Nutrient-related selection mechanisms in marine phytoplankton communities and the impact of eutrophication on the planktonic food web

1995 ◽  
Vol 32 (4) ◽  
pp. 63-75 ◽  
Author(s):  
R. Riegman
Keyword(s):  
Algal Blooms ◽  
Algal Biomass ◽  
Resource Competition ◽  
Water Quality Management ◽  
Algal Species ◽  
Marine Phytoplankton ◽  
Commercial Fish ◽  
N Limitation ◽  
Phytoplankton Communities ◽  
The Impact

A general increase in nutrient discharges during the last few decades has caused various changes in the algal community structure along the European continental coast. Coincidentally and maybe consequently, the foodweb structure and functioning has altered in local areas causing various phenomena like oxygen depletion, mortality of groups of organisms, foam on beaches, and an increase in the productivity of benthic communities and some commercial fish species. The observed increases in algal biomass and shifts in species composition are discussed in relation to the involved key mechanisms: resource competition and selective grazing. Along the Dutch coastal zone of the North Sea eutrophication has caused a doubling of the yearly averaged algal biomass during the past three decades. The sudden appearance of Phaeocystis summer blooms coincided with a shift from P-limitation towards N-limitation in the Dutch coastal area due to a stronger increase in P-discharge relative to the increase in N-discharge. Competition experiments in continuous cultures showed Phaeocystis to become dominant under N-limitation. Additionally, the large Phaeocystis colonies, which can reach a diameter up to one centimetre, escape from microzooplankton grazing. A computer model is presented which demonstrates a shift from bottom-up towards top-down control if the pelagic environment becomes eutrophicated. Implementation of this concept in a size-differential phytoplankton control model generates the prediction that algal blooms are dominated by species that escape from grazing by those zooplankton species which have a high potential numerical response. In marine environments these are microzooplankton species. These organisms mainly feed on cyanobacteria, prochlorophytes and some nano-algal species. One of the consequences for foodweb structure and the carbon fluxes in marine foodwebs is that eutrophication will lead to the dominance of poorly edible algal species. Eutrophication favours the downward transport of carbon and nutrients towards the sediments not only due to higher algal biomasses but also as a consequence of a shift towards larger algal species with higher sedimentation characteristics. An example is given how these new insights can be used for water quality management purposes.

scholarly journals A Review of Nontraditional Biomanipulation

2008 ◽  
Vol 8 ◽  
pp. 1184-1196 ◽  
Author(s):  
Xia Zhang ◽  
Ping Xie ◽  
Xiaoping Huang
Keyword(s):  
Algal Blooms ◽  
Algal Species ◽  
Planktivorous Fish ◽  
Bighead Carp ◽  
Cyanobacterial Blooms ◽  
Management Tool ◽  
Nutrient Concentrations ◽  
Effective Management ◽  
Nuisance Algae ◽  
The Impact

The aim of this review is to identify problems, find general patterns, and extract recommendations for successful management using nontraditional biomanipulation to improve water quality. There are many obstacles that prevent traditional biomanipulation from achieving expectations: expending largely to remove planktivorous fish, reduction of external and internal phosphorus, and macrophyte re-establishment. Grazing pressure from large zooplankton is decoupled in hypereutrophic waters where cyanobacterial blooms flourish. The original idea of biomanipulation (increased zooplankton grazing rate as a tool for controlling nuisance algae) is not the only means of controlling nuisance algae via biotic manipulations. Stocking phytoplanktivorous fish may be considered to be a nontraditional method; however, it can be an effective management tool to control nuisance algal blooms in tropical lakes that are highly productive and unmanageable to reduce nutrient concentrations to low levels.Although small enclosures increase spatial overlap between predators and prey, leading to overestimates of the impact of predation, microcosm and whole-lake experiments have revealed similar community responses to major factors that regulate lake communities, such as nutrients and planktivorous fish. Both enclosure experiments and large-scale observations revealed that the initial phytoplankton community composition greatly impacted the success of biomanipulation. Long-term observations in Lake Donghu and Lake Qiandaohu have documented that silver carp (Hypophthalmichthys molitrix) and bighead carp (H. nobilis) (two filter-feeding planktivorous species commonly used in management) can suppress Microcystis blooms efficiently. The introduction of silver and bighead carp could be an effective management technique in eutrophic systems that lack macrozooplankton. We confirmed that nontraditional biomanipulation is only appropriate if the primary aim is to reduce nuisance blooms of large algal species, which cannot be controlled effectively by large herbivorous zooplankton. Alternatively, this type of biomanipulation did not work efficiently in less eutrophic systems where nanophytoplankton dominated.

scholarly journals Diversity of dinoflagellate assemblages in coastal temperate and offshore tropical waters of Australia

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Tahnee Manning ◽  
Arjun Venkatesh Thilagaraj ◽  
Dmitri Mouradov ◽  
Richard Piola ◽  
Clare Grandison ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
High Throughput ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
High Throughput Sequencing ◽  
Environmental Parameters ◽  
Marine Phytoplankton ◽  
Tropical Waters ◽  
Total Sequence ◽  
Phytoplankton Communities

Abstract Background Dinoflagellates are a ubiquitous and ecologically important component of marine phytoplankton communities, with particularly notable species including those associated with harmful algal blooms (HABs) and those that bioluminesce. High-throughput sequencing offers a novel approach compared to traditional microscopy for determining species assemblages and distributions of dinoflagellates, which are poorly known especially in Australian waters. Results We assessed the composition of dinoflagellate assemblages in two Australian locations: coastal temperate Port Phillip Bay and offshore tropical waters of Davies Reef (Great Barrier Reef). These locations differ in certain environmental parameters reflecting latitude as well as possible anthropogenic influences. Molecular taxonomic assessment revealed more species than traditional microscopy, and it showed statistically significant differences in dinoflagellate assemblages between locations. Bioluminescent species and known associates of HABs were present at both sites. Dinoflagellates in both areas were mainly represented by the order Gymnodiniales (66%—82% of total sequence reads). In the warm waters of Davies Reef, Gymnodiniales were equally represented by the two superclades, Gymnodiniales sensu stricto (33%) and Gyrodinium (34%). In contrast, in cooler waters of Port Phillip Bay, Gymnodiniales was mainly represented by Gyrodinium (82%). In both locations, bioluminescent dinoflagellates represented up to 0.24% of the total sequence reads, with Protoperidinium the most abundant genus. HAB-related species, mainly represented by Gyrodinium, were more abundant in Port Phillip Bay (up to 47%) than at Davies Reef (28%), potentially reflecting anthropogenic influence from highly populated and industrial areas surrounding the bay. The entire assemblage of dinoflagellates, as well as the subsets of HAB and bioluminescent species, were strongly correlated with water quality parameters (R2 = 0.56–0.92). Significant predictors differed between the subsets: HAB assemblages were explained by salinity, temperature, dissolved oxygen, and total dissolved solids; whereas, bioluminescent assemblages were explained only by salinity and dissolved oxygen, and had greater variability. Conclusion High-throughput sequencing and genotyping revealed greater diversity of dinoflagellate assemblages than previously known in both subtropical and temperate Australian waters. Significant correlations of assemblage structure with environmental variables suggest the potential for explaining the distribution and composition of both HAB species and bioluminescent species.

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 Investigating the effect of nickel concentration on phytoplankton growth to inform the assessment of ocean alkalinity enhancement

2022 ◽  
Author(s):  
Jiaying Abby Guo ◽  
Robert Strzepek ◽  
Anusuya Willis ◽  
Aaron Ferderer ◽  
Lennart Thomas Bach
Keyword(s):  
Nitrogen Source ◽  
Organic Ligand ◽  
Marine Phytoplankton ◽  
Growth Media ◽  
Accelerated Weathering ◽  
Marine Biota ◽  
Phytoplankton Species ◽  
Phytoplankton Communities ◽  
Wide Range ◽  
The Impact

Abstract. Ocean alkalinity enhancement (OAE) is a proposed method for removing carbon dioxide (CO2) from the atmosphere by the accelerated weathering of (ultra-) basic minerals to increase alkalinity – the chemical capacity of seawater to store CO2. During the weathering of OAE-relevant minerals relatively large amounts of trace metals will be released and may perturb pelagic ecosystems. Nickel (Ni) is of particular concern as it is abundant in olivine, one of the most widely considered minerals for OAE. However, so far there is limited knowledge about the impact of Ni on marine biota including phytoplankton. To fill this knowledge gap, this study tested the growth and photo-physiological response of 11 marine phytoplankton species to a wide range of dissolved Ni concentrations (from 0 nmol/L to 50,000 nmol/L). We found that the phytoplankton species were not very sensitive to Ni concentrations under the culturing conditions established in our experiments, but the responses were species-specific. The growth rates of 6 of the 11 tested species showed small but significant responses to changing Ni concentrations. Photosynthetic performance, assessed by measuring the maximum quantum yield (Fv/Fm) and the functional absorption cross-section (σPSII) of photosystem II, was also only mildly sensitive to changing Ni in 3 out of 11 species and 4 out of 11 species, respectively. The limited effect of Ni may be partly due to the provision of nitrate as the nitrogen source for growth, as previous studies suggest higher sensitivities when urea is the nitrogen source. Furthermore, limited influence may be due to the relatively high concentrations of organic ligands in the growth media in our experiments. These ligands reduced bioavailable Ni (i.e., “free Ni2+”) concentrations by binding the majority of the dissolved Ni. Our data suggest that dissolved Ni does not have a strong effect on phytoplankton under our experimental conditions, but we emphasize that a deeper understanding of nitrogen sources, ligand concentrations and phytoplankton composition is needed when assessing the influence of Ni release associated with OAE. We discuss if applications of OAE with Ni-rich minerals may be safer in regions with high organic ligand concentrations and low concentrations of urea as such boundary conditions may lead to less impact of Ni on phytoplankton communities.

Factors controlling primary productivity in a wet–dry tropical river

2013 ◽  
Vol 64 (7) ◽  
pp. 585 ◽  
Author(s):  
S. J. Faggotter ◽  
I. T. Webster ◽  
M. A. Burford
Keyword(s):  
Algal Blooms ◽  
Algal Biomass ◽  
Arid Zone ◽  
River System ◽  
Dry Season ◽  
Trophic Levels ◽  
Nutrient Inputs ◽  
Tropical River ◽  
Algal Production ◽  
The Impact

Algal production in rivers fuels foodwebs, and factors controlling this production ultimately affect food availability. Conversely, excessive algal production can have negative effects on higher trophic levels. The present study examined permanent waterholes in a disconnected wet–dry tropical river to determine the controls on algal production. Primary production in this river system was high compared with arid-zone and perennially flowing tropical rivers. Phytoplankton biomass increased over the dry season but this appeared to be because waterhole volume decreased, due to evaporation. Nitrogen (N) was the key limiting nutrient for phytoplankton, with rapid N turnover times, depletion of particulate 15N-nitrogen reflecting increasing N fixationover the dry season, and N stimulation in phytoplankton bioassays. The waterholes were shallow, providing sufficient light for accumulation of benthic algal biomass. Exclosure experiments were also conducted to determine the impact of top–down control on benthic algal biomass, with no evidence that exclusion of fish and crustaceans increased benthic algal biomass. The shallow off-channel waterhole in our study had substantially higher concentrations of nutrients and chlorophyll a than did the on-channel waterholes. This suggests that future anthropogenic changes, such as increased water extraction and increased nutrient inputs, could make the waterholes more vulnerable to deteriorating water quality, such as e.g. algal blooms, low concentrations of dissolved oxygen.

scholarly journals VARIACIÓN ESPACIO-TEMPORAL DE LA BIOMASA DEL ALGA CAULERPA SERTULARIOIDES EN POBLACIONES NATURALES Y EN CONDICIONES DE CULTIVO EN ESTANQUES DE CAMARÓN EN LA BAHÍA DE TUMACO, PACÍFICO COLOMBIANO

2016 ◽  
Vol 43 (1) ◽  
Author(s):  
Hernel Marín Salgado ◽  
Enrique Javier Peña Salamanca
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Algal Biomass ◽  
Algal Species ◽  
Natural Populations ◽  
Ammonia Nitrogen ◽  
Shrimp Ponds ◽  
Relative Growth ◽  
Culture Techniques ◽  
The Impact

The biomass of natural populations and biomass under cultured conditions in shrimp ponds of the green alga Caulerpa sertularioides (Chlorophyta, Bryopsidales) was evaluated during March-December 2010 and January- June 2011. The algal biomass in the estuary was collected monthly at low tide using 625 cm2 quadrants. Water quality variables, such as dissolved oxygen, salinity, temperature, Secchi disk, NO3 -, NH3 and PO4 3-, were taken simultaneously with algal samples. Algal biomass was taken to the lab to remove debris. Afterward, wet and dry weights were obtained to get final biomass. Relative growth rate (RGR% d-1) in ponds as well as physicochemical variables was evaluated weekly. Growth rates of plants registered a mean of 1.69 % day-1 (± 0.97). There were no significant differences (p = 0.315) in terms of biomass of C. sertularioides between Natal and Pajal creeks, showing averages between 4.09 and 4.67 g cm-2. Algal biomass showed significant differences between seasons (p = 0.000039), with highest values recorded between July and September. Salinity in Natal creek showed a direct relationship with seasonal variation of algal biomass (p = 0.019), with highest values of biomass in July-September related to higher levels of salinity in the study area. In contrast, salinity values and algal biomass in Pajal creek did not show significant relationship (p = 0.97). Nitrates, ammonia nitrogen, and orthophosphate were not significant with respect to changes in algal biomass (p = 0.93; p = 0.33; p = 0.55, respectively). Significant differences (p = 0.0021) between biomass of natural populations and algal biomass in shrimp ponds were reported, with higher values in cultured conditions, being those three times the biomass of natural creeks. Values of algal biomass from natural creeks suggested the importance of perform culture techniques, since natural populations would not sustain a commercial exploitation of this species. This study reports the first data of growth of a potential algal species and it is necessary to develop additional experiments to assess the impact of additional environmental factors on the relative growth rate.

scholarly journals Coexistence of dominant marine phytoplankton species sustained by nutrient specialization

2021 ◽  
Author(s):  
Takako Masuda ◽  
Keisuke Inomura ◽  
Jan Mareš ◽  
Taketoshi Kodama ◽  
Takuhei Shiozaki ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Nitrate Reductase ◽  
Surface Waters ◽  
Nitrate Uptake ◽  
Resource Competition ◽  
Ecological Model ◽  
Marine Phytoplankton ◽  
Phytoplankton Species ◽  
N Limitation

Abstract Prochlorococcus and Synechococcus are the two dominant picocyanobacteria in the low-nutrient surface waters of the subtropical ocean, but the basis for their coexistence in these biomes is still unclear. Here we combine in situ microcosm experiments and an ecological model to show that this coexistence can arise from specialization in the uptake of distinct nitrogen (N) substrates. In field incubations, the response of both Prochlorococcus and Synechococcus to nanomolar N amendments demonstrates N limitation of growth in both populations, but Prochlorococcus showed a higher affinity to ammonium whereas Synechococcus was more adapted to nitrate uptake. A simple ecological model demonstrates that the differential nutrient affinity of these species can explain their coexistence. Phylogenetic analysis of the presence of nitrate reductase and nitrite reductase further support the higher nitrate affinity of Synechococcus compared to Prochlorococcus. Our study suggests that the evolution of differential nutrient affinities is an important mechanism for sustaining coexistence of species under resource competition.

scholarly journals Effects of Nutrient Limitation on the Synthesis of N-Rich Phytoplankton Toxins: A Meta-Analysis

Toxins ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 221 ◽  
Author(s):  
Karen Brandenburg ◽  
Laura Siebers ◽  
Joost Keuskamp ◽  
Thomas G. Jephcott ◽  
Dedmer B. Van de Waal
Keyword(s):  
Nutrient Limitation ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Meta Analysis ◽  
Algal Species ◽  
Paralytic Shellfish Poisoning ◽  
Shellfish Poisoning ◽  
N Limitation ◽  
P Limitation ◽  
Toxin Content

Eutrophication has played a major role in the worldwide increase of harmful algal blooms (HABs). Higher input of key nutrients, such as nitrogen (N) and phosphorus (P), can stimulate the growth of harmful algal species in freshwater, estuarine, and coastal marine ecosystems. Some HAB-forming taxa, particularly several cyanobacteria and dinoflagellate species, are harmful through the production of N-rich toxins that have detrimental effects on the environment and human health. Here, we test how changes in nutrient availability affect N-rich toxin synthesis in cyanobacteria and dinoflagellates using a meta-analysis approach. Overall, N-rich toxin content showed an increase with P limitation, while it tended to decrease with N limitation, but we also observed substantial variation in responses both within and across genera and toxin groups. For instance, in response to N limitation, microcystin content varied from a 297% decrease up to a 273% increase, and paralytic shellfish poisoning (PSP) toxin content varied from a 204% decrease to an 82% increase. Cylindrospermopsin, produced by N2-fixing cyanobacteria, showed no clear direction in response to nutrient limitation, and cellular contents of this compound may thus vary independently of nutrient fluctuations. Our results confirm earlier reported stoichiometric regulation of N-rich phytoplankton toxins, showing increased toxin content with an increase in cellular N:P ratios, and vice versa. Thus, changes in N-rich toxin content largely follow the changes in relative cellular N content. Consequently, although nutrient limitation may limit bloom biomass and thereby bloom toxicity, our results warn that P limitation can cause accumulation of cellular toxins and thus lead to unexpected increases in bloom toxicity.

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