Microplankton biomass and diversity in the Vietnamese upwelling area during SW Monsoon under normal conditions and after an ENSO event

Microplankton biomass and diversity in the Vietnamese upwelling area during SW Monsoon under normal conditions and after an ENSO event

Natalie Loick-Wilde(a), Deniz Bombar (a, b), Hai Nhu Doan(c), Lam Ngoc Nguyen(c), Anh Mai Nguyen-Thi(c), Maren Voss(a), Joachim W. Dippner(a) a Leibniz-Institute for Baltic Sea Research Warnemünde, FR, Germany b University of Copenhagen, Copenhagen, Denmark c Institute of Oceanography, VAST, Viet Nam Received 10 February 2016, Accepted 5 April 2017, Available online 6 April 2017

Investigating microplankton biomass and diversity under different climatological conditions is key to the understanding of cascading effects of climate change on nutrient cycles and biological productivity. Here we have used data collected during two contrasting summers along the coast of Viet Nam to show how climatological-driven changes can have a significant influence on the distribution of microplankton communities and their biomass via its impact on nutrient concentrations in the water column. The first summer in July 2003 followed a weak El-Nino Southern Oscillation (ENSO) event and was characterized by weak coastal upwelling, in the second summer during July 2004, upwelling was normal.

Very low silicate (SiO4) concentrations and SiO4:DIN ratios characterized the source water mass for upwelling in July 2004, and dynamic SiO4 to dissolved inorganic nitrogen ratios (SiO4:DIN) mainly below the Redfield-Brzezinski ratio and DIN to phosphate ratios (DIN:PO43-) below the Redfield ratio were a common feature off Viet Nam. Much higher particle concentrations and PSi/PC ratios during normal upwelling revealed major changes in the micro-plankton community structure among summers. Small dinoflagellates (10-20 µm) prevailed ubiquitously during reduced upwelling. During normal upwelling, the diatom Rhizosolenia sp. dominated the cell-carbon biomass in the silicate poor upwelling waters. Trichodesmium erythraeum dominated in the Mekong-influenced and nutrient depleted offshore waters, where it co-occurred with Rhizosolenia sp. Both species were directly associated with the much higher primary production (PP) and N2 fixation rates that were quantified in earlier studies, as well as with much higher diversities at these offshore sites. Along the coast, the correlation between Rhizosolenia sp. and PP rates was less clear and the factors regulating the biomass of Rhizosolenia sp. in the upwelling waters are discussed. The very low silicate concentrations in the source water mass for upwelling and the offshore deflection of the Mekong river plume likely triggered the observed ecological differences in the microplankton communities off Viet Nam in the normal upwelling season compared to the post ENSO conditions.

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Species diversity of sections conica and tabulata in the genus Protoperidinium (Dinophyceae) from tropical waters of the South China Sea

Species diversity of sections conica and tabulata in the genus Protoperidinium (Dinophyceae) from tropical waters of the South China Sea

Phan-Tan, Luom; Nguyen-Ngoc, Lam; Doan-Nhu, Hai
Nova Hedwigia Band 103 Heft 3-4 (2016), p. 515 - 545 published: Nov 1, 2016
DOI: 10.1127/nova_hedwigia/2016/0369

About 600 phytoplankton samples were collected from Vietnamese coastal waters including around the Spratly Islands. Cell morphology and shapes of apical plates (1′), intercalary plates (2a), and other plate patterns were squashed and photographed to support species identification. Fourteen species of the sections conica and tabulata in the genus Protoperidinium were described, among them 8 species including P. decollatum, P. laciniosum, P. rhombiforme, P. symmetricum and P. tohrui (conica section); these are the first reports of P. balechii, P. nudum, P. punctulatum (tabulata section) among the tropical phytoplankton flora of the South China Sea.

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Species diversity of Protoperidinium sect. Oceanica (Dinophyceae, Peridiniales) in Vietnamese waters, with description of the new species P. larsenii sp. nov.

Species diversity of Protoperidinium sect. Oceanica (Dinophyceae, Peridiniales) in Vietnamese waters, with description of the new species P. larsenii sp. nov.

Phan, Luom; Nguyen, Lam; Doan, Hai; Larsen, Jacob; Raine, Robin

First published: 23 March 2017
Published by Wiley Online Library
DOI: 10.1111/njb.01230

Protoperidinium is one of the most important genera of armoured marine dinoflagellates. Despite its importance and many previous studies on this genus, the descriptions of many species are incomplete, their diagnostic features not properly described and illustrated and most species have been illustrated, if at all, only by line drawings and not documented by micro-photography. As here described, examinations of about 600 phytoplankton net samples collected from Viet Nam and adjacent coastal waters over the last decade revealed about 100 species of Protoperidinium, ten of which belong to the section Oceanica and this paper is the first in a series describing all species of Protoperidinium found in Vietnamese waters. The Oceanica species are described and illustrated by light, and for some also by scanning electron, microscopy. The species are: Protoperidinium claudicans, P. depressum, P. depressum var. claudicanoides, P. larsenii sp. nov., P. murrayi, P. oceanicum f. bisintercalares comb. nov., P. oceanicum var. tenellum comb. nov., P. paraoblongum, P. venustum and P. venustum var. facetum. Protoperidinium larsenii L. Phan Tan, L. Nguyen-Ngoc, and H. Doan-Nhu is new to science. It was found in the coastal waters of Rach Gia in Kien Giang Province, western part of south Viet Nam (Gulf of Thailand). The new species is characterized by its broad shape, conical epitheca and short, non-divergent antapical horns; the 1’ plate is asymmetrical, there are 3 anterior intercalary plates, the 2a plate is quadrangular; and the sutures connecting the 6” plate with the 4’ plate and the 7” form an almost straight line. By these features P. larsenii differs from the similar species P. claudicans and P. latidorsale. Protoperidinium oceanicum (Vanh ffen) Balech () f. bisintercalares (Graham) H. Doan-Nhu, L. Phan-Tan, L. Nguyen-Ngoc, and J. Larsen comb. nov. and Protoperidinium oceanicum (Vanh ffen) Balech () var. tenellum (Graham) L. Nguyen-Ngoc, L. Phan-Tan, H. Doan-Nhu and J. Larsen comb. nov. are two new combinations.

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Red Tide

HABViet Project

 HABViet Project
1999-2001, 2001-2004, and 2005-2008

Background: Almost 100 algal species are now known or suspected to produce toxins, and both the frequency, intensity, and geographical distribution of the harmful algal blooms (HAB) appear to have increased over the last few decades. Many blooms have severe ecological and socio-economic impact as they may cause damage or be fatal to other flora and fauna including human beings. Five human syn-dromes are presently caused by consumption of seafood contaminated by algal toxins, and particularly paralytic shellfish poisoning (PSP) which can be fatal to humans, and ciguatera are widespread in the tropics. Algal toxins accumulated in seafood products are not destroyed by cooking. In addition to serious health risks associated with the consumption of contaminated seafood, some toxic algal species produce hemolytic toxins with devastating effects on fish, both in the wild and in aquacultures with major economic losses for the aquaculture industry. Monitoring and control of  algal toxins in seafood is now recognized as an important issue by the authorities in most countries including Vietnam.

In the recent years, seafood has been the third- fourth most important trade export product, and the value is expected to increase even further according to the Vietnamese Ministry of Fisheries. Artisanal mussel fishery and large scale aquaculture for export markets is particularly important in the Southern Provinces of Vietnam, where there is a long tradition for exploiting species such as e.g. Chlamys nobilis, Modiolus philippinus, and Meretrix lyrata. Molluscs represent a possible growth industry and major export markets include Thailand, Singapore, Japan and the EU.
Vietnam has high priority national plans for the development of the aquaculture industry. The Vietnamese Ministry of Fisheries (MOFI) is developing the aqua-culture sector through the newly established National Fisheries Extension Centre. Three Danida funded initiatives are contributing to this strategy. One of them is SEAQIP, the Seafood Quality Improvement Project within the National Fisheries Inspection and Quality Assurance Centre (NAFIQACEN), through which the monitoring system for bivavles was established. Until recently, the lack of appropriate monitoring programmes, including monitoring of harmful algae, to control the safety of the seafood products called a closure upon export to the EU. In the spring of 2000 the monitoring programme established with Danish support by NAFIQACEN, was approved by the EU and the export has now been resumed. NAFIQACEN staff attended training courses in Vietnam and Denmark, and participated in the training activities organized during Phase I of HABViet.
Support for Brackish Water and Marine Aqua culture (SUMA) is one of the elements of the larger Fisheries Sector Programme Support established between Vietnam and Denmark. The strong focus on development of aqua culture makes it foreseeable that there will be a future demand for scientific experts in harmful algae for both research and monitoring purposes. MOFI has very recently appointed NIO to monitor for toxic algae in the Binh Tuan Province on behalf of Hai Nam Co. Ltd. The Company wishes to introduce a new bivalve species, Argopecten irradias, from China to replace the decreasing stocks of the traditionally exploited species Chlamys nobilis, and the monitoring is a requirement to the company before introduction of the new crop species in Binh Thuan waters is permitted. Hai Nam Co. Ltd. is receiving DANIDA support to improve sea food processing techniques.

International or regional organizations are also conducting activities on, or in relation to, harmful algae and algal toxins in Vietnam and South East Asia, e.g. under the Asian-Pacific Economic Cooperation (APEC). The activities are in their beginning only, but a regional network of institutions is planned in order to establish common regulations and analysis procedures for  seafood safety and algal toxins respectively. NIO is also part of the ASEAN Red Tide Alert Network. In 1999 a cooperation agreement between UNESCO and Vietnam was established, and this identifies as a priority specialized training for scientists in the prevention of harmful algal blooms.
Harmful algae is not only a problem in relation to fisheries resources, but also to the exploitation of surface water reservoirs as drinking water. Blooms of cyanobacteria occur widespread in both temperate and tropical freshwater. These algae may produce both neuro- and hepatotoxins, and the cyanobacterial toxins are now recognized by the environmental authorities in many countries as a human health issue. According to Institute of Tropical Biology, HCMC, 70% of the population of HCMC and surroundings (approx. 8 mill. people) receive their drinking water supply from 3 large freshwater reservoirs. The presence of cyanobacterial toxins in drinking water in Vietnam has not yet been investigated, but cyanobacteria blooms have been recorded in the reservoirs around HCMC.

HABViet Project, Phase 1 1999-2001
During phase I, the involved scientists of all partner institutions have obtained a thorough taxonomic knowledge of harmful algae. With this background, It is planned during phase II to develop different expertise at the different institutions depending on their research interests, capacity, and relevance to a sustainable development and exploitation of natural resources (aqua culture and drinking water). The focus will be as follows:

1) NIO is the national focal point for HAB studies, taxonomy is further strengthened with focus on naked flagellates and dinoflagellates, toxicological and ecological studies are initiated during Phase II. The HABViet Project will continue to enhance the ability of NIO in providing data to the regional APEC and ASEAN network and to interact better with colleagues in the surrounding countries.
2) HIO will focus on further development of the taxonomic expertise in order to function as HAB expert centre for the northern part of the country.
3) ITB will maintain the expertise in identification of harmful diatoms together with HUS. ITB will carry out a pilot project to survey the occurrence of potentially toxic blue-green algae in freshwater reservoirs.
4) HUS will cooperate with ITB on identification of harmful diatoms, but focus on curriculum building with emphasis on HAB. Strengthening of the teaching capacity in Hue will enhance the possibilities of educating HAB experts nationally.


HABViet Project, Phase 2 2002-2005
Research strategy, work plan and schedule for activities

Research strategy. The strategy for Phase II will focus on three themes: 1) Survey and Autecological studies. 2) Long term capacity building. 3) Dissemination of results and public awareness.

The coastal waters at the border of the Nghe An – Ha Tinh Provinces and Kien Giang Province will be surveyed for the occurrence, distribution and abundance of potentially toxic algal species. The areas have been identified by the Vietnamese Ministry of Fisheries and the Danish Fisheries Sector Programme/SUMA for near future aqua culture development. The sampling programme will be linked to existing environmental monitoring programmes and to other investigations carried out by NAFIQACEN to assess the potential for aqua culture in the selected areas. The result of the surveys may be used as a tool in future development of a sustainable aqua culture industry. The harmful species encountered during the survey will be isolated into cultures where possible. This will allow detailed autecological studies including toxicity of selected algal species, and toxin accumulation and de-toxification of shellfish. Phase II will also encompass a pilot survey of potentially toxic cyanobacteria in drinking water reservoirs around HCMC. The tools and expertise for this has been partly established during Phase I, and might generate potential for a separate future research area for ITB.
Long term investment in teaching and research capacity within HAB and marine phytoplankton in general botany will be addressed through an upgrading of the teaching facilities at HUS combined with a cooperation agreement between HUS and NIO concerning a PhD programme. The teaching laboratories at HUS will be renovated and supplied with modern equipment. The participating research laboratories which were not upgraded with research equipment in Phase I will be so during Phase II. This will also include a continued up-grading of the existing library facilities with a selection of classical and modern literature on phytoplankton and toxic algae.
Phase II will also pay attention to dissemination of results to the public. It is proposed to prepare an exhibition on marine plankton including harmful algae, their ecological role, and related research at NIO as part of the permanent exhibition at the National Oceanographic Museum at NIO. The target group is school children, students, the general public, and tourists. The museum has more than 120.000 visitors per year. The section presenting research activities at NIO addresses the significant number of  visiting scientists, administrators, politicians, international delegations, guests, etc. The text will be in Vietnamese and English (French to be considered if relevant). Agreement has been made between the NIO, PRP and Danmarks Akvarium for cooperation in the establishment of the new exhibit. The exhibition will be prepared in Vietnam by NIO staff and local artists.

Phase II thus consists of 3 activity modules:
Survey and Autecological studies, Phase II
* Survey of harmful marine microalgae in two areas identified for aquaculture developmen
* Autecological and toxicological studies of selected toxic algal species.
* Toxin accumulation and de-toxification of selected species of shellfish


International Scientific Conference & Forum “Bien Dong 2017”



95 Years of Dedication to Marine Science (1922 – 2017)
International Scientific Conference & Forum
“Bien Dong 2017”
Bien Dong (the South China Sea) is one of the world’s richest marine biodiversity marginal seas, high abundant and diverse in marine resources, and extremely significant in a geopolitical sense. However, Bien Dong is being challenged in enormous environmental and resource issues, which are transboundary, spreadingly impacting from the coast to the open ocean. Thus it has been increasingly attracting research interests not only from the countries surrounding the Bien Dong, which are depending largely upon its natural resources, but also from countries from the other parts of the world.
During its 95 years of development, in cooperation with Vietnamese and foreign partners, the Institute of Oceanography has carried out series of scientific investigations and researches, achieved significant knowledge on Bien Dong, making remarkable contribution to sustainable development and conservation of biodiversity and environment in Bien Dong.
The Scientific Conference “Bien Dong” was first organized in 2000, followed by the second in 2002, and then repeated every five years. The conferences were aimed to providing chances for syntheses and presenting scientific reasearch, places for marine managers and scientists to meet and discuss concerned themes in marine science and environment problems, and to promote cooperation on marine science in this region. The Scientific Conference “Bien Dong” beginned to extend to a broader international scientific and non-scientific audiences since 2007.
On the occasion of its 95th anniversary (14/09/1922 – 14/09/2017), the Institute of Oceanography, Vietnam Academy of Science and Technology is going to organize the International Scientific Conference & Forum “Bien Dong 2017: Science for Blue Growth in the South China Sea” in order to review the scientific research results and achievement on Bien Dong over the last five years, advance marine scientific knowledge and promote international cooperation toward a blue economy in this region.
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A Changing River: Measuring Nutrient fluxes to the South China Sea

A case study to set the scene

640px-south_china_seaThe Mekong River is one of the world’s great river systems. It flows along 4,909 km and through six countries including China, Myanmar, Thailand, Laos, Cambodia, and Vietnam.  It is the twelfth longest river in the world and the seventh longest in Asia. It is also is one of the most biologically diverse rivers in the world—second only to the Amazon. The Mekong River’s biodiversity is fundamental to the natural resource-based rural livelihoods of a large population. At the end of the Mekong, the river flows through an extensive delta and meets the South China Sea.

The South China Sea is adjacent to a region in Vietnam of rapid land use change, strongly influenced by riverine inputs, including a seasonal offshore jet that transports the Mekong River plume well offshore. The drainage basin into which the river flows is rather small when compared to its discharge volume. The riverine fluxes of water, sediments, and nutrients likely are affecting the natural balance of the South China Sea. This area provides an excellent site for exploring and characterizing the role of riverine inputs with human-induced modifications, as well as the role of ocean circulation in controlling productivity in a tropical coastal marine ecosystem. A variety of biological processes are affected by the circulation of the South China Sea, especially during upwelling, which has a strong effect on the spatial distribution of phytoplankton biomass and activity.


New species recorded

Trong khuôn khổ nhiệm vụ “Đa dạng tảo Vàng ánh (Chrysophyceae và Synurophyceae) ở Việt Nam: những vấn đề về hình thái học và di truyền họchợp tác giữa Viện Hàn lâm Khoa học và Công nghệ Việt Nam và Quỹ Nghiên cứu cơ bản Nga, từ giữa năm 2014, các nhà khoa học của Viện Hải dương học và Viện Sinh học các thủy vực nội đồng đã thực hiện các đợt khảo sát ở Nam Cát Tiên (Đồng Nai), Cam Ranh, Nha Trang (Khánh Hòa), Phan Thiết (Bình Thuận), Ba Bể (Bắc Kạn) và Hà Nội.