Future Blooms Research Articles

The role of tropical cyclones in stimulating cyanobacterial (Microcystis spp.) blooms in hypertrophic Lake Taihu, China

Weather-related disturbances, such as wind-generated waves, major rainfall events and large temperature shifts associated with frontal passages, are important drivers of ecological processes in shallow lakes. The influence of Pacific tropical cyclones on cyanobacterial blooms in China's third largest lake, Taihu, was studied during the passage of two typhoons using a continuous monitoring as part of an on-lake high-frequency recording platform, coupled to satellite-based remote sensing data. Short-term (on the order of hours) nutrient pulsing resulting from the passage of typhoons played a key role in bloom initiation and maintenance. Decreasing wind speeds and increasing air and water temperatures in the aftermath of cyclones were accompanied by elevated phytoplankton biomass concentrations. The synergistic effects of nutrient pulsing, elevated water temperatures and increased water column stratification after the passage of the cyclones stimulated blooms of the toxic cyanobacteria Microcystis spp. There were short-term successions of blooms following typhoons, and as blooms “crashed” they provided nutrient inocula for future blooms. Trends determined from historical in situ data indicated higher frequencies and intensities of blooms in “cyclone years”. Typhoons are an important driver of biogeochemical and water quality perturbations at the ecosystem-level in this hypertrophic lake. These events play a key role in our ability to forecast blooms over both short (days) and longer-term (weeks) periods.

Comparison of the efficacy of MODIS and MERIS data for detecting cyanobacterial blooms in the southern Caspian Sea

Medium Resolution Imaging Spectrometer (MERIS) data, Moderate Resolution Imaging Spectroradiometer (MODIS) data, and hydro-biological measurements were used to detect two very severe blooms in the southern Caspian Sea in 2005 and 2010. The MERIS Cyanobacteria Index (CIMERIS) was more reliable for detecting cyanobacterial blooms. The CIMERIS and MODIS cyanobacteria indices (CIMODIS) were compared in an effort to find a reliable method for detecting future blooms, as MERIS data were not available after April 2012. The CIMODIS had a linear relationship with and similar spatial patterns to the CIMERIS. On the CIMODIS images, extremely high biomass cyanobacteria patches were masked. A comparison of classified in situ data with the CIMODIS and Floating Algal Index (FAI) from four images of a severe bloom event in 2005 showed that the FAI is a reliable index for bloom detection over extremely dense patches. The corrected CIMODIS, the MODIS FAI and in situ data are adequate tools for cyanobacterial bloom monitoring in the southern Caspian Sea.

Predicting harmful algal blooms: a case study with Dinophysis ovum in the Gulf of Mexico

Blooms of Dinophysis ovum and Mesodinium spp. have been observed in the Gulf of Mexico since 2007 using the Imaging FlowCytobot technology. Bloom dynamics of these two organisms in conjunction with ancillary environmental data for a 5-year period were analyzed to identify the conditions necessary for bloom initiation or presence with the goal of predicting future blooms of D. ovum. Using time-series analysis, we observed a positive time-lagged correlation between the two organisms in each year when both were present, which suggests that the presence of Mesodinium may be useful as a leading indicator for a D. ovum bloom. Although in some cases D. ovum and Mesodinium co-occurred, no strong predator– prey relationship was observed. We identified a narrow range of temperature and salinity that could be necessary for bloom initiation of D. ovum and Mesodinium in the Gulf of Mexico. Analysis of images over the time series revealed a wide range in the size of Mesodinium cells, which suggests that species other than M. rubrum may be present in the Gulf of Mexico. Based on the occurrence of a D. ovum bloom preceded by low abundances of Mesodinium, we suggest that D. ovum is able to utilize ciliates other than M. rubrum as prey. Our observations indicate that environmental conditions, as well as Mesodinium abundance and species composition, can affect initiation, presence or abundance of D. ovum and thus may help in the prediction of future blooms.

Driving factors behind the distribution of dinocyst composition and abundance in surface sediments in a western Mediterranean coastal lagoon: Report from a high resolution mapping study

Species composition and abundance of dinocysts in relation to environmental factors were studied at 123 stations of surface sediment in Bizerte Lagoon. Forty-eight dinocyst types were identified, mainly dominated by Brigantidinium simplex, Votadinum spinosum, Alexandrium pseudogonyaulax, Alexandrium catenella, and Lingulodinum machaerophorum along with many round brown cysts and spiny round brown cysts. Cysts ranged from 1276 to 20126cystsg−1dry weight sediment. Significant differences in cyst distribution pattern were recorded among the zones, with a higher cyst abundance occurring in the lagoon’s inner areas. Redundancy analyses showed two distinct associations of dinocysts according to location and environmental variables. Ballast water discharges are potential introducers of non-indigenous species, especially harmful ones such as A. catenella and Polysphaeridium zoharyi, with currents playing a pivotal role in cyst distribution. Findings concerning harmful cyst species indicate potential seedbeds for initiation of future blooms and outbreaks of potentially toxic species in the lagoon.

A sensitive LC-MS/MS assay for brevisulcenal and brevisulcatic acid toxins produced by the dinoflagellate Karenia brevisulcata

A toxic dinoflagellate, Karenia brevisulcata, devastated almost all marine life in Wellington Harbour, New Zealand during the late summer of 1998. Brevisulcatic acids (BSXs) and brevisulcenals (KBTs), both polycyclic ether toxins, have been identified as the causative agents. A liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the sensitive and specific determination of BSXs and KBTs in culture medium, seawater and shellfish. Acidified algal culture, or seawater, was extracted using reverse phase solid phase extraction cartridges. Shellfish tissue homogenate was blended with methanol-water (9:1) and partitioned with hexane to remove non-polar lipids. This extraction protocol is similar to that used for analysis of lipophilic shellfish toxins. LC-MS/MS (triple quadrupole) was used for quantitative analysis with gradient elution (acidic buffer), positive electrospray ionization and multiple-reaction monitoring. Purified toxins were available for 4 KBTs (KBT-F, -G, -H and -I) and 4 BSXs (-1, -2, -4, and -5), and were used to calibrate the instrument responses. Relative response factors were used for semi-quantitative analysis of BSX-3 and BSX-6, using BSX-1 and BSX-4 respectively. Calibration curves for all toxins monitored were linear over the concentration range tested (5–200 ng mL−1) with r2 values >0.99. The method limit of quantitation was determined to be 2 ng mL−1 for BSXs and KBTs, except KBT-I, which was 5 ng mL−1. Validation data was generated for culture medium and shellfish. Toxin recoveries were typically >70% with relative standard deviations <20% across all of the matrices tested. In addition, toxins specific to K. brevisulcata were able to be detected in seawater at a cell concentration of 10,000 cells L−1, which represents the suggested trigger level for this harmful algal species. This method shows suitable performance characteristics to be regarded a useful tool to monitor toxin levels in a variety of sample matrices during future bloom events.

Predicting the potential habitat of the harmful cyanobacteria Lyngbya majuscula in the Canary Islands (Spain)

This study presents the ecological niche and the potential distribution of Lyngbya majuscula in the Canary Islands (Spain) based on a bloom of this species on the eastern side of the Canarian Archipelago, in the Marine Reserve of La Graciosa (MRG). This finding represents the first L. majuscula bloom recorded in waters around the Canary Islands and this side of the Atlantic Ocean. The modeled suitability map revealed a potential distribution of L. majuscula in rocky and sandy habitats within shallow and sheltered areas exposed to sedimentation; where L. majuscula blooms had not previously been reported. The L. majuscula bloom detected in MRG is affecting rocky and sandy communities in this area. The possible expansion of these blooms may have harmful effects on important communities in the Canary Islands, including some of high ecological importance such as the Cymodocea nodosa meadows. Results of the L. majuscula distribution model presented here can be used to develop management strategies that avoid or minimize the risk of future bloom occurrences or expansions and their negative effects on the environment. The causes of L. majuscula blooms in MRG are being investigated.

Future Bloom and Blossom Frost Risk for Malus domestica Considering Climate Model and Impact Model Uncertainties

The future bloom and risk of blossom frosts for Malus domestica were projected using regional climate realizations and phenological ( = impact) models. As climate impact projections are susceptible to uncertainties of climate and impact models and model concatenation, the significant horizon of the climate impact signal was analyzed by applying 7 impact models, including two new developments, on 13 climate realizations of the IPCC emission scenario A1B. Advancement of phenophases and a decrease in blossom frost risk for Lower Saxony (Germany) for early and late ripeners was determined by six out of seven phenological models. Single model/single grid point time series of bloom showed significant trends by 2021–2050 compared to 1971–2000, whereas the joint signal of all climate and impact models did not stabilize until 2043. Regarding blossom frost risk, joint projection variability exceeded the projected signal. Thus, blossom frost risk cannot be stated to be lower by the end of the 21st century despite a negative trend. As a consequence it is however unlikely to increase. Uncertainty of temperature, blooming date and blossom frost risk projection reached a minimum at 2078–2087. The projected phenophases advanced by 5.5 d K−1, showing partial compensation of delayed fulfillment of the winter chill requirement and faster completion of the following forcing phase in spring. Finally, phenological model performance was improved by considering the length of day.

Alexandrium fundyense cysts in the Gulf of Maine: Long-term time series of abundance and distribution, and linkages to past and future blooms

Here we document Alexandrium fundyense cyst abundance and distribution patterns over nine years (1997 and 2004–2011) in the coastal waters of the Gulf of Maine (GOM) and identify linkages between those patterns and several metrics of the severity or magnitude of blooms occurring before and after each autumn cyst survey. We also explore the relative utility of two measures of cyst abundance and demonstrate that GOM cyst counts can be normalized to sediment volume, revealing meaningful patterns equivalent to those determined with dry weight normalization.Cyst concentrations were highly variable spatially. Two distinct seedbeds (defined here as accumulation zones with>300cystscm−3) are evident, one in the Bay of Fundy (BOF) and one in mid-coast Maine. Overall, seedbed locations remained relatively constant through time, but their area varied 3–4 fold, and total cyst abundance more than 10 fold among years. A major expansion of the mid-coast Maine seedbed occurred in 2009 following an unusually intense A. fundyense bloom with visible red-water conditions, but that feature disappeared by late 2010. The regional system thus has only two seedbeds with the bathymetry, sediment characteristics, currents, biology, and environmental conditions necessary to persist for decades or longer. Strong positive correlations were confirmed between the abundance of cysts in both the 0–1 and the 0–3cm layers of sediments in autumn and geographic measures of the extent of the bloom that occurred the next year (i.e., cysts→blooms), such as the length of coastline closed due to shellfish toxicity or the southernmost latitude of shellfish closures. In general, these metrics of bloom geographic extent did not correlate with the number of cysts in sediments following the blooms (blooms→cysts). There are, however, significant positive correlations between 0–3cm cyst abundances and metrics of the preceding bloom that are indicative of bloom intensity or vegetative cell abundance (e.g., cumulative shellfish toxicity, duration of detectable toxicity in shellfish, and bloom termination date). These data suggest that it may be possible to use cyst abundance to empirically forecast the geographic extent of the forthcoming bloom and, conversely, to use other metrics from bloom and toxicity events to forecast the size of the subsequent cyst population as the inoculum for the next year's bloom. This is an important step towards understanding the excystment/encystment cycle in A. fundyense bloom dynamics while also augmenting our predictive capability for this HAB-forming species in the GOM.

Effects of hydrology and river management on the distribution, abundance and persistence of cyanobacterial blooms in the Murray River, Australia

Major cyanobacterial blooms (biovolume>4mm3L−1) occurred in the main water reservoirs on the upper Murray River, Australia during February and March 2010. Cyanobacterial-infested water was released and contaminated rivers downstream. River flow velocities were sufficiently high that in-stream bloom development was unlikely. The location has a temperate climate but experienced drought in 2010, causing river flows that were well below the long-term median values. This coupled with very low bed gradients meant turbulence was insufficient to destroy the cyanobacteria in-stream. Blooms in the upper 500km of the Murray and Edward Rivers persisted for 5 weeks, but in the mid and lower Murray blooms were confined to a small package of water that moved progressively downstream for another 650km. Anabaena circinalis was the dominant species present, confirmed by 16S rRNA gene sequencing, but other potentially toxic species were also present in smaller amounts. Saxitoxin (sxtA), microcystin (mcyE) and cylindrospermopsin (aoaA) biosynthesis genes were also detected, although water sample analysis rarely detected these toxins. River water temperature and nutrient concentrations were optimal for bloom survival. The operational design of weirs and retention times within weir pools, as well as tributary inflows to and diversions from the Murray River all influenced the distribution and persistence of the blooms. Similar flow, water quality and river regulation factors were underlying causes of another bloom in these rivers in 2009. Global climate change is likely to promote future blooms in this and other lowland rivers.

Record-setting algal bloom in Lake Erie caused by agricultural and meteorological trends consistent with expected future conditions.

In 2011, Lake Erie experienced the largest harmful algal bloom in its recorded history, with a peak intensity over three times greater than any previously observed bloom. Here we show that long-term trends in agricultural practices are consistent with increasing phosphorus loading to the western basin of the lake, and that these trends, coupled with meteorological conditions in spring 2011, produced record-breaking nutrient loads. An extended period of weak lake circulation then led to abnormally long residence times that incubated the bloom, and warm and quiescent conditions after bloom onset allowed algae to remain near the top of the water column and prevented flushing of nutrients from the system. We further find that all of these factors are consistent with expected future conditions. If a scientifically guided management plan to mitigate these impacts is not implemented, we can therefore expect this bloom to be a harbinger of future blooms in Lake Erie.

Effect of Atlantic water inflow on timing of the phytoplankton spring bloom in a high Arctic fjord (Kongsfjorden, Svalbard)

The spring bloom in Kongsfjorden, Svalbard was followed during the years 2006–2008 to study the bloom dynamics in relation to environmental factors. Usual timing of the bloom in this normally ice-filled fjord has been May with few exceptions. But in 2006 the bloom occurred in April. This was the first of 3 consecutive spring seasons with no ice in the fjord. But even so the bloom was delayed until May both in 2007 and 2008. The 2006 bloom was characterized by high phytoplankton biomass and a mix of diatoms and Phaeocystis pouchetii. The 2007 and 2008 spring blooms were delayed until mid/late May, and the biomass and biodiversity were significantly reduced, with a more pronounced dominance of Phaeocystis relative to diatoms. The different bloom developments are discussed in relation to Atlantic water inflow, which varied between the years in question and seemed to be the main controlling factor of the spring blooms. Possible future bloom scenarios are also discussed.

For 'sated' peoples no future blooms The concept of 'S�ttigung' in Max Weber's work

Despite the absence of an explicit definition in Max Weber, the concept of Sättigung runs through his whole works, from Der Nationalstaat und die Volkswirtschaftspolitik to Wissenschaft als Beruf. To date Weberian exegesis has underestimated the hermeneutical value of this notion; this article seeks to rectify this providing a reconstruction of the occurrences of this semantics, which plays–in my opinion–a significant role in Weber's reflection. Moreover, the analysis of this concept could be useful also in contemporary debate.

Distribution of dinoflagellate cysts in recent sediments from Izmir Bay (Aegean Sea, Eastern Mediterranean)

Abstract To determine the species composition, abundance and horizontal distribution of dinoflagellate cysts in recent marine sediments, samples were collected at 13 stations in Izmir Bay, Aegean Sea. At least thirty-six dinoflagellate cyst types were identified, with the assemblages mainly dominated by Lingulodinium machaerophorum , Polykrikos kofoidii , Operculodinium centrocarpum , Gymnodinium cf. nolleri and Quinquecuspis concreta . Total cyst concentrations ranged from 41 to 3292 cystsg − 1 dry weight sediment. The majority of the cysts occurred in the inner and middle parts of the bay, where higher cyst concentrations were observed. According to the One Way Anova test, the difference between stations was significant statistically (p Gymnodinium cf. nolleri and Oblea acanthocysta . Alexandrium minutum and Alexandrium affine type cyst were observed at almost all stations although the cyst type of the Alexandrium catenella/tamarense complex was only found in the outer bay. These findings indicate potential seedbeds for initiation of future blooms and outbreaks of potentially toxic species in Izmir Bay.

Occurrence of a Cylindrospermopsis bloom in Louisiana

Cylindrospermopsis raciborskii occurs predominantly in tropical to subtropical freshwaters but appears to be spreading to temperate regions. After the hurricanes of 2005, a bloom of this organism took place in Lake Dauterive and Lake Fausse Pointe in Louisiana. The cyanobacterium dominated the phytoplankton community for three months. Of the three known morphotypes (straight, coiled and spiral) only coiled and spiral were found. In June 2006, 60% of the organisms were of the spiral morphotype but the relative abundance of this morphotype decreased dramatically within the month of June. However, the average density for both morphotypes remained the same until September. Densities (up to 160,000 cells/mL) significantly exceeded the threshold for toxicity. Because the sampled region offers optimal light and nutrient conditions, it is likely that C. raciborskii has been established in this region and future blooms can be expected. Therefore, a monitoring program should be implemented.

Environmental factors influencing the variability of Lingulodinium polyedrum and Scrippsiella trochoidea (Dinophyceae) cyst production

This study analyzes the temporal variability of the abundance of Lingulodinium polyedrum and Scrippsiella trochoidea resting cysts in surface sediments, as well as the temporary cysts and vegetative cells of L. polyedrum in the upper water column of Todos Santos Bay (Baja California, Mexico). Samples were collected monthly from January 2002 to June 2005 at four sites. Multidimensional scaling analysis and analysis of similarities revealed that resting cysts are distributed heterogeneously according to the sedimentary environment. Surface water temperature, inorganic dissolved phosphate, and the abundance of temporary cysts were the main factors influencing the abundance of L. polyedrum resting cysts, while the variability of temporary cysts was explained by the abundance of planktonic cells. Scrippsiella trochoidea resting cysts showed no statistical relationship with the environmental factors considered. Local runoff during the rainy season and sewage from the city of Ensenada contribute to the eutrophication of the bay. This is an important factor for future blooms since inorganic dissolved nitrate + nitrite and daylight hours during the spring-summer season are not limiting factors for dinoflagellate growth. After the dinoflagellate blooms, there was massive cyst production of both species, and the new cysts settled on the surface sediments. Surface water temperatures between 17°C and 22.5°C during spring-summer appear to trigger excystment in these species.

Species composition and seasonal changes in macroalgal blooms in lagoons along the southeastern Gulf of California

Abstract Species composition and seasonal changes in macroalgal blooms in six coastal lagoons highly impacted by human activities were tracked for the three seasons between May 2004 and April 2005. Though temperatures were lower during the cold season than during the dry and rainy seasons and some locations showed variations in salinity during the rainy season, nutrient concentrations showed no defined pattern and varied according to season and location. A total of 10 seaweed species and the cyanobacterium Microcoleus lyngbyaceus had biomasses &gt;1 g m-2 dry weight, but only four species represented &gt;1% of the annual biomass. During the dry season, Spyridia filamentosa had the highest biomass (57.5 g m-2). During the rainy season, Gracilaria vermiculophylla was the most conspicuous and abundant species (64.0–291.0 g m-2) and during the cold season, Caulerpa sertularioides had the highest biomass (180.1 g m-2). Abundances of these species were higher than previously reported for this region. Correlation analyses showed a positive correlation between total phosphorus and the biomass of G. vermiculophylla, suggesting that this nutrient might be limiting its growth. C. sertularioides abundance had a positive correlation with N:P ratios, suggesting that high concentrations of nitrogen relative to low phosphorus levels favor its growth. These analyses revealed that nutrient concentrations are most likely to affect macroalgal growth, but temperature and salinity also play a role. This information may be useful for monitoring future blooms and determining changes over time.

Marine birds and harmful algal blooms: sporadic victims or under-reported events?

From the late Pliocene to now, blooms of toxic algae are associated with mortalities of marine birds. Given the long historical presence of harmful algal blooms (HABs) worldwide and the numbers of seabirds that feed on filter-feeding fish and shellfish, it is surprising that relatively few incidents of seabird deaths as a result of toxic algae have been reported. The limited information available tends to come from major events, whereas the rare events are missed and hence not reported. Much is anecdotal and still more probably is not published. We suspect that factors working in concert may lead to deaths and wrecks that might not occur as a result of anyone factor working independently, e.g. starvation tends to render birds more vulnerable to stress. “Seabird wrecks”, very much larger than usual concentration of seabird corpses washed ashore over a short period of time, often provide evidence of deleterious conditions in offshore populations, e.g. weather, food, pollution, fishing activities, and parasites. It is noted in the literature that wrecks caused by natural toxins such as botulism and algal toxins are apparently less common; however, this perception may be due to a combination of factors including the bird species involved, size of populations, location, and chance of discovery. Wrecks involving near-shore species probably provide a more accurate estimate of total mortality for any given event than offshore species. A survey of available data on the impacts of toxic algae on seabirds revealed an array of responses ranging from reduced feeding activity, inability to lay eggs, and loss of motor coordination to death. Severe impacts on recruitment have been noted in some populations. There are few experimental studies; however, evidence has been provided for the ability of some species to ‘learn’ to avoid toxic food sources. We present a summary of available data on seabird/toxic algal interactions and suggestions of how impacts on seabirds during future blooms of harmful algae be recorded.

The sedimentary record of dinoflagellate cysts: looking back into the future of phytoplankton blooms

SUMMARY: Marine systems are not as well understood as terrestrial systems, and there is still a great need for more primary observations, in the tradition of the old-time naturalists, before newer methods such as molecular genetics and modeling can be fully utilized. The scientific process whereby the smaller, detailed “building blocks” of observation are ultimately linked towards better understanding natural systems is illustrated from my own career experience, especially with regard to the dinoflagellates and plankton blooms. Some dinoflagellates produce a fossilizable resting stage (cyst) in their life cycle, and dinoflagellate cysts have become one of the most important groups of microfossils used in geological exploration (e.g. oil and gas). This has stimulated both paleontological and biological research producing detailed “building blocks” of information, currently scattered throughout the respective literature. Here, I attempt to bring together the present day perspective, from biology, with the past, from paleontology, as the most comprehensive basis for future work on the group. This shows the cysts to be the critical link needed for focusing future molecular genetics studies towards a more verifiable view of evolutionary pathways, and it also suggests new integrated methods for studying past, present, and future blooms. The large, rapidly growing field of harmful algal bloom studies is producing many different “building blocks”, but plankton blooms as episodic phenomena are still poorly understood. This is largely due to the general lack of long-term datasets allowing identification of the changing environmental factors that permit certain species to bloom at unpredictable intervals of time. Cysts in sediments are useful environmental indicators today, e.g. reflecting aspects of climate and pollution, and provide information directly relevant to some dinoflagellate blooms. They therefore may be used for obtaining retrospective information from the sedimentary record on the history of blooms, in turn suggesting information relevant for future blooms and the way we study them.

Response of Onondaga Lake to Restoration Efforts

The continuing restoration program for polluted, hypereutrophic Onondaga Lake, is examined, including descriptions of ecosystem responses to reclamation measures and evaluations of the various characteristics specific to the lake as they may affect future responses. Major responses to the program have included: (1)Substantial changes in phytoplankton composition; (2)reduction in concentrations of heavy metals; and (3)a dramatic increase in zooplankton biomass. Despite a major reduction in phosphorus loading, phytoplankton biomass has remained essentially unchanged. Further reductions in phosphorus loading, anticipated with the new (1981) tertiary sewage treatment plant, may result in phosphorus limited phytoplankton growth. The increase in zooplankton implies increased phytoplankton turnover rates and phosphorus recycling within the lake, which may prolong future phytoplankton blooms.