scholarly journals Spatiotemporal Distribution of Harmful Algal Flora in the Tropical Estuarine Complex of Goa, India

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Suraksha M. Pednekar ◽  
S. G. Prabhu Matondkar ◽  
Vijaya Kerkar
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Nutrient Loading ◽  
Algal Species ◽  
Spatiotemporal Variability ◽  
Algal Flora ◽  
The Past ◽  
Tropical Estuarine ◽  
Mandovi And Zuari Estuaries ◽  
Hab Species

Mandovi and Zuari estuarine complex is monsoon-influenced estuaries located along the central west coast of India. During the past few years, there has been an increase in nutrient loading specially during monsoonal runoff which is responsible for the growth of harmful algal flora. To understand occurrence and distribution of harmful algal blooms species, daily/alternate day samplings were carried out in Mandovi and Zuari estuaries during 2007-2008 and 2008-2009 periods, respectively, comprising of monsoon (June–November) and nonmonsoon (December–May). In Mandovi, total 54 HAB species with 49 in monsoon and 36 during nonmonsoon period were reported. In Zuari, total 46 HAB species with 38 in monsoon and 41 were reported during nonmonsoon period. Bray-Curtis cluster analysis based on log-transformed phytoplankton density detected seven well-defined groups revealing spatiotemporal variability. The density of the dominant harmful algal species was significantly positively correlated with nutrients, but negatively correlated with salinity. The results of the study indicate that monsoon plays an important role in occurrence and distribution of harmful algal species having direct correlation with salinity variations and nutrient loading.

Occurrence characteristics of harmful and non-harmful algal species related to coastal environments in the southern sea of Korea

2019 ◽  
Vol 70 (6) ◽  
pp. 794 ◽  
Author(s):  
Jin Ho Kim ◽  
Minji Lee ◽  
Young Kyun Lim ◽  
Yun Ji Kim ◽  
Seung Ho Baek
Keyword(s):  
South Korea ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Phytoplankton Community ◽  
Algal Species ◽  
Coastal Environments ◽  
Survey Period ◽  
Offshore Area ◽  
Occurrence Characteristics ◽  
Hab Species

Because the phytoplankton community and blooms are regulated by various environmental factors, it is difficult to define the cause and occurrence of the phenomenon of harmful algal blooms (HABs). This study evaluated the phytoplankton community and occurrence characteristic of HAB species related to coastal environments in South Korea, 2016. In summer, because of strong upwelling event, the surface sweater temperature around Geoje Island was abnormally low (17°C), and an unusual high temperature (29°C) and low salinity (29psu) were measured in offshore area. Diatoms and dinoflagellates showed contrasting occurrences during the survey period. Diatoms were dominant in the inshore area, whereas dinoflagellates occurred in the offshore area. The phytoplankton-community structures were established depending on different hydro-oceanographic characteristics. In statistical analysis, HABs of dinoflagellate Karenia appeared in upwelling areas with a high nutritional content, whereas Gymnodinium, Gyrodinium and Prorocentrum appeared in areas of low nutrients in June, and HAB species showed an equivalent tendency to appear at high water temperature and low saline level in August. Our results indicated that hydro-oceanographic events such as river discharge, current and upwelling play important roles in determining the phytoplankton community and potential occurrence characteristics of HABs in the coastal environment of South Korea.

scholarly journals Developing an Atlas of Harmful Algal Blooms in the Red Sea: Linkages to Local Aquaculture

2020 ◽  
Vol 12 (22) ◽  
pp. 3695
Author(s):  
Elamurugu Alias Gokul ◽  
Dionysios E. Raitsos ◽  
John A. Gittings ◽  
Ibrahim Hoteit
Keyword(s):  
Saudi Arabia ◽  
Red Sea ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Large Scale ◽  
Nutrient Loading ◽  
National Level ◽  
Spatiotemporal Variability ◽  
Wastewater Management ◽  
Spatial Coverage

Harmful algal blooms (HABs) are one of the leading causes of biodiversity loss and alterations to ecosystem services. The Red Sea is one of the least studied large marine ecosystems (LMEs), and knowledge on the large-scale spatiotemporal distribution of HABs remains limited. We implemented the recently developed remote sensing algorithm of Gokul et al. (2019) to produce a high-resolution atlas of HAB events in the Red Sea and investigated their spatiotemporal variability between 2003 and 2017. The atlas revealed that (i) the southern part of the Red Sea is subject to a higher occurrence of HABs, as well as long-lasting and large-scale events, in comparison to the northern part of the basin, and (ii) the Red Sea HABs exhibited a notable seasonality, with most events occurring during summer. We further investigated the potential interactions between identified HAB events and the National Aquaculture Group (NAQUA), Al-Lith (Saudi Arabia)—the largest aquaculture facility on the Red Sea coast. The results suggest that the spatial coverage of HABs and the elevated chlorophyll-a concentration (Chl-a) (> 1 mg m−3; a proxy for high nutrient concentration), in the coastal waters of Al-Lith during summer, increased concurrently with the local aquaculture annual production over a nine-year period (2002–2010). This could be attributed to excessive nutrient loading from the NAQUA facility’s outfall, which enables the proliferation of HABs in an otherwise oligotrophic region during summer. Aquaculture is an expanding, high-value industry in the Kingdom of Saudi Arabia. Thus, a wastewater management plan should ideally be implemented at a national level, in order to prevent excessive nutrient loading. Our results may assist policy-makers’ efforts to ensure the sustainable development of the Red Sea’s coastal economic zone.

scholarly journals Promotion of harmful algal blooms by zooplankton predatory activity

2006 ◽  
Vol 2 (2) ◽  
pp. 194-197 ◽  
Author(s):  
Aditee Mitra ◽  
Kevin J Flynn
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Harmful Algal Bloom ◽  
Algal Species ◽  
Algal Growth ◽  
Nutrient Stress ◽  
Nutrient Ratios ◽  
Predator Prey ◽  
Predator Prey Model ◽  
Hab Species

The relationship between algae and their zooplanktonic predators typically involves consumption of nutrients by algae, grazing of the algae by zooplankton which in turn enhances predator biomass, controls algal growth and regenerates nutrients. Eutrophication raises nutrient levels, but does not simply increase normal predator–prey activity; rather, harmful algal bloom (HAB) events develop often with serious ecological and aesthetic implications. Generally, HAB species are outwardly poor competitors for nutrients, while their development of grazing deterrents during nutrient stress ostensibly occurs too late, after the nutrients have largely been consumed already by fast-growing non-HAB species. A new mechanism is presented to explain HAB dynamics under these circumstances. Using a multi-nutrient predator–prey model, it is demonstrated that these blooms can develop through the self-propagating failure of normal predator–prey activity, resulting in the transfer of nutrients into HAB growth at the expense of competing algal species. Rate limitation of this transfer provides a continual level of nutrient stress that results in HAB species exhibiting grazing deterrents protecting them from top-down control. This process is self-stabilizing as long as nutrient demand exceeds supply, maintaining the unpalatable status of HABs; such events are most likely under eutrophic conditions with skewed nutrient ratios.

scholarly journals Removal effect of algicidal modified clay on Phaeocystis globosa blooms in culturing enclosure experiments: A short communication

2021 ◽  
Vol 869 (1) ◽  
pp. 012068
Author(s):  
X Qin ◽  
X Chen ◽  
F Li ◽  
H Ya ◽  
D Zhu ◽  
...  
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Control Group ◽  
Beibu Gulf ◽  
Blank Control Group ◽  
Phaeocystis Globosa ◽  
Marine Aquaculture ◽  
Modified Clay ◽  
The Past ◽  
Field Culture

Abstract With the increased scale of marine aquaculture in the Beibu Gulf, as well as accelerating urbanization and industrialization, frequent harmful algal blooms (HABs) have occurred in this area, especially those formed by Phaeocystis globosa in the past several years. As the P. globosa bloom has been a serious marine ecological disaster in the Beibu Gulf, research on quick and effective methods to eliminate P. globosa blooms is a hot research topic. In this study, the bacteria Streptomyces yatensis B4503 combined with modified diatomite was used to prepare algicidal modified clay, which was then used to study the removal effect on P. globosa blooms in field culture enclosures. The results showed that after 6 h of treatment with algicidal modified clay, compared with the blank control group, the cell density and chlorophyll a content of P. globosa decreased by 26.86% and 64.03%, respectively, and they decreased by 75.23% and 84.81%, respectively, after 24 h. The study indicated that algicidal modified clay can be applied to eliminate HABs caused by P. globosa in coastal water.

scholarly journals Is Occurrence of Harmful Algal Blooms in the Exclusive Economic Zone of India on the Rise?

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
K. B. Padmakumar ◽  
N. R. Menon ◽  
V. N. Sanjeevan
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Exclusive Economic Zone ◽  
Prorocentrum Lima ◽  
Clear Cut ◽  
The Past ◽  
Spatial Coverage ◽  
Indian Waters ◽  
Frequency Intensity

Occurrence, increase in frequency, intensity and spatial coverage of harmful algal blooms during the past decade in the EEZ of India are documented here. Eighty algal blooms were recorded during the period 1998–2010. Of the eighty algal blooms, 31 blooms were formed by dinoflagellates, 27 by cyanobacteria, and 18 by diatoms. Three raphidophyte and one haptophyte blooms were also observed. Potentially toxic microalgae recorded from the Indian waters were Alexandrium spp., Gymnodinium spp. Dinophysis spp., Coolia monotis, Prorocentrum lima, and Pseudo-nitzschia spp. Examination of available data from the literature during the last hundred years and in situ observations during 1998–2010 indicates clear-cut increase in the occurrence of HABs in the Indian EEZ.

scholarly journals Harmful Algal Blooms: Physiology, Behavior, Population Dynamics and Global Impacts- A Review

2005 ◽  
Vol 10 ◽  
pp. 1
Author(s):  
H.M. Al-Ghelani ◽  
A.Y.A AlKindi ◽  
S. Amer ◽  
Y.K Al-Akhzami
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Global Climate ◽  
Algal Species ◽  
Molecular Probes ◽  
Screening Methods ◽  
Global Climate Changes ◽  
Global Impacts ◽  
Anthropogenic Loading ◽  
Global Increase

Harmful, toxic algae are now considered as one of the important players in the newly emerging environmental risk factors. The apparent global increase in harmful algal blooms (HABs) is becoming a serious problem in both aquaculture and fisheries populations. Not only has the magnitude and intensity of public health and economic impacts of these blooms increased in recent years, but the number of geographic locations experiencing toxic algal blooms has also increased dramatically. There are two primary factors causing HABs outbreaks. The natural processes such as upwelling and relaxation, and the anthropogenic loading resulting in eutrophication. However, the influence of global climate changes on algal bloom phenomenon cannot be ignored. The problem warrants development of effective strategies for the management and mitigation of HABs. Progress made in the routine coastal monitoring programs, development of methods for detection of algal species and toxins and coastal modeling activities for predicting HABs reflect the international concerns regarding the impacts of HABs. Innovative techniques using molecular probes will hopefully result in development of rapid, reliable screening methods for phycotoxins and the causative organisms.            

scholarly journals Comparison of Short-Term Toxicity of 14 Common Phycotoxins (Alone and in Combination) To The Survival of Brine Shrimp Artemia Salina

2021 ◽  
Author(s):  
Yu Ting Zhang ◽  
Shanshan SONG ◽  
Bin ZHANG ◽  
Yang ZHANG ◽  
Miao TIAN ◽  
...  
Keyword(s):  
Ecological Risk ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Algal Species ◽  
Natural Populations ◽  
Marine Ecosystems ◽  
Artemia Salina ◽  
Marine Organisms ◽  
Short Term ◽  
The Impact

Abstract Toxic harmful algal blooms (HABs) can cause deleterious effects in marine organisms, threatening the stability of marine ecosystems. It is well known that different strains, natural populations and growth conditions of the same toxic algal species may lead to different amount of phycotoxin production and the ensuing toxicity. To fully assess the ecological risk of toxic HABs, it is of great importance to investigate the toxic effects of phycotoxins in marine organisms. In this study, the short-term toxicity of 14 common phycotoxins (alone and in combination) in the marine zooplankton Artemia salina was investigated. On the basis of 48 h LC50, the order of toxicity in A. salina was AZA3 (with a LC50 of 0.0203 µg/ml)＞AZA2 (0.0273 µg/ml) ＞PTX2 (0.0396 µg/ml)＞DTX1 (0.0819 µg/ml)＞AZA1 (0.106 µg/ml)＞ SPX1 (0.144 µg/ml)＞YTX (0.172 µg/ml)＞dcSTX (0.668 µg/ml)＞OA (0.728 µg/ml)＞STX (1.042 µg/ml)＞GYM (1.069 µg/ml)＞PbTx3 (1.239 µg/ml)＞hYTX (1.799 µg/ml)＞PbTx2 (2.415 µg/ml). For the binary exposure, additive effects of OA and DTX1, DTX1 and hYTX; antagonistic effects of OA and PTX2, OA and STX; and synergetic effects of DTX1 and STX, DTX1 and YTX, DTX1 and PTX2, PTX2 and hYTX on the mortality of A. salina were observed. These results provide valuable toxicological data for assessing the impact of phycotoxins on marine planktonic species and highlight the potential ecological risk of toxic HABs in marine ecosystems.

scholarly journals Review of Harmful Algal Blooms in the Coastal Mediterranean Sea, with a Focus on Greek Waters

Diversity ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 396
Author(s):  
Christina Tsikoti ◽  
Savvas Genitsaris
Keyword(s):  
Mediterranean Sea ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Ecosystem Health ◽  
Algal Species ◽  
Coastal Areas ◽  
Population Increase ◽  
Nutrient Inputs ◽  
Environmental Pressures ◽  
Marine Eutrophication

Anthropogenic marine eutrophication has been recognized as one of the major threats to aquatic ecosystem health. In recent years, eutrophication phenomena, prompted by global warming and population increase, have stimulated the proliferation of potentially harmful algal taxa resulting in the prevalence of frequent and intense harmful algal blooms (HABs) in coastal areas. Numerous coastal areas of the Mediterranean Sea (MS) are under environmental pressures arising from human activities that are driving ecosystem degradation and resulting in the increase of the supply of nutrient inputs. In this review, we aim to present the recent situation regarding the appearance of HABs in Mediterranean coastal areas linked to anthropogenic eutrophication, to highlight the features and particularities of the MS, and to summarize the harmful phytoplankton outbreaks along the length of coastal areas of many localities. Furthermore, we focus on HABs documented in Greek coastal areas according to the causative algal species, the period of occurrence, and the induced damage in human and ecosystem health. The occurrence of eutrophication-induced HAB incidents during the past two decades is emphasized.

scholarly journals Harmful algal blooms and climate change: Learning from the past and present to forecast the future

Harmful Algae ◽  
2015 ◽  
Vol 49 ◽  
pp. 68-93 ◽  
Author(s):  
Mark L. Wells ◽  
Vera L. Trainer ◽  
Theodore J. Smayda ◽  
Bengt S.O. Karlson ◽  
Charles G. Trick ◽  
...  
Keyword(s):  
Climate Change ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
The Past ◽  
The Future

Unprecedented toxic algal blooms impact on Tasmanian seafood industry

2016 ◽  
Vol 37 (3) ◽  
pp. 143 ◽  
Author(s):  
Gustaaf Hallegraeff ◽  
Christopher Bolch
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
East Coast ◽  
Economic Losses ◽  
Human Society ◽  
Rock Lobster ◽  
Negative Effects ◽  
Risk Area ◽  
Seafood Industry ◽  
Hab Species

While most microscopic algae provide food for filter-feeding shellfish and larvae of crustaceans and finfish, other so-called Harmful Algal Blooms (HABs) can have negative effects, causing severe economic losses to aquaculture, fisheries and tourism. Of greatest concern to human society are blooms of toxic HAB species that cause illness and death of fish, seabirds and mammals via toxins transferred through the food web. Unprecedented Alexandrium (Dinophyceae) blooms along the East Coast of Tasmania in 2012 and 2015, a previously low biotoxin risk area, led to major impacts on the local oyster, mussel, scallop and rock lobster industries. Four human hospitalisations also occurred from eating wild shellfish.

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