scholarly journals High Densities of a Prochlorophyte (Unresolved Species) Inhibit Grazing by the Herbivorous Copepod Parvocalanus crassirostris

2021 ◽  
Vol 8 ◽  
Author(s):  
Xiao Ma ◽  
Charles A. Jacoby ◽  
Kevin B. Johnson
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Algal Species ◽  
Indian River Lagoon ◽  
Isochrysis Galbana ◽  
Total Density ◽  
Top Down ◽  
Parvocalanus Crassirostris ◽  
High Concentrations ◽  
Cell Densities

Harmful algal blooms (HABs) are increasing in frequency and severity, underscoring the importance of understanding potential top-down controls of blooms. In the Indian River Lagoon (IRL), a shallow subtropical estuary, one harmful bloom was co-dominated by an unresolved prochlorophyte in the Family Prochlorothricaceae, which reached densities of > 106 cells ml–1 engendering the term “Superbloom.” Experiments were conducted to evaluate grazing rates and the potential for top-down control by an abundant herbivorous copepod, Parvocalanus crassirostris, on the prochlorophyte. Those grazing rates were lower than the rates on a palatable alternative algal food, Isochrysis galbana, when both algal species were presented in monocultures with identical densities. Grazing on the prochlorophyte decreased or ceased at densities over 4.8 × 105 cells ml–1. When the prochlorophyte and the palatable alternative each comprised half of the total density, both species were consumed, but grazing on I. galbana was reduced compared to the grazing rates in a monoculture of this species, especially at higher cell densities. Copepod mortality was observed in treatments with high concentrations of the prochlorophyte, and these treatments contained mucilage. Experiments simulating viscosities produced by prochlorophyte mucilage yielded results consistent with the original grazing experiments (i.e., copepods showed lower grazing rates and higher mortality rates in higher viscosity treatments). Results reveal potential limitations of top-down controls by this grazer on prochlorophyte blooms and HABs that produce mucilage.

scholarly journals Grazing by the Copepod Parvocalanus crassirostris on Picochlorum sp. at Harmful Bloom Densities and the Role of Particle Size

2021 ◽  
Vol 8 ◽  
Author(s):  
Xiao Ma ◽  
Charles A. Jacoby ◽  
Kevin B. Johnson
Keyword(s):  
Harmful Algal Bloom ◽  
Algal Species ◽  
Indian River Lagoon ◽  
Isochrysis Galbana ◽  
Top Down ◽  
Indian River ◽  
Parvocalanus Crassirostris ◽  
Potential Food ◽  
Shape Of Potential

Harmful blooms of nanophytoplankton (2–20 μm) are increasingly common and sometimes severe, but requirements and controls of such blooms (e.g., water quality constraints, requirements for nutrients, and the presence of different guilds of grazers) are poorly understood. Laboratory grazing experiments were conducted to evaluate the potential for top-down control by the copepod Parvocalanus crassirostris on a small harmful algal species (an unidentified chlorophyte Picochlorum, 1–4 μm) and to test the effects of cell sizes on grazing rates. The Picochlorum sp. is a strain isolated from a long-lasting harmful algal bloom in the Indian River Lagoon that reached high densities (>1 × 106 cells ml–1). Experiments contrasted grazing on Picochlorum sp. with grazing on the palatable prymnesiophyte Isochrysis galbana (4–6 μm) in monocultures and mixed cultures. When presented in monocultures, grazing rates on Picochlorum sp. were lower than grazing rates on the palatable alternative. When Picochlorum sp. were presented alongside I. galbana, copepods essentially ceased feeding on the former. In additional experiments, P. crassirostris were fed plastic beads with diameters of 2.0–17.9 μm to control for differences in taste, toxicity, production of mucilage and shape of potential food. Paracalanus crassirostris fed most efficiently on beads with diameters of 7.0–7.9 μm. Results revealed that P. crassirostris can consume Picochlorum sp., but small size and the presence of palatable cells reduces the likelihood of top-down control of blooms of Picochlorum sp.

scholarly journals Metatranscriptomic Evidence for Co-Occurring Top-Down and Bottom-Up Controls on Toxic Cyanobacterial Communities

2015 ◽  
Vol 81 (9) ◽  
pp. 3268-3276 ◽  
Author(s):  
Morgan M. Steffen ◽  
B. Shafer Belisle ◽  
Sue B. Watson ◽  
Gregory L. Boyer ◽  
Richard A. Bourbonniere ◽  
...  
Keyword(s):  
Microbial Community ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Lake Erie ◽  
Sequence Data ◽  
Top Down ◽  
Western Basin ◽  
Bottom Up ◽  
Content Type ◽  
Cyanobacterial Harmful Algal Blooms

ABSTRACTLittle is known about the molecular and physiological function of co-occurring microbes within freshwater cyanobacterial harmful algal blooms (cHABs). To address this, community metatranscriptomes collected from the western basin of Lake Erie during August 2012 were examined. Using sequence data, we tested the hypothesis that the activity of the microbial community members is independent of community structure. Predicted metabolic and physiological functional profiles from spatially distinct metatranscriptomes were determined to be ≥90% similar between sites. Targeted analysis ofMicrocystis aeruginosa, the historical causative agent of cyanobacterial harmful algal blooms over the past ∼20 years, as well as analysis ofPlanktothrix agardhiiandAnabaena cylindrica, revealed ongoing transcription of genes involved in microcystin toxin synthesis as well as the acquisition of both nitrogen and phosphorus, nutrients often implicated as independent bottom-up drivers of eutrophication in aquatic systems. Transcription of genes involved in carbon dioxide (CO2) concentration and metabolism also provided support for the alternate hypothesis that high-pH conditions and dense algal biomass result in CO2-limiting conditions that further favor cyanobacterial dominance. Additionally, the presence ofMicrocystis-specific cyanophage sequences provided preliminary evidence of possible top-down virus-mediated control of cHAB populations. Overall, these data provide insight into the complex series of constraints associated withMicrocystisblooms that dominate the western basin of Lake Erie during summer months, demonstrating that multiple environmental factors work to shape the microbial community.

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 High-Resolution Spatiotemporal Dynamics of Harmful Algae in the Indian River Lagoon (Florida)—A Case Study of Aureoumbra lagunensis, Pyrodinium bahamense, and Pseudo-nitzschia

2021 ◽  
Vol 8 ◽  
Author(s):  
Cary B. Lopez ◽  
Charles L. Tilney ◽  
Eric Muhlbach ◽  
Josée N. Bouchard ◽  
Maria Célia Villac ◽  
...  
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Seasonal Pattern ◽  
Indian River Lagoon ◽  
Early Summer ◽  
Temperature Cycle ◽  
Estuarine Ecosystem ◽  
Indian River ◽  
Pyrodinium Bahamense ◽  
Aureoumbra Lagunensis

The Indian River Lagoon (IRL), located on the east coast of Florida, is a complex estuarine ecosystem that is negatively affected by recurring harmful algal blooms (HABs) from distinct taxonomic/functional groups. Enhanced monitoring was established to facilitate rapid quantification of three recurrent bloom taxa, Aureoumbra lagunensis, Pyrodinium bahamense, and Pseudo-nitzschia spp., and included corroborating techniques to improve the identification of small-celled nanoplankton (<10 μm in diameter). Identification and enumeration of these target taxa were conducted during 2015–2020 using a combination of light microscopy and species-specific approaches, specifically immunofluorescence flow cytometry as well as a newly developed qPCR assay for A. lagunensis presented here for the first time. An annual bloom index (ABI) was established for each taxon based on occurrence and abundance data. Blooms of A. lagunensis (>2 × 108 cells L–1) were observed in all 6 years sampled and across multiple seasons. In contrast, abundance of P. bahamense, largely driven by the annual temperature cycle that moderates life cycle transitions and growth, displayed a strong seasonal pattern with blooms (105–107 cells L–1) generally developing in early summer and subsiding in autumn. However, P. bahamense bloom development was delayed and abundance was significantly lower in years and locations with sustained A. lagunensis blooms. Pseudo-nitzschia spp. were broadly distributed with sporadic bloom concentrations (reaching 107 cells L–1), but with minimal concentrations of the toxin domoic acid detected (<0.02 μg L–1). In summer 2020, multiple monitoring tools characterized a novel nano-cyanobacterium bloom (reaching 109 cells L–1) that coincided with a decline in A. lagunensis and persisted into autumn. Statistical and time-series analyses of this spatiotemporally intensive dataset highlight prominent patterns in variability for some taxa, but also identify challenges of characterizing mechanisms underlying more episodic yet persistent events. Nevertheless, the intersect of temperature and salinity as environmental proxies proved to be informative in delineating niche partitioning, not only in the case of taxa with long-standing data sets but also for seemingly unprecedented blooms of novel nanoplanktonic taxa.

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.

Volunteer Algae Monitoring Program (VAMP) in the Indian River Lagoon

2018 ◽  
Vol 52 (4) ◽  
pp. 88-93
Author(s):  
Susan Hamburger ◽  
Kenneth T. Gioeli ◽  
David Berthold ◽  
H. Dail Laughinghouse
Keyword(s):  
Water Quality ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Monitoring Program ◽  
Indian River Lagoon ◽  
Fort Lauderdale ◽  
Quality Testing ◽  
Indian River ◽  
Research And Education ◽  
The University

AbstractThe University of Florida's Institute of Food and Agricultural Sciences (UF/IFAS) Florida Master Naturalist Program (FMNP) is an adult environmental education program with more than 450 trained program graduates in St. Lucie County, Florida. It is a collaborative effort of the UF/IFAS Extension St. Lucie County, St. Lucie County Environmental Resources Department, and partner agencies. Four UF/IFAS Florida Master Naturalist volunteers were recruited and received training and supplies to conduct water quality testing and algae collection in the Indian River Lagoon as part of the Volunteer Algae Monitoring Program (VAMP). The UF/IFAS research and extension faculty developed VAMP in response to the 2016 harmful algal blooms (HABs) in the Indian River Lagoon that resulted in dramatic impacts on businesses, residents, and visitors in Martin, St. Lucie, and Indian River counties. These HAB episodes demonstrate the importance of having informed citizen scientists with an understanding of the problems and threats. The VAMP citizen scientists conducted a water quality awareness survey with the general public after proactively scouting for HABs by collecting samples and conducting water quality testing at three waypoints in the Indian River Lagoon during May to November 2017 (excluding October) and February 2018. They utilized UF/IFAS Water Watch chemistry tests and processed and shipped water samples to the Laughinghouse Lab at the UF/IFAS Fort Lauderdale Research and Education Center, which conducted algae counts and genetic testing to determine the presence of harmful algae expressing microcystin-producing genes. Test results indicated fluctuating and inconsistent levels of saxitoxin but no indications of microcystins across the three sites and over time.

Shellfish toxins a public health concern for Canadians

2014 ◽  
Vol 57 (01) ◽  
pp. 16-21 ◽  
Author(s):  
Etran Bouchouar ◽  
Samantha Bruzzese ◽  
Chelsea Pyles ◽  
Kate Stechyshyn
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
The United States ◽  
Health Concern ◽  
Human Consumption ◽  
Shellfish Poisoning ◽  
Algal Toxins ◽  
Heat Stable ◽  
Marine Traffic ◽  
High Concentrations

Harmful algal blooms (HABs) are increasing worldwide as a result of climate change and global marine traffic. HABs contain high concentrations of algal toxins. Toxin contaminated shellfish cannot be detected by taste, sight, or smell; the toxins are heat-stable and therefore are not destroyed by cooking. Human consumption of toxin-contaminated shellfish leads to illness. Treatment of shellfish poisoning is limited to symptom management. The burden of shellfish poisoning in humans is often underestimated, and the effects of chronic exposure are unknown. Currently there are regulatory practices for shellfish monitoring in Canada and the United States. Yet there is poor communication of HAB risks to the public.

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 Bacterial Composition Associated With Giant Colonies of the Harmful Algal Species Phaeocystis globosa

2021 ◽  
Vol 12 ◽  
Author(s):  
Zhu Zhu ◽  
Rui Meng ◽  
Walker O. Smith Jr. ◽  
Hai Doan-Nhu ◽  
Lam Nguyen-Ngoc ◽  
...  
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Algal Species ◽  
Microbial Consortia ◽  
Colony Development ◽  
Microbial Composition ◽  
Phaeocystis Globosa ◽  
Ambient Seawater ◽  
Bacterial Composition ◽  
Bacterial Consortia

The cosmopolitan algae Phaeocystis globosa forms harmful algal blooms frequently in a number of tropical and subtropical coastal regions in the past two decades. During the bloom, the giant colony, which is formed by P. globosa, is the dominant morphotype. However, the microenvironment and the microbial composition in the intracolonial fluid are poorly understood. Here, we used high-throughput 16S rRNA amplicon sequencing to examine the bacterial composition and predicted functions in intracolonial fluid. Compared with the bacterial consortia in ambient seawater, intracolonial fluids possessed the lower levels of microbial richness and diversity, implying selectivity of bacteria by the unique intracolonial microenvironment enclosed within the P. globosa polysaccharide envelope. The bacterial consortia in intracolonial fluid were dominated by Balneola (48.6% of total abundance) and Labrezia (28.5%). The bacteria and microbial function enriched in intracolonial fluid were involved in aromatic benzenoid compounds degradation, DMSP and DMS production and consumption, and antibacterial compounds synthesis. We suggest that the P. globosa colonial envelope allows for the formation of a specific microenvironment; thus, the unique microbial consortia inhabiting intracolonial fluid has close interaction with P. globosa cells, which may benefit colony development.

Sign in / Sign up

Export Citation Format

Share Document