-continuous laboratory competition experiment used mixed cultures of K. veneficum, P. minimum, and H. akashiwo grown at dissolved N:P ratios of 5, 16, and 25. At an N:P of 16 and 25 P. minimum was the dominant alga at the end of the experiment, even at a temperature that was much higher than that at which this alga was found to bloom in the field (27 °C). P. minimum and H. akashiwo had highest densities in the N:P of 25. K. veneficum grew equally well at all three N:P ratios, and was co-dominant at times at an N:P of 5. H. akashiwo had the lowest densities of the three algae in the laboratory experiment. Laboratory and field results showed both interesting similarities and significant differences in the influences of important environmental factors on competition between these harmful algal species, suggesting the need for more work to fully understand HAB dynamics in the DIB.     

Vietnam and the Code of Conduct for the South China Sea

This article portrays and characterizes the Vietnamese position toward the settlement of the island disputes in the South China Sea. The situation in the South China Sea has become more complicated since 1988 when China made its steps toward the Spratlys. After analyzing the situation in the South China Sea, the author emphasizes the need to have a code of conduct for this disputed area.     

A mechanism for offshore initiation of harmful algal blooms in the coastal Gulf of Maine

A combination of observations and model results suggest a mechanismby which coastal blooms of the toxic dinoflagellate Alexandriumfundyense can be initiated from dormant cysts located in offshoresediments. The mechanism arises from the joint effects of organismbehavior and the wind-driven response of a surface-trapped plumeof fresh water originating from riverine sources. During upwelling-favorablewinds, the plume thins vertically and extends offshore; downwellingwinds thicken the plume and confine it to the nearshore region.In the western Gulf of Maine, the offshore extent of the riverplume during upwelling conditions is sufficient to entrain upward-swimmingA. fundyense cells germinated from offshore cyst beds. Subsequentdownwelling conditions then transport those populations towardsthe coast.     

China's Nine Dotted Lines in the South China Sea: The 2011 Exchange of Diplomatic Notes Between the Philippines and China

Important events relating to the sovereignty dispute over the Spratly Islands have arisen by fits and starts since 2009, marking the start of a new phase in the legal battle over territorial and maritime claims in the South China Sea. While the exchange of legal arguments between the parties has gradually laid bare their maritime claims, much still remains shrouded in uncertainty. Among the obscure claims wanting clarification is China's infamous nine-dotted-line map, which in 2011 elicited a response and counterresponse between the Philippines and China. This article examines the maritime and territorial claims of the Philippines and China as revealed in the recent discord over the nine-dotted-line map.     

The presence of the potentially toxic genera Ostreopsis and Coolia (Dinophyceae) in the North Aegean Sea, Greece

The examination of macrophyte, water and sediment samples, collected at depths less than 1.5 m from 50 different sites along the North Aegean coasts, has revealed, for the first time in Greek coastal waters, the presence of two Ostreopsis species (O. ovata and O. cf. siamensis) and Coolia monotis in the majority of the sampling sites (94% and 100%, respectively). Other epiphytic dinoflagellates of the genera Prorocentrum and Amphidinium and diatoms were accompanying species in this epiphytic community. Morphometric features, plate formula and thecal ornamentation were used for species identification. O. ovata cells were smaller in dorsoventral (DV) diameter and width (W) (26.18–61.88 μm and 13.09–47.60 μm, respectively) in comparison with O. cf. siamensis (35.70–65.45 μm and 23.80–49.98 μm, respectively). In contrast, the anterioposterior (AP) diameter of O. cf. siamensis was smaller (14.28–26.18 μm) resulting in DV/AP ≈ 3, whereas the above ratio for O. ovata was less than 2 (AP ranging between 14.28–35.70 μm). Moreover, the theca of O. ovata cells was ornamented with scattered pores, which fluctuated in a wider range (0.07–0.32 μm) than those of O. cf. siamensis (0.23–0.29 μm). Coolia monotis cells were almost round with average DV diameter 26.88 μm, AP 25.66 μm and width 26.76 μm. Small and large cells were recorded in both field and culture populations of Ostreopsis spp. and C. monotis, while hyaline cysts were observed for O. ovata. The presence of O. ovata and O. cf. siamensis exhibited a clear seasonal pattern dominating (maximum abundance up to 4.05 × 10⁵ cells gr⁻¹ fwm) the period from midsummer to late autumn in years 2003 and 2004, while C. monotis was found also in winter and spring months.