Detection of red tide events in the Ariake Sound, Japan

Science.gov (United States)

Ishizaka, Joji

2003-05-01

High resolution SeaWiFS data was used to detect a red tide event occurred in the Ariake Sound, Japan, in winter of 2000 to 2001. The area is small embayment surrounding by tidal flat, and it is known as one of the most productive areas in coast of Japan. The red tide event damaged to seaweed (Nori) culture, and the relation to the reclamation at the Isahaya Bay in the Sound has been discussed. SeaWiFS chlorophyll data showed the red tide started early December 2000, from the Isahaya Bay, although direct relationship to the reclamation was not clear. The red tide persisted to the end of February. Monthly average of SeaWiFS data from May 1998 to December 2001 indicated that the chlorophyll increased twice a year, early summer and fall after the rain. The red tide event was part of the fall bloom which started later and continued longer than other years. Ocean color is useful to detect the red tide; however, it is required to improve the algorithms to accurately estimate chlorophyll in high turbid water and to discriminate toxic flagellates.

Dinoflagellate community structure from the stratified environment of the Bay of Bengal, with special emphasis on harmful algal bloom species

Digital Repository Service at National Institute of Oceanography (India)

Naik, R.K.; Hegde, S.; Anil, A.C.

the total marine phytoplankton species, approximately 7% are capable of forming algal blooms (red tides) (Sournia 1995); dinoflagellates are the most important group producing toxic and harmful algal blooms (Steidinger 1983, 1993; Anderson 1989... Taxonomic identification revealed 134 species of dinoflagellates in surface waters of the BOB during the observation period (Table 2). Further grouping of these identified species based on their nutritional mode, revealed 40 autotrophic, 50 mixotrophic...

Risk in daily newspaper coverage of red tide blooms in Southwest Florida.

Science.gov (United States)

Li, Zongchao; Garrison, Bruce; Ullmann, Steven G; Kirkpatrick, Barbara; Fleming, Lora E; Hoagland, Porter

This study investigated newspaper coverage of Florida red tide blooms in four metropolitan areas of Southwest Florida during a 25-year period, 1987-2012. We focused on how journalists framed red tide stories with respect to environmental risk, health risk, and economic risk. We determined risk to be a key factor in this news coverage, being an aspect of coverage of red tide itself in terms of environmental risk, tourism risk, and public health risk. The study found that red tide news coverage is most often framed as an environmental story.

Specific toxic effect of dinoflagellate Heterocapsa circularisquama on the rotifer Brachionus plicatilis.

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Kim, D; Sato, Y; Oda, T; Muramatsu, T; Matsuyama, Y; Honjo, T

2000-12-01

Heterocapsa circularisquama (Dinophyceae), a noxious red tide dinoflagellate, is known to have a specifically lethal effect on shellfish, especially bivalves such as pearl oyster (Pinctada fucata), but no detrimental effects of this alga on fishes have not been observed so far. In this study, we found that H. circularisquama was toxic to a microzooplankton, a rotifer (Brachionus plicatilis) in a cell concentration-dependent manner, while the cultured supernatant or ultrasonic ruptured H. circularisquama had no significant toxic effect on the rotifer. Since no such toxic effects on the rotifer were observed in Chattonella marina, Heterosigma akashiwo, or Cochlodinium polykrikoides, other species of harmful red tide plankton, H. circularisquama may have a strictly specific toxic mechanism against the rotifer as well as bivalves.

Benthic dinoflagellate blooms in tropical intertidal rock pools: Elucidation of photoprotection mechanisms

Digital Repository Service at National Institute of Oceanography (India)

Patil, J.S.; Rodrigues, R.V.; Paul, P.; Sathish, K.; Rafi, M.; Anil, A.C.

(HT), mid tide (MT), and low tide (LT) zones on the rocky shores of Anjuna, Goa (India) facing the Arabian Sea. MT-RPs and LT-RPs were dominated by diatoms and HT-RPs by dinoflagellates due to the blooms of autotrophic benthic dinoflagellates belonging...

Atmospheric Transport of Nutrient Matter during a Red Tide Event

Science.gov (United States)

Tian, R.; Weng, H.; Lin, Q.

2017-12-01

Harmful algal blooms (HABs) resulting from an explosive increase in algae population have become a global problem in coastal marine environment. During 3rd -8th, May of 2006, large-scale, mixed prorocentrum dentatum stein and skeletonema costatum bloom developed in those water off the coast of Zhejiang province (Zhoushan city and Liuheng Island) of China. Using Global Nested Air Quality Prediction Modeling System (GNAQPMS), we find an atmospheric transport of considerable nutrient matter (nitrate, ammonium, Fe (Ⅱ)) to East China Sea (ECS) before the red tide event. It be inferred that the atmospheric transport of nutrient matter is a significant source of nutrient matter in the water of East China Sea whose hydrological setting is dominated by oligotrophic Taiwan Warm Current in spring. Such atmospheric transport of nutrient matter is likely a cause factor of red tide in the coast of East China Sea, especially during dust event. The study provides new information for discovering the occurring mechanism of the red tides in ECS and the essential parameters for the red tide research.

A Plan to Develop a Red Tide Warning System for Seawater Desalination Process Management

Science.gov (United States)

Kim, Tae Woo; Yun, Hong Sik

2017-04-01

The holt of the seawater desalination process for fifty five days due to the eight-month long red tide in 2008 in the Persian Gulf, the Middle East, had lost about 10 billion KRW. The POSCO Seawater Desalination facility, located in Gwangyang Bay Area in the Southern Sea, has produced 30,000 tons of fresh water per day since 2014. Since there has been an incident of red time in the area for three months in August, 2012, it is necessary to establish a warning system for red tide that threatens the stable operation of the seawater desalination facility. A red tide warning system can offer the seawater desalination facility manager customized services on red tide information and potential red tide inflow to the water intake. This study aimed to develop a red tide warning system in Gwangyang Bay Area by combining RS, modeling and monitoring technologies, which provides red tide forecasting information with which to effectively control the seawater desalination process. Using the proposed system, the seawater desalination facility manager can take phased measures to cope with the inflow of red tide. ACKNOWLEDGMENTS This research was supported by a grant(16IFIP-C088924-03) from Industrial Facilities & Infrastructure Research Program funded by Ministry of Land, Infrastructure and Transport(MOLIT) of the Korea government and the Korea Agency for Infrastructure Technology Advancement (KAIA). This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(NRF-2014R1A1A2054975).

The Prevalence of Benthic Dinoflagellates Associated with Ciguatera in the Central Red Sea

KAUST Repository

Catania, Daniela

2012-12-01

This study confirms the presence of Gambierdiscus sp., Ostreopsis sp. as well as other epiphytic benthic dinoflagellates associated with Ciguatera Fish Poisoning (CFP) in the Central Red Sea, highlighting the potential occurrence of CFP in this region. These species are reported for the first time in Saudi Arabian coastal waters. A total of 80 Turbinaria and Halimeda macroalgae samples were collected from coral reefs off the Saudi Arabian coast. Sample analyses indicated low average cell abundances (< 40 cells g-1 wet weight algae) of Gambierdiscus sp. and Ostreopsis sp. Subsequent statistical analyses indicated a significant difference in the cell abundances of both genera between sampling sites, between species and between inshore and offshore reefs. The presence of several potentially toxigenic dinoflagellate species in the Red Sea and the statistical differences in abundances between different sampling sites merits future study on possible impacts of these dinoflagellates on marine food webs and human health.

NOAA NCCOS: New England Red Tide Research

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National Oceanic and Atmospheric Administration, Department of Commerce — Alexandrium blooms are one of several algal bloom types often called "red tides," but more correctly referred to as Harmful Algal Blooms (HABs). Alexandrium produces...

Seasonal variation in composition and abundance of harmful dinoflagellates in Yemeni waters, southern Red Sea.

Science.gov (United States)

Alkawri, Abdulsalam

2016-11-15

General abundance and species composition of a dinoflagellate community in Yemeni coastal waters of Al Salif (southern Red Sea) were studied with a view to understand the annual variations in particular the toxic species. Dinoflagellates were more abundant among phytoplankton. Thirty five dinoflagellate taxa were identified, among which 12 were reported as potentially toxic species. A significant change in seasonal abundance was recorded with the maximum (2.27∗10 6 cellsl -1 ) in May, and the minimum (2.50∗10 2 cellsl -1 ) recorded in January. Kryptoperidinium foliaceum, which was reported for the first time from the Red Sea, was the most abundant species with a maximum in May 2013 (2.26∗10 6 cellsl -1 ). Spearman's rank correlation analysis indicates that, total harmful dinoflagellate cells, K. foliaceum, Prorocentrum gracile and Prorocentrum micans were significantly correlated with temperature. This study suggests that Yemeni waters should be monitored to investigate harmful species and to identify areas and seasons at higher risk. Copyright © 2016 Elsevier Ltd. All rights reserved.

Allelopathic interactions between the red-tide causative dinoflagellate Prorocentrum donghaiense and the diatom Phaeodactylum tricornutum* This study was supported by the Natural Science Foundation of China-Guangdong Province Joint Key Project (U1133003 Science Technology Planning Project of Guangdong Province (2012B020307009 Open Fund from Key Laboratory of Aquatic Eutrophication Control of Harmful Algal Blooms of Guangdong Higher Education Institutes Open Fund from Key Laboratory of Microbial Resources Collection Preservation Ministry of Agriculture.

Directory of Open Access Journals (Sweden)

Zhuoping Cai

2014-06-01

Full Text Available The interactions between the red-tide causing dinoflagellate Prorocentrum donghaiense and the marine diatom Phaeodactylum tricornutum were investigated using a co-culture experiment and an enriched culture filtrate experiment. The results showed that when the two microalgae were cultured together with different initial cell densities, the growth of one species was basically suppressed by the other one. In addition, the enriched culture filtrates of one species had generally inhibitory effects on the other one. Our result inferred that P. donghaiense and P. tricornutum would interfere with each other mainly by releasing allelochemicals into the culture medium, and that the degree of allelopathic effects was dependent on the initial cell densities and growth phases. The allelopathic interactions between microalgal species may contribute to the formation and succession of red tides.

Red Tide Strands South African Rock Lobsters

Science.gov (United States)

2002-01-01

Although some red tides form a healthy part of phytoplankton production, recurrent harmful or toxic blooms also occur, with results depending upon the type of plankton and on atmospheric and oceanic conditions. At Elands Bay in South Africa's Western Cape province, about 1000 tons of rock lobsters beached themselves during February 2002, when the decay of dense blooms of phytoplankton caused a rapid reduction in the oxygen concentration of nearshore waters. The lobsters (or crayfish, as they are known locally) moved toward the breaking surf in search of oxygen, but were stranded by the retreating tide. The Multi-angle Imaging SpectroRadiometer's nadir camera acquired these red, green, blue composites on February 2 and 18, 2002, during Terra orbits 11315 and 11548. The colors have been accentuated to highlight the bloom, and land and water have been enhanced separately. The two views show the shoreward migration of the algal bloom. Each image represents an area of about 205 kilometers x 330 kilometers. Elands Bay is situated near the mouth of the Doring River, about 75 kilometers northeast of the jutting Cape Columbine. The term 'red tide' is used to refer to a number of different types of phytoplankton blooms of various hues. The wine color of certain parts of this bloom are consistent with the ciliate species Mesodinium rubrum, which has been associated with recurring harmful algal blooms along the Western Cape coast. Under these conditions, the lobsters are not poisoned. During the recent event, government and military staff transported as many of the living lobsters as possible to areas that were less affected by the red tide. At the same time, people came from across South Africa to gather the undersized creatures for food. The effects of the losses on the maritime economy are expected to be felt over the next few years. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra

Risk in Daily Newspaper Coverage of Red Tide Blooms in Southwest Florida

Science.gov (United States)

Li, Zongchao; Garrison, Bruce; Ullmann, Steven G.; Kirkpatrick, Barbara; Fleming, Lora E.; Hoagland, Porter

2015-01-01

This study investigated newspaper coverage of Florida red tide blooms in four metropolitan areas of Southwest Florida during a 25-year period, 1987-2012. We focused on how journalists framed red tide stories with respect to environmental risk, health risk, and economic risk. We determined risk to be a key factor in this news coverage, being an…

Study of ocean red tide multi-parameter monitoring technology based on double-wavelength airborne lidar system

Science.gov (United States)

Lin, Hong; Wang, Xinming; Liang, Kun

2010-10-01

For monitoring and forecasting of the ocean red tide in real time, a marine environment monitoring technology based on the double-wavelength airborne lidar system is proposed. An airborne lidar is father more efficient than the traditional measure technology by the boat. At the same time, this technology can detect multi-parameter about the ocean red tide by using the double-wavelength lidar.It not only can use the infrared laser to detect the scattering signal under the water and gain the information about the red tise's density and size, but also can use the blue-green laser to detect the Brillouin scattering signal and deduce the temperature and salinity of the seawater.The red tide's density detecting model is firstly established by introducing the concept about the red tide scattering coefficient based on the Mie scattering theory. From the Brillouin scattering theory, the relationship about the blue-green laser's Brillouin scattering frequency shift value and power value with the seawater temperature and salinity is found. Then, the detecting mode1 of the saewater temperature and salinity can be established. The value of the red tide infrared scattering signal is evaluated by the simulation, and therefore the red tide particles' density can be known. At the same time, the blue-green laser's Brillouin scattering frequency shift value and power value are evaluated by simulating, and the temperature and salinity of the seawater can be known. Baed on the multi-parameters, the ocean red tide's growth can be monitored and forecasted.

Grazing of heterotrophic dinoflagellate Noctiluca scintillans (Mcartney) Kofoid on Gymnodinium catenatum Graham.

Science.gov (United States)

Alonso Rodríguez, Rosalba; Ochoa, José Luis; Uribe Alcocer, Manuel

2005-01-01

A dinoflagellate bloom ("red tide" event) dominated by the toxic Gymnodinium catenatum Graham (Gymnodiniales, Dinophyceae; 99.7%) and the noxious Noctiluca scintillans (Mcartney) Kofoid (Noctilucaceae, Dinophyceae; 0.3%) was observed in Bahia de Mazatlán Bay, México, on 24-26 January 2000. Photographic and microscopic analysis of samples during such an event, allowed us to collect evidence of a marked The particularity of grazing of G. catrenatum by by N. scintillans cells, suggesting a mechanism of "biocontrol" between these species that may contribute to attenuate a potentially toxic phenomenon under natural conditions.

Occurrence of red tide caused by Karenia mikimotoi (toxic dinoflagellate) in the Southwest coast of India

Digital Repository Service at National Institute of Oceanography (India)

Madhu, N.V.; Reny, P.D.; Paul, M.; Ullas, N.; Resmi, P.

.5-39.9 mu M) and chlorophyll a (av. 56.8 + or -23.7 mg m sup(-3)) concentration were observed during the bloom period. Microscopic analysis revealed that the discoloration was caused by an unarmored toxic dinoflagellate, Karenia mikimotoi Miyake & Kominami...

Characterizing the interactions among a dinoflagellate, flagellate and bacteria in the phycosphere of Alexandrium tamarense (Dinophyta

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Lidan eHu

2015-11-01

Full Text Available A small flagellate alga was isolated from the phycosphere of a toxic red tide dinoflagellate Alexandrium tamarense. Phylogenetic analysis and ultrastructural observations demonstrated that the samll flagellate alga is a species belong to Ochrophyte Ochromonas sp. The process of ingesting bacteria by Ochromonas sp. was recorded by a time lapse capture under a light microscope. Through the use of different assemblages in the co-culture experiment, the species interactions in this phycosphere microenvironment were analyzed. We demonstrated that the growth of Ochromonas sp. was supported by bacteria. Three strains of bacteria ingested by Ochromonas sp. were isolated and identified to belong to α-, δ- and γ-Proteobacteria. The growth of A. tamarense was suppressed when co-cultured with bacteria. In contrast, Ochromonas sp. triggered the growth of A. tamarense by inhibiting the growth of algicidal bacteria. This result firstly demonstrated a positive effect of a flagellate on a dinoflagellate in the phycosphere of A. tamarense. Combined with other negative effects between dinoflagellates and bacteria or bacteria and flagellates, this study showed a series of clear interactions among dinoflagellate, bacterium, and flagellate in the dinoflagellate microenvironment.

Red tide discolouration and its impact on fisheries

Digital Repository Service at National Institute of Oceanography (India)

Devassy, V.P.

months. Although the earlier two red tides did not provide any direct evidence of fish mortality, the 1987 one was followed by a substantial fall in fish catch. The prevailing environmental conditions and the probable impact on the fisheries during...

Environmental barcoding reveals massive dinoflagellate diversity in marine environments.

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Rowena F Stern

2010-11-01

Full Text Available Dinoflagellates are an ecologically important group of protists with important functions as primary producers, coral symbionts and in toxic red tides. Although widely studied, the natural diversity of dinoflagellates is not well known. DNA barcoding has been utilized successfully for many protist groups. We used this approach to systematically sample known "species", as a reference to measure the natural diversity in three marine environments.In this study, we assembled a large cytochrome c oxidase 1 (COI barcode database from 8 public algal culture collections plus 3 private collections worldwide resulting in 336 individual barcodes linked to specific cultures. We demonstrate that COI can identify to the species level in 15 dinoflagellate genera, generally in agreement with existing species names. Exceptions were found in species belonging to genera that were generally already known to be taxonomically challenging, such as Alexandrium or Symbiodinium. Using this barcode database as a baseline for cultured dinoflagellate diversity, we investigated the natural diversity in three diverse marine environments (Northeast Pacific, Northwest Atlantic, and Caribbean, including an evaluation of single-cell barcoding to identify uncultivated groups. From all three environments, the great majority of barcodes were not represented by any known cultured dinoflagellate, and we also observed an explosion in the diversity of genera that previously contained a modest number of known species, belonging to Kareniaceae. In total, 91.5% of non-identical environmental barcodes represent distinct species, but only 51 out of 603 unique environmental barcodes could be linked to cultured species using a conservative cut-off based on distances between cultured species.COI barcoding was successful in identifying species from 70% of cultured genera. When applied to environmental samples, it revealed a massive amount of natural diversity in dinoflagellates. This highlights

Condition of red tide appearance in Wakasa Bay based on Terra, Aqua/MODIS images

Science.gov (United States)

Aoyama, Takashi; Oya, Hiroshi

2006-12-01

Since June, 2004, studies on triggering factors of the red tide have been carried out in Awara Space Radio Observatory (ASRO), Fukui University of Technology utilizing directly received data of MODIS on the Terra and Aqua satellites which have been acquired in ASRO. Preliminary results of the data analyses for the period from July, 2001 to April, 2005 indicate conditions, for the appearance of the red tide bloom in Wakasa bay as follows: (1) the threshold amount of chlorophyll-a is close to 1.5mg/m 3, (2) the range of sea surface temperature (SST) is limited in a range from 12 to 20 °C and (3) the period of sunlit time in spring is also a significantly sensitive factor. We propose here to utilize MODIS band1 images corresponding to a red band with spatial resolution of 250m together with NDVI (Normalized Difference Vegetation Index) images which has also spatial resolution of 250m, for the confirmation of the red tide. The problem of coincidence between colored region due to SS (Suspended Sediment) and red tide region using only band1 of MODIS, has been solved by using NDVI images in addition to band1 images together as two dimensional diagram.

Sublethal red tide toxin exposure in free-ranging manatees (Trichechus manatus) affects the immune system through reduced lymphocyte proliferation responses, inflammation, and oxidative stress

International Nuclear Information System (INIS)

Walsh, Catherine J.; Butawan, Matthew; Yordy, Jennifer; Ball, Ray; Flewelling, Leanne; Wit, Martine de; Bonde, Robert K.

2015-01-01

Highlights: • Sublethal brevetoxin exposure affects manatee immune function. • Plasma brevetoxin levels correlate with oxidative stress in rescued manatees. • Brevetoxin exposure affects lymphocyte proliferation in rescued manatees. • Plasma brevetoxin concentrations ranged from 0 to 19 ng PbTx-3 eq/mL. - Abstract: The health of many Florida manatees (Trichechus manatus latirostris) is adversely affected by exposure to blooms of the toxic dinoflagellate, Karenia brevis. K. brevis blooms are common in manatee habitats of Florida’s southwestern coast and produce a group of cyclic polyether toxins collectively referred to as red tide toxins, or brevetoxins. Although a large number of manatees exposed to significant levels of red tide toxins die, several manatees are rescued from sublethal exposure and are successfully treated and returned to the wild. Sublethal brevetoxin exposure may potentially impact the manatee immune system. Lymphocyte proliferative responses and a suite of immune function parameters in the plasma were used to evaluate effects of brevetoxin exposure on health of manatees rescued from natural exposure to red tide toxins in their habitat. Blood samples were collected from rescued manatees at Lowry Park Zoo in Tampa, FL and from healthy, unexposed manatees in Crystal River, FL. Peripheral blood leukocytes (PBL) isolated from whole blood were stimulated with T-cell mitogens, ConA and PHA. A suite of plasma parameters, including plasma protein electrophoresis profiles, lysozyme activity, superoxide dismutase (SOD) activity, and reactive oxygen/nitrogen (ROS/RNS) species, was also used to assess manatee health. Significant decreases (p < 0.05) in lymphocyte proliferation were observed in ConA and PHA stimulated lymphocytes from rescued animals compared to non-exposed animals. Significant correlations were observed between oxidative stress markers (SOD, ROS/RNS) and plasma brevetoxin concentrations. Sublethal exposure to brevetoxins in the

Sublethal red tide toxin exposure in free-ranging manatees (Trichechus manatus) affects the immune system through reduced lymphocyte proliferation responses, inflammation, and oxidative stress

Energy Technology Data Exchange (ETDEWEB)

Walsh, Catherine J., E-mail: cjwalsh@mote.org [Marine Immunology Program, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236 (United States); Butawan, Matthew, E-mail: mattbutawan@outlook.com [Marine Immunology Program, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236 (United States); Yordy, Jennifer, E-mail: jennifer.e.balmer@gmail.com [Marine Immunology Program, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236 (United States); Ball, Ray, E-mail: Ray.Ball@lowryparkzoo.com [Lowry Park Zoo, 1101 W Sligh Ave, Tampa, FL 33604 (United States); Flewelling, Leanne, E-mail: Leanne.Flewelling@MyFWC.com [Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, 100 8th Ave SE, St. Petersburg, FL 33701 (United States); Wit, Martine de, E-mail: Martine.deWit@MyFWC.com [Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, 100 8th Ave SE, St. Petersburg, FL 33701 (United States); Bonde, Robert K., E-mail: rbonde@usgs.gov [U.S. Geological Survey, Sirenia Project, 7920 NE 71st Street, Gainesville, FL 32653 (United States)

2015-04-15

Highlights: • Sublethal brevetoxin exposure affects manatee immune function. • Plasma brevetoxin levels correlate with oxidative stress in rescued manatees. • Brevetoxin exposure affects lymphocyte proliferation in rescued manatees. • Plasma brevetoxin concentrations ranged from 0 to 19 ng PbTx-3 eq/mL. - Abstract: The health of many Florida manatees (Trichechus manatus latirostris) is adversely affected by exposure to blooms of the toxic dinoflagellate, Karenia brevis. K. brevis blooms are common in manatee habitats of Florida’s southwestern coast and produce a group of cyclic polyether toxins collectively referred to as red tide toxins, or brevetoxins. Although a large number of manatees exposed to significant levels of red tide toxins die, several manatees are rescued from sublethal exposure and are successfully treated and returned to the wild. Sublethal brevetoxin exposure may potentially impact the manatee immune system. Lymphocyte proliferative responses and a suite of immune function parameters in the plasma were used to evaluate effects of brevetoxin exposure on health of manatees rescued from natural exposure to red tide toxins in their habitat. Blood samples were collected from rescued manatees at Lowry Park Zoo in Tampa, FL and from healthy, unexposed manatees in Crystal River, FL. Peripheral blood leukocytes (PBL) isolated from whole blood were stimulated with T-cell mitogens, ConA and PHA. A suite of plasma parameters, including plasma protein electrophoresis profiles, lysozyme activity, superoxide dismutase (SOD) activity, and reactive oxygen/nitrogen (ROS/RNS) species, was also used to assess manatee health. Significant decreases (p < 0.05) in lymphocyte proliferation were observed in ConA and PHA stimulated lymphocytes from rescued animals compared to non-exposed animals. Significant correlations were observed between oxidative stress markers (SOD, ROS/RNS) and plasma brevetoxin concentrations. Sublethal exposure to brevetoxins in the

Nutrient and chlorophyll a anomaly in red-tide periods of 2003-2008 in Sishili Bay, China

Science.gov (United States)

Hao, Yanju; Tang, Danling; Yu, Long; Xing, Qianguo

2011-05-01

Sishili Bay is the most important aquiculture and tourism area for the city of Yantai, China; however, red tides occurred frequently and have caused huge economic losses in this bay in recent years. To gain a better understanding of the local ecological environments in the bay, we conducted this research between 2003 and 2008 to analyze variations in nutrients and chlorophyll (chl- a) during high frequency red tide period (May to September). The results show that the chl- a concentration increased from 2.70 in 2003 to 7.26 mg/m3 in 2008, while the concentration of total inorganic nitrogen (TIN) and silicate (SiO3-Si) increased lineally from 5.18 and 1.45 μmol/L in 2003 to 18.57 and 9.52 μmol/L in 2008, respectively, and the annual phosphate (PO4-P) varied between 0.15 and 0.46 μmol/L. Special attention was given to a red tide in August 2007 occurred when water temperature was high and nutrient concentrations increased sharply because of a heavy rainfall. Overall, the results show the P limitation in Sishili Bay, and reveal that red tides were caused by eutrophication from terrestrial inputs and local warm weather, particularly during rainy periods. Therefore, to control red tide, greater efforts should be made to reduce sewage discharges into Sishili Bay, particularly during rainfall seasons.

Human responses to Florida red tides: policy awareness and adherence to local fertilizer ordinances.

Science.gov (United States)

Kirkpatrick, Barbara; Kohler, Kate; Byrne, Margaret; Fleming, Lora E; Scheller, Karen; Reich, Andrew; Hitchcock, Gary; Kirkpatrick, Gary; Ullmann, Steven; Hoagland, Porter

2014-09-15

To mitigate the damages of natural hazards, policy responses can be beneficial only if they are effective. Using a self-administered survey approach, this paper focuses on the adherence to local fertilizer ordinances (i.e., county or municipal rules regulating the application of fertilizer to private lawns or facilities such as golf courses) implemented in jurisdictions along the Southwest Florida coast in response to hazardous blooms of Florida red tides (Karenia brevis). These ordinances play a role in the context of evolving programs of water pollution control at federal, state, water basin, and local levels. With respect to policy effectiveness, while the strength of physical linkages is of critical importance, the extent to which humans affected are aware of and adhere to the relevant rules, is equally critical. We sought to understand the public's depth of understanding about the rationales for local fertilizer ordinances. Respondents in Sarasota, Florida, were asked about their fertilizer practices in an area that has experienced several major blooms of Florida red tides over the past two decades. A highly educated, older population of 305 residents and "snowbirds" reported relatively little knowledge about a local fertilizer ordinance, its purpose, or whether it would change the frequency, size, or duration of red tides. This finding held true even among subpopulations that were expected to have more interest in or to be more knowledgeable about harmful algal blooms. In the face of uncertain science and environmental outcomes, and with individual motivations at odds with evolving public policies, the effectiveness of local community efforts to decrease the impacts of red tides may be compromised. Targeted social-science research on human perceptions about the risks of Florida red tides and education about the rationales for potential policy responses are warranted. Copyright © 2014 Elsevier B.V. All rights reserved.

RETAID DI PERAIRAN PESISIR BARAT TABLASUPA KABUPATEN JAYAPURA, PAPUA (Red-tide at Western Coast of Tablasupa, Jayapura, Papua

Directory of Open Access Journals (Sweden)

Suwarno Hadisusanto

2010-11-01

Full Text Available ABSTRAK Retaid (red-tide adalah fenomena alam yang sering terjadi baik di perairan laut dan tawar. Fenomena ini menunjukkan perubahan warna dari biru laut menjadi merah, coklat, kuning bahkan putih susu. Penelitian ini bertujuan untuk mengetahui potensi terjadinya retaid di perairan Tablasupa, Jayapura, Papua. Pencuplikan plankton dilakukan pada tanggal 8-10 Agustus 2007 di dua lokasi dengan empat ulangan waktu (pagi, siang, sore dan malanr. Hasil analisis laboratorium menunjukkan adanya 18 genus tetapi hanya dua genus yang berpotensi menimbulkan retaid yaitu Ceratium dan Chaetoceros. Kemungkinan kecil terjadinya retaid di perairan Tablasupa karena kemelimpahan fitoplankton cukup rendah.   ABSTRACT Red-tide is natural fenomenon and can be raised at marine and fresh-waters. This fenomenon was visualized by color changes from dark-blue to become redess, browness, yellowish and milkess. The objectives to find red-tide potentially at Tablasupa west coast, Jayapura, Papua. The sample was collected on August 8-10st, 2007, at two locations and four replicated. The results there were 18 genera and two red-tide potential genera was Ceratium dan Chaetoceros. There will no red-tide in Tablasupa because low abundance of phytoplankton.

Effects of Florida Red Tides on histone variant expression and DNA methylation in the Eastern oyster Crassostrea virginica.

Science.gov (United States)

Gonzalez-Romero, Rodrigo; Suarez-Ulloa, Victoria; Rodriguez-Casariego, Javier; Garcia-Souto, Daniel; Diaz, Gabriel; Smith, Abraham; Pasantes, Juan Jose; Rand, Gary; Eirin-Lopez, Jose M

2017-05-01

Massive algal proliferations known as Harmful Algal Blooms (HABs) represent one of the most important threats to coastal areas. Among them, the so-called Florida Red Tides (FRTs, caused by blooms of the dinoflagellate Karenia brevis and associated brevetoxins) are particularly detrimental in the southeastern U.S., causing high mortality rates and annual losses in excess of $40 million. The ability of marine organisms to cope with environmental stressors (including those produced during HABs) is influenced by genetic and epigenetic mechanisms, the latter resulting in phenotypic changes caused by heritable modifications in gene expression, without involving changes in the genetic (DNA) sequence. Yet, studies examining cause-effect relationships between environmental stressors, specific epigenetic mechanisms and subsequent responses are still lacking. The present work contributes to increase this knowledge by investigating the effects of Florida Red Tides on two types of mechanisms participating in the epigenetic memory of Eastern oysters: histone variants and DNA methylation. For that purpose, a HAB simulation was conducted in laboratory conditions, exposing oysters to increasing concentrations of K. brevis. The obtained results revealed, for the first time, the existence of H2A.X, H2A.Z and macroH2A genes in this organism, encoding histone variants potentially involved in the maintenance of genome integrity during responses to the genotoxic effect of brevetoxins. Additionally, an increase in H2A.X phosphorylation (γH2A.X, a marker of DNA damage) and a decrease in global DNA methylation were observed as the HAB simulation progressed. Overall, the present work provides a basis to better understand how epigenetic mechanisms participate in responses to environmental stress in marine invertebrates, opening new avenues to incorporate environmental epigenetics approaches into management and conservation programs. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of Florida Red Tides on histone variant expression and DNA methylation in the Eastern oyster Crassostrea virginica

Energy Technology Data Exchange (ETDEWEB)

Gonzalez-Romero, Rodrigo; Suarez-Ulloa, Victoria [Environmental Epigenetics Group, Department of Biological Sciences, Florida International University, North Miami, FL 33181 (United States); Rodriguez-Casariego, Javier [Environmental Epigenetics Group, Department of Biological Sciences, Florida International University, North Miami, FL 33181 (United States); Ecotoxicology and Risk Assessment Laboratory, Southeast Environmental Research Center, Florida International University, North Miami, FL 33181 (United States); Garcia-Souto, Daniel [Departamento de Bioquimica, Xenetica e Inmunoloxia, Universidade de Vigo, E-36310 Vigo (Spain); Diaz, Gabriel [Environmental Epigenetics Group, Department of Biological Sciences, Florida International University, North Miami, FL 33181 (United States); Smith, Abraham [Ecotoxicology and Risk Assessment Laboratory, Southeast Environmental Research Center, Florida International University, North Miami, FL 33181 (United States); Pasantes, Juan Jose [Departamento de Bioquimica, Xenetica e Inmunoloxia, Universidade de Vigo, E-36310 Vigo (Spain); Rand, Gary [Ecotoxicology and Risk Assessment Laboratory, Southeast Environmental Research Center, Florida International University, North Miami, FL 33181 (United States); Eirin-Lopez, Jose M., E-mail: jeirinlo@fiu.edu [Environmental Epigenetics Group, Department of Biological Sciences, Florida International University, North Miami, FL 33181 (United States)

2017-05-15

Massive algal proliferations known as Harmful Algal Blooms (HABs) represent one of the most important threats to coastal areas. Among them, the so-called Florida Red Tides (FRTs, caused by blooms of the dinoflagellate Karenia brevis and associated brevetoxins) are particularly detrimental in the southeastern U.S., causing high mortality rates and annual losses in excess of $40 million. The ability of marine organisms to cope with environmental stressors (including those produced during HABs) is influenced by genetic and epigenetic mechanisms, the latter resulting in phenotypic changes caused by heritable modifications in gene expression, without involving changes in the genetic (DNA) sequence. Yet, studies examining cause-effect relationships between environmental stressors, specific epigenetic mechanisms and subsequent responses are still lacking. The present work contributes to increase this knowledge by investigating the effects of Florida Red Tides on two types of mechanisms participating in the epigenetic memory of Eastern oysters: histone variants and DNA methylation. For that purpose, a HAB simulation was conducted in laboratory conditions, exposing oysters to increasing concentrations of K. brevis. The obtained results revealed, for the first time, the existence of H2A.X, H2A.Z and macroH2A genes in this organism, encoding histone variants potentially involved in the maintenance of genome integrity during responses to the genotoxic effect of brevetoxins. Additionally, an increase in H2A.X phosphorylation (γH2A.X, a marker of DNA damage) and a decrease in global DNA methylation were observed as the HAB simulation progressed. Overall, the present work provides a basis to better understand how epigenetic mechanisms participate in responses to environmental stress in marine invertebrates, opening new avenues to incorporate environmental epigenetics approaches into management and conservation programs.

Effects of Florida Red Tides on histone variant expression and DNA methylation in the Eastern oyster Crassostrea virginica

International Nuclear Information System (INIS)

Gonzalez-Romero, Rodrigo; Suarez-Ulloa, Victoria; Rodriguez-Casariego, Javier; Garcia-Souto, Daniel; Diaz, Gabriel; Smith, Abraham; Pasantes, Juan Jose; Rand, Gary; Eirin-Lopez, Jose M.

2017-01-01

Massive algal proliferations known as Harmful Algal Blooms (HABs) represent one of the most important threats to coastal areas. Among them, the so-called Florida Red Tides (FRTs, caused by blooms of the dinoflagellate Karenia brevis and associated brevetoxins) are particularly detrimental in the southeastern U.S., causing high mortality rates and annual losses in excess of $40 million. The ability of marine organisms to cope with environmental stressors (including those produced during HABs) is influenced by genetic and epigenetic mechanisms, the latter resulting in phenotypic changes caused by heritable modifications in gene expression, without involving changes in the genetic (DNA) sequence. Yet, studies examining cause-effect relationships between environmental stressors, specific epigenetic mechanisms and subsequent responses are still lacking. The present work contributes to increase this knowledge by investigating the effects of Florida Red Tides on two types of mechanisms participating in the epigenetic memory of Eastern oysters: histone variants and DNA methylation. For that purpose, a HAB simulation was conducted in laboratory conditions, exposing oysters to increasing concentrations of K. brevis. The obtained results revealed, for the first time, the existence of H2A.X, H2A.Z and macroH2A genes in this organism, encoding histone variants potentially involved in the maintenance of genome integrity during responses to the genotoxic effect of brevetoxins. Additionally, an increase in H2A.X phosphorylation (γH2A.X, a marker of DNA damage) and a decrease in global DNA methylation were observed as the HAB simulation progressed. Overall, the present work provides a basis to better understand how epigenetic mechanisms participate in responses to environmental stress in marine invertebrates, opening new avenues to incorporate environmental epigenetics approaches into management and conservation programs.

Characterization of an epoxide hydrolase from the Florida red tide dinoflagellate, Karenia brevis.

Science.gov (United States)

Sun, Pengfei; Leeson, Cristian; Zhi, Xiaoduo; Leng, Fenfei; Pierce, Richard H; Henry, Michael S; Rein, Kathleen S

2016-02-01

Epoxide hydrolases (EH, EC 3.3.2.3) have been proposed to be key enzymes in the biosynthesis of polyether (PE) ladder compounds such as the brevetoxins which are produced by the dinoflagellate Karenia brevis. These enzymes have the potential to catalyze kinetically disfavored endo-tet cyclization reactions. Data mining of K. brevis transcriptome libraries revealed two classes of epoxide hydrolases: microsomal and leukotriene A4 (LTA4) hydrolases. A microsomal EH was cloned and expressed for characterization. The enzyme is a monomeric protein with molecular weight 44kDa. Kinetic parameters were evaluated using a variety of epoxide substrates to assess substrate selectivity and enantioselectivity, as well as its potential to catalyze the critical endo-tet cyclization of epoxy alcohols. Monitoring of EH activity in high and low toxin producing cultures of K. brevis over a three week period showed consistently higher activity in the high toxin producing culture implicating the involvement of one or more EH in brevetoxin biosynthesis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nutrient environment of red tide- infested waters off south-west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Joseph, T.; Shaiju, P.; Laluraj, C.M.; Balachandran, K.K.; Nair, M.; George, R.; Nair, K.K.C.; Sahayak, S.; Prabhakaran, M.P.

/Accepted: 28 August 2007 /Published online: 19 September 2007 # Springer Science + Business Media B.V. 2007 Abstract The bloom-infested waters along the south- west coast of India were assessed to bring about... tides, a natural phenomenon, are now common in many coastal waters. Various factors contribute to red tide formation such as insolation, wind, rain, salinity and nutrient input from land or by upwelling. Nitrogen and phosphorus are involved in phytoplank...

Five red tide species in genus Prorocentrum including the description of Prorocentrum donghaiense Lu SP. nov. from the East China Sea

Science.gov (United States)

Lu, Dou-Ding; Goebel, Jeanette

2001-12-01

A new planktonic dinoflagellate, Prorocentrum donghaiense Lu sp. nov., is described in the present paper. The water sample was collected from the Changjiang Estuary, the East China Sea. The species identification is based on shape, size, surface micro-morphology, ornamentation of thecal plates and the architecture of the periflagellar area and the intercalary bands as seen by light and scanning electron microscope. Prorocentrum donghaiense Lu sp. nov. is compared with other prorocentrum species with respect to morphological characteristics and bloom behavior. It is not known whether Prorocentrum donghaiense Lu sp. nov produces phycotoxins like some other Prorocentrum species. Four other red tide species in the family Prorocentraceae (Dinophyceae), namely P. balticum, P. minimum, P. micans, P. triestinum, were examined and identified by light and scanning electron microscope. They have been recorded as bloom-forming species. Some aggregates of Prorocentrum are observed at the end of blooms. An event of strong discoloration caused by P. donghaiense could be detected by satellite sensor in the East China Sea in the late spring of 1995.

The prevalence of benthic dinoflagellates associated with ciguatera fish poisoning in the central Red Sea.

Science.gov (United States)

Catania, Daniela; Richlen, Mindy L; Mak, Yim Ling; Morton, Steve L; Laban, Elizabeth H; Xu, Yixiao; Anderson, Donald M; Chan, Leo Lai; Berumen, Michael L

2017-09-01

This study confirms the presence of the toxigenic benthic dinoflagellates Gambierdiscus belizeanus and Ostreopsis spp. in the central Red Sea. To our knowledge, this is also the first report of these taxa in coastal waters of Saudi Arabia, indicating the potential occurrence of ciguatera fish poisoning (CFP) in that region. During field investigations carried out in 2012 and 2013, a total of 100 Turbinaria and Halimeda macroalgae samples were collected from coral reefs off the Saudi Arabian coast and examined for the presence of Gambierdiscus and Ostreopsis, two toxigenic dinoflagellate genera commonly observed in coral reef communities around the world. Both Gambierdiscus and Ostreopsis spp. were observed at low densities (weight algae). Cell densities of Ostreopsis spp. were significantly higher than Gambierdiscus spp. at most of the sampling sites, and abundances of both genera were negatively correlated with seawater salinity. To assess the potential for ciguatoxicity in this region, several Gambierdiscus isolates were established in culture and examined for species identity and toxicity. All isolates were morphologically and molecularly identified as Gambierdiscus belizeanus. Toxicity analysis of two isolates using the mouse neuroblastoma cell-based assay for ciguatoxins (CTX) confirmed G. belizeanus as a CTX producer, with a maximum toxin content of 6.50±1.14×10 -5 pg P-CTX-1 eq. cell -1 . Compared to Gambierdiscus isolates from other locations, these were low toxicity strains. The low Gambierdiscus densities observed along with their comparatively low toxin contents may explain why CFP is unidentified and unreported in this region. Nevertheless, the presence of these potentially toxigenic dinoflagellate species at multiple sites in the central Red Sea warrants future study on their possible effects on marine food webs and human health in this region. Copyright © 2017 Elsevier B.V. All rights reserved.

The prevalence of benthic dinoflagellates associated with ciguatera fish poisoning in the central Red Sea

KAUST Repository

Catania, Daniela

2017-09-09

This study confirms the presence of the toxigenic benthic dinoflagellates Gambierdiscus belizeanus and Ostreopsis spp. in the central Red Sea. To our knowledge, this is also the first report of these taxa in coastal waters of Saudi Arabia, indicating the potential occurrence of ciguatera fish poisoning (CFP) in that region. During field investigations carried out in 2012 and 2013, a total of 100 Turbinaria and Halimeda macroalgae samples were collected from coral reefs off the Saudi Arabian coast and examined for the presence of Gambierdiscus and Ostreopsis, two toxigenic dinoflagellate genera commonly observed in coral reef communities around the world. Both Gambierdiscus and Ostreopsis spp. were observed at low densities (<200 cells g−1 wet weight algae). Cell densities of Ostreopsis spp. were significantly higher than Gambierdiscus spp. at most of the sampling sites, and abundances of both genera were negatively correlated with seawater salinity. To assess the potential for ciguatoxicity in this region, several Gambierdiscus isolates were established in culture and examined for species identity and toxicity. All isolates were morphologically and molecularly identified as Gambierdiscus belizeanus. Toxicity analysis of two isolates using the mouse neuroblastoma cell-based assay for ciguatoxins (CTX) confirmed G. belizeanus as a CTX producer, with a maximum toxin content of 6.50±1.14×10−5pg P-CTX-1 eq. cell−1. Compared to Gambierdiscus isolates from other locations, these were low toxicity strains. The low Gambierdiscus densities observed along with their comparatively low toxin contents may explain why CFP is unidentified and unreported in this region. Nevertheless, the presence of these potentially toxigenic dinoflagellate species at multiple sites in the central Red Sea warrants future study on their possible effects on marine food webs and human health in this region.

Global transcriptional profiling of the toxic dinoflagellate Alexandrium fundyense using Massively Parallel Signature Sequencing

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Anderson Donald M

2006-04-01

Full Text Available Abstract Background Dinoflagellates are one of the most important classes of marine and freshwater algae, notable both for their functional diversity and ecological significance. They occur naturally as free-living cells, as endosymbionts of marine invertebrates and are well known for their involvement in "red tides". Dinoflagellates are also notable for their unusual genome content and structure, which suggests that the organization and regulation of dinoflagellate genes may be very different from that of most eukaryotes. To investigate the content and regulation of the dinoflagellate genome, we performed a global analysis of the transcriptome of the toxic dinoflagellate Alexandrium fundyense under nitrate- and phosphate-limited conditions using Massively Parallel Signature Sequencing (MPSS. Results Data from the two MPSS libraries showed that the number of unique signatures found in A. fundyense cells is similar to that of humans and Arabidopsis thaliana, two eukaryotes that have been extensively analyzed using this method. The general distribution, abundance and expression patterns of the A. fundyense signatures were also quite similar to other eukaryotes, and at least 10% of the A. fundyense signatures were differentially expressed between the two conditions. RACE amplification and sequencing of a subset of signatures showed that multiple signatures arose from sequence variants of a single gene. Single signatures also mapped to different sequence variants of the same gene. Conclusion The MPSS data presented here provide a quantitative view of the transcriptome and its regulation in these unusual single-celled eukaryotes. The observed signature abundance and distribution in Alexandrium is similar to that of other eukaryotes that have been analyzed using MPSS. Results of signature mapping via RACE indicate that many signatures result from sequence variants of individual genes. These data add to the growing body of evidence for widespread gene

Severe fish mortality associated with 'red tide' observed in the sea off Cochin

Digital Repository Service at National Institute of Oceanography (India)

Naqvi, S.W.A.; George, M; Narvekar, P.V.; Jayakumar, D.A.; Shailaja, M; Sardessai, S.; Sarma, V.V.S.S.; Shenoy, D.M; Naik, H.; Maheswaran, P.A.; KrishnaKumari, L.; Rajesh, G.; Sudhir, A.K.; Binu, M

Severe fish mortality associated with the "red tide" phenomenon caused by Noctiluca blooms was observed in the sea off Cochin, Kerala, India at depths less than 40 m. The dead fish, almost entirely comprised of the threadfin bream (Nemipterus...

Inhibitory activity of an extract from a marine bacterium Halomonas sp. HSB07 against the red-tide microalga Gymnodinium sp. (Pyrrophyta)

Science.gov (United States)

Liu, Juan; Li, Fuchao; Liu, Ling; Jiang, Peng; Liu, Zhaopu

2013-11-01

In recent years, red tides occurred frequently in coastal areas worldwide. Various methods based on the use of clay, copper sulfate, and bacteria have been successful in controlling red tides to some extent. As a new defensive agent, marine microorganisms are important sources of compounds with potent inhibitory bioactivities against red-tide microalgae, such as Gymnodinium sp. (Pyrrophyta). In this study, we isolated a marine bacterium, HSB07, from seawater collected from Hongsha Bay, Sanya, South China Sea. Based on its 16S rRNA gene sequence and biochemical characteristics, the isolated strain HSB07 was identified as a member of the genus Halomonas. A crude ethyl acetate extract of strain HSB07 showed moderate inhibition activity against Gymnodinium sp. in a bioactive prescreening experiment. The extract was further separated into fractions A, B, and C by silica gel column chromatography. Fractions B and C showed strong inhibition activities against Gymnodinium. This is the first report of inhibitory activity of secondary metabolites of a Halomonas bacterium against a red-tide-causing microalga.

Benthic dinoflagellates from Red Sea, Egypt: Early records

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Nermin El Semary

2016-06-01

Full Text Available Dinoflagellates from Red Sea are hardly studied, in particular the benthic forms. Samples collected from shallow intertidal zone, Ain Sokhna, Egypt were microscopically examined. Three genera with seven species were recorded. The most frequently-encountered was Katodinium sp., a small mushroom-like with epitheca being consistently larger than hypotheca. Light micrographs revealed the presence of a nucleus in the hyposome and descending cingulum. Scanning electromicrographs (SEM confirmed this orientation and revealed the presence of apical pore system. Another species showed similarity to the mushroom-like morphology but with large conical episome and small hyposome. Heterotrophic, naked Gyrodinium cf dominans and Gyrodinium sp. were also observed where in the former, there were conspicuous longitudinal striations. A frequently-observed species had naked Gyrodinium-like morphology but with much smaller size. One photosynthetic species had a characteristic stigma similar to type B eyespot in “dinotoms” and episome being slightly larger than hyposome. Gymnodinium sp. with sulcus extending slightly in the episome but deeply to the end of hyposome was also recorded. This genus is reported to be mostly toxic and its presence should be monitored. Finally, this study presents some early records for benthic dinophytes from rather underexplored locality and raises alerts about genus with reported toxicity.

Studies on woloszynskioid dinoflagellates III:

DEFF Research Database (Denmark)

Moestrup, Øjvind; Hansen, Gert; Daugbjerg, Niels

2008-01-01

. dodgei may form brown, never truly red blooms as in the case of T. sanguinea. The transverse flagellum of Borghiella carries, in addition to thin hairs found also in other dinoflagellates, a row of shorter, thicker hairs resembling the curly hairs on the homologous, anterior flagellum of the perkinsid...

Correlations between atmospheric aerosol trace element concentrations and red tide at Port Aransas, Texas, on the Gulf of Mexico

International Nuclear Information System (INIS)

Biegalski, S.R.; Villareal, T.A.

2005-01-01

Neutron activation analysis (NAA) was employed as an analytical technique to measure atmospheric aerosol concentrations of trace metals in Port Aransas, TX on the Gulf of Mexico. The sources of atmospheric aerosols and the seasonal variation of the sources are explored. High atmospheric iron concentrations are then shown to have a possible correlation to the occurrences of red tide in this region. The data shows that this correlation is plausible, but due to the many factors that affect red tide growth a definitive conclusion may not be reached. The period of study for these measurements was September 12, 2000 to January 4, 2002. (author)

Identification Of Some Strains Of Dinoflagellates Based On Morphology And Molecular Analysis

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Hikmah Thoha

2008-11-01

Full Text Available Dinoflagellates are the important primary producers in aquatic environments. In oceans, they play interesting role in ecological functions such as red tide forming organisms, symbiont of coral reef or sea anemone and DSP (Diarrhetic Shellfish Poisoning or PSP (Paralytic Shellfish Poisoning producing organisms. Morphology and molecular analysis of dinoflagellates were conducted on November 2002 to March 2003. The phylogenetic studies based on 18S rDNA analyses, sequence have begun to appear more frequently in the literature, as attention has turned to relationships within the major eukaryotic lineages, particular importance for the taxonomy of the armored and unarmored genera of dinoflagellates (Gyrodinium sp., Cachonina sp., Gymnodinium sp., Amphidinium sp., because many of the genera cause extensive plankton blooms, fish kills and other harmful events, were studied used to amplify 18S rDNA, present in the total DNA extracted from algal pellet. The amplify approximately 1400 bp of the nuclear-encoded LSU rDNA gene using terminal primeirs DIR, products were cheked by 1.0 % agarose gel electrophoresis, then cloning with TA cloning KIT. Sequencing were analyzed by the GENETIX Mac Software, Homology search by Blast and Phylogenetic analysis. Results of hylogenetic analysis of 18S rDNA are: Strain no. 10893 (un identified from the genera, it is belonging Gymnodinium or Polarella. Strain no. 10795 is closely related other species Cachonina hallii. We tentatively named strain no 11151 and 11160 similar to Gyrodinium or Gymnodinium based on morphology, but these strain indepently position in this tree and is not a real of Gymnodinium sensu stricto. It is possible, we can establish the new genera for strain no. 11151; 11160 because this not cluster any other unarmored species.

The dinoflagellate Lingulodinium polyedrum responds to N depletion by a polarized deposition of starch and lipid bodies.

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Steve Dagenais Bellefeuille

Full Text Available Dinoflagellates are important contributors to the marine phytoplankton and global carbon fixation, but are also infamous for their ability to form the spectacular harmful algal blooms called red tides. While blooms are often associated with high available nitrogen, there are instances where they are observed in oligotrophic environments. In order to maintain their massive population in conditions of nitrogen limitation, dinoflagellates must have evolved efficient adaptive mechanisms. Here we report the physiological responses to nitrogen deprivation in Lingulodinium polyedrum. We find that this species reacts to nitrogen stress, as do most plants and microalgae, by stopping cell growth and diminishing levels of internal nitrogen, in particular in the form of protein and chlorophyll. Photosynthesis is maintained at high levels for roughly a week following nitrate depletion, resulting in accumulated photosynthetic products in the form of starch. During the second week, photosynthesis rates decrease due to a reduction in the number of chloroplasts and the accumulation of neutral lipid droplets. Surprisingly, the starch granules and lipid droplets are seen to accumulate at opposite poles of the cell. Lastly, we observe that cells acclimated to nitrogen-depleted conditions resume normal growth after addition of inorganic nitrogen, but are able to maintain high cell densities far longer than cells grown continuously in nitrogen-replete conditions.

Mixotrophy and Nitrogen Uptake by Pfiesteria Piscicida (Dinophyceae)

Science.gov (United States)

Alan J. Lewitus; Bonnie M. Willis; Kenneth C. Hayes; JoAnn M. Burkholder; Howard B. Gasgow; Patricia M. Gilbert

1999-01-01

The nutritional versatility of dinoflagellates is a complicating factor in identifying potential links between nutrient eurichment and the proliferation of harmful algal bloom. For exmaple, although dinoflagellates associated with hamful algal blooms (e.g. red tides) are generally considered to be phototrophic and we inorganic nutrients such as nitrate or phosphate,...

The bloom of the dinoflagellate (Noctiluca miliaris) in the North Eastern Arabian Sea: Ship and Satellite study

Digital Repository Service at National Institute of Oceanography (India)

Matondkar, S.G.P.; Basu, S.; Parab, S.G.; Pednekar, S.; Dwivedi, R.M.; Raman, M.; Goes, J.I.; Gomes, H.

The bloom of Noctiluca miliaris (a dinoflagellate) which appears in the form of a green tide was studied from 2003-2011. This bloom covered a large area of the Arabian Sea from the west coast of India to the coast of Oman. The bloom was easily...

Light spectrum regulates cell accumulation during daytime in the raphidophyte Chattonella antiqua causing noxious red tides.

Science.gov (United States)

Shikata, Tomoyuki; Matsunaga, Shigeru; Kuwahara, Yusuke; Iwahori, Sho; Nishiyama, Yoshitaka

2016-07-01

Most marine raphidophyte species cause noxious red tides in temperate coastal areas around the world. It is known that swimming abilities enable raphidophytes to accumulation of cells and to actively acquire light at surface layers and nutrients over a wide depth range. However, it remains unclear how the swimming behavior is affected by environmental conditions, especially light condition. In the present study, we observed the accumulation of the harmful red-tide raphidophyte Chattonella antiqua under various light conditions during the daytime in the laboratory. When exposed to ultraviolet-A/blue light (320-480nm) or red light (640-680nm) from above, cells moved downward. In the case of blue light (455nm), cells started to swim downward after 5-15min of irradiation at a photon flux density≥10μmolm(-2)s(-1). When exposed to monochromatic lights (400-680nm) from the side, cells moved away from the blue light source and then descended, but just moved downward under red light. However, mixing of green/orange light (520-630nm) diminished the effects of blue light. When exposed to a mixture of 30μmolm(-2)s(-1) of blue light (440nm) and ≥6μmolm(-2)s(-1) of yellow light (560nm) from above, cells did not move downward. These results indicate that blue light induces negative phototaxis and ultraviolet-A/blue and red lights induce descending, and green/orange light cancels out their effects in C. antiqua. Copyright © 2016 Elsevier B.V. All rights reserved.

Changes in phytoplankton composition in response to tides, wind-induced mixing conditions, and freshwater outflows in an urbanised estuarine complex.

Science.gov (United States)

Moser, G A O; Ciotti, A M; Giannini, M F C; Tonini, R T; Harari, J

2012-02-01

Recent reports have shown an increase in potentially harmful phytoplankton in Santos bay (Southeastern Brazilian Coast), located in a highly urbanised estuarine complex. Prediction of blooms is, thus, essential but the phytoplankton community structure in very dynamic regions is difficult to determine. In the present work, we discriminate bloom forming microphytoplankton dominance and their relationship to physical and meteorological variables to look for patterns observed in different tides and seasons. Comparing 8 distinct situations, we found five scenarios of dominance that could be related to winds, tides and rainfall: i) Surfers, diatoms occurring during high surf zone energies; ii) Sinkers, represented by larger celled diatoms during spring tide, after periods of high precipitation rates; iii) Opportunistic mixers, composed of chain forming diatoms with small or elongate cells occurring during neap tides; iv) Local mixers, microplanktonic diatoms and dinoflagellates which occurred throughout the 298 sampling stations; and v) Mixotrophic dinoflagellates, after intense estuarine discharges. Results suggest alterations in the temporal patterns for some bloom-forming species, while others appeared in abundances above safe limits for public health. This approach can also illustrate possible impacts of changes in freshwater discharge in highly urbanised estuaries.

Mycosporine-like amino acids and xanthophyll-cycle pigments favour a massive spring bloom development of the dinoflagellate Prorocentrum minimum in Grande Bay (Argentina), an ozone hole affected area

Science.gov (United States)

Carreto, José I.; Carignan, Mario O.; Montoya, Nora G.; Cozzolino, Ezequiel; Akselman, Rut

2018-02-01

In Grande Bay (Southern Patagonian Shelf) in a eutrophic and recirculating area slightly stratified during spring, we observed an intense (up to 1 × 107 cells L- 1) and shallow, quasi mono-specific bloom of the dinoflagellate Prorocentrum minimum. Peridinin was the most abundant carotenoid, but the relative amounts of the xanthophyll cycle carotenoids (diadinoxanthin + diatoxanthin = DT) to light-harvesting pigments were high (DT/Chl a ratio = 0.32 and DT/peridinin ratio = 0.40). Shinorine, usujirene, palythene, mycosporine-serine-glycine methyl ester and palythenic acid were the primary mycosporine-like amino acids (MAAs), followed by mycosporine-glycine, palythine, and porphyra-334. The ΣMAAs/Chl a ratios (up to 27.9 nmol/nmol) were in the upper range reported either in nutrient-replete dinoflagellate cultures or natural populations. We monitored, from space (using satellite ocean colour data), the spatial and temporal bloom variability (from September 22 to October 31, 2005) using an approach to discriminate dinoflagellate from diatom blooms. The results indicated that an intense diatom bloom started in early spring but was rapidly replaced by an intense bloom of the dinoflagellate P. minimum, although the nutrient concentrations were apparently not limiting. The most notorious change in this period was a sharp increase in the levels of solar UVB radiation (UVB index 9.0) as a consequence of the overpass of the polar vortex over this area. We postulated that the synthesis and accumulation of MAAs and xanthophyll pigments, were competitive advantages for the opportunistic red tide dinoflagellate P. minimum over the sensitive diatoms, favouring the development of their surface blooms in this seasonally solar UVB radiation (UVBR) affected area.

Spatio-temporal distribution of the dominant Diatom and Dinoflagellate species in the Bay of Tunis (SW Mediterranean Sea

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O. DALY YAHIA-KEFI

2005-06-01

Full Text Available Microphytoplankton composition and its relationships with hydrology and nutrient distributions were investigated over 24 months (December 1993 - November 1995 in the Bay of Tunis ( SW Mediterranean Sea. A new index, the ‘Specific Preference Index’ (SPI obtained by computing the median value of each parameter weighed by the numerical value of each species density was developed. Using this index, the relationships between each species and temperature, salinity and major nutrients were analysed. The distribution of chlorophyll a did not show a clear correlation with microplankton abundance suggesting that other factors contribute to chlorophyll concentration, such as smaller phytoplankton size fractions or detritus. The winter-spring diatom blooms did not show a regular pattern during both years. High nutrient inputs in late summer, associated with mild meteorological conditions, contributed to the development of a large diatom bloom in autumn 1995 where significant silicate depletion was witnessed. Generally, diatoms were more stenotherm than dinoflagellates in the Bay, whereas dinoflagellates were more stenohaline than diatoms. The statistical analyses showed that the two species, Bellerochea horologicalis , and Lithodesmioides polymorpha, var., tunisiense, appeared in a wide range of environmental conditions. An excess of phosphateversus nitrate appeared to be associated with red tides of, Gymnodinium spp, whereas Peridinium quinquecorne, showed the opposite. Phosphate concentrations appear to be crucial in this coastal environment, where diatom blooms are often limited by low silicate availability.

Phytoplankton and bacterial community structures and their interaction during red-tide phenomena

Science.gov (United States)

Ismail, Mona Mohamed; Ibrahim, Hassan Abd Allah

2017-09-01

Phytoplankton and bacteria diversity were studied before, during and after red tide phenomena during spring season 2015 in the Eastern Harbour (E.H.) of Alexandria, Egypt. Fifty five species of phytoplankton were identified and represented different distinct classes "Bacillariophyceae; Dinophyceae, Chlorophyceae, Cyanophyceae and Eugelenophyceae". Also, Diatom formed the most dominant group. The average number of the phytoplankton density varied from 4.8 × 104 to 1.1 × 106 cell l-1 during the study period and Skeletonema costatum was the agent causing the red tide. The existence percentages of bacteria ranged from 2.6 to 17.9% on all media tested. The bacterial isolates on the nutrient agar medium represented the highest existence with a total percentage of 43.6%, followed by MSA medium (25.7%), while the lowest percentage was for the AA medium at 7.8%. However, twelve isolates were selected as representative for bacterial community during study interval. Based on the morphological, biochemical, physiological and enzymatic characteristics, the bacterial strains were described. Depending on the 16S rDNA gene sequence, three common antagonists were aligned as: Vibrio toranzoniae strain Vb 10.8, Ruegeria pelagia strain NBRC 102038 and Psychrobacter adeliensis strain DSM 15333. The interaction between these bacteria and S. costatum was studied. The growth of S. costatum was significantly lower whenever each bacterium was present as compared to axenic culture. More specifically, 30% (v/v) of the all tested bacteria showed the strongest algicidal activities, as all S. costatum cells were killed after two days. 10% of R. pelagia and P. adeliensis also showed significant algicidal activities within six days.

The killer tides

Digital Repository Service at National Institute of Oceanography (India)

Devassy, V.P.; Bhat, S.R.

. Various measures adopted to control or contain such harmful events have either proved ineffective or are economically unviable. Red tides generally break out under favourable environmental conditions such as calm, sunny weather and gently breeze or when...

An expert elicitation process to project the frequency and magnitude of Florida manatee mortality events caused by red tide (Karenia brevis)

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Martin, Julien; Runge, Michael C.; Flewelling, Leanne J.; Deutsch, Charles J.; Landsberg, Jan H.

2017-11-20

Red tides (blooms of the harmful alga Karenia brevis) are one of the major sources of mortality for the Florida manatee (Trichechus manatus latirostris), especially in southwest Florida. It has been hypothesized that the frequency and severity of red tides may increase in the future because of global climate change and other factors. To improve our ecological forecast for the effects of red tides on manatee population dynamics and long-term persistence, we conducted a formal expert judgment process to estimate probability distributions for the frequency and relative magnitude of red-tide-related manatee mortality (RTMM) events over a 100-year time horizon in three of the four regions recognized as manatee management units in Florida. This information was used to update a population viability analysis for the Florida manatee (the Core Biological Model). We convened a panel of 12 experts in manatee biology or red-tide ecology; the panel met to frame, conduct, and discuss the elicitation. Each expert provided a best estimate and plausible low and high values (bounding a confidence level of 80 percent) for each parameter in each of three regions (Northwest, Southwest, and Atlantic) of the subspecies’ range (excluding the Upper St. Johns River region) for two time periods (0−40 and 41−100 years from present). We fitted probability distributions for each parameter, time period, and expert by using these three elicited values. We aggregated the parameter estimates elicited from individual experts and fitted a parametric distribution to the aggregated results.Across regions, the experts expected the future frequency of RTMM events to be higher than historical levels, which is consistent with the hypothesis that global climate change (among other factors) may increase the frequency of red-tide blooms. The experts articulated considerable uncertainty, however, about the future frequency of RTMM events. The historical frequency of moderate and intense RTMM (combined) in

Investigation of phagotrophy in natural assemblages of the benthic dinoflagellates Ostreopsis, Prorocentrum and Coolia

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Eliliane Vasconcelos Corrêa Almada

Full Text Available Abstract Mixotrophy has been shown to be a common trait among dinoflagellates and its importance in the nutritional ecology of harmful algae has been hypothesized. Benthic harmful species have not been extensively investigated as their planktonic counterparts and there are major gaps in the knowledge of their nutritional strategies. In this study the occurrence of phagotrophy was investigated in natural assemblages of benthic dinoflagellates using epi-fluorescence microscopy with DAPI and LysoSensor staining. The study was conducted at five sites along the coast of Rio de Janeiro that were visited in January, August and December 2010. In total, 1659 dinoflagellate cells were observed. From these, only 0.4% of 1195 Ostreopsis cf. ovata and 2.2% of 134 Coolia spp. cells presented evidence of phagotrophy with vacuoles stained by LysoSensor or a DAPI (4',6-diamidino-2-phenylindole stained inclusion. Stained vacuoles were not registered in the 330 Prorocentrum spp. cells observed. Few O. cf. ovata cells contained round red inclusions ("red spots" that were not stained either by DAPI or LysoSensor, suggesting that these structures are not ingested prey. The results showed that phagotrophy was not a frequent nutritional strategy in benthic dinoflagellates during the study period.

Brevetoxin, the Dinoflagellate Neurotoxin, Localizes to Thylakoid Membranes and Interacts with the Light-Harvesting Complex II (LHCII) of Photosystem II.

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Cassell, Ryan T; Chen, Wei; Thomas, Serge; Liu, Li; Rein, Kathleen S

2015-05-04

The brevetoxins are neurotoxins that are produced by the "Florida red tide" dinoflagellate Karenia brevis. They bind to and activate the voltage-gated sodium channels in higher organisms, specifically the Nav 1.4 and Nav 1.5 channel subtypes. However, the native physiological function that the brevetoxins perform for K. brevis is unknown. By using fluorescent and photoactivatable derivatives, brevetoxin was shown to localize to the chloroplast of K. brevis where it binds to the light-harvesting complex II (LHCII) and thioredoxin. The LHCII is essential to non-photochemical quenching (NPQ), whereas thioredoxins are critical to the maintenance of redox homeostasis within the chloroplast and contribute to the scavenging of reactive oxygen. A culture of K. brevis producing low levels of toxin was shown to be deficient in NPQ and produced reactive oxygen species at twice the rate of the toxic culture, implicating a role in NPQ for the brevetoxins. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

HIGH BREVETOXIN CONCENTRATIONS IN GYMNODINIUM BREVE BLOOMS ALONG THE NORTHWEST FLORIDA COAST DURING 1999.

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Blooms of the dinoflagellate Gymnodinium breve (i.e. red tides) produce brevetoxins (PbTx) that negatively impact the Gulf of Mexico ecosystem, human health, and local economics. Characterizing and predicting bloom events and their impacts requires knowledge of G. breve abundance...

A red tide of Alexandrium fundyense in the Gulf of Maine

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McGillicuddy, D. J.; Brosnahan, M. L.; Couture, D. A.; He, R.; Keafer, B. A.; Manning, J. P.; Martin, J. L.; Pilskaln, C. H.; Townsend, D. W.; Anderson, D. M.

2014-05-01

In early July 2009, an unusually high concentration of the toxic dinoflagellate Alexandrium fundyense occurred in the western Gulf of Maine, causing surface waters to appear reddish brown to the human eye. The discolored water appeared to be the southern terminus of a large-scale event that caused shellfish toxicity along the entire coast of Maine to the Canadian border. Rapid-response shipboard sampling efforts together with satellite data suggest the water discoloration in the western Gulf of Maine was a highly ephemeral feature of less than two weeks in duration. Flow cytometric analysis of surface samples from the red water indicated the population was undergoing sexual reproduction. Cyst fluxes downstream of the discolored water were the highest ever measured in the Gulf of Maine, and a large deposit of new cysts was observed that fall. Although the mechanisms causing this event remain unknown, its timing coincided with an anomalous period of downwelling-favorable winds that could have played a role in aggregating upward-swimming cells. Regardless of the underlying causes, this event highlights the importance of short-term episodic phenomena on regional population dynamics of A. fundyense.

Complexities of bloom dynamics in the toxic dinoflagellate Alexandrium fundyense revealed through DNA measurements by imaging flow cytometry coupled with species-specific rRNA probes

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Brosnahan, Michael L.; Farzan, Shahla; Keafer, Bruce A.; Sosik, Heidi M.; Olson, Robert J.; Anderson, Donald M.

2014-05-01

Measurements of the DNA content of different protist populations can shed light on a variety of processes, including cell division, sex, prey ingestion, and parasite invasion. Here, we modified an Imaging FlowCytobot (IFCB), a custom-built flow cytometer that records images of microplankton, to measure the DNA content of large dinoflagellates and other high-DNA content species. The IFCB was also configured to measure fluorescence from Cy3-labeled rRNA probes, aiding the identification of Alexandrium fundyense (syn. A. tamarense Group I), a photosynthetic dinoflagellate that causes paralytic shellfish poisoning (PSP). The modified IFCB was used to analyze samples from the development, peak and termination phases of an inshore A. fundyense bloom (Salt Pond, Eastham, MA, USA), and from a rare A. fundyense ‘red tide’ that occurred in the western Gulf of Maine, offshore of Portsmouth, NH (USA). Diploid or G2 phase (‘2C’) A. fundyense cells were frequently enriched at the near-surface, suggesting an important role for aggregation at the air-sea interface during sexual events. Also, our analysis showed that large proportions of A. fundyense cells in both the Salt Pond and red tide blooms were planozygotes during bloom decline, highlighting the importance of sexual fusion to bloom termination. At Salt Pond, bloom decline also coincided with a dramatic rise in infections by the parasite genus Amoebophrya. The samples that were most heavily infected contained many large cells with higher DNA-associated fluorescence than 2C vegetative cells, but these cells' nuclei were also frequently consumed by Amoebophrya trophonts. Neither large cell size nor increased DNA-associated fluorescence could be replicated by infecting an A. fundyense culture of vegetative cells. Therefore, we attribute these characteristics of the large Salt Pond cells to planozygote maturation rather than Amoebophrya infection, though an interaction between infection and planozygote maturation may

Fish Kill Incidents and Harmful Algal Blooms in Omani Waters

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Hamed Mohammed Al Gheilani

2011-01-01

Full Text Available Red tide, one of the harmful algal blooms (HABs is a natural ecological phenomenon and often this event is accompanied by severe impacts on coastal resources, local economies, and public health. The occurrence of red tides has become more frequent in Omani waters in recent years. Some of them caused fish kill, damaged fishery resources and mariculture, threatened the marine environment and the osmosis membranes of desalination plants. However, a number of them have been harmless. The most common dinoflagellate Noctiluca scintillans is associated with the red tide events in Omani waters. Toxic species like Karenia selliformis, Prorocentrum arabianum, and Trichodesmium erythraeum have also been reported recently. Although red tides in Oman have been considered a consequence of upwelling in the summer season (May to September, recent phytoplankton outbreaks in Oman are not restricted to summer. Frequent algal blooms have been reported during winter (December to March. HABs may have contributed to hypoxia and/or other negative ecological impacts.

Biosynthetic Studies on Water-Soluble Derivative 5c (DTX5c

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José J. Fernández

2012-10-01

Full Text Available The dinoflagellate Prorocentrum belizeanum is responsible for the production of several toxins involved in the red tide phenomenon known as Diarrhetic Shellfish Poisoning (DSP. In this paper we report on the biosynthetic origin of an okadaic acid water-soluble ester derivative, DTX5c, on the basis of the spectroscopical analysis of 13C enriched samples obtained by addition of labelled sodium [l-13C], [2-13C] acetate to artificial cultures of this dinoflagellate.

Critical micelle concentrations of allelopathic substances produced by Nannochloris oculata which affect a red tide organism, Gymnodinium breve.

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Pérez, E; Martin, D F

2001-01-01

Laboratory cultures of the green algae Nannochloris oculata and Nannochloris eucaryotum are known to cause lysis of Gymnodinium breve, which is Florida's red tide organism. Two cytolytic agents were previously identified as methyl palmitate and methyl stearate. In this study, the critical micelle concentrations of these substances were determined by ultraviolet light and turbidimetric methods to be 3.5 +/- 0.3 ppm (methyl stearate) and 4.3 +/- 0.6 (methyl palmitate). There were no significant differences in results obtained using the two methods.

[Acute toxicity effects of three red tide algae on Brachionus plicatilis].

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Zhou, Wen-Li; Xiao, Hui; Wang, You; Zhai, Hong-Chang; Tang, Xue-Xi

2008-11-01

Acute toxicity testing method was used to study effects of different density of Prorocentrum donghaiense, Heterosigma akashiwo and Alexandrium tamarense on mortality rates and population growth parameter of Brachionus plicatilis under controlled experimental conditions. Results showed that 24 h LC50 values of Prorocentrum donghaiense, Heterosigma akashiwo and Alexandrium tamarense treatment to mortality rate of Brachionus plicatilis were 3.56, 1.21 and 0.49 (x 10(4) cells/mL) respectively. Marked density effects were presented when three species of red tide microalga showed their toxicity to Brachionus plicatilis. There were significant inhibitory effects on Brachionus plicatilis when it was exposed to cells of Prorocentrum donghaiense at the concentration of 10(4) cells/mL, filtrate and cell contents of Heterosigma akashiwo at the concentration of 10(5) cells/mL, and cells, filtrate and cell contents of Alexandrium tamarense at the concentration of 10(3) cells/mL respectively. Inhibitory effects of three species of microalga on Brachionus plicatilis were enhanced with increasing of microalgal density.

Isolation on the West Florida Shelf with implications for red tides and pollutant dispersal in the Gulf of Mexico

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Olascoaga, M. J.

2011-01-01

Analysis of year-long drifter trajectories and records of simulated surface Lagrangian Coherent Structures (LCSs) have suggested the presence of a resilient Cross-Shelf Transport Barrier (CSTB) on the West Florida Shelf (WFS). The CSTB was conjectured to provide a large degree of isolation, which is consequential for the fueling of red tides on the southern WFS by nutrients possibly released by rivers and canals directly on the region. Here this conjecture is thoroughly tested by identifying LCSs as well as performing tracer advection calculations based on seven-year-long records of surface and subsurface currents produced by a HYbrid-Coordinate Ocean Model (HYCOM) simulation of the Gulf of Mexico (GoM). The identified LCSs suggest that the CSTB extends downward in the water column. The tracer calculations suggest that, while the majority of the nutrients possibly released by rivers and canals directly on the southern WFS are retained within the region for long times, only a small fraction of the nutrients possibly released by rivers outside the WFS reach the southern WFS, mainly accompanying shoreward excursions of the CSTB. These results add importance to the role played by the CSTB in controlling red tide development on the WFS. Implications of the results for the dispersal of pollutants, such as oil, in the GoM are discussed. PMID:22287830

Relationship Between Light Intensity and Abundance of Dinoflagellate in Samalona Island, Makassar (Keterkaitan Intensitas Cahaya dan Kelimpahan Dinoflagellate di Pulau Samalona, Makassar

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Albida Rante Tasak

2015-06-01

Full Text Available Cahaya merupakan salah satu faktor penting dalam proses fotosintesis dinoflagellate dan pertumbuhan variabilitas harian. Intensitas cahaya memengaruhi aktivitas fotosintesis dan kelimpahan dinoflagellate. Studi ini bertujuan untuk menunjukkan pola kecenderungan kelimpahan dinoflagellate dan klorofil serta lama penyinaran terhadap kelimpahan dinoflagellate di Perairan Pulau Samalona. Penelitian dilakukan dengan menginkubasi sampel dinoflagellate kedalam botol sejak pagi-sore hari dengan inkubasi waktu pengamatan setiap 2 jam dengan ulangan sebanyak 3 kali. Pengambilan mencakup kelimpahan dinoflagellate, nutrient dan intensitas cahaya dalam perairan. Analisis data menggunakan regresi linear sederhana. Hasil penelitian menunjukkan bahwa nilai intensitas cahaya berkisar antara 50–3000 lux; kelimpahan dinoflagellate berkisar antara 9–1105 sel.L-1, dan kandungan klorofil a lebih dominan dengan kisaran  0.00069–0.50321 µg.L-1. Intensitas cahaya mempengaruhi kelimpahan dinoflagellate, namun pengaruh kandungan nutrient sangat kecil terhadap kelimpahan dinoflagellate. Pola kelimpahan dinoflagellate bervariasi dari pagi hingga sore hari yang dipengaruhi oleh intensitas cahaya dalam melakukan proses fotosintesis serta kondisi lingkungan lain seperti klorofil a dan nutrient. Hasil penelitian ini memberikan informasi variasi temporal harian kelimpahan dinoflagellate di Pulau Samalona, Makassar.

BIOMARKER LIPIDS IN RED TIDE (GYMNODINIUM BREVE) BLOOMS ALONG THE NORTHWEST FLORIDA COAST

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The ability to characterize phytoplankton communities and algal blooms using lipids as biomarkers requires knowledge of their distribution and taxonomic significance. Such an approach would have application, for example, in distinguishing and tracking certain dinoflagellates suc...

Death of Prorocentrum donghaiense may be a programmed autolysis

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Yang, Guanpin; Liu, Yongjian; Li, Bingjun

2008-08-01

Prorocentrum donghaiense, one of the dinoflagellate, has continuously caused large scale red tides along the Chinese coast in recent years. These red tides have brought tremendous loss to the local economy and serious impacts to the local environment. Unfortunately, little was known about the mechanism of the fast appearance and extinction of the red tide caused by this alga. In this study, the full-length cDNA of a caspase encoding gene of P. donghaiense was cloned and characterized, and the transcription of this gene during the senescence of the alga was semi-quantitatively determined. The cDNA was 520 bp in length. It contained a 258 bp open reading frame (ORF) which encoded a peptide of 85 amino acids. The amount of transcripts of the caspase encoding gene increased with the senescence of P. donghaiense and started to decrease gradually when the autolysis of P. donghaiense cells took place. We proposed that the death of P. donghaiense may be a caspase mediated programmed autolysis.

Evolution and Distribution of Saxitoxin Biosynthesis in Dinoflagellates

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Kjetill S. Jakobsen

2013-08-01

Full Text Available Numerous species of marine dinoflagellates synthesize the potent environmental neurotoxic alkaloid, saxitoxin, the agent of the human illness, paralytic shellfish poisoning. In addition, certain freshwater species of cyanobacteria also synthesize the same toxic compound, with the biosynthetic pathway and genes responsible being recently reported. Three theories have been postulated to explain the origin of saxitoxin in dinoflagellates: The production of saxitoxin by co-cultured bacteria rather than the dinoflagellates themselves, convergent evolution within both dinoflagellates and bacteria and horizontal gene transfer between dinoflagellates and bacteria. The discovery of cyanobacterial saxitoxin homologs in dinoflagellates has enabled us for the first time to evaluate these theories. Here, we review the distribution of saxitoxin within the dinoflagellates and our knowledge of its genetic basis to determine the likely evolutionary origins of this potent neurotoxin.

Toxicity of clay flocculation of the toxic dinoflagellate, Karenia brevis, to estuarine invertebrates and fish

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The benthic environmental effects of proposed control procedures for red tide events are relatively unknown but important to understand. The objective of this study was to determine the laboratory-derived toxicities of a clay flocculation technique proposed for the Florida red ti...

Utilizing the algicidal activity of aminoclay as a practical treatment for toxic red tides.

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Lee, Young-Chul; Jin, EonSeon; Jung, Seung Won; Kim, Yeon-Mi; Chang, Kwang Suk; Yang, Ji-Won; Kim, Si-Wouk; Kim, Young-Ok; Shin, Hyun-Jae

2013-01-01

In recent decades, harmful algal blooms (HABs) - commonly known as red tides - have increasingly impacted human health, caused significant economic losses to fisheries and damaged coastal environments and ecosystems. Here, we demonstrate a method to control and suppress HABs through selective algal lysis. The approach harnesses the algicidal effects of aminoclays, which are comprised of a high density of primary amine groups covalently bonded by metal cation backbones. Positively charged colloidals of aminoclays induce cell lysis in HABs within several minutes exposure but have negligible impact on non-harmful phytoplankton, zooplankton and farmed fish. This selective lysis is due to the ammonium characteristics of the aminoclay and the electrostatic attraction between the clay nanoparticles and the algal cells. In contrast, yellow loess clay, a recognized treatment for HABs, causes algal flocs with little cell lysis. Thus, the aminoclay loading can be effective for the mitigation of HABs.

Antioxidant response of ridgetail white prawn Exopalaemon carinicauda to harmful dinoflagellate Prorocentrum minimum exposure and its histological change

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Mu, Cuimin; Ren, Xianyun; Ge, Qianqian; Wang, Jiajia; Li, Jian

2017-04-01

The dinoflagellate Prorocentrum minimum, one of the most widespread red tide causing species, affects marine aquaculture and ecosystems worldwide. In this study, ridgetail white prawn Exopalaemon carinicauda were exposed to P. minimum cells (5 × 104 cells mL-1) to investigate its harmful effects on the shrimp. Antioxidant activities and histological changes were used as indicators of health status of the shrimp. In 72 hours, the mortality of E. carinicauda was not affected, but its antioxidant response and histology were statistically different from those of control. Elevated superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities and depressed catalase (CAT) activity were observed in gill; while increased SOD, glutathione S-transferase (GST), CAT activities and modulated GPX activity were observed in hepatopancreas. Thus, antioxidant activities in gill and hepatopancreas seem to respond differentially to harmful alga exposure. Increased malondialdehyde (MDA) content in early a few hours indicates the damage of the antioxidant defense system. Although MDA content recovered to a low level thereafter, a series of histological abnormalities including accumulation or infiltration of hemocytes, tissue lesions and necrosis were discovered in gill and hepatopancreas. Exposure to P. minimum induced sublethal effects on E. carinicauda, including temporary oxidative damage and histological injury.

Evolution of saxitoxin synthesis in cyanobacteria and dinoflagellates.

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Hackett, Jeremiah D; Wisecaver, Jennifer H; Brosnahan, Michael L; Kulis, David M; Anderson, Donald M; Bhattacharya, Debashish; Plumley, F Gerald; Erdner, Deana L

2013-01-01

Dinoflagellates produce a variety of toxic secondary metabolites that have a significant impact on marine ecosystems and fisheries. Saxitoxin (STX), the cause of paralytic shellfish poisoning, is produced by three marine dinoflagellate genera and is also made by some freshwater cyanobacteria. Genes involved in STX synthesis have been identified in cyanobacteria but are yet to be reported in the massive genomes of dinoflagellates. We have assembled comprehensive transcriptome data sets for several STX-producing dinoflagellates and a related non-toxic species and have identified 265 putative homologs of 13 cyanobacterial STX synthesis genes, including all of the genes directly involved in toxin synthesis. Putative homologs of four proteins group closely in phylogenies with cyanobacteria and are likely the functional homologs of sxtA, sxtG, and sxtB in dinoflagellates. However, the phylogenies do not support the transfer of these genes directly between toxic cyanobacteria and dinoflagellates. SxtA is split into two proteins in the dinoflagellates corresponding to the N-terminal portion containing the methyltransferase and acyl carrier protein domains and a C-terminal portion with the aminotransferase domain. Homologs of sxtB and N-terminal sxtA are present in non-toxic strains, suggesting their functions may not be limited to saxitoxin production. Only homologs of the C-terminus of sxtA and sxtG were found exclusively in toxic strains. A more thorough survey of STX+ dinoflagellates will be needed to determine if these two genes may be specific to SXT production in dinoflagellates. The A. tamarense transcriptome does not contain homologs for the remaining STX genes. Nevertheless, we identified candidate genes with similar predicted biochemical activities that account for the missing functions. These results suggest that the STX synthesis pathway was likely assembled independently in the distantly related cyanobacteria and dinoflagellates, although using some

Dinoflagellates associated with freshwater sponges from the ancient lake baikal.

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Annenkova, Natalia V; Lavrov, Dennis V; Belikov, Sergey I

2011-04-01

Dinoflagellates are a diverse group of protists that are common in both marine and freshwater environments. While the biology of marine dinoflagellates has been the focus of several recent studies, their freshwater relatives remain little-investigated. In the present study we explore the diversity of dinoflagellates in Lake Baikal by identifying and analyzing dinoflagellate sequences for 18S rDNA and ITS-2 from total DNA extracted from three species of endemic Baikalian sponges (Baikalospongia intermedia,Baikalospongia rectaand Lubomirskia incrustans). Phylogenetic analyses of these sequences revealed extensive dinoflagellate diversity in Lake Baikal. We found two groups of sequences clustering within the order Suessiales, known for its symbiotic relationships with various invertebrates. Thus they may be regarded as potential symbionts of Baikalian sponges. In addition,Gyrodinium helveticum, representatives from the genus Gymnodinium, dinoflagellates close to the family Pfiesteriaceae, and a few dinoflagellates without definite affiliation were detected. No pronounced difference in the distribution of dinoflagellates among the studied sponges was found, except for the absence of the Piscinoodinium-like dinoflagellates inL. incrustans. To the best of our knowledge, this is the first study of the diversity of dinoflagellates in freshwater sponges, the first systematic investigation of dinoflagellate molecular diversity in Lake Baikal and the first finding of members of the order Suessiales as symbionts of freshwater invertebrates. Copyright © 2010 Elsevier GmbH. All rights reserved.

Remarkable difference in paralytic shellfish poisoning toxin distribution in tissues of pen shell atrina pectinata exposed to toxic red tide bloom

International Nuclear Information System (INIS)

Narceda, Ronald Jefferson A.; Montojo, Ulysses M.; Cayme, Mirriam F.; Borja, Valeriano M.

2011-01-01

tissues and shellfish body lengths or age were also assessed and were found to be uncorrelated. Note worthily, STX was the only toxin detected in the abductor muscle suggesting a bioconversion of all other toxin derivatives. Based from the findings, abductor muscle of A. pectinata accumulates minimal toxicity level, thus removal of the part from the whole body for marketing suggests safe human consumption despite toxic red tide episodes, provided that strict quality assurance on the said product is applied. (author)

Ocean tides

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Hendershott, M. C.

1975-01-01

A review of recent developments in the study of ocean tides and related phenomena is presented. Topics briefly discussed include: the mechanism by which tidal dissipation occurs; continental shelf, marginal sea, and baroclinic tides; estimation of the amount of energy stored in the tide; the distribution of energy over the ocean; the resonant frequencies and Q factors of oceanic normal modes; the relationship of earth tides and ocean tides; and numerical global tidal models.

Cell Biology of Cnidarian-Dinoflagellate Symbiosis

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Allemand, Denis; Weis, Virginia M.

2012-01-01

Summary: The symbiosis between cnidarians (e.g., corals or sea anemones) and intracellular dinoflagellate algae of the genus Symbiodinium is of immense ecological importance. In particular, this symbiosis promotes the growth and survival of reef corals in nutrient-poor tropical waters; indeed, coral reefs could not exist without this symbiosis. However, our fundamental understanding of the cnidarian-dinoflagellate symbiosis and of its links to coral calcification remains poor. Here we review what we currently know about the cell biology of cnidarian-dinoflagellate symbiosis. In doing so, we aim to refocus attention on fundamental cellular aspects that have been somewhat neglected since the early to mid-1980s, when a more ecological approach began to dominate. We review the four major processes that we believe underlie the various phases of establishment and persistence in the cnidarian/coral-dinoflagellate symbiosis: (i) recognition and phagocytosis, (ii) regulation of host-symbiont biomass, (iii) metabolic exchange and nutrient trafficking, and (iv) calcification. Where appropriate, we draw upon examples from a range of cnidarian-alga symbioses, including the symbiosis between green Hydra and its intracellular chlorophyte symbiont, which has considerable potential to inform our understanding of the cnidarian-dinoflagellate symbiosis. Ultimately, we provide a comprehensive overview of the history of the field, its current status, and where it should be going in the future. PMID:22688813

Comparative aspects of basic chromatin proteins in dinoflagellates.

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Rizzo, P J

1981-01-01

Previous work on histone-like proteins in dinoflagellates is summarized, together with some new data to give an overview of basic proteins in these algae. The first two dinoflagellates studied were both found to contain one major acid-soluble protein that migrated to the same position in acidic-urea gels. When several other genera were studied however, it became apparent that the histone-like proteins from different dinoflagellates were similar but not identical. In view of the great diversity of living dinoflagellates it is speculated that further differences in dinoflagellate basic chromatin proteins will be revealed. Electrophoretic data from the eukaryotic (endosymbiont) nucleus of Peridinium balticum showed the presence of five major components. It is speculated that two of these proteins represent an H1-like doublet and two others correspond to the highly conserved histones H3 and H4. The fifth component is a new histone that may substitute for H2A and H2B in the nucleosome. Because histones and nucleosomes are present in all higher organisms but completely lacking in procaryotes, studies on basic proteins in dinoflagellates will provides insights into the evolution of histones and eucaryotic chromatin organization.

Dinoflagellates of the Trentino Province, Italy

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Giovanna FLAIM

2007-08-01

Full Text Available The Trentino Province (Italy has more than 320 lakes diverse in size, geological substrate, altitude and trophic status, and representing most physico-chemical types of temperate lakes. A recent research project (SALTO offered the opportunity to study the dinoflagellate flora of 27 of these water bodies representing all lake types. In this paper 34 taxa of dinoflagellates assigned to eight genera (Ceratium, Glenodiniopsis, Glochidinium, Gymnodinium, Gyrodinium, Peridinium, Peridiniopsis and Tovellia in five families (Ceratiaceae, Glenodiniopsidaceae, Gymnodiniaceae, Peridiniaceae and Tovelliaceae and four genera of uncertain collocation (Baldinia, Borghiella, Durinskia and Staszicella are described. Two previously undescribed species and two new combinations are also included. Classification is based in part on Popovsk´y and Pfiester (1990, modified according to the results of recent molecular and ultrastructural analyses. Dinoflagellate taxonomy is currently undergoing extensive revision, and taxonomic decisions in the present article follow the recent orientations in dinoflagellate systematics. The taxonomical issues of the more problematic genera are discussed. Where appropriate, comments on ecological features of the species are also given.

Metabolic pathway redundancy within the apicomplexan-dinoflagellate radiation argues against an ancient chromalveolate plastid

KAUST Repository

Waller, Ross F.

2015-12-08

The chromalveolate hypothesis presents an attractively simple explanation for the presence of red algal-derived secondary plastids in 5 major eukaryotic lineages: “chromista” phyla, cryptophytes, haptophytes and ochrophytes; and alveolate phyla, dinoflagellates and apicomplexans. It posits that a single secondary endosymbiotic event occurred in a common ancestor of these diverse groups, and that this ancient plastid has since been maintained by vertical inheritance only. Substantial testing of this hypothesis by molecular phylogenies has, however, consistently failed to provide support for the predicted monophyly of the host organisms that harbour these plastids—the “chromalveolates.” This lack of support does not disprove the chromalveolate hypothesis per se, but rather drives the proposed endosymbiosis deeper into the eukaryotic tree, and requires multiple plastid losses to have occurred within intervening aplastidic lineages. An alternative perspective on plastid evolution is offered by considering the metabolic partnership between the endosymbiont and its host cell. A recent analysis of metabolic pathways in a deep-branching dinoflagellate indicates a high level of pathway redundancy in the common ancestor of apicomplexans and dinoflagellates, and differential losses of these pathways soon after radiation of the major extant lineages. This suggests that vertical inheritance of an ancient plastid in alveolates is highly unlikely as it would necessitate maintenance of redundant pathways over very long evolutionary timescales.

Metabolic pathway redundancy within the apicomplexan-dinoflagellate radiation argues against an ancient chromalveolate plastid

KAUST Repository

Waller, Ross F.; Gornik, Sebastian G.; Koreny, Ludek; Pain, Arnab

2015-01-01

The chromalveolate hypothesis presents an attractively simple explanation for the presence of red algal-derived secondary plastids in 5 major eukaryotic lineages: “chromista” phyla, cryptophytes, haptophytes and ochrophytes; and alveolate phyla, dinoflagellates and apicomplexans. It posits that a single secondary endosymbiotic event occurred in a common ancestor of these diverse groups, and that this ancient plastid has since been maintained by vertical inheritance only. Substantial testing of this hypothesis by molecular phylogenies has, however, consistently failed to provide support for the predicted monophyly of the host organisms that harbour these plastids—the “chromalveolates.” This lack of support does not disprove the chromalveolate hypothesis per se, but rather drives the proposed endosymbiosis deeper into the eukaryotic tree, and requires multiple plastid losses to have occurred within intervening aplastidic lineages. An alternative perspective on plastid evolution is offered by considering the metabolic partnership between the endosymbiont and its host cell. A recent analysis of metabolic pathways in a deep-branching dinoflagellate indicates a high level of pathway redundancy in the common ancestor of apicomplexans and dinoflagellates, and differential losses of these pathways soon after radiation of the major extant lineages. This suggests that vertical inheritance of an ancient plastid in alveolates is highly unlikely as it would necessitate maintenance of redundant pathways over very long evolutionary timescales.

Hv 1 Proton Channels in Dinoflagellates: Not Just for Bioluminescence?

Science.gov (United States)

Kigundu, Gabriel; Cooper, Jennifer L; Smith, Susan M E

2018-04-26

Bioluminescence in dinoflagellates is controlled by H V 1 proton channels. Database searches of dinoflagellate transcriptomes and genomes yielded hits with sequence features diagnostic of all confirmed H V 1, and show that H V 1 is widely distributed in the dinoflagellate phylogeny including the basal species Oxyrrhis marina. Multiple sequence alignments followed by phylogenetic analysis revealed three major subfamilies of H V 1 that do not correlate with presence of theca, autotrophy, geographic location, or bioluminescence. These data suggest that most dinoflagellates express a H V 1 which has a function separate from bioluminescence. Sequence evidence also suggests that dinoflagellates can contain more than one H V 1 gene. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Depth distribution of benthic dinoflagellates in the Caribbean Sea

Science.gov (United States)

Boisnoir, Aurélie; Pascal, Pierre-Yves; Cordonnier, Sébastien; Lemée, Rodolophe

2018-05-01

Monitoring of benthic dinoflagellates is usually conducted between sub-surface and 5 m depth, where these organisms are supposed to be in highest abundances. However, only few studies have focused on the small-scale depth distribution of benthic dinoflagellates. In the present study, abundances of dinoflagellates were evaluated on an invasive macrophyte Halophila stipulacea in two coastal sites in Guadeloupe (Caribbean Sea) along a depth gradient from sub-surface to 3 m at Gosier and until 20 m at Rivière Sens during the tropical wet and dry seasons. Species of genus Ostreopsis and Prorocentrum were the most abundant. Depth did not influence total dinoflagellate abundance but several genera showed particular depth-distribution preferences. The highest abundances of Ostreopsis and Gambierdiscus species were estimated preferentially in surface waters, whereas Coolia spp. were found in the same proportions but in deeper waters. Halophila stipulacea biomass was positively correlated with Ostreopsis spp. abundance. Our study suggests that sampling of benthic dinoflagellates should be conducted at different water depths taking into account the presence of the macroalgal substrate as well. In the Caribbean area, special attention should be addressed to the presence of H. stipulacea which tends to homogenize the marine landscape and represents a substrate for hosting dinoflagellate growth.

On the generation and evolution of internal solitary waves in the southern Red Sea

KAUST Repository

Guo, Daquan

2015-04-01

Satellite observations recently revealed the existence of trains of internal solitary waves in the southern Red Sea between 16.0°N and 16.5°N, propagating from the centre of the domain toward the continental shelf [Da silva et al., 2012]. Given the relatively weak tidal velocity in this area and their generation in the central of the domain, Da Silva suggested three possible mechanisms behind the generation of the waves, namely Resonance and disintegration of interfacial tides, Generation of interfacial tides by impinging, remotely generated internal tidal beams and for geometrically focused and amplified internal tidal beams. Tide analysis based on tide stations data and barotropic tide model in the Red Sea shows that tide is indeed very weak in the centre part of the Red Sea, but it is relatively strong in the northern and southern parts (reaching up to 66 cm/s). Together with extreme steep slopes along the deep trench, it provides favourable conditions for the generation of internal solitary in the southern Red Sea. To investigate the generation mechanisms and study the evolution of the internal waves in the off-shelf region of the southern Red Sea we have implemented a 2-D, high-resolution and non-hydrostatic configuration of the MIT general circulation model (MITgcm). Our simulations reproduce well that the generation process of the internal solitary waves. Analysis of the model\\'s output suggests that the interaction between the topography and tidal flow with the nonlinear effect is the main mechanism behind the generation of the internal solitary waves. Sensitivity experiments suggest that neither tidal beam nor the resonance effect of the topography is important factor in this process.

The inverse problem: Ocean tides derived from earth tide observations

Science.gov (United States)

Kuo, J. T.

1978-01-01

Indirect mapping ocean tides by means of land and island-based tidal gravity measurements is presented. The inverse scheme of linear programming is used for indirect mapping of ocean tides. Open ocean tides were measured by the numerical integration of Laplace's tidal equations.

Arctic Oil Spill Response Guide for the Alaskan Beaufort Sea

Science.gov (United States)

1988-03-01

skimmers. Oiled soil and debris, which could not be cleaned by this technique, was removed and placed in heavy duty plastic bags and 55-gallon drums. 6.5.9...burned in a smokeless flare burner. Oiled debris was burned in the Coast Guard Trecan Incinerator which was set up at Prudhoe Bay. Oiled soil was placed...skeletons that form diatomite . Dinoflagellates: any of an order to planktonic forms important in aquatic food chains and including forms causing red tides

NanoSIMS study of trophic interactions in the coral-dinoflagellate endosymbiosis

Science.gov (United States)

Kopp, Christophe; Mathieu, Pernice; Domart-Coulon, Isabelle; Djediat, Chakib; Spangenberg, Jorge; Alexander, Duncan; Hignette, Michel; Meziane, Tarik; Meibom, Anders

2013-04-01

Tropical and subtropical reef-building corals generally form a stable endosymbiotic association with autotrophic single-celled dinoflagellate algae, commonly known as "zooxanthellae", which is crucial for the development of coral reef ecosystems. In the present work, the spatial and temporal dynamics of trophic interactions between corals and their dinoflagellates was investigated in situ and at a subcellular level in the reef-building coral Pocillopora damicornis. Transmission electron microscopy (TEM) and quantitative NanoSIMS isotopic imaging of tissue ultra-thin sections (70 nm) were combined to precisely track the assimilation and the fate of 15N-labeled compounds (ammonium, nitrate and aspartic acid) within each symbiotic partner of the coral-dinoflagellate association. Among our main results, we found that (i) both dinoflagellate algae and coral tissue rapidly assimilate ammonium and aspartic acid from the environment, (ii) however only the dinoflagellates assimilate nitrate, (ii) nitrogen is rapidly and temporary stored within the dinoflagellate cells into uric acid crystals, and (iii) the dinoflagellate endosymbionts translocate nitrogenous compounds to their coral host. This study paves the way for exploring in details the wide range of metabolic interactions between partners of any symbiosis in the biosphere.

Diverse Bacterial PKS Sequences Derived From Okadaic Acid-Producing Dinoflagellates

Directory of Open Access Journals (Sweden)

Kathleen S. Rein

2008-05-01

Full Text Available Okadaic acid (OA and the related dinophysistoxins are isolated from dinoflagellates of the genus Prorocentrum and Dinophysis. Bacteria of the Roseobacter group have been associated with okadaic acid producing dinoflagellates and have been previously implicated in OA production. Analysis of 16S rRNA libraries reveals that Roseobacter are the most abundant bacteria associated with OA producing dinoflagellates of the genus Prorocentrum and are not found in association with non-toxic dinoflagellates. While some polyketide synthase (PKS genes form a highly supported Prorocentrum clade, most appear to be bacterial, but unrelated to Roseobacter or Alpha-Proteobacterial PKSs or those derived from other Alveolates Karenia brevis or Crytosporidium parvum.

Current Knowledge and Recent Advances in Marine Dinoflagellate Transcriptomic Research

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Muhamad Afiq Akbar

2018-02-01

Full Text Available Dinoflagellates are essential components in marine ecosystems, and they possess two dissimilar flagella to facilitate movement. Dinoflagellates are major components of marine food webs and of extreme importance in balancing the ecosystem energy flux in oceans. They have been reported to be the primary cause of harmful algae bloom (HABs events around the world, causing seafood poisoning and therefore having a direct impact on human health. Interestingly, dinoflagellates in the genus Symbiodinium are major components of coral reef foundations. Knowledge regarding their genes and genome organization is currently limited due to their large genome size and other genetic and cytological characteristics that hinder whole genome sequencing of dinoflagellates. Transcriptomic approaches and genetic analyses have been employed to unravel the physiological and metabolic characteristics of dinoflagellates and their complexity. In this review, we summarize the current knowledge and findings from transcriptomic studies to understand the cell growth, effects on environmental stress, toxin biosynthesis, dynamic of HABs, phylogeny and endosymbiosis of dinoflagellates. With the advancement of high throughput sequencing technologies and lower cost of sequencing, transcriptomic approaches will likely deepen our understanding in other aspects of dinoflagellates’ molecular biology such as gene functional analysis, systems biology and development of model organisms.

Dinoflagellate blooms in upwelling systems: Seeding, variability, and contrasts with diatom bloom behaviour

Science.gov (United States)

Smayda, T. J.; Trainer, V. L.

2010-04-01

The influence of diatom bloom behaviour, dinoflagellate life cycles, propagule type and upwelling bloom cycles on the seeding of dinoflagellate blooms in eastern boundary current upwelling systems is evaluated. Winter-spring diatom bloom behaviour is contrasted with upwelling bloom behaviour because their phenology impacts dinoflagellate blooms. The winter-spring diatom bloom is usually sustained, whereas the classical upwelling diatom bloom occurs as a series of separate, recurrent mini-blooms intercalated by upwelling-relaxation periods, during which dinoflagellates often bloom. Four sequential wind-regulated phases characterize upwelling cycles, with each phase having different effects on diatom and dinoflagellate bloom behaviour: bloom “spin up”, bloom maximum, bloom “spin down”, and upwelling relaxation. The spin up - bloom maximum is the period of heightened diatom growth; the spin down - upwelling-relaxation phases are the periods when dinoflagellates often bloom. The duration, intensity and ratio of the upwelling and relaxation periods making up upwelling cycles determine the potential for dinoflagellate blooms to develop within a given upwelling cycle and prior to the subsequent “spin up” of upwelling that favours diatom blooms. Upwelling diatoms and meroplanktonic dinoflagellates have three types of propagules available to seed blooms: vegetative cells, resting cells and resting cysts. However, most upwelling dinoflagellates are holoplanktonic, which indicates that the capacity to form resting cysts is not an absolute requirement for growth and survival in upwelling systems. The long-term (decadal) gaps in bloom behaviour of Gymnodinium catenatum and Lingulodinium polyedrum, and the unpredictable bloom behaviour of dinoflagellates generally, are examined from the perspective of seeding strategies. Mismatches between observed and expected in situ bloom behaviour and resting cyst dynamics are common among upwelling dinoflagellates. This

The brevetoxins; Le brevetossine

Energy Technology Data Exchange (ETDEWEB)

Marchiori, Enrico [Istituto Sperimentale per la Zootecnia, Rome (Italy); Bruno, Cinzia [Ospedale Regionale ``San Giovanni``, Rome (Italy); Bruno, Milena [Istituto Superiore Sanita`, Rome (Italy). Laboratorio di Igiene Ambientale

1997-03-01

Gymnodinium breve DAVIS is a marine non-thecate dinoflagellate, the causing agent of algal toxic ``red tides`` in the Gulf of Mexico and New Zealand. The toxins produced, called brevetoxins have neurologic effects on a wide range of vertebrate and invertebrate species, and can infect man via skin contacts with dermatitis, through airway smooth muscle contraction, and through feeding on contaminated mussels. The review deals with the chemical characteristics of the toxins, their ecological and health effects and efficient methods for detection.

Potentiality of benthic dinoflagellate cultures and screening of their ...

African Journals Online (AJOL)

Taken together, this is the first report on the growth potential and biomass production of benthic dinoflagellate strains isolated from Jeju Island in appropriate culture medium as well as their importance in potential pharmacological applications. Key words: Amphidinium carterae, benthic dinoflagellates, biomass, bioactivities, ...

Red Tides: Mass casualty and whole blood at sea Red Tides.

Science.gov (United States)

Miller, Benjamin T; Lin, Andrew H; Clark, Susan C; Cap, Andrew P; Dubose, Joseph J

2018-02-13

The U.S. Navy's casualty-receiving ships provide remote damage control resuscitation (RDCR) platforms to treat injured combatants deployed afloat and ashore. We report a significant mass casualty incident aboard the USS Bataan, and the most warm fresh whole blood (WFWB) transfused at sea for traumatic hemorrhagic shock since the Vietnam War. Casualty-receiving ships have robust medical capabilities, including a frozen blood bank with packed red blood cells (pRBC) and fresh frozen plasma (FFP). The blood supply can be augmented with WFWB collected from a "walking blood bank" (WBB). Following a helicopter crash, six patients were transported by MV-22 Osprey to the USS Bataan. Patient 1 had a pelvic fracture, was managed with a pelvic binder, and received 4 units of pRBC, 2 units of FFP, and 6 units of WFWB. Patient 2, with a comminuted tibia and fibula fracture, underwent lower extremity four-compartment fasciotomy, and received 4 units of WFWB. Patient 3 underwent several procedures, including left anterior thoracotomy, aortic cross-clamping, exploratory laparotomy, small bowel resection, and tracheostomy. He received 8 units of pRBC, 8 units of FFP, and 28 units of WFWB. Patients 4 and 5 had suspected spine injuries and were managed non-operatively. Patient 6, with open tibia and fibula fractures, underwent lower extremity four-compartment fasciotomy with tibia external fixation and received 1 unit of WFWB. All patients survived aeromedical evacuation to a Role 4 medical facility and subsequent transfer to local hospitals. Maritime military mass casualty incidents are challenging, but the U.S. Navy's casualty-receiving ships are ready to perform RDCR at sea. Activation of the ship's WBB to transfuse WFWB is essential for hemostatic resuscitations afloat. V STUDY TYPE: Case series.

RNA-Seq as an Emerging Tool for Marine Dinoflagellate Transcriptome Analysis: Process and Challenges

Directory of Open Access Journals (Sweden)

Muhamad Afiq Akbar

2018-01-01

Full Text Available Dinoflagellates are the large group of marine phytoplankton with primary studies interest regarding their symbiosis with coral reef and the abilities to form harmful algae blooms (HABs. Toxin produced by dinoflagellates during events of HABs cause severe negative impact both in the economy and health sector. However, attempts to understand the dinoflagellates genomic features are hindered by their complex genome organization. Transcriptomics have been employed to understand dinoflagellates genome structure, profile genes and gene expression. RNA-seq is one of the latest methods for transcriptomics study. This method is capable of profiling the dinoflagellates transcriptomes and has several advantages, including highly sensitive, cost effective and deeper sequence coverage. Thus, in this review paper, the current workflow of dinoflagellates RNA-seq starts with the extraction of high quality RNA and is followed by cDNA sequencing using the next-generation sequencing platform, dinoflagellates transcriptome assembly and computational analysis will be discussed. Certain consideration needs will be highlighted such as difficulty in dinoflagellates sequence annotation, post-transcriptional activity and the effect of RNA pooling when using RNA-seq.

Seasonality and toxin production of Pyrodinium bahamense in a Red Sea lagoon

KAUST Repository

Banguera Hinestroza, Eulalia; Eikrem, W.; Mansour, H.; Solberg, Ingrid; Curdia, Joao; Holtermann, Karie Ellen; Edvardsen, B.; Kaartvedt, Stein

2016-01-01

Harmful algal blooms of the dinoflagellate Pyrodinium bahamense have caused human and economic losses in the last decades. This study, for the first time, documents a bloom of P. bahamense in the Red Sea. The alga was recurrently present in a semi

Tides and Decadal Variability

Science.gov (United States)

Ray, Richard D.

2003-01-01

This paper reviews the mechanisms by which oceanic tides and decadal variability in the oceans are connected. We distinguish between variability caused by tides and variability observed in the tides themselves. Both effects have been detected at some level. The most obvious connection with decadal timescales is through the 18.6-year precession of the moon's orbit plane. This precession gives rise to a small tide of the same period and to 18.6-year modulations in the phase and amplitudes of short-period tides. The 18.6-year "node tide" is very small, no more than 2 cm anywhere, and in sea level data it is dominated by the ocean's natural Variability. Some authors have naively attributed climate variations with periods near 19 years directly to the node tide, but the amplitude of the tide is too small for this mechanism to be operative. The more likely explanation (Loder and Garrett, JGR, 83, 1967-70, 1978) is that the 18.6-y modulations in short-period tides, especially h e principal tide M2, cause variations in ocean mixing, which is then observed in temperature and other climatic indicators. Tidally forced variability has also been proposed by some authors, either in response to occasional (and highly predictable) tidal extremes or as a nonlinear low-frequency oscillation caused by interactions between short-period tides. The former mechanism can produce only short-duration events hardly more significant than normal tidal ranges, but the latter mechanism can in principle induce low-frequency oscillations. The most recent proposal of this type is by Keeling and Whorf, who highlight the 1800-year spectral peak discovered by Bond et al. (1997). But the proposal appears contrived and should be considered, in the words of Munk et al. (2002), "as the most likely among unlikely candidates."

Strategies of marine dinoflagellate survival and some rules of assembly

Science.gov (United States)

Smayda, Theodore J.; Reynolds, Colin S.

2003-03-01

Dinoflagellate ecology is based on multiple adaptive strategies and species having diverse habitat preferences. Nine types of mixing-irradiance-nutrient habitats selecting for specific marine dinoflagellate life-form types are recognised, with five rules of assembly proposed to govern bloom-species selection and community organisation within these habitats. Assembly is moulded around an abiotic template of light energy, nutrient supply and physical mixing in permutative combinations. Species selected will have one of three basic ( C-, S-, R-) strategies: colonist species ( C-) which predominate in chemically disturbed habitats; nutrient stress tolerant species ( S-), and species ( R-) tolerant of shear/stress forces in physically disturbed water masses. This organisational plan of three major habitat variables and three major adaptive strategies is termed the 3-3 plan. The bloom behaviour and habitat specialisation of dinoflagellates and diatoms are compared. Dinoflagellates behave as annual species, bloom soloists, are ecophysiologically diverse, and habitat specialists whose blooms tend to be monospecific. Diatoms behave as perennial species, guild members, are habitat cosmopolites, have a relatively uniform bloom strategy based on species-rich pools and exhibit limited habitat specialisation. Dinoflagellate bloom-species selection follows a taxonomic hierarchical pathway which progresses from phylogenetic to generic to species selection, and in that sequence. Each hierarchical taxonomic level has its own adaptive requirements subject to rules of assembly. Dinoflagellates would appear to be well suited to exploit marine habitats and to be competitive with other phylogenetic groups, yet fail to do so.

Simulation and analysis of a model dinoflagellate predator-prey system

Science.gov (United States)

Mazzoleni, M. J.; Antonelli, T.; Coyne, K. J.; Rossi, L. F.

2015-12-01

This paper analyzes the dynamics of a model dinoflagellate predator-prey system and uses simulations to validate theoretical and experimental studies. A simple model for predator-prey interactions is derived by drawing upon analogies from chemical kinetics. This model is then modified to account for inefficiencies in predation. Simulation results are shown to closely match the model predictions. Additional simulations are then run which are based on experimental observations of predatory dinoflagellate behavior, and this study specifically investigates how the predatory dinoflagellate Karlodinium veneficum uses toxins to immobilize its prey and increase its feeding rate. These simulations account for complex dynamics that were not included in the basic models, and the results from these computational simulations closely match the experimentally observed predatory behavior of K. veneficum and reinforce the notion that predatory dinoflagellates utilize toxins to increase their feeding rate.

Dinoflagellate phylogeny as inferred from heat shock protein 90 and ribosomal gene sequences.

Directory of Open Access Journals (Sweden)

Mona Hoppenrath

2010-10-01

Full Text Available Interrelationships among dinoflagellates in molecular phylogenies are largely unresolved, especially in the deepest branches. Ribosomal DNA (rDNA sequences provide phylogenetic signals only at the tips of the dinoflagellate tree. Two reasons for the poor resolution of deep dinoflagellate relationships using rDNA sequences are (1 most sites are relatively conserved and (2 there are different evolutionary rates among sites in different lineages. Therefore, alternative molecular markers are required to address the deeper phylogenetic relationships among dinoflagellates. Preliminary evidence indicates that the heat shock protein 90 gene (Hsp90 will provide an informative marker, mainly because this gene is relatively long and appears to have relatively uniform rates of evolution in different lineages.We more than doubled the previous dataset of Hsp90 sequences from dinoflagellates by generating additional sequences from 17 different species, representing seven different orders. In order to concatenate the Hsp90 data with rDNA sequences, we supplemented the Hsp90 sequences with three new SSU rDNA sequences and five new LSU rDNA sequences. The new Hsp90 sequences were generated, in part, from four additional heterotrophic dinoflagellates and the type species for six different genera. Molecular phylogenetic analyses resulted in a paraphyletic assemblage near the base of the dinoflagellate tree consisting of only athecate species. However, Noctiluca was never part of this assemblage and branched in a position that was nested within other lineages of dinokaryotes. The phylogenetic trees inferred from Hsp90 sequences were consistent with trees inferred from rDNA sequences in that the backbone of the dinoflagellate clade was largely unresolved.The sequence conservation in both Hsp90 and rDNA sequences and the poor resolution of the deepest nodes suggests that dinoflagellates reflect an explosive radiation in morphological diversity in their recent

THE TOXIC DINOFLAGELLATE GYMNODINIUM CATENATUM (DINOPHYCEAE) REQUIRES MARINE BACTERIA FOR GROWTH(1).

Science.gov (United States)

Bolch, Christopher J S; Subramanian, Thaila A; Green, David H

2011-10-01

Interactions with the bacterial community are increasingly considered to have a significant influence on marine phytoplankton populations. Here we used a simplified dinoflagellate-bacterium experimental culture model to conclusively demonstrate that the toxic dinoflagellate Gymnodinium catenatum H. W. Graham requires growth-stimulatory marine bacteria for postgermination survival and growth, from the point of resting cyst germination through to vegetative growth at bloom concentrations (10(3)  cells · mL(-1) ). Cysts of G. catenatum were germinated and grown in unibacterial coculture with antibiotic-resistant or antibiotic-sensitive Marinobacter sp. DG879 or Brachybacterium sp., and with mixtures of these two bacteria. Addition of antibiotics to cultures grown with antibiotic-sensitive strains of bacteria resulted in death of the dinoflagellate culture, whereas cultures grown with antibiotic-resistant bacteria survived antibiotic addition and continued to grow beyond the 21 d experiment. Removal of either bacterial type from mixed-bacterial dinoflagellate cultures (using an antibiotic) resulted in cessation of dinoflagellate growth until bacterial concentration recovered to preaddition concentrations, suggesting that the bacterial growth factors are used for dinoflagellate growth or are labile. Examination of published reports of axenic dinoflagellate culture indicate that a requirement for bacteria is not universal among dinoflagellates, but rather that species may vary in their relative reliance on, and relationship with, the bacterial community. The experimental model approach described here solves a number of inherent and logical problems plaguing studies of algal-bacterium interactions and provides a flexible and tractable tool that can be extended to examine bacterial interactions with other phytoplankton species. © 2011 Phycological Society of America.

What Causes Tides?

Science.gov (United States)

Donovan, Deborah

2004-01-01

The phenomenon of tides has a faraway source. This rise and fall of the water level over a period of several hours is a result of the gravitational pull of the Moon and the Sun on Earth's oceans. Tides exhibit predictable cycles on daily, monthly, and yearly scales. The magnitude of the tides is dependent on the position of the Earth and Moon in…

Feeding on copepod fecal pellets: a new trophic role of dinoflagellates as detritivores

DEFF Research Database (Denmark)

Poulsen, Louise K.; Moldrup, M.; Berge, T.

2011-01-01

Recent field studies indicate that dinoflagellates are key degraders of copepod fecal pellets. This study is the first to publish direct evidence of pellet grazing by dinoflagellates. Feeding and growth on copepod fecal pellets were studied for both heterotrophic (4 species) and mixotrophic...... dinoflagellates (Gyrodinium dominans, Gyrodinium spirale, Diplopsalis lenticula, Protoperidinium depressum) studied fed on fecal pellets. Using natural concentrations of dinoflagellates and copepod fecal pellets, average ingestion rates of 0.2 and 0.1 pellets cell−1 d−1 and clearance rates of between 0.2 and 0...

Intracellular bacteria: the origin of dinoflagellate toxicity.

Science.gov (United States)

Silva, E S

1990-01-01

Dinoflagellate blooms of the same species have been registered either as toxic or nontoxic and, in the latter case, toxicity may be of different types. A hypothesis has been formulated according to which the bacteria having in some way taken part in the toxin formation are either inside the dinoflagellate cell or in the nutritive liquid. The presence of intracellular bacteria in those microorganisms has been studied mainly in material from cultures, a few from the sea, and several strains were isolated from different species. Experiments with crossed inoculations have shown that the bacterial strain from Gonyaulax tamarensis caused the cells of some other species to become toxic. From nontoxic clonal cultures of Prorocentrum balticum, Glenodinium foliaceum, and Gyrodinium instriatum, after inoculation of that bacterial strain, cultures were obtained whose cell extracts showed the same kind of toxicity as G. tamarensis. No toxic action could be found in the extracts of the bacterial cells form the assayed strains. The interference of intracellular bacteria in the metabolism of dinoflagellates must be the main cause of their toxicity.

Improving the Analysis of Dinoflagellate Phylogeny based on rDNA

DEFF Research Database (Denmark)

Murray, Shauna; Jørgensen, Mårten Flø; Ho, Simon Y.W.

2005-01-01

Phylogenetic studies of dinoflagellates are often conducted using rDNA sequences. In analyses to date, the monophyly of some of the major lineages of dinoflagellates remain to be demonstrated. There are several reasons for this uncertainty, one of which may be the use of models of evolution that ...

Lunar tides in Loch Ness, Scotland

OpenAIRE

Pugh, David T.; Woodworth, Philip L.; Bos, Machiel S.

2011-01-01

Measurements have been made of the astronomical tide in Loch Ness, Scotland, which is not directly connected to marine tides. Our measurements of the loch tide are, so far as we know, the first in a European lake where the tide originates primarily from ocean tide loading. Loch Ness is a readily accessible lake and is in a region for which the neighboring ocean tides are large and described well by modern global ocean tide models. The principal tidal constituent, M2, was observed to have an a...

Isolation of a dinoflagellate mitotic cyclin by functional complementation in yeast

International Nuclear Information System (INIS)

Bertomeu, Thierry; Morse, David

2004-01-01

Dinoflagellates are parasite with permanently condensed chromosomes that lack histones and whose nuclear membrane remains intact during mitosis. These unusual nuclear characters have suggested that the typical cell cycle regulators might be slightly different than those in more typical eukaryotes. To test this, a cyclin has been isolated from the dinoflagellate Gonyaulax polyedra by functional complementation in cln123 mutant yeast. This GpCyc1 sequence contains two cyclin domains in its C-terminal region and a degradation box typical of mitotic cyclins. Similar to other dinoflagellate genes, GpCyc1 has a high copy number, with ∼5000 copies found in the Gonyaulax genome. An antibody raised against the N-terminal region of the GpCYC1 reacts with a 68 kDa protein on Western blots that is more abundant in cell cultures enriched for G2-phase cells than in those containing primarily G1-phase cells, indicating its cellular level follows a pattern expected for a mitotic cyclin. This is the first report of a cell cycle regulator cloned and sequenced from a dinoflagellate, and our results suggest control of the dinoflagellate cell cycle will be very similar to that of other organisms

Apparent amitosis in the binucleate dinoflagellate Peridinium balticum.

Science.gov (United States)

Tippit, D H; Pickett-Heaps, J D

1976-07-01

Mitosis and cytokinesis in the free-living binucleate dinoflagellate Peridinium balticum are described, P. balticum contains 2 nuclei; one is a typical dinoflagellate nucleus and the other resembles the interphase nuclei of some eucaryotic cells and is here named the supernumerary nucleus (formerly called the eucaryotic nucleus). The dinoflagellate nucleus divides in the characteristic manner already described for certain other dinoflagellates. The supernumerary nucleus does not undergo normal mitosis; its chromatin does not condense, a spindle is not differentiated for its division, nor are any microtubules present inside the nucleus during any stage of its division. Instead the supernumerary nucleus divides by simple cleavage, which is concurrent with cytoplasmic cleavage. The nucleus cleaves first on its side facing the wall, but later it cleaves circumferentially as the cytoplasmic cleavage furrow draws closer. Invariably at late cytokinesis, a portion of the dividing nucleus passes through the only remaining uncleaved area of the cell. The final separation of the supernumerary nucleus is probably accomplished by the ingrowing furrow pinching the nucleus in two. There is no apparent precise segregation of genetic material during division, nor are there any structural changes inside the dividing nucleus which distinguish it from the interphase nucleus. Certain aspects of amitosis, and previously postulated theories concerning the endosymbiont origin of the second nucleus, are discussed.

In-situ production of humic-like fluorescent dissolved organic matter during Cochlodinium polykrikoides blooms

Science.gov (United States)

Kwon, Hyeong Kyu; Kim, Guebuem; Lim, Weol Ae; Park, Jong Woo

2018-04-01

We investigated phytoplankton pigments, dissolved organic carbon (DOC), and fluorescent dissolved organic matter (FDOM) during the summers of 2013 and 2016 in the coastal area of Tongyeong, Korea, where Cochlodinium polykrikoides blooms often occur. The density of red tides was evaluated using a dinoflagellate pigment, peridinin. The concentrations of peridinin and DOC in the patch areas were 15- and 4-fold higher than those in the non-patch areas. The parallel factor analysis (PARAFAC) model identified one protein-like FDOM (FDOMT) and two humic-like FDOM, classically classified as marine FDOM (FDOMM) and terrestrial FDOM (FDOMC). The concentrations of FDOMT in the patch areas were 5-fold higher than those in the non-patch areas, likely associated with biological production. In general, FDOMM and FDOMC are known to be dependent exclusively on salinity in any surface waters of the coastal ocean. However, in this study, we observed strikingly enhanced FDOMC concentration over that expected from the salinity mixing, whereas FDOMM increases were not clear. These FDOMC concentrations showed a significant positive correlation against peridinin, indicating that the production of FDOMC is associated with the red tide blooms. Our results suggest that FDOMC can be naturally enriched by some phytoplankton species, without FDOMM enrichment. Such naturally produced FDOM may play a critical role in biological production as well as biogeochemical cycle in red tide regions.

Tides and tsunamis

Science.gov (United States)

Zetler, B. D.

1972-01-01

Although tides and tsunamis are both shallow water waves, it does not follow that they are equally amenable to an observational program using an orbiting altimeter on a satellite. A numerical feasibility investigation using a hypothetical satellite orbit, real tide observations, and sequentially increased levels of white noise has been conducted to study the degradation of the tidal harmonic constants caused by adding noise to the tide data. Tsunami waves, possibly a foot high and one hundred miles long, must be measured in individual orbits, thus requiring high relative resolution.

Using an Altimeter-Derived Internal Tide Model to Remove Tides from in Situ Data

Science.gov (United States)

Zaron, Edward D.; Ray, Richard D.

2017-01-01

Internal waves at tidal frequencies, i.e., the internal tides, are a prominent source of variability in the ocean associated with significant vertical isopycnal displacements and currents. Because the isopycnal displacements are caused by ageostrophic dynamics, they contribute uncertainty to geostrophic transport inferred from vertical profiles in the ocean. Here it is demonstrated that a newly developed model of the main semidiurnal (M2) internal tide derived from satellite altimetry may be used to partially remove the tide from vertical profile data, as measured by the reduction of steric height variance inferred from the profiles. It is further demonstrated that the internal tide model can account for a component of the near-surface velocity as measured by drogued drifters. These comparisons represent a validation of the internal tide model using independent data and highlight its potential use in removing internal tide signals from in situ observations.

Tides in astronomy and astrophysics

CERN Document Server

Mathis, Stéphane; Tokieda, Tadashi

2013-01-01

Based on the lecture notes of a school titled ‘Tides in Astronomy and Astrophysics’ that brought together students and researchers, this book focuses on the fundamental theories of tides at different scales of the universe—from tiny satellites to whole galaxies—and on the most recent developments. It also attempts to place the study of tides in a historical perspective. Starting with a general tutorial on tides, the theme of tides is approached in 9 chapters from many directions. They allow non-experts to pick up a physical intuition and a sense of orders of magnitude in the theory of tides. These carefully prepared lecture notes by leaders in the field include many illustrative figures and drawings. Some even offer a variety of simple back-of the-envelope problems.

Nutrient regeneration by zooplankton during a red tide off Peru, with notes on biomass and species composition of zooplankton

Energy Technology Data Exchange (ETDEWEB)

Smith, S.L.

1978-01-01

During March and April 1976, a red tide, dominated by the dinoflagallate Gymnodinium splendens Lebour, developed in the vicinity of 15/sup 0/O6'S and 76/sup 0/31'W off Peru. At the height of the bloom, the euphotic zone was 6 m deep and the chlorophyll a at the surface was 48 ..mu..g 1/sup -1/. A daily collection of zooplankton at 09.00 hrs showed large fluctuations of biomass, from 0.2 to 3.84 g dry weight m/sup -2/ in a water column of 120 m. Copepodids and nauplii dominated the collections. During a period of reduced wind, the adult copepods were a mixture of the species characteristic of the coastal upwelling system and the neritic species associated with more northerly, tropical waters. Nitrogen regeneration by the zooplankton varied with the development of the bloom, the type of zooplankton dominating the experiment, and biomass fluctuations, but never accounted for more than 25% of the nitrogen uptake by phytoplankton.

Neurotoxins from Marine Dinoflagellates: A Brief Review

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Da-Zhi Wang

2008-06-01

Full Text Available Dinoflagellates are not only important marine primary producers and grazers, but also the major causative agents of harmful algal blooms. It has been reported that many dinoflagellate species can produce various natural toxins. These toxins can be extremely toxic and many of them are effective at far lower dosages than conventional chemical agents. Consumption of seafood contaminated by algal toxins results in various seafood poisoning syndromes: paralytic shellfish poisoning (PSP, neurotoxic shellfish poisoning (NSP, amnesic shellfish poisoning (ASP, diarrheic shellfish poisoning (DSP, ciguatera fish poisoning (CFP and azaspiracid shellfish poisoning (ASP. Most of these poisonings are caused by neurotoxins which present themselves with highly specific effects on the nervous system of animals, including humans, by interfering with nerve impulse transmission. Neurotoxins are a varied group of compounds, both chemically and pharmacologically. They vary in both chemical structure and mechanism of action, and produce very distinct biological effects, which provides a potential application of these toxins in pharmacology and toxicology. This review summarizes the origin, structure and clinical symptoms of PSP, NSP, CFP, AZP, yessotoxin and palytoxin produced by marine dinoflagellates, as well as their molecular mechanisms of action on voltage-gated ion channels.

An Ephemeral Dinoflagellate Bloom during Summer Season in Nearshore Water of Puri, East Coast of India

Science.gov (United States)

Baliarsingh, Sanjiba Kumar; Dwivedi, Rashmin; Lotliker, Aneesh A.; Jayashankar, Reeta; Sahu, Biraja Kumar; Srichandan, Suchismita; Samanta, Alakes; Parida, Chandanlal; Srinivasakumar, Tummala; Sahu, Kali Charan

2018-03-01

The present paper reports on the phenomenon of pinkish-red discoloration of the nearshore water of Puri, Odisha on 12th May 2016. Many local newspapers covered this event, as Puri city is a major tourist and pilgrimage place on the east coast of India. Field observations were carried out in order to provide a scientific basis to the event and to elicit possible causes of this discoloration. Taxonomic analysis of the phytoplankton samples revealed the dominance of red colored dinoflagellate species Gonyaulax polygramma, contributing 90% to total phytoplankton population. The localized concentration of G. polygramma was responsible for the pinkish-red discoloration of nearshore water. The exact factor that lay behind the genesis of this bloom could not be delineated due to the short period of its persistence. But two factors - upwelling and anthropogenic nutrient influx - can be viewed as the main cause for this ephemeral bloom. Non-hypoxic conditions in the coastal water following the ephemeral bloom event indicated no significant risk of ecological deterioration to the ambient medium.

Broad genomic and transcriptional analysis reveals a highly derived genome in dinoflagellate mitochondria

Directory of Open Access Journals (Sweden)

Keeling Patrick J

2007-09-01

Full Text Available Abstract Background Dinoflagellates comprise an ecologically significant and diverse eukaryotic phylum that is sister to the phylum containing apicomplexan endoparasites. The mitochondrial genome of apicomplexans is uniquely reduced in gene content and size, encoding only three proteins and two ribosomal RNAs (rRNAs within a highly compacted 6 kb DNA. Dinoflagellate mitochondrial genomes have been comparatively poorly studied: limited available data suggest some similarities with apicomplexan mitochondrial genomes but an even more radical type of genomic organization. Here, we investigate structure, content and expression of dinoflagellate mitochondrial genomes. Results From two dinoflagellates, Crypthecodinium cohnii and Karlodinium micrum, we generated over 42 kb of mitochondrial genomic data that indicate a reduced gene content paralleling that of mitochondrial genomes in apicomplexans, i.e., only three protein-encoding genes and at least eight conserved components of the highly fragmented large and small subunit rRNAs. Unlike in apicomplexans, dinoflagellate mitochondrial genes occur in multiple copies, often as gene fragments, and in numerous genomic contexts. Analysis of cDNAs suggests several novel aspects of dinoflagellate mitochondrial gene expression. Polycistronic transcripts were found, standard start codons are absent, and oligoadenylation occurs upstream of stop codons, resulting in the absence of termination codons. Transcripts of at least one gene, cox3, are apparently trans-spliced to generate full-length mRNAs. RNA substitutional editing, a process previously identified for mRNAs in dinoflagellate mitochondria, is also implicated in rRNA expression. Conclusion The dinoflagellate mitochondrial genome shares the same gene complement and fragmentation of rRNA genes with its apicomplexan counterpart. However, it also exhibits several unique characteristics. Most notable are the expansion of gene copy numbers and their arrangements

Explorers Presentation: Explaining the Tides to Children

OpenAIRE

Institute, Marine

2015-01-01

Explaining the tides to children Presentation includes information about: Orbits of the Earth, Moon and Sun; Moon phases and the lunar cycle; Gravity; Gravity and the tide; Types of tides; The tides and me!; Tide tables; Extra insight

Barometric Tides from ECMWF Operational Analyses

Science.gov (United States)

Ray, R. D.; Ponte, R. M.

2003-01-01

The solar diurnal and semidiurnal tidal oscillations in surface pressure are extracted from the the operational analysis product of the European Centre for Medium Range Weather Forecasting (ECMWF). For the semidiurnal tide this involves a special temporal interpolation, following Van den Dool and colleagues. The resulting tides are compared with a ground truth tide dataset, a compilation of well-determined tide estimates deduced from long time series of station barometer measurements. These comparisons show that the ECMWF tides are significantly more accurate than the tides deduced from two other widely available reanalysis products. Spectral analysis of ECMWF pressure series shows that the tides consist of sharp central peaks with modulating sidelines at integer multiples of 1 cycle/year, superimposed on a broad cusp of stochastic energy. The integrated energy in the cusp dominates that of the sidelines. This complicates development of a simple model that can characterize the full temporal variability of the tides.

Genomes of coral dinoflagellate symbionts highlight evolutionary adaptations conducive to a symbiotic lifestyle

KAUST Repository

Aranda, Manuel

2016-12-22

Despite half a century of research, the biology of dinoflagellates remains enigmatic: they defy many functional and genetic traits attributed to typical eukaryotic cells. Genomic approaches to study dinoflagellates are often stymied due to their large, multi-gigabase genomes. Members of the genus Symbiodinium are photosynthetic endosymbionts of stony corals that provide the foundation of coral reef ecosystems. Their smaller genome sizes provide an opportunity to interrogate evolution and functionality of dinoflagellate genomes and endosymbiosis. We sequenced the genome of the ancestral Symbiodinium microadriaticum and compared it to the genomes of the more derived Symbiodinium minutum and Symbiodinium kawagutii and eukaryote model systems as well as transcriptomes from other dinoflagellates. Comparative analyses of genome and transcriptome protein sets show that all dinoflagellates, not only Symbiodinium, possess significantly more transmembrane transporters involved in the exchange of amino acids, lipids, and glycerol than other eukaryotes. Importantly, we find that only Symbiodinium harbor an extensive transporter repertoire associated with the provisioning of carbon and nitrogen. Analyses of these transporters show species-specific expansions, which provides a genomic basis to explain differential compatibilities to an array of hosts and environments, and highlights the putative importance of gene duplications as an evolutionary mechanism in dinoflagellates and Symbiodinium.

Genomes of coral dinoflagellate symbionts highlight evolutionary adaptations conducive to a symbiotic lifestyle

KAUST Repository

Aranda, Manuel; Li, Yangyang; Liew, Yi Jin; Baumgarten, Sebastian; Simakov, O.; Wilson, M. C.; Piel, J.; Ashoor, Haitham; Bougouffa, Salim; Bajic, Vladimir B.; Ryu, Tae Woo; Ravasi, Timothy; Bayer, Till; Micklem, G.; Kim, H.; Bhak, J.; LaJeunesse, T. C.; Voolstra, Christian R.

2016-01-01

Despite half a century of research, the biology of dinoflagellates remains enigmatic: they defy many functional and genetic traits attributed to typical eukaryotic cells. Genomic approaches to study dinoflagellates are often stymied due to their large, multi-gigabase genomes. Members of the genus Symbiodinium are photosynthetic endosymbionts of stony corals that provide the foundation of coral reef ecosystems. Their smaller genome sizes provide an opportunity to interrogate evolution and functionality of dinoflagellate genomes and endosymbiosis. We sequenced the genome of the ancestral Symbiodinium microadriaticum and compared it to the genomes of the more derived Symbiodinium minutum and Symbiodinium kawagutii and eukaryote model systems as well as transcriptomes from other dinoflagellates. Comparative analyses of genome and transcriptome protein sets show that all dinoflagellates, not only Symbiodinium, possess significantly more transmembrane transporters involved in the exchange of amino acids, lipids, and glycerol than other eukaryotes. Importantly, we find that only Symbiodinium harbor an extensive transporter repertoire associated with the provisioning of carbon and nitrogen. Analyses of these transporters show species-specific expansions, which provides a genomic basis to explain differential compatibilities to an array of hosts and environments, and highlights the putative importance of gene duplications as an evolutionary mechanism in dinoflagellates and Symbiodinium.

STRATEGIES OF MARINE DINOFLAGELLATE SURVIVAL AND SOME RULES OF ASSEMBLY. (R829368)

Science.gov (United States)

Dinoflagellate ecology is based on multiple adaptive strategies and species having diverse habitat preferences. Nine types of mixing-irradiance-nutrient habitats selecting for specific marine dinoflagellate life-form types are recognised, with five rules of assembly proposed t...

Molecular phylogeny of the ocelloid-bearing dinoflagellates erythropsidinium and warnowia (warnowiaceae, dinophyceae).

Science.gov (United States)

Gómez, Fernando; López-García, Purificación; Moreira, David

2009-01-01

Members of the family Warnowiaceae are unarmored phagotrophic dinoflagellates that possess an ocelloid. The genus Erythropsidinium (=Erythropsis) has also developed a unique dynamic appendage, the piston, which is able to independently retract and extend for at least 2 min after the cell lyses. We provide the first small subunit ribosomal RNA gene sequences of warnowiid dinoflagellates, those of the type Erythropsidinium agile and one species of Warnowia. Phylogenetic analyses show that warnowiid dinoflagellates branch within the Gymnodinium sensu stricto group, forming a cluster separated from the Polykrikos clade and with autotrophic Pheopolykrikos beauchampii as closest relative. This reinforces their classification as unarmored dinoflagellates based on the shape of the apical groove, despite the strong ecological and ultrastructural diversity of the Gymnodinium s.s. group. Other structures, such as the ocelloid and piston, have no systematic value above the genus level.

Paralytic shellfish toxin biosynthesis in cyanobacteria and dinoflagellates: A molecular overview.

Science.gov (United States)

Wang, Da-Zhi; Zhang, Shu-Fei; Zhang, Yong; Lin, Lin

2016-03-01

Paralytic shellfish toxins (PSTs) are a group of water soluble neurotoxic alkaloids produced by two different kingdoms of life, prokaryotic cyanobacteria and eukaryotic dinoflagellates. Owing to the wide distribution of these organisms, these toxic secondary metabolites account for paralytic shellfish poisonings around the world. On the other hand, their specific binding to voltage-gated sodium channels makes these toxins potentially useful in pharmacological and toxicological applications. Much effort has been devoted to the biosynthetic mechanism of PSTs, and gene clusters encoding 26 proteins involved in PST biosynthesis have been unveiled in several cyanobacterial species. Functional analysis of toxin genes indicates that PST biosynthesis in cyanobacteria is a complex process including biosynthesis, regulation, modification and export. However, less is known about the toxin biosynthesis in dinoflagellates owing to our poor understanding of the massive genome and unique chromosomal characteristics [1]. So far, few genes involved in PST biosynthesis have been identified from dinoflagellates. Moreover, the proteins involved in PST production are far from being totally explored. Thus, the origin and evolution of PST biosynthesis in these two kingdoms are still controversial. In this review, we summarize the recent progress on the characterization of genes and proteins involved in PST biosynthesis in cyanobacteria and dinoflagellates, and discuss the standing evolutionary hypotheses concerning the origin of toxin biosynthesis as well as future perspectives in PST biosynthesis. Paralytic shellfish toxins (PSTs) are a group of potent neurotoxins which specifically block voltage-gated sodium channels in excitable cells and result in paralytic shellfish poisonings (PSPs) around the world. Two different kingdoms of life, cyanobacteria and dinoflagellates are able to produce PSTs. However, in contrast with cyanobacteria, our understanding of PST biosynthesis in

Lunar tides in Loch Ness, Scotland

Science.gov (United States)

Pugh, David T.; Woodworth, Philip L.; Bos, Machiel S.

2011-11-01

Measurements have been made of the astronomical tide in Loch Ness, Scotland, which is not directly connected to marine tides. Our measurements of the loch tide are, so far as we know, the first in a European lake where the tide originates primarily from ocean tide loading. Loch Ness is a readily accessible lake and is in a region for which the neighboring ocean tides are large and described well by modern global ocean tide models. The principal tidal constituent, M2, was observed to have an amplitude of approximately 1.5 mm, and to be in antiphase, at each end of the loch. These values are in close agreement with the theoretical combined effects of the direct gravitational tide (body tide) and the tilt effects due to ocean tide loading, computed using Green's functions based on conventional elastic-Earth models. By analyzing over long periods for coherent tidal signals, we are able to significantly improve the signal-to-noise ratio in the tilt values compared with values obtained by direct level differencing. Our tilt accuracy of better than 10-8, measured over 35 km, demonstrates Loch Ness as one the world's longest and most accurate tiltmeters. Despite this unprecedented accuracy, Earth tidal models are still at least as accurate as our ability to measure them.

Decadal-scale changes of dinoflagellates and diatoms in the anomalous baltic sea spring bloom.

Directory of Open Access Journals (Sweden)

Riina Klais

Full Text Available The algal spring bloom in the Baltic Sea represents an anomaly from the winter-spring bloom patterns worldwide in terms of frequent and recurring dominance of dinoflagellates over diatoms. Analysis of approximately 3500 spring bloom samples from the Baltic Sea monitoring programs revealed (i that within the major basins the proportion of dinoflagellates varied from 0.1 (Kattegat to >0.8 (central Baltic Proper, and (ii substantial shifts (e.g. from 0.2 to 0.6 in the Gulf of Finland in the dinoflagellate proportion over four decades. During a recent decade (1995-2004 the proportion of dinoflagellates increased relative to diatoms mostly in the northernmost basins (Gulf of Bothnia, from 0.1 to 0.4 and in the Gulf of Finland, (0.4 to 0.6 which are typically ice-covered areas. We hypothesize that in coastal areas a specific sequence of seasonal events, involving wintertime mixing and resuspension of benthic cysts, followed by proliferation in stratified thin layers under melting ice, favors successful seeding and accumulation of dense dinoflagellate populations over diatoms. This head-start of dinoflagellates by the onset of the spring bloom is decisive for successful competition with the faster growing diatoms. Massive cyst formation and spreading of cyst beds fuel the expanding and ever larger dinoflagellate blooms in the relatively shallow coastal waters. Shifts in the dominant spring bloom algal groups can have significant effects on major elemental fluxes and functioning of the Baltic Sea ecosystem, but also in the vast shelves and estuaries at high latitudes, where ice-associated cold-water dinoflagellates successfully compete with diatoms.

Microbial arms race: Ballistic "nematocysts" in dinoflagellates represent a new extreme in organelle complexity.

Science.gov (United States)

Gavelis, Gregory S; Wakeman, Kevin C; Tillmann, Urban; Ripken, Christina; Mitarai, Satoshi; Herranz, Maria; Özbek, Suat; Holstein, Thomas; Keeling, Patrick J; Leander, Brian S

2017-03-01

We examine the origin of harpoon-like secretory organelles (nematocysts) in dinoflagellate protists. These ballistic organelles have been hypothesized to be homologous to similarly complex structures in animals (cnidarians); but we show, using structural, functional, and phylogenomic data, that nematocysts evolved independently in both lineages. We also recorded the first high-resolution videos of nematocyst discharge in dinoflagellates. Unexpectedly, our data suggest that different types of dinoflagellate nematocysts use two fundamentally different types of ballistic mechanisms: one type relies on a single pressurized capsule for propulsion, whereas the other type launches 11 to 15 projectiles from an arrangement similar to a Gatling gun. Despite their radical structural differences, these nematocysts share a single origin within dinoflagellates and both potentially use a contraction-based mechanism to generate ballistic force. The diversity of traits in dinoflagellate nematocysts demonstrates a stepwise route by which simple secretory structures diversified to yield elaborate subcellular weaponry.

Scientometrical review of Dinoflagellate studies in Brazil

Directory of Open Access Journals (Sweden)

Pietro Martins Barbosa Noga

2018-06-01

Full Text Available ABSTRACT Scientific production in developing countries is currently increasing, but there is still an unbalanced distribution of scientific production between developed and developing countries. With the need to elucidate disparities in scientific production, this paper aims to review publications on dinoflagellates in Brazil by discussing spatial and temporal trends. A search for papers referring to dinoflagellates was performed in the Scopus database up to the year of 2016. A total of 125 papers were found, but only 106 were selected according to established criteria. A linear regression was used to evaluate the increasing temporal trend in production and non-parametric ANOVA for comparisons among study categories. Dinoflagellate and toxic taxa-based publications have increased from 1990 to 2016 for Brazil, yet a discrepancy in performance with other countries is evident. There is a constant increase in the number of functional ecology studies focusing on toxin-producing species related to blooms. The spatial distribution of production in Brazil revealed that the Southeast and South regions are the most productive, where there more graduate programs and advanced research centers. Investments in this ecological subject are fundamental to the management of biodiversity, and a call for more equal resource distribution in developing countries is imperative.

Hypothesis: Gene-rich plastid genomes in red algae may be an outcome of nuclear genome reduction.

Science.gov (United States)

Qiu, Huan; Lee, Jun Mo; Yoon, Hwan Su; Bhattacharya, Debashish

2017-06-01

Red algae (Rhodophyta) putatively diverged from the eukaryote tree of life >1.2 billion years ago and are the source of plastids in the ecologically important diatoms, haptophytes, and dinoflagellates. In general, red algae contain the largest plastid gene inventory among all such organelles derived from primary, secondary, or additional rounds of endosymbiosis. In contrast, their nuclear gene inventory is reduced when compared to their putative sister lineage, the Viridiplantae, and other photosynthetic lineages. The latter is thought to have resulted from a phase of genome reduction that occurred in the stem lineage of Rhodophyta. A recent comparative analysis of a taxonomically broad collection of red algal and Viridiplantae plastid genomes demonstrates that the red algal ancestor encoded ~1.5× more plastid genes than Viridiplantae. This difference is primarily explained by more extensive endosymbiotic gene transfer (EGT) in the stem lineage of Viridiplantae, when compared to red algae. We postulate that limited EGT in Rhodophytes resulted from the countervailing force of ancient, and likely recurrent, nuclear genome reduction. In other words, the propensity for nuclear gene loss led to the retention of red algal plastid genes that would otherwise have undergone intracellular gene transfer to the nucleus. This hypothesis recognizes the primacy of nuclear genome evolution over that of plastids, which have no inherent control of their gene inventory and can change dramatically (e.g., secondarily non-photosynthetic eukaryotes, dinoflagellates) in response to selection acting on the host lineage. © 2017 Phycological Society of America.

Symbiodinium transcriptomes: genome insights into the dinoflagellate symbionts of reef-building corals.

KAUST Repository

Bayer, Till

2012-04-18

Dinoflagellates are unicellular algae that are ubiquitously abundant in aquatic environments. Species of the genus Symbiodinium form symbiotic relationships with reef-building corals and other marine invertebrates. Despite their ecologic importance, little is known about the genetics of dinoflagellates in general and Symbiodinium in particular. Here, we used 454 sequencing to generate transcriptome data from two Symbiodinium species from different clades (clade A and clade B). With more than 56,000 assembled sequences per species, these data represent the largest transcriptomic resource for dinoflagellates to date. Our results corroborate previous observations that dinoflagellates possess the complete nucleosome machinery. We found a complete set of core histones as well as several H3 variants and H2A.Z in one species. Furthermore, transcriptome analysis points toward a low number of transcription factors in Symbiodinium spp. that also differ in the distribution of DNA-binding domains relative to other eukaryotes. In particular the cold shock domain was predominant among transcription factors. Additionally, we found a high number of antioxidative genes in comparison to non-symbiotic but evolutionary related organisms. These findings might be of relevance in the context of the role that Symbiodinium spp. play as coral symbionts.Our data represent the most comprehensive dinoflagellate EST data set to date. This study provides a comprehensive resource to further analyze the genetic makeup, metabolic capacities, and gene repertoire of Symbiodinium and dinoflagellates. Overall, our findings indicate that Symbiodinium possesses some unique characteristics, in particular the transcriptional regulation in Symbiodinium may differ from the currently known mechanisms of eukaryotic gene regulation.

Atmospheric Tides in Gale Crater, Mars

Science.gov (United States)

Guzewich, Scott D,; Newman, C. E; de la Torre Juarez, M.; Wilson, R. J.; Lemmon, M.; Smith, M. D.; Kahanpaa, H.; Harri, A.-M.

2015-01-01

Atmospheric tides are the primary source of daily air pressure variation at the surface of Mars. These tides are forced by solar heating of the atmosphere and modulated by the presence of atmospheric dust, topography, and surface albedo and thermal inertia. This results in a complex mix of sun-synchronous and nonsun- synchronous tides propagating both eastward and westward around the planet in periods that are integer fractions of a solar day. The Rover Environmental Monitoring Station on board the Mars Science Laboratory has observed air pressure at a regular cadence for over 1 Mars year and here we analyze and diagnose atmospheric tides in this pressure record. The diurnal tide amplitude varies from 26 to 63 Pa with an average phase of 0424 local true solar time, while the semidiurnal tide amplitude varies from 5 to 20 Pa with an average phase of 0929. We find that both the diurnal and semidiurnal tides in Gale Crater are highly correlated to atmospheric opacity variations at a value of 0.9 and to each other at a value of 0.77, with some key exceptions occurring during regional and local dust storms. We supplement our analysis with MarsWRF general circulation modeling to examine how a local dust storm impacts the diurnal tide in its vicinity. We find that both the diurnal tide amplitude enhancement and regional coverage of notable amplitude enhancement linearly scales with the size of the local dust storm. Our results provide the first long-term record of surface pressure tides near the martian equator.

The lunar tide in sporadic E

Directory of Open Access Journals (Sweden)

R. J. Stening

1999-10-01

Full Text Available It seems that the wind shear theory is accepted for the explanation of sporadic E at mid and low latitudes. Some examples from Arecibo are displayed to show this. The effect of lunar tides should then modify the wind-shear theory in a manner that yields the observed features of the lunar tide in the critical frequency foEs and the height h'Es of the sporadic E. This is shown to imply that the phase of the lunar tide in h'Es should be the same as the phase of the lunar tide in the eastward wind and that the phase of the lunar tide in foEs is three hours later. Hourly values of foEs, f bEs (the blanketing critical frequency and h'Es from several observatories are analysed for the lunar semidiurnal tide. It is found that the phase of the tide in foEs is often about 3 hours later than for h'Es in agreement with the theory. Seasonal variations in the tide are also examined with the statistically most significant results (largest amplitudes usually occurring in summer. After reviewing the many difficulties associated with determining the lunar tide in Es, both experimentally and theoretically, the analysed phase results are compared with what might be expected from Hagan's global scale wave model. Agreement is only fair (a success rate of 69% among the cases examined but probably as good as might be expected.Key words. Ionosphere (ionosphere – atmosphere interactions – ionospheric irregularities, Meteorology and atmosphere dynamics (waves and tides

 Serial replacement of diatom endosymbiont in two freshwater dinoflagellates, Peridiniopsis spp., (Peridiniales, Dinophyceae)

DEFF Research Database (Denmark)

Takano, Y.; Hansen, Gert; Fujita, D.

2008-01-01

Two freshwater armoured dinoflagellates, Peridiniopsis cf. kevei from Japan and Peridiniopsis penardii from Japan and Italy, were examined by means of light, scanning and transmission electron microscopy. Morphological studies indicated that the two dinoflagellates had similar type of cellular......-harbouring dinoflagellates. On the contrary, the phylogenetic analyses based on plastid-encoded rbcL and nuclear-encoded SSU rDNA of the endosymbionts included the endosymbiont of these two freshwater dinoflagellates in the Thalassiosira/Skeletonema-clade (Centrales), whereas the endosymbionts of other diatom...

Ocean tides for satellite geodesy

Science.gov (United States)

Dickman, S. R.

1990-01-01

Spherical harmonic tidal solutions have been obtained at the frequencies of the 32 largest luni-solar tides using prior theory of the author. That theory was developed for turbulent, nonglobal, self-gravitating, and loading oceans possessing realistic bathymetry and linearized bottom friction; the oceans satisfy no-flow boundary conditions at coastlines. In this theory the eddy viscosity and bottom drag coefficients are treated as spatially uniform. Comparison of the predicted degree-2 components of the Mf, P1, and M2 tides with those from numerical and satellite-based tide models allows the ocean friction parameters to be estimated at long and short periods. Using the 32 tide solutions, the frequency dependence of tidal admittance is investigated, and the validity of sideband tide models used in satellite orbit analysis is examined. The implications of admittance variability for oceanic resonances are also explored.

Tides and tidal currents

NARCIS (Netherlands)

Roos, A.

1997-01-01

Basic phenomena, origin and generation of tides, analysis and prediction of tides, basic equation and types of long waves in one dimension, tidal propagation in one dimension, tidal propagation in two directions, analytical tidal computation, numerical tidal computation.

Virus-like particles suppress growth of the red-tide-forming marine dinoflagellate Gymnodinium mikimotoi.

Science.gov (United States)

Onji, Masashi; Nakano, Shin-ichi; Suzuki, Satoru

2003-01-01

We isolated 2 virus-like agents that suppressed growth of Gymnodinium mikimotoi from coastal waters of the Uwa Sea, Japan. The agents found in the flagellate cells, named GM6 and GM7, were filterable in a 0.22-microm-pore filter with approximately 100-nm shapes. Electron microscopic observation showed the presence of virus-like particles in severely damaged G. mikimotoi cells infected by GM6. The growth-suppression activity of the agents (GM6 or GM7) was lost by heating at 50 degrees C, with treatments of DNase and protease, and filtration through a 0.05-microm filter. Our results suggest that the agents are DNA viruses infectious to and virulent for G. mikimotoi. This is the first report of a virus-like agent specific to G. mikimotoi.

Synchronized sexuality of an algal symbiont and its dinoflagellate host, Peridinium balticum (Levander) Lemmermann.

Science.gov (United States)

Chesnick, J M; Cox, E R

1987-01-01

We report synchronized sexual reproduction between the chlorophyll c-containing algal endosymbiont and its dinoflagellate host in Peridinium balticum (Pyrrhophyta). This organism's importance lies in that it may represent an intermediate between primitive non-photosynthetic and advanced photosynthetic dinoflagellates. Fusion of the endosymbionts and their nuclei occurred concomitantly with syngamy of the host gametes. Significant morphological changes, including condensation of chromatin and crystalline rod formation, occurred in the symbiont nucleus during zygote development. These observations provide evidence that the endosymbiotic nucleus is not passive in sexual processes, as opposed to its reported passive state during mitosis. P. balticum may not only represent an intermediate in the evolution of chloroplast acquisition by dinoflagellates, but also, an intermediate in the evolution of the peridinian dinoflagellate sexual life history.

Bacterial Associates Modify Growth Dynamics of the Dinoflagellate Gymnodinium catenatum.

Science.gov (United States)

Bolch, Christopher J S; Bejoy, Thaila A; Green, David H

2017-01-01

Marine phytoplankton cells grow in close association with a complex microbial associate community known to affect the growth, behavior, and physiology of the algal host. The relative scale and importance these effects compared to other major factors governing algal cell growth remain unclear. Using algal-bacteria co-culture models based on the toxic dinoflagellate Gymnodinium catenatum , we tested the hypothesis that associate bacteria exert an independent effect on host algal cell growth. Batch co-cultures of G. catenatum were grown under identical environmental conditions with simplified bacterial communities composed of one-, two-, or three-bacterial associates. Modification of the associate community membership and complexity induced up to four-fold changes in dinoflagellate growth rate, equivalent to the effect of a 5°C change in temperature or an almost six-fold change in light intensity (20-115 moles photons PAR m -2 s -1 ). Almost three-fold changes in both stationary phase cell concentration and death rate were also observed. Co-culture with Roseobacter sp. DG874 reduced dinoflagellate exponential growth rate and led to a more rapid death rate compared with mixed associate community controls or co-culture with either Marinobacter sp. DG879, Alcanivorax sp. DG881. In contrast, associate bacteria concentration was positively correlated with dinoflagellate cell concentration during the exponential growth phase, indicating growth was limited by supply of dinoflagellate-derived carbon. Bacterial growth increased rapidly at the onset of declining and stationary phases due to either increasing availability of algal-derived carbon induced by nutrient stress and autolysis, or at mid-log phase in Roseobacter co-cultures potentially due to the onset of bacterial-mediated cell lysis. Co-cultures with the three bacterial associates resulted in dinoflagellate and bacterial growth dynamics very similar to more complex mixed bacterial community controls, suggesting that

New insights on the species-specific allelopathic interactions between macrophytes and marine HAB dinoflagellates.

Directory of Open Access Journals (Sweden)

Hela Ben Gharbia

Full Text Available Macrophytes are known to release allelochemicals that have the ability to inhibit the proliferation of their competitors. Here, we investigated the effects of the fresh leaves of two magnoliophytes (Zostera noltei and Cymodocea nodosa and thalli of the macroalgae Ulva rigida on three HAB-forming benthic dinoflagellates (Ostreopsis cf. ovata, Prorocentrum lima, and Coolia monotis. The effects of C. nodosa and U. rigida were also tested against the neurotoxic planktonic dinoflagellate Alexandrium pacificum Litaker sp. nov (former Alexandrium catenella. Co-culture experiments were conducted under controlled laboratory conditions and potential allelopathic effects of the macrophytes on the growth, photosynthesis and toxin production of the targeted dinoflagellates were evaluated. Results showed that U. rigida had the strongest algicidal effect and that the planktonic A. pacificum was the most vulnerable species. Benthic dinoflagellates seemed more tolerant to potential allelochemicals produced by macrophytes. Depending on the dinoflagellate/macrophyte pairs and the weight of leaves/thalli tested, the studied physiological processes were moderately to heavily altered. Our results suggest that the allelopathic activity of the macrophytes could influence the development of HAB species.

New insights on the species-specific allelopathic interactions between macrophytes and marine HAB dinoflagellates.

Science.gov (United States)

Ben Gharbia, Hela; Kéfi-Daly Yahia, Ons; Cecchi, Philippe; Masseret, Estelle; Amzil, Zouher; Herve, Fabienne; Rovillon, Georges; Nouri, Habiba; M'Rabet, Charaf; Couet, Douglas; Zmerli Triki, Habiba; Laabir, Mohamed

2017-01-01

Macrophytes are known to release allelochemicals that have the ability to inhibit the proliferation of their competitors. Here, we investigated the effects of the fresh leaves of two magnoliophytes (Zostera noltei and Cymodocea nodosa) and thalli of the macroalgae Ulva rigida on three HAB-forming benthic dinoflagellates (Ostreopsis cf. ovata, Prorocentrum lima, and Coolia monotis). The effects of C. nodosa and U. rigida were also tested against the neurotoxic planktonic dinoflagellate Alexandrium pacificum Litaker sp. nov (former Alexandrium catenella). Co-culture experiments were conducted under controlled laboratory conditions and potential allelopathic effects of the macrophytes on the growth, photosynthesis and toxin production of the targeted dinoflagellates were evaluated. Results showed that U. rigida had the strongest algicidal effect and that the planktonic A. pacificum was the most vulnerable species. Benthic dinoflagellates seemed more tolerant to potential allelochemicals produced by macrophytes. Depending on the dinoflagellate/macrophyte pairs and the weight of leaves/thalli tested, the studied physiological processes were moderately to heavily altered. Our results suggest that the allelopathic activity of the macrophytes could influence the development of HAB species.

Studies on phytoplankton with reference to dinoflagellates

Digital Repository Service at National Institute of Oceanography (India)

Naik, R.K.

Bibliography Publications Appendices Statement As required under the University ordinance 0.19.8 (vi), I state that the present thesis titled ³Studies on phytoplankton with reference to dinoflagellates´ is my original contribution...

Physico-chemical and biological factors influencing dinoflagellate cyst production in the Cariaco Basin

Science.gov (United States)

Bringué, Manuel; Thunell, Robert C.; Pospelova, Vera; Pinckney, James L.; Romero, Oscar E.; Tappa, Eric J.

2018-04-01

We present a 2.5-year-long sediment trap record of dinoflagellate cyst production in the Cariaco Basin, off Venezuela (southern Caribbean Sea). The site lies under the influence of wind-driven, seasonal upwelling which promotes high levels of primary productivity during boreal winter and spring. Changes in dinoflagellate cyst production is documented between November 1996 and May 1999 at ˜ 14-day intervals and interpreted in the context of in situ observations of physico-chemical and biological parameters measured at the mooring site. Dinoflagellate cyst assemblages are diverse (57 taxa) and dominated by cyst taxa of heterotrophic affinity, primarily Brigantedinium spp. (51 % of the total trap assemblage). Average cyst fluxes to the trap are high (17.1 × 103 cysts m-2 day-1) and show great seasonal and interannual variability. On seasonal timescales, dinoflagellate cyst production responds closely to variations in upwelling strength, with increases in cyst fluxes of several protoperidinioid taxa observed during active upwelling intervals, predominantly Brigantedinium spp. Cyst taxa produced by autotrophic dinoflagellates, in particular Bitectatodinium spongium, also respond positively to upwelling. Several spiny brown cysts contribute substantially to the assemblages, including Echinidinium delicatum (9.7 %) and Echinidinium granulatum (7.3 %), and show a closer affinity to weaker upwelling conditions. The strong El Niño event of 1997/98 appears to have negatively impacted cyst production in the basin with a 1-year lag, and may have contributed to the unusually high fluxes of cysts type Cp (possibly the cysts of the toxic dinoflagellate Cochlodinium polykrikoides sensu Li et al., 2015), with cyst type Cp fluxes up to 11.8 × 103 cysts m-2 day-1 observed during the weak upwelling event of February-May 1999. Possible trophic interactions between dinoflagellates and other major planktonic groups are also investigated by comparing the timing and magnitude of cyst

A novel hematoxylin and eosin stain assay for detection of the parasitic dinoflagellate Amoebophrya.

Science.gov (United States)

Li, Caiwen; Chen, Tiantian

2017-02-01

The parasitic dinoflagellate Amoebophrya infects broad range of marine organisms. Particularly, Amoebophrya infections in planktonic dinoflagellates can prevent or delay the formation of algal blooms, and recycle undergrazed planktonic dinoflagellates back to the microbial loop by disrupting host cells. Its ecological significance was gradually recognized along with the discovery of its enormous molecular diversity in oceanic and coastal ecosystems. Thus, we developed a reliable, easily accessible and less time-consuming assay, to detect and assess Amoebophrya infections in planktonic dinoflagellates. The modified hematoxylin and eosin staining assay provided reliable diagnosis of Amoebophrya infection by identifying the characteristic "beehive" of the multinucleate trophonts. After staining, the typical multinucleate "beehive" is evidently distinguishable from the compact nuclei of uninfected host cells. The modified hematoxylin and eosin (H & E) staining assay is easy to use, that can be routinely performed within 3h (up to 20 samples/batch) using general laboratory equipment, supplies and chemical reagents. The produced slides with agar-embedded dinoflagellate cells can be stored for several months or even years in a dry place without noticeable loss in quality of staining. With suitable calculation, the modified H & E assay can be applied to assess the prevalence of Amoebophrya infection in planktonic dinoflagellates. This efficient and powerful assay will facilitate the investigation on the ecological roles of Amoebophryidae in coastal and oceanic ecosystem. Copyright © 2016 Elsevier B.V. All rights reserved.

When naked became armored: an eight-gene phylogeny reveals monophyletic origin of theca in dinoflagellates.

Directory of Open Access Journals (Sweden)

Russell J S Orr

Full Text Available The dinoflagellates are a diverse lineage of microbial eukaryotes. Dinoflagellate monophyly and their position within the group Alveolata are well established. However, phylogenetic relationships between dinoflagellate orders remain unresolved. To date, only a limited number of dinoflagellate studies have used a broad taxon sample with more than two concatenated markers. This lack of resolution makes it difficult to determine the evolution of major phenotypic characters such as morphological features or toxin production e.g. saxitoxin. Here we present an improved dinoflagellate phylogeny, based on eight genes, with the broadest taxon sampling to date. Fifty-five sequences for eight phylogenetic markers from nuclear and mitochondrial regions were amplified from 13 species, four orders, and concatenated phylogenetic inferences were conducted with orthologous sequences. Phylogenetic resolution is increased with addition of support for the deepest branches, though can be improved yet further. We show for the first time that the characteristic dinoflagellate thecal plates, cellulosic material that is present within the sub-cuticular alveoli, appears to have had a single origin. In addition, the monophyly of most dinoflagellate orders is confirmed: the Dinophysiales, the Gonyaulacales, the Prorocentrales, the Suessiales, and the Syndiniales. Our improved phylogeny, along with results of PCR to detect the sxtA gene in various lineages, allows us to suggest that this gene was probably acquired separately in Gymnodinium and the common ancestor of Alexandrium and Pyrodinium and subsequently lost in some descendent species of Alexandrium.

When Naked Became Armored: An Eight-Gene Phylogeny Reveals Monophyletic Origin of Theca in Dinoflagellates

Science.gov (United States)

Orr, Russell J. S.; Murray, Shauna A.; Stüken, Anke; Rhodes, Lesley; Jakobsen, Kjetill S.

2012-01-01

The dinoflagellates are a diverse lineage of microbial eukaryotes. Dinoflagellate monophyly and their position within the group Alveolata are well established. However, phylogenetic relationships between dinoflagellate orders remain unresolved. To date, only a limited number of dinoflagellate studies have used a broad taxon sample with more than two concatenated markers. This lack of resolution makes it difficult to determine the evolution of major phenotypic characters such as morphological features or toxin production e.g. saxitoxin. Here we present an improved dinoflagellate phylogeny, based on eight genes, with the broadest taxon sampling to date. Fifty-five sequences for eight phylogenetic markers from nuclear and mitochondrial regions were amplified from 13 species, four orders, and concatenated phylogenetic inferences were conducted with orthologous sequences. Phylogenetic resolution is increased with addition of support for the deepest branches, though can be improved yet further. We show for the first time that the characteristic dinoflagellate thecal plates, cellulosic material that is present within the sub-cuticular alveoli, appears to have had a single origin. In addition, the monophyly of most dinoflagellate orders is confirmed: the Dinophysiales, the Gonyaulacales, the Prorocentrales, the Suessiales, and the Syndiniales. Our improved phylogeny, along with results of PCR to detect the sxtA gene in various lineages, allows us to suggest that this gene was probably acquired separately in Gymnodinium and the common ancestor of Alexandrium and Pyrodinium and subsequently lost in some descendent species of Alexandrium. PMID:23185516

The pole tide in deep oceans

Science.gov (United States)

Dickman, S. R.

1990-01-01

The fluid-dynamical theory of the pole tide is examined by describing the oceanic response to the Chandler wobble and assessing its implications for mantle anelasticity and low-frequency ocean dynamics. The Laplace tide equations accounting for bottom friction are given, and a spherical harmonic approach is delineated in which the time-independent portion of the tide height is expanded. Pole-tide height and related inertia products are linearly proportional to wobble amplitude, and the final equations are modified to account for mantle elasticity and oceanic loading. Results for pole tide effects are given for various earth models with attention to the role of boundary constraints. A dynamic effect is identified which lengthens the Chandler period by about 1 day more than static lengthening, a contribution that suggests a vigorous low-frequency response. The values derived are shown to agree with previous models that do not incorporate the effects of the pole tide.

MICROSPECTROPHOTOMETRY AS A METHOD TO IDENTIFY KLEPTOPLASTIDS IN THE NAKED FRESHWATER DINOFLAGELLATE GYMNODINIUM ACIDOTUM(1).

Science.gov (United States)

Barsanti, Laura; Evangelista, Valtere; Passarelli, Vincenzo; Frassanito, Anna Maria; Coltelli, Primo; Gualtieri, Paolo

2009-12-01

A relatively small number of freshwater dinoflagellates are involved in symbiotic association with cryptophytes. The chloroplasts of the cryptophytes are retained by the dinoflagellate and give it the characteristic phycobilin pigmentation, either phycoerythrin or phycocyanin. The pigment characterization of the retained chloroplasts can give precise and accurate information about the type of cryptophyte preyed upon by the dinoflagellate. For this purpose, we performed microspectrophotometric evaluation of the pigments of Gymnodinium acidotum Nygaard and three different cryptophytes present in samples collected from a tributary of the river Arno, in Tuscany (Italy). The comparison of the different spectroscopic data allowed us to discriminate effectively among the cryptophytes preyed upon by the dinoflagellate. © 2009 Phycological Society of America.

Identification of Msf tide amplification using a network of spatially distributed tide gauges

Digital Repository Service at National Institute of Oceanography (India)

Joseph, A.; Mehra, P.; Sivadas, T.K.; Desai, R.G.P.; Srinivas, K.; Thottam, T.; Vijayan, P.R.; Revichandran, C.; Balachandran, K.K.

. Phys. Maths. Soc. Jpn., 3, 372-380. [17]. Noye, B.J., 1974. Tide-well systems I: Some non-linear effects of the conventional tide-well. J. Marine Res., 32 (2), 129-153. [18]. Picaut, J., and Verstraete, J.M., 1979. Propagation of a 14.7-day wave...

The influence of demersal trawl fishing gears on the resuspension of dinoflagellate cysts.

Science.gov (United States)

Brown, Lyndsay; Bresnan, Eileen; Summerbell, Keith; O'Neill, Finbarr Gerard

2013-01-15

To investigate the influence of towed demersal fishing gears on dinoflagellate cyst resuspension, towing trials with four gear components were carried out at three sites of differing sediment type in the Moray Firth, Scotland. Samples of sediment plumes were collected using plankton nets mounted on a towed sledge. Diversity of resuspended dinoflagellate cysts was similar at all sites and included Protoperidinium and Gonyaulax spp., Proroceratium reticulatum and unidentified 'round brown' cysts. Cyst concentrations per gram of resuspended sediment varied by gear component and sediment particle size distribution. Gear components with lower hydrodynamic drag generated wakes with smaller shear stresses, mobilising fewer larger sand particles, giving larger concentrations of cysts. Muddy sediments contained higher cyst concentrations which declined with increasing grain size. This study has shown that fishing gear and sediment type can influence the redistribution of dinoflagellate cysts and highlights the importance this may have in relation to dinoflagellate blooms. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

Evolutionary acquisition and loss of saxitoxin biosynthesis in dinoflagellates: the second "core" gene, sxtG.

Science.gov (United States)

Orr, Russell J S; Stüken, Anke; Murray, Shauna A; Jakobsen, Kjetill S

2013-04-01

Saxitoxin and its derivatives are potent neurotoxins produced by several cyanobacteria and dinoflagellate species. SxtA is the initial enzyme in the biosynthesis of saxitoxin. The dinoflagellate full mRNA and partial genomic sequences have previously been characterized, and it appears that sxtA originated in dinoflagellates through a horizontal gene transfer from a bacterium. So far, little is known about the remaining genes involved in this pathway in dinoflagellates. Here we characterize sxtG, an amidinotransferase enzyme gene that putatively encodes the second step in saxitoxin biosynthesis. In this study, the entire sxtG transcripts from Alexandrium fundyense CCMP1719 and Alexandrium minutum CCMP113 were amplified and sequenced. The transcripts contained typical dinoflagellate spliced leader sequences and eukaryotic poly(A) tails. In addition, partial sxtG transcript fragments were amplified from four additional Alexandrium species and Gymnodinium catenatum. The phylogenetic inference of dinoflagellate sxtG, congruent with sxtA, revealed a bacterial origin. However, it is not known if sxtG was acquired independently of sxtA. Amplification and sequencing of the corresponding genomic sxtG region revealed noncanonical introns. These introns show a high interspecies and low intraspecies variance, suggesting multiple independent acquisitions and losses. Unlike sxtA, sxtG was also amplified from Alexandrium species not known to synthesize saxitoxin. However, amplification was not observed for 22 non-saxitoxin-producing dinoflagellate species other than those of the genus Alexandrium or G. catenatum. This result strengthens our hypothesis that saxitoxin synthesis has been secondarily lost in conjunction with sxtA for some descendant species.

On the generation and evolution of internal solitary waves in the southern Red Sea

KAUST Repository

Guo, Daquan

2016-11-28

Satellite observations recently revealed trains of internal solitary waves (ISWs) in the off-shelf region between 16.0 degrees N and 16.5 degrees N in the southern Red Sea. The generation mechanism of these waves is not entirely clear, though, as the observed generation sites are far away (50 km) from the shelf break and tidal currents are considered relatively weak in the Red Sea. Upon closer examination of the tide properties in the Red Sea and the unique geometry of the basin, it is argued that the steep bathymetry and a relatively strong tidal current in the southern Red Sea provide favorable conditions for the generation of ISWs. To test this hypothesis and further explore the evolution of ISWs in the basin, 2-D numerical simulations with the nonhydrostatic MIT general circulation model (MITgcm) were conducted. The results are consistent with the satellite observations in regard to the generation sites, peak amplitudes and the speeds of first-mode ISWs. Moreover, our simulations suggest that the generation process of ISWs in the southern Red Sea is similar to the tide-topography interaction mechanism seen in the South China Sea. Specifically, instead of ISWs arising in the immediate vicinity of the shelf break via a hydraulic lee wave mechanism, a broad, energetic internal tide is first generated, which subsequently travels away from the shelf break and eventually breaks down into ISWs. Sensitivity runs suggest that ISW generation may also be possible under summer stratification conditions, characterized by an intermediate water intrusion from the strait of Bab el Mandeb.

Galalctic Tides & the Sinusoidal Potential

Science.gov (United States)

Bartlett, David F.

2011-05-01

The sinusoidal potential is a nonNewtonian alternative to dark matter. Instead of φ = -GM/r we write φ = -(GM/r) cos kor, where ko= 2π/ λo and λo = Ro/20= 400 pc. Evidence for this choice for the "wavelength” λo has been given in one article and many previous meetings of the AAS & DDA. The solar system and nearby stars are trapped in a local groove of width Δr Quality (4 types) and semi-major axis aoriginal . For 10 of the 12 classes radial tides dominate Z-tides. The classic Oort cloud comets (1851-1996) have a particularly strong modulation with galactic longitude. This modulation is exactly in those directions where a radial tide would be important. The equally numerous recent Oort comets (1996-2008) show a different evidence for strong radial tides. The recent comets generally have much larger perihelion distances q than the classic ones. Here the evidence is that a radial tide is removing angular momentum from the orbit and thus bringing the perihelion closer to the earth and to observers.

Tide Predictions, California, 2014, NOAA

Data.gov (United States)

U.S. Environmental Protection Agency — The predictions from the web based NOAA Tide Predictions are based upon the latest information available as of the date of the user's request. Tide predictions...

Investigating tides, where does all the water go?

OpenAIRE

Institute, Marine

2013-01-01

Students will aim to complete a project investigating and researching tides. Each student should seek to develop an understanding of what causes tides and why sea levels change between high and low tide. Investigate and become familiar with tides as a natural feature in the local environment. Explore ways in which tides affect the behaviour of plants, animals and people.

Physico-chemical and biological factors influencing dinoflagellate cyst production in the Cariaco Basin

Directory of Open Access Journals (Sweden)

M. Bringué

2018-04-01

Full Text Available We present a 2.5-year-long sediment trap record of dinoflagellate cyst production in the Cariaco Basin, off Venezuela (southern Caribbean Sea. The site lies under the influence of wind-driven, seasonal upwelling which promotes high levels of primary productivity during boreal winter and spring. Changes in dinoflagellate cyst production is documented between November 1996 and May 1999 at ∼ 14-day intervals and interpreted in the context of in situ observations of physico-chemical and biological parameters measured at the mooring site. Dinoflagellate cyst assemblages are diverse (57 taxa and dominated by cyst taxa of heterotrophic affinity, primarily Brigantedinium spp. (51 % of the total trap assemblage. Average cyst fluxes to the trap are high (17.1  ×  103 cysts m−2 day−1 and show great seasonal and interannual variability. On seasonal timescales, dinoflagellate cyst production responds closely to variations in upwelling strength, with increases in cyst fluxes of several protoperidinioid taxa observed during active upwelling intervals, predominantly Brigantedinium spp. Cyst taxa produced by autotrophic dinoflagellates, in particular Bitectatodinium spongium, also respond positively to upwelling. Several spiny brown cysts contribute substantially to the assemblages, including Echinidinium delicatum (9.7 % and Echinidinium granulatum (7.3 %, and show a closer affinity to weaker upwelling conditions. The strong El Niño event of 1997/98 appears to have negatively impacted cyst production in the basin with a 1-year lag, and may have contributed to the unusually high fluxes of cysts type Cp (possibly the cysts of the toxic dinoflagellate Cochlodinium polykrikoides sensu Li et al., 2015, with cyst type Cp fluxes up to 11.8  ×  103 cysts m−2 day−1 observed during the weak upwelling event of February–May 1999. Possible trophic interactions between dinoflagellates and other major planktonic groups are

Evolutionary relationship between dinoflagellates bearing obligate diatom endosymbionts: insight into tertiary endosymbiosis.

Science.gov (United States)

Inagaki, Y; Dacks, J B; Doolittle, W F; Watanabe, K I; Ohama, T

2000-11-01

The marine dinoflagellates Peridinium balticum and Peridinium foliaceum are known for bearing diatom endosymbionts instead of peridinin-containing plastids. While evidence clearly indicates that their endosymbionts are closely related, the relationship between the host dinoflagellate cells is not settled. To examine the relationship of the two dinoflagellates, the DNA sequences of nuclear small-subunit rRNA genes (SSU rDNA) from Peridinium balticum, Peridinium foliaceum and one other peridinin-containing species, Peridinium bipes, were amplified, cloned and sequenced. While phylogenetic analyses under simple models of nucleotide substitution weakly support the monophyly of Peridinium balticum and Peridinium foliaceum, analyses under more sophisticated models significantly increased the statistical support for this relationship. Combining these results with the similarity between the two endosymbionts, it is concluded that (i) the two hosts have the closest sister relationship among dinoflagellates tested, (ii) the hypothesis that the diatom endosymbiosis occurred prior to the separation of the host cells is most likely to explain their evolutionary histories, and (iii) phylogenetic inferences under complex nucleotide evolution models seem to be able to compensate significant rate variation in the two SSU rDNA.

Tides, the PIG, and 'warm' water

International Nuclear Information System (INIS)

Robertson, Robin

2010-01-01

The present rapid melting of the Pine Island Glacier (PIG) has been attributed to basal melting driven by the ocean. Specifically, this ocean melting is attributed to currents and tides pumping 'warm' Circumpolar Deep Water (CDW) into the ice shelf cavity. To identify tidal activity in the region, an observational time series of yo-yo CTD (Conductivity, Temperature, and Depth) data collected in the PIG outflow region was analyzed. The water column in front of the PIG consisted of two primary layers, a meltwater layer exiting the ice shelf cavity over a layer of CDW. Semidiurnal tides were present in both layers, with both the strength and direction of the tides differing between the two layers. The upper layer tides were stronger and directed in and out of the cavity, while the lower layer tides were primarily directed along the front of the cavity. Energy was found to be transferred from the semidiurnal tide to other frequencies and to be reflected by the ice shelf front. These mechanisms were most prominent at the interfaces between layers and indicate potential mixing between the layers. In conclusion, tides were found to contribute to the circulation into the ice shelf cavity and also to mixing of the exiting water, which influences pumping of the CDW into the ice shelf cavity and melting of the PIG.

Mapping Hurricane Rita inland storm tide

Science.gov (United States)

Berenbrock, Charles; Mason, Jr., Robert R.; Blanchard, Stephen F.; Simonovic, Slobodan P.

2009-01-01

Flood-inundation data are most useful for decision makers when presented in the context of maps of effected communities and (or) areas. But because the data are scarce and rarely cover the full extent of the flooding, interpolation and extrapolation of the information are needed. Many geographic information systems (GIS) provide various interpolation tools, but these tools often ignore the effects of the topographic and hydraulic features that influence flooding. A barrier mapping method was developed to improve maps of storm tide produced by Hurricane Rita. Maps were developed for the maximum storm tide and at 3-hour intervals from midnight (0000 hour) through noon (1200 hour) on September 24, 2005. The improved maps depict storm-tide elevations and the extent of flooding. The extent of storm-tide inundation from the improved maximum storm-tide map was compared to the extent of flood-inundation from a map prepared by the Federal Emergency Management Agency (FEMA). The boundaries from these two maps generally compared quite well especially along the Calcasieu River. Also a cross-section profile that parallels the Louisiana coast was developed from the maximum storm-tide map and included FEMA high-water marks.

Ocean tides from Seasat-A

Science.gov (United States)

Hendershott, M. C.; Munk, W. H.; Zetler, B. D.

1974-01-01

Two procedures for the evaluation of global tides from SEASAT-A altimetry data are elaborated: an empirical method leading to the response functions for a grid of about 500 points from which the tide can be predicted for any point in the oceans, and a dynamic method which consists of iteratively modifying the parameters in a numerical solution to Laplace tide equations. It is assumed that the shape of the received altimeter signal can be interpreted for sea state and that orbit calculations are available so that absolute sea levels can be obtained.

Comparative analysis of membrane lipids in psychrophilic and mesophilic freshwater dinoflagellates

Directory of Open Access Journals (Sweden)

Andrea eAnesi

2016-04-01

Full Text Available Here we report the lipid profiles of ten dinoflagellate species originating from different freshwater habitats and grown at 4, 13 or 20°C akin to their natural occurrence. Lipids were determined by High Performance Liquid Chromatography-ElectroSpray Ionization-Mass Spectrometry in positive and negative ion modes. Besides the well-studied monogalactosyldiacylglycerol (MGDG and digalactosyldiacylglycerol (DGDG lipids, our study revealed the presence of intact molecular lipid species of trigalactosyldiacylglycerols (TGDG, betaine diacylglyceryl-carboxyhydroxymethylcholine (DGCC, sulfolipid sulfoquinovosyldiacylglycerols (SQDG and phospholipids, in particular phosphatidylcholine (PC, phosphatidylethanolamine (PE and phosphatidylglycerol (PG.In multivariate ordination, the freshwater dinoflagellates studied could be distinguished into two groups based on their lipid profiles. Peridinium aciculiferum, Borghiella dodgei, B. tenuissima and Tovellia coronata belonged to group 1 while Ceratium cornutum, Gymnodinium palustre, Jadwigia applanata, P. cinctum, P. willei and P. gatunense belonged to group 2. Indicator species analysis evidenced that group 1 was characterized by 36:9 MGDG and 36:9 DGDG and group 2 by 38:9 and 38:10 MGDG, 38:9 and 38:10 DGDG and 34:1 SQDG. We suggest that the grouping of dinoflagellates indicated their range of temperature tolerance. Furthermore, non-thylakoid lipids were linked to dinoflagellate phylogeny based on the large ribosomal sub-unit (28S LSU rather than their temperature tolerance. Thus certain lipids better reflected habitat adaptation while other lipids better reflected genetic diversity.

King Tides and Climate Change

Science.gov (United States)

The highest predicted high tide of the year at a coastal location can bring unusually high water levels and can cause flooding. Learn about these tides including what they are, when they occur, and what they can mean for the future.

Evolutionary Acquisition and Loss of Saxitoxin Biosynthesis in Dinoflagellates: the Second “Core” Gene, sxtG

Science.gov (United States)

Orr, Russell J. S.; Stüken, Anke; Murray, Shauna A.

2013-01-01

Saxitoxin and its derivatives are potent neurotoxins produced by several cyanobacteria and dinoflagellate species. SxtA is the initial enzyme in the biosynthesis of saxitoxin. The dinoflagellate full mRNA and partial genomic sequences have previously been characterized, and it appears that sxtA originated in dinoflagellates through a horizontal gene transfer from a bacterium. So far, little is known about the remaining genes involved in this pathway in dinoflagellates. Here we characterize sxtG, an amidinotransferase enzyme gene that putatively encodes the second step in saxitoxin biosynthesis. In this study, the entire sxtG transcripts from Alexandrium fundyense CCMP1719 and Alexandrium minutum CCMP113 were amplified and sequenced. The transcripts contained typical dinoflagellate spliced leader sequences and eukaryotic poly(A) tails. In addition, partial sxtG transcript fragments were amplified from four additional Alexandrium species and Gymnodinium catenatum. The phylogenetic inference of dinoflagellate sxtG, congruent with sxtA, revealed a bacterial origin. However, it is not known if sxtG was acquired independently of sxtA. Amplification and sequencing of the corresponding genomic sxtG region revealed noncanonical introns. These introns show a high interspecies and low intraspecies variance, suggesting multiple independent acquisitions and losses. Unlike sxtA, sxtG was also amplified from Alexandrium species not known to synthesize saxitoxin. However, amplification was not observed for 22 non-saxitoxin-producing dinoflagellate species other than those of the genus Alexandrium or G. catenatum. This result strengthens our hypothesis that saxitoxin synthesis has been secondarily lost in conjunction with sxtA for some descendant species. PMID:23335767

A data mining approach to dinoflagellate clustering according to sterol composition: Correlations with evolutionary history.

Science.gov (United States)

This study examined the sterol compositions of 102 dinoflagellates (including several previously unexamined species) using clustering techniques as a means of determining the relatedness of the organisms. In addition, dinoflagellate sterol-based relationships were compared statistically to dinoflag...

Future Change to Tide-Influenced Deltas

Science.gov (United States)

Nienhuis, Jaap H.; Hoitink, A. J. F. (Ton); Törnqvist, Torbjörn E.

2018-04-01

Tides tend to widen deltaic channels and shape delta morphology. Here we present a predictive approach to assess a priori the effect of fluvial discharge and tides on deltaic channels. We show that downstream channel widening can be quantified by the ratio of the tide-driven discharge and the fluvial discharge, along with a second metric representing flow velocities. A test of our new theory on a selection of 72 deltas globally shows good correspondence to a wide range of environments, including wave-dominated deltas, river-dominated deltas, and alluvial estuaries. By quantitatively relating tides and fluvial discharge to delta morphology, we offer a first-order prediction of deltaic change that may be expected from altered delta hydrology. For example, we expect that reduced fluvial discharge in response to dam construction will lead to increased tidal intrusion followed by enhanced tide-driven sediment import into deltas, with implications for navigation and other human needs.

Energetics of global ocean tides from Geosat altimetry

Science.gov (United States)

Cartwright, David E.; Ray, Richard D.

1991-01-01

The present paper focuses on resonance and energetics of the daily tides, especially in the southern ocean, the distribution of gravitational power input of daily and half-daily tides, and comparison with other estimates of global dissipation rates. The present global tidal maps, derived from Geosat altimetry, compare favorably with ground truth data at about the same rms level as the models of Schwiderski (1983), and are slightly better in lunar than in solar tides. Diurnal admittances clearly show Kelvin wave structure in the southern ocean and confirm the resonant mode of Platzman (1984) at 28.5 + or - 0.1 hr with an apparent Q of about 4. Driving energy is found to enter dominantly in the North Pacific for the daily tides and is strongly peaked in the tropical oceans for the half-daily tides. Global rates of working on all major tide constituents except S2 agree well with independent results from analyses of gravity through satellite tracking. Comparison at S2 is improved by allowing for the air tide in gravitational results but suggests deficiencies in all solar tide models.

Allelopathic inhibition of photosynthesis in the red tide-causing marine alga, Scrippsiella trochoidea (Pyrrophyta), by the dried macroalga, Gracilaria lemaneiformis (Rhodophyta)

Science.gov (United States)

Ye, Changpeng; Liao, Heping; Yang, Yufeng

2014-07-01

The red tide-causing microalga, Scrippsiella trochoidea was co-cultured with different quantities of dried macroalga Gracilaria lemaneiformis under laboratory conditions, to characterize the allelopathic inhibition effect of the seaweed on photosynthesis of the microalga. Photosynthetic oxygen evolution was measured, and chlorophyll a (Chl a) fluorescence transient O-J-I-P (O, J, I and P point in primary photochemistry reaction curve in photosystem II) curves associated with its specific parameters were determined. A concentration-dependent inhibition of S. trochoidea was observed when the dried seaweed was added. The rate of light-saturated maximum photosynthetic oxygen evolution (Pmax) was markedly decreased, and the O-J-I-P curve coupled with its specific parameters was reduced. The inhibitory effects of the macroalga on the microalga, according to the JIP-test (the relative fluorescence analysis based on O-J-I-P curve) and the activity of oxygen evolution, include a decrease in the number of active reaction centers, the blocking-up of the electron transport chain, and the damage to the oxygen-evolving complex. This study suggests that dried G. lemaneiformis is effective in inhibiting photosynthesis of S. trochoidea, and could thus be a potential candidate for mitigating S. trochoidea blooms.

Paleogene dinoflagellate cysts and thermal maturity from Pabdeh ...

African Journals Online (AJOL)

MICHAEL HORSFALL

forest development as a consequence of increase in climate humidity. The species are .... the Middle to Late Early Eocene, the oceans and seas are characterized ..... walled dinoflagellate cyst assemblages in the tropical Atlantic. Ocean and ...

[The red tide caused by the dinoflagellate Alexandrium tamarense in the Colombian Pacific coast (2001)].

Science.gov (United States)

García-Hansen, Ingrid; Cortés-Altamirano, Roberto; Sierra-Beltrán, Arturo P

2004-09-01

From April 26th to May 15th 2001, a large algae bloom was observed off Tumaco Bay on the Pacific coast of Colombia. This was the first harmful algae bloom (HAB) reported in the region, and reached Gorgona Island, about 120 km north. A year later, starting March 2002, an offshore HAB developed from Cabo Corrientes North to Solano Bay. The typical abundance during the blooms reached 7.5 x 10(6) cells l(-1) for the 2001 event and 1.6 x 10(6) cells l(-1) for the 2002 event. During both events, low temperature and high salinity were recorded. Typical measurements in the area are 27-27.5 degrees C and 30-31.5 psu. Values observed during the two events were 24-24.6 degrees C and 33-34 psu; 3 degrees C below normal and more than 2.5 psu above average values. These conditions are indicative of local upwelling processes at the time of the events. On both occasions, cells corresponding to the Alexandrium catenella/fundeyense/tamarense complex represented 99-100% of the biomass. It was difficult to differentiate the cells from A. catenella, but the presence of short chains of only 4 cells (single cells represented most of the biomass) was suggestive of A. tamarense. Shape, dimensions, and detailed structure of the apical pore complex, first apical plate, posterior sulcal plate, and position of the ventral pore on plate 1' of cells were consistent with the description of A. tamarense, which has not been reported in the tropical East Pacific. The Control Center of Pacific Contamination of the Maritime General Direction of the Colombian Navy has been monitoring the area since 1994 without finding this species or HABs. This leads us to consider the two events as caused by recently introduced species, where local upwelling processes favor permanent and cyclic HABs. However, during these two events, there were no reports of effects on marine biota or of human poisoning, probably because the blooms occurred some distance offshore and far from exploited shellfish beds.

The Global S$_1$ Ocean Tide

Science.gov (United States)

Ray, Richard D.; Egbert, G. D.

2003-01-01

The small S$_1$ ocean tide is caused primarily by diurnal atmospheric pressure loading. Its excitation is therefore unlike any other diurnal tide. The global character of $S-1$ is here determined by numerical modeling and by analysis of Topex/Poseidon satellite altimeter data. The two approaches yield reasonably consistent results, and large ( $ greater than $l\\cm) amplitudes in several regions are further confirmed by comparison with coastal tide gauges. Notwithstanding their excitation differences, S$-1$ and other diurnal tides are found to share several common features, such as relatively large amplitudes in the Arabian Sea, the Sea of Okhotsk, and the Gulf of Alaska. The most noticeable difference is the lack of an S$-1$ Antarctic Kelvin wave. These similarities and differences can be explained in terms of the coherences between near-diurnal oceanic normal modes and the underlying tidal forcings. While gravitational diurnal tidal forces excite primarily a 28-hour Antarctic-Pacific mode, the S$_1$ air tide excites several other near-diurnal modes, none of which has large amplitudes near Antarctica.

Propagation Velocity of Solid Earth Tides

Science.gov (United States)

Pathak, S.

2017-12-01

One of the significant considerations in most of the geodetic investigations is to take into account the outcome of Solid Earth tides on the location and its consequent impact on the time series of coordinates. In this research work, the propagation velocity resulting from the Solid Earth tides between the Indian stations is computed. Mean daily coordinates for the stations have been computed by applying static precise point positioning technique for a day. The computed coordinates are used as an input for computing the tidal displacements at the stations by Gravity method along three directions at 1-minute interval for 24 hours. Further the baseline distances are computed between four Indian stations. Computation of the propagation velocity for Solid Earth tides can be done by the virtue of study of the concurrent effect of it in-between the stations of identified baseline distance along with the time consumed by the tides for reaching from one station to another. The propagation velocity helps in distinguishing the impact at any station if the consequence at a known station for a specific time-period is known. Thus, with the knowledge of propagation velocity, the spatial and temporal effects of solid earth tides can be estimated with respect to a known station. As theoretically explained, the tides generated are due to the position of celestial bodies rotating about Earth. So the need of study is to observe the correlation of propagation velocity with the rotation speed of the Earth. The propagation velocity of Solid Earth tides comes out to be in the range of 440-470 m/s. This velocity comes out to be in a good agreement with the Earth's rotation speed.

A southern North Sea Miocene dinoflagellate cyst zonation

NARCIS (Netherlands)

Munsterman, D.K.; Brinkhuis, H.

2004-01-01

An integrated stratigraphical analysis emphasizing organic-walled dinoflagellate cyst (dinocyst) distribution has been carried out on multiple boreholes penetrating the Miocene in the subsurface of the Netherlands (southern North Sea Basin). The bulk of the investigated successions is attributed to

Novel insight into the role of heterotrophic dinoflagellates in the fate of crude oil in the sea

Science.gov (United States)

Almeda, Rodrigo; Connelly, Tara L.; Buskey, Edward J.

2014-12-01

Although planktonic protozoans are likely to interact with dispersed crude oil after a spill, protozoan-mediated processes affecting crude oil pollution in the sea are still not well known. Here, we present the first evidence of ingestion and defecation of physically or chemically dispersed crude oil droplets (1-86 μm in diameter) by heterotrophic dinoflagellates, major components of marine planktonic food webs. At a crude oil concentration commonly found after an oil spill (1 μL L-1), the heterotrophic dinoflagellates Noctiluca scintillans and Gyrodinium spirale grew and ingested ~0.37 μg-oil μg-Cdino-1 d-1, which could represent ~17% to 100% of dispersed oil in surface waters when heterotrophic dinoflagellates are abundant or bloom. Egestion of faecal pellets containing crude oil by heterotrophic dinoflagellates could contribute to the sinking and flux of toxic petroleum hydrocarbons in coastal waters. Our study indicates that crude oil ingestion by heterotrophic dinoflagellates is a noteworthy route by which petroleum enters marine food webs and a previously overlooked biological process influencing the fate of crude oil in the sea after spills.

A new clade, based on partial LSU rDNA sequences, of unarmoured dinoflagellates.

Science.gov (United States)

Reñé, Albert; de Salas, Miguel; Camp, Jordi; Balagué, Vanessa; Garcés, Esther

2013-09-01

The order Gymnodiniales comprises unarmoured dinoflagellates. However, the lack of sequences hindered determining the phylogenetic positions and systematic relationships of several gymnodinioid taxa. In this study, a monophyletic clade was defined for the species Ceratoperidinium margalefii Loeblich III, Gyrodinium falcatum Kofoid & Swezy, three Cochlodinium species, and two Gymnodinium-like dinoflagellates. Despite their substantial morphotypic differentiation, Cochlodinium cf. helix, G. falcatum and 'Gymnodinium' sp. 1 share a common shape of the acrobase. The phylogenetic data led to the following conclusions: (1) C. margalefii is closely related to several unarmoured dinoflagellates. Its sulcus shape has been observed for the first time. (2) G. falcatum was erroneously assigned to the genus Gyrodinium and is transferred to Ceratoperidinium (C. falcatum (Kofoid & Swezy) Reñé & de Salas comb. nov.). (3) The genus Cochlodinium is polyphyletic and thus artificial; our data support its separation into three different genera. (4) The two Gymnodinium-like species could not be morphologically or phylogenetically related to any other gymnodinioid species sequenced to date. While not all studied species have been definitively transferred to the correct genus, our study is a step forward in the classification of inconspicuous unarmoured dinoflagellates. The family Ceratoperidiniaeceae and the genus Ceratoperidinium are emended. Copyright © 2013 Elsevier GmbH. All rights reserved.

Systematics of a kleptoplastidal dinoflagellate, Gymnodinium eucyaneum Hu (Dinophyceae), and its cryptomonad endosymbiont.

Science.gov (United States)

Xia, Shuang; Zhang, Qi; Zhu, Huan; Cheng, Yingyin; Liu, Guoxiang; Hu, Zhengyu

2013-01-01

New specimens of the kleptoplastidal dinoflagellate Gymnodinium eucyaneum Hu were collected in China. We investigated the systematics of the dinoflagellate and the origin of its endosymbiont based on light morphology and phylogenetic analyses using multiple DNA sequences. Cells were dorsoventrally flattened with a sharply acute hypocone and a hemispherical epicone. The confusion between G. eucyaneum and G. acidotum Nygaard still needs to be resolved. We found that the hypocone was conspicuously larger than the epicone in most G. eucyaneum cells, which differed from G. acidotum, but there were a few cells whose hypocone and epicone were of nearly the same size. In addition, there was only one site difference in the partial nuclear LSU rDNA sequences of a sample from Japan given the name G. acidotum and G. eucyaneum in the present study, which suggest that G. eucyaneum may be a synonym of G. acidotum. Spectroscopic analyses and phylogenetic analyses based on nucleomorph SSU rDNA sequences and chloroplast 23 s rDNA sequences suggested that the endosymbiont of G. eucyaneum was derived from Chroomonas (Cryptophyta), and that it was most closely related to C. coerulea Skuja. Moreover, the newly reported kleptoplastidal dinoflagellates G. myriopyrenoides and G. eucyaneum in our study were very similar, and the taxonomy of kleptoplastidal dinoflagellates was discussed.

Phylogeny of five species of Nusuttodinium gen. nov. (Dinophyceae), a genus of unarmoured kleptoplastidic dinoflagellates.

Science.gov (United States)

Takano, Yoshihito; Yamaguchi, Haruyo; Inouye, Isao; Moestrup, Øjvind; Horiguchi, Takeo

2014-12-01

Cells of five unarmoured kleptoplastidic dinoflagellates, Amphidinium latum, Amphidinium poecilochroum, Gymnodinium amphidinioides, Gymnodinium acidotum and Gymnodinium aeruginosum were observed under light and/or scanning electron microscopy and subjected to single-cell PCR. The SSU rDNA and the partial LSU rDNA of all the examined species were sequenced, and the SSU rDNA of G. myriopyrenoides was sequenced. Phylogenetic analyses revealed that the unarmoured kleptoplastidic species formed a monophyletic clade within the Gymnodinium-clade sensu Daugbjerg et al. (2000). The sister taxa for this clade were Gymnodinium palustre and Spiniferodinium galeiforme, both of which possess brown-coloured chloroplasts. The results indicated that acquisition of kleptoplastidy in these unarmoured dinoflagellates was a single event and that these unarmoured kleptoplastidic dinoflagellates may have evolved from a form with permanent chloroplasts. Molecular trees suggested that the acquisition of kleptoplastidy took place in a marine habitat and later some species colonized the freshwater habitat. Because these unarmoured kleptoplastidic dinoflagellates are monophyletic and characterized by distinct morphological and cytological features (including the presence of the same type of apical groove, absence of nuclear chambers in the nuclear envelope, absence of genuine chloroplasts, and the possession of kleptochloroplasts), we propose the establishment of a new genus, Nusuttodinium, to accommodate all these dinoflagellates. Copyright © 2014 Elsevier GmbH. All rights reserved.

Precise Comparisons of Bottom-Pressure and Altimetric Ocean Tides

Science.gov (United States)

Ray, Richard D.

2013-01-01

A new set of pelagic tide determinations is constructed from seafloor pressure measurements obtained at 151 sites in the deep ocean. To maximize precision of estimated tides, only stations with long time series are used; median time series length is 567 days. Geographical coverage is considerably improved by use of the international tsunami network, but coverage in the Indian Ocean and South Pacific is still weak. As a tool for assessing global ocean tide models, the data set is considerably more reliable than older data sets : the root-mean-square difference with a recent altimetric tide model is approximately 5 mm for the M2 constituent. Precision is sufficiently high to allow secondary effects in altimetric and bottom-pressure tide differences to be studied. The atmospheric tide in bottom pressure is clearly detected at the S1, S2, and T2 frequencies. The altimetric tide model is improved if satellite altimetry is corrected for crustal loading by the atmospheric tide. Models of the solid body tide can also be constrained. The free corenutation effect in the K1 Love number is easily detected, but the overall estimates are not as accurate as a recent determination with very long baseline interferometry.

Precise comparisons of bottom-pressure and altimetric ocean tides

Science.gov (United States)

Ray, R. D.

2013-09-01

A new set of pelagic tide determinations is constructed from seafloor pressure measurements obtained at 151 sites in the deep ocean. To maximize precision of estimated tides, only stations with long time series are used; median time series length is 567 days. Geographical coverage is considerably improved by use of the international tsunami network, but coverage in the Indian Ocean and South Pacific is still weak. As a tool for assessing global ocean tide models, the data set is considerably more reliable than older data sets: the root-mean-square difference with a recent altimetric tide model is approximately 5 mm for the M2 constituent. Precision is sufficiently high to allow secondary effects in altimetric and bottom-pressure tide differences to be studied. The atmospheric tide in bottom pressure is clearly detected at the S1, S2, and T2 frequencies. The altimetric tide model is improved if satellite altimetry is corrected for crustal loading by the atmospheric tide. Models of the solid body tide can also be constrained. The free core-nutation effect in the K1 Love number is easily detected, but the overall estimates are not as accurate as a recent determination with very long baseline interferometry.

Brevetoxin (PbTx-2) influences the redox status and NPQ of Karenia brevis by way of thioredoxin reductase.

Science.gov (United States)

Chen, Wei; Colon, Ricardo; Louda, J William; Del Rey, Freddy Rodriguez; Durham, Michaella; Rein, Kathleen S

2018-01-01

The Florida red tide dinoflagellate, Karenia brevis, is the major harmful algal bloom dinoflagellate of the Gulf of Mexico and plays a destructive role in the region. Blooms of K. brevis can produce brevetoxins: ladder-shaped polyether (LSP) compounds, which can lead to adverse human health effects, such as reduced respiratory function through inhalation exposure, or neurotoxic shellfish poisoning through consumption of contaminated shellfish. The endogenous role of the brevetoxins remains uncertain. Recent work has shown that some forms of NADPH dependent thioredoxin reductase (NTR) are inhibited by brevetoxin-2 (PbTx-2). The study presented herein reveals that high toxin and low toxin K. brevis, which have a ten-fold difference in toxin content, also show a significant difference in their ability, not only to produce brevetoxin, but also in their cellular redox status and distribution of xanthophyll cycle pigments. These differences are likely due to the inhibition of NTR by brevetoxin. The work could shed light on the physiological role that brevetoxin fills for K. brevis. Copyright © 2017 Elsevier B.V. All rights reserved.

Dinoflagellates in a mesotrophic, tropical environment influenced by monsoon

Digital Repository Service at National Institute of Oceanography (India)

DeCosta, P.M.; Anil, A.C.; Patil, J.S.; Hegde, S.; DeSilva, M.S.; Chourasia, M.

The changes in dinoflagellate community structure in both e the water column and sediment in a mesotrophic, tropical port environment were investigated in this study. Since the South West Monsoon (SWM) is the main source of climatic variation...

Shallow-water loading tides in Japan from superconducting gravimetry

DEFF Research Database (Denmark)

Khan, Shfaqat Abbas; Hoyer, J.L.

2004-01-01

energetic constituents in the tide gauge observations are also seen in the gravity observations due to their loading effects on the deformation of the Earth. Even though the shallow-water tides at the Japanese east coast have an amplitude of only a few millimetres. they are still able to Generate a loading...... signal at gravity sites located several hundred kilometres inland. In particular, the S-3, S-4 and S-5 solar tides occur in both gravity and tide gauge observations. It is indicated that in other shelf regions with large shallow water tides, the shallow water loading signals account for a significant...

What can earth tide measurements tell us about ocean tides or earth structure?

Science.gov (United States)

Baker, T. F.

1978-01-01

Current experimental problems in Earth tides are reviewed using comparisons of tidal gravity and tilt measurements in Europe with loading calculations are examples. The limitations of present day instrumentation and installation techniques are shown as well as some of the ways in which they can be improved. Many of the geophysical and oceanographic investigations that are possible with Earth tide measurements are discussed with emphasis on the percentage accuracies required in the measurements in order to obtain new information about Earth or its oceans.

Free amino acids exhibit anthozoan "host factor" activity: they induce the release of photosynthate from symbiotic dinoflagellates in vitro.

Science.gov (United States)

Gates, R D; Hoegh-Guldberg, O; McFall-Ngai, M J; Bil, K Y; Muscatine, L

1995-08-01

Reef-building corals and other tropical anthozoans harbor endosymbiotic dinoflagellates. It is now recognized that the dinoflagellates are fundamental to the biology of their hosts, and their carbon and nitrogen metabolisms are linked in important ways. Unlike free living species, growth of symbiotic dinoflagellates is unbalanced and a substantial fraction of the carbon fixed daily by symbiont photosynthesis is released and used by the host for respiration and growth. Release of fixed carbon as low molecular weight compounds by freshly isolated symbiotic dinoflagellates is evoked by a factor (i.e., a chemical agent) present in a homogenate of host tissue. We have identified this "host factor" in the Hawaiian coral Pocillopora damicornis as a set of free amino acids. Synthetic amino acid mixtures, based on the measured free amino acid pools of P. damicornis tissues, not only elicit the selective release of 14C-labeled photosynthetic products from isolated symbiotic dinoflagellates but also enhance total 14CO2 fixation.

Comparative gene expression in toxic versus non-toxic strains of the marine dinoflagellate Alexandrium minutum

Directory of Open Access Journals (Sweden)

Glöckner Gernot

2010-04-01

Full Text Available Abstract Background The dinoflagellate Alexandrium minutum typically produces paralytic shellfish poisoning (PSP toxins, which are known only from cyanobacteria and dinoflagellates. While a PSP toxin gene cluster has recently been characterized in cyanobacteria, the genetic background of PSP toxin production in dinoflagellates remains elusive. Results We constructed and analysed an expressed sequence tag (EST library of A. minutum, which contained 15,703 read sequences yielding a total of 4,320 unique expressed clusters. Of these clusters, 72% combined the forward-and reverse reads of at least one bacterial clone. This sequence resource was then used to construct an oligonucleotide microarray. We analysed the expression of all clusters in three different strains. While the cyanobacterial PSP toxin genes were not found among the A. minutum sequences, 192 genes were differentially expressed between toxic and non-toxic strains. Conclusions Based on this study and on the lack of identified PSP synthesis genes in the two existent Alexandrium tamarense EST libraries, we propose that the PSP toxin genes in dinoflagellates might be more different from their cyanobacterial counterparts than would be expected in the case of a recent gene transfer. As a starting point to identify possible PSP toxin-associated genes in dinoflagellates without relying on a priori sequence information, the sequences only present in mRNA pools of the toxic strain can be seen as putative candidates involved in toxin synthesis and regulation, or acclimation to intracellular PSP toxins.

Comparative Transcriptome Analysis of a Toxin-Producing Dinoflagellate Alexandrium catenella and Its Non-Toxic Mutant

Directory of Open Access Journals (Sweden)

Yong Zhang

2014-11-01

Full Text Available The dinoflagellates and cyanobacteria are two major kingdoms of life producing paralytic shellfish toxins (PSTs, a large group of neurotoxic alkaloids causing paralytic shellfish poisonings around the world. In contrast to the well elucidated PST biosynthetic genes in cyanobacteria, little is known about the dinoflagellates. This study compared transcriptome profiles of a toxin-producing dinoflagellate, Alexandrium catenella (ACHK-T, and its non-toxic mutant form (ACHK-NT using RNA-seq. All clean reads were assembled de novo into a total of 113,674 unigenes, and 66,812 unigenes were annotated in the known databases. Out of them, 35 genes were found to express differentially between the two strains. The up-regulated genes in ACHK-NT were involved in photosynthesis, carbon fixation and amino acid metabolism processes, indicating that more carbon and energy were utilized for cell growth. Among the down-regulated genes, expression of a unigene assigned to the long isoform of sxtA, the initiator of toxin biosynthesis in cyanobacteria, was significantly depressed, suggesting that this long transcript of sxtA might be directly involved in toxin biosynthesis and its depression resulted in the loss of the ability to synthesize PSTs in ACHK-NT. In addition, 101 putative homologs of 12 cyanobacterial sxt genes were identified, and the sxtO and sxtZ genes were identified in dinoflagellates for the first time. The findings of this study should shed light on the biosynthesis of PSTs in the dinoflagellates.

The Jurassic of North-East Greenland: Jurassic dinoflagellate cysts from Hochstetter Forland, North-East Greenland

Directory of Open Access Journals (Sweden)

Piasecki, Stefan

2004-11-01

Full Text Available Three sections in Hochstetter Forland, North-East Greenland, referred to the Jurassic Payer Dal and Bernbjerg Formations, have been analysed for dinoflagellate cysts. The dinoflagellate cysts,new finds of ammonites and previously recorded marine faunas form the basis for improved dating of the succession. The basal strata of the Payer Dal Formation at Kulhus is here dated as Late Callovian, Peltoceras athleta Chronozone, based on the presence of relatively abundant Limbicysta bjaerkei, Mendicodinium groenlandicum, Rhychoniopsis cladophora and Tubotuberella dangeardii in an otherwise poor Upper Callovian dinoflagellate assemblage. Ammoniteshave not been recorded from these strata. The upper Payer Dal Formation at Agnetesøelven is dated as Late Oxfordian, Amoeboceras glosense – Amoeboceras serratum Chronozones, based onthe presence of Sciniodinium crystallinum, together with Cribroperidinium granuligera and Stephanelytron sp. The age is in accordance with ammonites present in the uppermost part ofthe formation at Søndre Muslingebjerg. New ammonites in the Bernbjerg Formation at Agnetesøelven together with dinoflagellate cysts indicate an earliest Kimmeridgian age, Raseniacymodoce and Aulacostephanoides mutabilis Chronozones.The Upper Callovian dinoflagellate cysts from Hochstetter Forland belong to a local brackish to marginal marine assemblage, which only allows a fairly broad correlation to coeval assemblagesin central East Greenland. In contrast, the Oxfordian and Kimmeridgian assemblages are fully marine and can be correlated from Milne Land in central East Greenland via Hochstetter Forland to Peary Land in eastern North Greenland.

Ocean Tide Loading Computation

Science.gov (United States)

Agnew, Duncan Carr

2005-01-01

September 15,2003 through May 15,2005 This grant funds the maintenance, updating, and distribution of programs for computing ocean tide loading, to enable the corrections for such loading to be more widely applied in space- geodetic and gravity measurements. These programs, developed under funding from the CDP and DOSE programs, incorporate the most recent global tidal models developed from Topex/Poscidon data, and also local tide models for regions around North America; the design of the algorithm and software makes it straightforward to combine local and global models.

Systematics of a kleptoplastidal dinoflagellate, Gymnodinium eucyaneum Hu (Dinophyceae, and its cryptomonad endosymbiont.

Directory of Open Access Journals (Sweden)

Shuang Xia

Full Text Available New specimens of the kleptoplastidal dinoflagellate Gymnodinium eucyaneum Hu were collected in China. We investigated the systematics of the dinoflagellate and the origin of its endosymbiont based on light morphology and phylogenetic analyses using multiple DNA sequences. Cells were dorsoventrally flattened with a sharply acute hypocone and a hemispherical epicone. The confusion between G. eucyaneum and G. acidotum Nygaard still needs to be resolved. We found that the hypocone was conspicuously larger than the epicone in most G. eucyaneum cells, which differed from G. acidotum, but there were a few cells whose hypocone and epicone were of nearly the same size. In addition, there was only one site difference in the partial nuclear LSU rDNA sequences of a sample from Japan given the name G. acidotum and G. eucyaneum in the present study, which suggest that G. eucyaneum may be a synonym of G. acidotum. Spectroscopic analyses and phylogenetic analyses based on nucleomorph SSU rDNA sequences and chloroplast 23 s rDNA sequences suggested that the endosymbiont of G. eucyaneum was derived from Chroomonas (Cryptophyta, and that it was most closely related to C. coerulea Skuja. Moreover, the newly reported kleptoplastidal dinoflagellates G. myriopyrenoides and G. eucyaneum in our study were very similar, and the taxonomy of kleptoplastidal dinoflagellates was discussed.

Still acting green: continued expression of photosynthetic genes in the heterotrophic Dinoflagellate Pfiesteria piscicida (Peridiniales, Alveolata.

Directory of Open Access Journals (Sweden)

Gwang Hoon Kim

Full Text Available The loss of photosynthetic function should lead to the cessation of expression and finally loss of photosynthetic genes in the new heterotroph. Dinoflagellates are known to have lost their photosynthetic ability several times. Dinoflagellates have also acquired photosynthesis from other organisms, either on a long-term basis or as "kleptoplastids" multiple times. The fate of photosynthetic gene expression in heterotrophs can be informative into evolution of gene expression patterns after functional loss, and the dinoflagellates ability to acquire new photosynthetic function through additional endosymbiosis. To explore this we analyzed a large-scale EST database consisting of 151,091 unique sequences (29,170 contigs, 120,921 singletons obtained from 454 pyrosequencing of the heterotrophic dinoflagellate Pfiesteria piscicida. About 597 contigs from P. piscicida showed significant homology (E-value dinoflagellates, while the light-harvesting genes are derived from diatoms, or diatoms that are tertiary plastids in other dinoflagellates. The continued expression of many genes involved in photosynthetic pathways indicates that the loss of transcriptional regulation may occur well after plastid loss and could explain the organism's ability to "capture" new plastids (i.e. different secondary endosymbiosis or tertiary symbioses to renew photosynthetic function.

Still acting green: continued expression of photosynthetic genes in the heterotrophic Dinoflagellate Pfiesteria piscicida (Peridiniales, Alveolata).

Science.gov (United States)

Kim, Gwang Hoon; Jeong, Hae Jin; Yoo, Yeong Du; Kim, Sunju; Han, Ji Hee; Han, Jong Won; Zuccarello, Giuseppe C

2013-01-01

The loss of photosynthetic function should lead to the cessation of expression and finally loss of photosynthetic genes in the new heterotroph. Dinoflagellates are known to have lost their photosynthetic ability several times. Dinoflagellates have also acquired photosynthesis from other organisms, either on a long-term basis or as "kleptoplastids" multiple times. The fate of photosynthetic gene expression in heterotrophs can be informative into evolution of gene expression patterns after functional loss, and the dinoflagellates ability to acquire new photosynthetic function through additional endosymbiosis. To explore this we analyzed a large-scale EST database consisting of 151,091 unique sequences (29,170 contigs, 120,921 singletons) obtained from 454 pyrosequencing of the heterotrophic dinoflagellate Pfiesteria piscicida. About 597 contigs from P. piscicida showed significant homology (E-value dinoflagellates, while the light-harvesting genes are derived from diatoms, or diatoms that are tertiary plastids in other dinoflagellates. The continued expression of many genes involved in photosynthetic pathways indicates that the loss of transcriptional regulation may occur well after plastid loss and could explain the organism's ability to "capture" new plastids (i.e. different secondary endosymbiosis or tertiary symbioses) to renew photosynthetic function.

Fortnightly Ocean Tides, Earth Rotation, and Mantle Anelasticity

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Ray, Richard; Egbert, Gary

2012-01-01

The fortnightly Mf ocean tide is the largest of the long-period tides (periods between 1 week and 18.6 years), but Mf is still very small, generally 2 cm or less. All long-period tides are thought to be near equilibrium with the astronomical tidal potential, with an almost pure zonal structure. However, several lines of evidence point to Mf having a significant dynamic response to forcing. We use a combination of numerical modeling, satellite altimetry, and observations of polar motion to determine the Mf ocean tide and to place constraints on certain global properties, such as angular momentum. Polar motion provides the only constraints on Mf tidal currents. With a model of the Mf ocean tide in hand, we use it to remove the effects of the ocean from estimates of fortnightly variations in length-of-day. The latter is dominated by the earth's body tide, but a small residual allows us to place new constraints on the anelasticity of the earth's mantle. The result gives the first experimental confirmation of theoretical predictions made by Wahr and Bergen in 1986.

Environmental Barcoding Reveals Massive Dinoflagellate Diversity in Marine Environments

Czech Academy of Sciences Publication Activity Database

Stern, R. F.; Horák, Aleš; Andrew, R. L.; Coffroth, M. A.; Andersen, R. A.; Kupper, F. C.; Jameson, I.; Hoppenrath, M.; Véron, B.; Kasai, F.; Brand, J.; James, E. R.; Keeling, P. J.

2010-01-01

Roč. 5, č. 11 (2010), e13991 E-ISSN 1932-6203 Keywords : RIBOSOMAL-RNA GENE * FREE-LIVING STRAIN * SP-NOV DINOPHYCEAE * TOXIC DINOFLAGELLATE * MOLECULAR PHYLOGENY * COASTAL WATERS * NATURAL-ENVIRONMENT * RDNA SEQUENCES * SYMBIODINIUM Impact factor: 4.411, year: 2010

Dynamic ocean-tide effects on Earth's rotation

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Dickman, S. R.

1993-01-01

This article develops 'broad-band' Liouville equations which are capable of determining the effects on the rotation of the Earth of a periodic excitation even at frequencies as high as semi-diurnal; these equations are then used to predict the rotational effects of altimetric, numerical and 32-constituent spherical harmonic ocean-tide models. The rotational model includes a frequency-dependent decoupled core, the effects of which are especially marked near retrograde diurnal frequencies; and a fully dynamic oceanic response, whose effects appear to be minor despite significant frequency dependence. The model also includes solid-earth effects which are frequency dependent as the result of both anelasticity at long periods and the fluid-core resonance at nearly diurnal periods. The effects of both tidal inertia and relative angular momentum on Earth rotation (polar motion, length of day, 'nutation' and Universal Time) are presented for 32 long- and short-period ocean tides determined as solutions to the author's spherical harmonic tide theory. The lengthening of the Chandler wobble period by the pole tide is also re-computed using the author's full theory. Additionally, using the spherical harmonic theory, tidal currents and their effects on rotation are determined for available numerical and altimetric tide height models. For all models, we find that the effects of tidal currents are at least as important as those of tide height for diurnal and semi-diurnal constituents.

Factor driving heterotrophic dinoflagellate in relation to environment conditions in Kerkennah Islands (eastern coast of Tunisa

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Mounir Ben Brahim

2015-09-01

Full Text Available Objective: To study the seasonal variability of heterotrophic dinoflagellate in the station of Cercina (southern coast of Tunisia. Methods: Sampling was done in 2007 in Cercina station located in the western coast of Kerkennah (34°41'27'' N; 11°07'45'' E (Southern Tunisia. Three replicates of water samples were taken during 10 days of each month. Environmental variables and nutrients were measured in situ. Results: A significant seasonal difference was observed for temperature and water salinity. The highest values were observed in spring and summer. No significant seasonal difference was, however, detected for nitrite, nitrate, ammonia, silica and phosphate. Sixty-five species of dinoflagellate were identified in the station of Cercina. Abundance of dinoflagellates fluctuated between seasons with values showing a significant seasonal and monthly difference. The highest mean abundance was recorded in spring in April, while the lowest abundance was detected in December in winter. Protoperidinium granii was the main species contributing to the dissimilarity between spring and winter with 13.98% followed by Peridinium sp. with 12.5% of dissimilarity and by Polykrikos sp. with 10.58%. Conclusions: Heterotrophic dinoflagellates proliferate in spring and summer. This increase was justified by the nutrient availability. Protoperidinium granii and Polykrikos kofoidii were the main heterotrophic dinoflagellate making difference between seasons and their densities were positively correlated with both temperature and salinity.

Impact of industrial pollution on recent dinoflagellate cysts in Izmir Bay (Eastern Aegean).

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Aydin, Hilal; Yürür, Emine Erdem; Uzar, Serdar; Küçüksezgin, Filiz

2015-05-15

The spatial distribution of dinoflagellate cysts was studied to understand the impact of industrial pollution on the surface sediment of Izmir Bay, Turkey. Forty two dinoflagellate cyst morphotypes belonging to 12 genera were identified and qualified at 12 sampling points. The cyst of Gymnodinium nolleri dominated the bay and had the highest abundance in most of the stations, following Spiniferites bulloideus and Lingulodinium machaerophorum. The highest cyst concentration was recorded in the inner part of the bay. Cyst concentration ranged between 384 and 9944 cyst g(-1) dry weight of sediment in the sampling area. Sediment metal concentrations were determined. Heavy metal levels in Izmir Inner Bay were higher than the Middle and Outer Bay. L. machaerophorum, Dubridinium caperatum and Polykrikos kofoidii showed significant positive correlation with some metals (Cd, Pb, Cu, Zn) and organic carbon content. However, there was no significant correlation between dinoflagellate cyst abundance and sediment type. Copyright © 2015 Elsevier Ltd. All rights reserved.

The magnetic tides of Honolulu

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Love, Jeffrey J.; Rigler, Erin Joshua

2013-01-01

We review the phenomenon of time-stationary, periodic quiet-time geomagnetic tides. These are generated by the ionospheric and oceanic dynamos, and, to a lesser-extent, by the quiet-time magnetosphere, and they are affected by currents induced in the Earth's electrically conducting interior. We examine historical time series of hourly magnetic-vector measurements made at the Honolulu observatory. We construct high-resolution, frequency-domain Lomb-periodogram and maximum-entropy power spectra that reveal a panorama of stationary harmonics across periods from 0.1 to 10000.0-d, including harmonics that result from amplitude and phase modulation. We identify solar-diurnal tides and their annual and solar-cycle sideband modulations, lunar semi-diurnal tides and their solar-diurnal sidebands, and tides due to precession of lunar eccentricity and nodes. We provide evidence that a method intended for separating the ionospheric and oceanic dynamo signals by midnight subsampling of observatory data time series is prone to frequency-domain aliasing. The tidal signals we summarize in this review can be used to test our fundamental understanding of the dynamics of the quiet-time ionosphere and magnetosphere, induction in the ocean and in the electrically conducting interior of the Earth, and they are useful for defining a quiet-time baseline against which magnetospheric-storm intensity is measured.

Multimission empirical ocean tide modeling for shallow waters and polar seas

DEFF Research Database (Denmark)

Cheng, Yongcun; Andersen, Ole Baltazar

2011-01-01

A new global ocean tide model named DTU10 (developed at Technical University of Denmark) representing all major diurnal and semidiurnal tidal constituents is proposed based on an empirical correction to the global tide model FES2004 (Finite Element Solutions), with residual tides determined using...... tide gauge sets show that the new tide model fits the tide gauge measurements favorably to other state of the art global ocean tide models in both the deep and shallow waters, especially in the Arctic Ocean and the Southern Ocean. One example is a comparison with 207 tide gauge data in the East Asian...... marginal seas where the root-mean-square agreement improved by 35.12%, 22.61%, 27.07%, and 22.65% (M-2, S-2, K-1, and O-1) for the DTU10 tide model compared with the FES2004 tide model. A similar comparison in the Arctic Ocean with 151 gauge data improved by 9.93%, 0.34%, 7.46%, and 9.52% for the M-2, S-2...

Impact of tropical storms and drought on the dinoflagellates ...

African Journals Online (AJOL)

North Carolina experienced three hurricanes during autumn 1999, an ongoing drought from October 2001 to October 2002, one hurricane during autumn 2003, and remnants from seven tropical systems during August–September 2004. These weather events impacted the abundance patterns of both dinoflagellates.

Geodynamic Effects of Ocean Tides: Progress and Problems

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Richard, Ray

1999-01-01

Satellite altimetry, particularly Topex/Poseidon, has markedly improved our knowledge of global tides, thereby allowing significant progress on some longstanding problems in geodynamics. This paper reviews some of that progress. Emphasis is given to global-scale problems, particularly those falling within the mandate of the new IERS Special Bureau for Tides: angular momentum, gravitational field, geocenter motion. For this discussion I use primarily the new ocean tide solutions GOT99.2, CSR4.0, and TPXO.4 (for which G. Egbert has computed inverse-theoretic error estimates), and I concentrate on new results in angular momentum and gravity and their solid-earth implications. One example is a new estimate of the effective tidal Q at the M_2 frequency, based on combining these ocean models with tidal estimates from satellite laser ranging. Three especially intractable problems are also addressed: (1) determining long-period tides in the Arctic [large unknown effect on the inertia tensor, particularly for Mf]; (2) determining the global psi_l tide [large unknown effect on interpretations of gravimetry for the near-diurnal free wobble]; and (3) determining radiational tides [large unknown temporal variations at important frequencies]. Problems (2) and (3) are related.

Impact of sea level rise on tide gate function.

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Walsh, Sean; Miskewitz, Robert

2013-01-01

Sea level rise resulting from climate change and land subsidence is expected to severely impact the duration and associated damage resulting from flooding events in tidal communities. These communities must continuously invest resources for the maintenance of existing structures and installation of new flood prevention infrastructure. Tide gates are a common flood prevention structure for low-lying communities in the tidal zone. Tide gates close during incoming tides to prevent inundation from downstream water propagating inland and open during outgoing tides to drain upland areas. Higher downstream mean sea level elevations reduce the effectiveness of tide gates by impacting the hydraulics of the system. This project developed a HEC-RAS and HEC-HMS model of an existing tide gate structure and its upland drainage area in the New Jersey Meadowlands to simulate the impact of rising mean sea level elevations on the tide gate's ability to prevent upstream flooding. Model predictions indicate that sea level rise will reduce the tide gate effectiveness resulting in longer lasting and deeper flood events. The results indicate that there is a critical point in the sea level elevation for this local area, beyond which flooding scenarios become dramatically worse and would have a significantly negative impact on the standard of living and ability to do business in one of the most densely populated areas of America.

DIEL PHASING OF THE CELL-CYCLE IN THE FLORIDA RED TIDE DINOFLAGELLATE, GYMNODINIUM BREVE. (R827085)

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

ACCUMULATION OF THE FLORIDA RED-TIDE DINOFLAGELLATE, GYMNODINIUM BREVE DAVIS, ALONG COASTAL DENSITY FRONTS. (R827085)

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Lipid biomarkers in Symbiodinium dinoflagellates: new indicators of thermal stress

KAUST Repository

Kneeland, J.; Hughen, K.; Cervino, J.; Hauff, B.; Eglinton, T.

2013-01-01

Lipid content and fatty acid profiles of corals and their dinoflagellate endosymbionts are known to vary in response to high-temperature stress. To better understand the heat-stress response in these symbionts, we investigated cultures

Statistical selection of tide gauges for Arctic sea-level reconstruction

DEFF Research Database (Denmark)

Svendsen, Peter Limkilde; Andersen, Ole Baltazar; Nielsen, Allan Aasbjerg

2015-01-01

In this paper, we seek an appropriate selection of tide gauges for Arctic Ocean sea-level reconstruction based on a combination of empirical criteria and statistical properties (leverages). Tide gauges provide the only in situ observations of sea level prior to the altimetry era. However, tide...... the "influence" of each Arctic tide gauge on the EOF-based reconstruction through the use of statistical leverage and use this as an indication in selecting appropriate tide gauges, in order to procedurally identify poor-quality data while still including as much data as possible. To accommodate sparse...

Fortnightly Earth Rotation, Ocean Tides, and Mantle Anelasticity

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Ray, Richard D.; Egbert, Gary D.

2011-01-01

Sustained accurate measurements of earth rotation are one of the prime goals of Global Geodetic Observing System (GGOS). We here concentrate on the fortnightly (Mf) tidal component of earth-rotation data to obtain new results concerning anelasticity of the mantle at this period. The study comprises three parts: (1) a new determination of the Mf component of polar motion and length-of-day from a multi-decade time series of space-geodetic data; (2) the use of the polar-motion determination as one constraint in the development of a hydrodynamic ocean model of the Mf tide; and (3) the use of these results to place new constraints on mantle anelasticity. Our model of the Mf ocean tide assimilates more than fourteen years of altimeter data from the Topex/Poseidon and Jason-1 satellites. The polar motion data, plus tide-gauge data and independent altimeter data, give useful additional information, with only the polar motion putting constraints on tidal current velocities. The resulting ocean-tide model, plus the dominant elastic body tide, leaves a small residual in observed length-of-day caused by mantle anelasticity. The inferred effective tidal 0 of the anelastic body tide is 90 and is in line with a omega-alpha frequency dependence with alpha in the range 0.2--0.3.

Potentiality of benthic dinoflagellate cultures and screening of their ...

African Journals Online (AJOL)

aghomotsegin

2014-02-05

Feb 5, 2014 ... 3Department of Earth and Marine Sciences, College of Ocean Sciences, Jeju National University, Jeju 690-756, Korea. Accepted 24 .... epifluorescence microscope (violate excitation ca 430 nm, blue emission ca 490 nm; ...... feeding as a newly identified survival strategy of the dinoflagellate symbiodinium.

Performance of modern tide gauges: towards mm-level accuracy

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Belén Martín Míguez

2012-09-01

Full Text Available Considerable efforts are being made worldwide to upgrade tide gauge networks using new technologies. Because of the unique location of the Kerguelen Islands, the measurement of sea level there has received particular attention, with up to four systems equipped with modern sensors functioning simultaneously (two pressure tide gauges, a radar tide gauge, and a GPS-equipped buoy. We analysed and compared the sea level data obtained with these systems from 2003 to 2010, together with a time series of tide pole observations. This is the first time that a multi-comparison study with tide gauges has been undertaken over such a long time span and that the stability of modern radar tide gauges has been examined. The multi-comparison enabled us to evaluate the performance of the tide gauges in several frequency ranges, identify errors and estimate their magnitude. The drift of the pressure sensors (up to 8.0 mm/yr was found to be one of the most relevant sources of systematic error. Other sources of difference such as clock drift, scale error and different locations of the instruments were also detected. After correcting the time series of sea level for these errors we estimated an upper bound for the radar instrumental error in field condition at ~0.3 cm.

Effects of brevetoxin exposure on the immune system of loggerhead sea turtles.

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Walsh, Catherine J; Leggett, Stephanie R; Carter, Barbara J; Colle, Clarence

2010-05-10

Blooms of the toxic dinoflagellate, Karenia brevis, occur almost annually off the Florida coast. These blooms, commonly called "red tides", produce a group of neurotoxins collectively termed brevetoxins. Many species of sealife, including sea turtles, are severely impacted by brevetoxin exposure. Effects of brevetoxins on immune cells were investigated in rescued loggerhead sea turtles, Caretta caretta, as well as through in vitro experiments using peripheral blood leukocytes (PBL) collected from captive sea turtles. In rescued animals, plasma brevetoxin concentrations were measured using a competitive ELISA. Plasma lysozyme activity was measured using a turbidity assay. Lysozyme activity correlated positively with plasma brevetoxin concentrations. Differential expression of genes affected by brevetoxin exposure was determined using two separate suppression subtractive hybridization experiments. In one experiment, genes from PBL collected from sea turtles rescued from red tide toxin exposure were compared to genes from PBL collected from healthy captive loggerhead sea turtles. In the second experiment, PBL from healthy captive loggerhead sea turtles were exposed to brevetoxin (500 ng PbTx-2/ml) in vitro for 18 h and compared to unexposed PBL. Results from the subtraction hybridization experiment conducted with red tide rescued sea turtle PBL indicated that genes involved in oxidative stress or xenobiotic metabolism were up-regulated. Using quantitative real-time PCR, a greater than 2-fold increase in superoxide dismutase and thioredoxin and greater than 10-fold increase in expression of thiopurine S-methyltransferase were observed. Results from the in vitro subtraction hybridization experiment indicated that genes coding for cytochrome c oxidases were the major up-regulated genes. Using quantitative real-time PCR, a greater than 8-fold increase in expression of beta-tubulin and greater than 3-fold increase in expression of ubiquinol were observed. Brevetoxin

Global ocean tide models on the eve of Topex/Poseidon

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Ray, Richard D.

1993-01-01

Some existing global ocean tide models that can provide tide corrections to Topex/Poseidon altimeter data are described. Emphasis is given to the Schwiderski and Cartwright-Ray models, as these are the most comprehensive, highest resolution models, but other models that will soon appear are mentioned. Differences between models for M2 often exceed 10 cm over vast stretches of the ocean. Comparisons to 80 selected pelagic and island gauge measurements indicate the Schwiderski model is more accurate for the major solar tides, Cartwright-Ray for the major lunar tides. The adequacy of available tide models for studying basin-scale motions is probably marginal at best.

A diverse host thrombospondin-type-1 repeat protein repertoire promotes symbiont colonization during establishment of cnidarian-dinoflagellate symbiosis.

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Neubauer, Emilie-Fleur; Poole, Angela Z; Neubauer, Philipp; Detournay, Olivier; Tan, Kenneth; Davy, Simon K; Weis, Virginia M

2017-05-08

The mutualistic endosymbiosis between cnidarians and dinoflagellates is mediated by complex inter-partner signaling events, where the host cnidarian innate immune system plays a crucial role in recognition and regulation of symbionts. To date, little is known about the diversity of thrombospondin-type-1 repeat (TSR) domain proteins in basal metazoans or their potential role in regulation of cnidarian-dinoflagellate mutualisms. We reveal a large and diverse repertoire of TSR proteins in seven anthozoan species, and show that in the model sea anemone Aiptasia pallida the TSR domain promotes colonization of the host by the symbiotic dinoflagellate Symbiodinium minutum . Blocking TSR domains led to decreased colonization success, while adding exogenous TSRs resulted in a 'super colonization'. Furthermore, gene expression of TSR proteins was highest at early time-points during symbiosis establishment. Our work characterizes the diversity of cnidarian TSR proteins and provides evidence that these proteins play an important role in the establishment of cnidarian-dinoflagellate symbiosis.

Evaluating the Addition of a Dinoflagellate Phytoplankton Functional Type Using Radiance Anomalies for Monterey Bay, CA

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Houskeeper, H. F.; Kudela, R. M.

2016-12-01

Ocean color sensors have enabled daily, global monitoring of phytoplankton productivity in the world's oceans. However, to observe key structures such as food webs, or to identify regime shifts of dominant species, tools capable of distinguishing between phytoplankton functional types using satellite remote sensing reflectance are necessary. One such tool developed by Alvain et al. (2005), PHYSAT, successfully linked four phytoplankton functional types to chlorophyll-normalized remote sensing spectra, or radiance anomalies, in case-1 waters. Yet this tool was unable to characterize dinoflagellates because of their ubiquitous background presence in the open ocean. We employ a radiance anomaly technique based on PHYSAT to target phytoplankton functional types in Monterey Bay, a region where dinoflagellate populations are larger and more variable than in open ocean waters, and thus where they may be viable targets for satellite remote sensing characterization. We compare with an existing Santa Cruz Wharf photo-pigment time series spanning from 2006 to the present to regionally ground-truth the method's predictions, and we assess its accuracy in characterizing dinoflagellates, a phytoplankton group that impacts the region's fish stocks and water quality. For example, an increase in dinoflagellate abundance beginning in 2005 led to declines in commercially important fish stocks that persisted throughout the following year. Certain species of dinoflagellates in Monterey Bay are also responsible for some of the harmful algal bloom events that negatively impact the shellfish industry. Moving toward better tools to characterize phytoplankton blooms is important for understanding ecosystem shifts, as well as protecting human health in the surrounding areas.

Orthogonal stack of global tide gauge sea level data

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Trupin, A.; Wahr, J.

1990-01-01

Yearly and monthly tide gauge sea level data from around the globe are fitted to numerically generated equilibrium tidal data to search for the 18.6 year lunar tide and 14 month pole tide. Both tides are clearly evident in the results, and their amplitudes and phases are found to be consistent with a global equilibrium response. Global, monthly sea level data from outside the Baltic sea and Gulf of Bothnia are fitted to global atmospheric pressure data to study the response of the ocean to pressure fluctuations. The response is found to be inverted barometer at periods greater than two months. Global averages of tide gauge data, after correcting for the effects of post glacial rebound on individual station records, reveal an increase in sea level over the last 80 years of between 1.1 mm/yr and 1.9 mm/yr.

The IERS Special Bureau for Tides

Science.gov (United States)

Ray, Richard D.; Chao, B. F.; Desai, S. D.

2002-01-01

The Global Geophysical Fluids Center of the International Earth Rotation Service (IERS) comprises 8 special bureaus, one of which is the Special Bureau for Tides. Its purpose is to facilitate studies related to tidal effects in earth rotation. To that end it collects various relevant datasets and distributes them, primarily through its website at bowie.gsfc.nasa.gov/ggfc/tides. Example datasets include tabulations of tidal variations in angular momentum and in earth rotation as estimated from numerical ocean tide models and from meteorological reanalysis products. The web site also features an interactive tidal prediction "machine" which generates tidal predictions (e.g., of UT1) from lists of harmonic constants. The Special Bureau relies on the tidal and earth-rotation communities to build and enlarge its datasets; further contributions from this community are most welcome.

Decadal variations in diatoms and dinoflagellates on the inner shelf of the East China Sea, China

Science.gov (United States)

Abate, Rediat; Gao, Yahui; Chen, Changping; Liang, Junrong; Mu, Wenhua; Kifile, Demeke; Chen, Yanghang

2017-11-01

Diatoms and dinoflagellates are two major groups of phytoplankton that flourish in the oceans, particularly in coastal zone and upwelling systems, and their contrasting production have been reported in several world seas. However, this information is not available in the coastal East China Sea (ECS). Thus, to investigate and compare the decadal trends in diatoms and dinoflagellates, a sediment core, 47 cm long, was collected from the coastal zone of the ECS. Sediment chlorophyll- a (Chl- a), phytoplankton-group specific pigment signatures of diatoms and dinoflagellates, and diatom valve concentrations were determined. The sediment core covered the period from 1961 to 2011 AD. The chlorophyll- a contents ranged from 2.32 to 73 µg/g dry sediment (dw) and averaged 9.81 µg/g dw. Diatom absolute abundance ranged from 29152 to 177501 valve/gram (v/g) dw and averaged 72137 v/g dw. Diatom valve and diatom specific pigment marker concentrations were not significantly correlated. Peridinin increased after the 1980s in line with intensified use of fertilizer and related increases in nutrient inputs into the marine environment. The increased occurrence of dinoflagellate dominance after the 1980s can be mostly explained by the increase in nutrients. However, the contribution of dinoflagellates to total phytoplankton production (Chl- a) decreased during the final decade of this study, probably because of the overwhelming increase in diatom production that corresponded with the construction of the Three Gorges Dam (TGD) and related light availability. Similarly, the mean ratio of fucoxanthin/peridinin for the period from 1982 to 2001 was 6% less than for 1961 to 1982, while the ratio for 2001 to 2011 was 45.3% greater than for 1982 to 2001. The decadal variation in the fucoxanthin/peridinin ratio implies that dinoflagellate production had been gradually increasing until 2001. We suggest that the observed changes can be explained by anthropogenic impacts, such as nutrient

Tide-surge interaction in the English Channel

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D. Idier

2012-12-01

Full Text Available The English Channel is characterised by strong tidal currents and a wide tidal range, such that their influence on surges is expected to be non-negligible. In order to better assess storm surges in this zone, tide-surge interactions are investigated. A preliminary data analysis on hourly surges indicates some preferential times of occurrence of large storm surges at rising tide, especially in Dunkerque. To examine this further, a numerical modelling approach is chosen, based on the 2DH shallow-water model (MARS. The surges are computed both with and without tide interaction. For the two selected events (the November 2007 North Sea and March 2008 Atlantic storms, it appears that the instantaneous tide-surge interaction is seen to be non-negligible in the eastern half of the English Channel, reaching values of 74 cm (i.e. 50% of the same event maximal storm surge in the Dover Strait for the studied cases. This interaction decreases in westerly direction. In the risk-analysis community in France, extreme water levels have been determined assuming skew surges and tide as independent. The same hydrodynamic model is used to investigate this dependence in the English Channel. Simple computations are performed with the same meteorological forcing, while varying the tidal amplitude, and the skew surge differences D_SS are analysed. Skew surges appear to be tide-dependent, with negligible values of D_SS (<0.05 m over a large portion of the English Channel, although reaching several tens of centimetres in some locations (e.g. the Isle of Wight and Dover Strait.

Lunar tidal acceleration obtained from satellite-derived ocean tide parameters

Science.gov (United States)

Goad, C. C.; Douglas, B. C.

1978-01-01

One hundred sets of mean elements of GEOS-3 computed at 2-day intervals yielded observation equations for the M sub 2 ocean tide from the long periodic variations of the inclination and node of the orbit. The 2nd degree Love number was given the value k sub 2 = 0.30 and the solid tide phase angle was taken to be zero. Combining obtained equations with results for the satellite 1967-92A gives the M sub 2 ocean tide parameter values. Under the same assumption of zero solid tide phase lag, the lunar tidal acceleration was found mostly due to the C sub 22 term in the expansion of the M sub 2 tide with additional small contributions from the 0 sub 1 and N sub 2 tides. Using Lambeck's (1975) estimates for the latter, the obtained acceleration in lunar longitudal in excellent agreement with the most recent determinations from ancient and modern astronomical data.

Tides at the east coast of Lanzarote Island

Science.gov (United States)

Benavent, M.; Arnoso, J.; Vélez, E. J.

2012-04-01

The main goal of this work is the study of the ocean tides at the east coast of Lanzarote (Canary Islands). We have analyzed time series of tide gauge and bottom pressure observations available in the region and we have made a further comparative validation with recent global and local ocean tide models. Lanzarote island shows singular features, with regard its volcanic structure and geomorphological properties and, also, concerning the characteristics of the ocean tides in the surrounding waters. For this reason, this region experiences a great interest in Geodesy and Geodynamics. Particularly, an accurate modelization of the ocean tides is of great importance to correct with high accuracy the effect of the ocean over the multiple geodetic measurements that are being carried out in the Geodynamic Laboratory of Lanzarote, LGL (Vieira et al., 1991; 2006). Furthermore, the analysis of tide gauge and bottom pressure records in this area is of great importance to investigate sea level variations, to evaluate and quantify the causes of these changes and the possible correlation with vertical movements of the Earth's crust. The time series of sea level and bottom pressure data considered in this work are obtained at two different locations of the island and, in each of them, using several sensors at different periods of time. First location is Jameos del Agua (JA) station, which belongs to the LGL. This station is placed in the open ocean, 200 meters distant from the northeastern coast of the island and at 8 meters depth. The observations have been carried out using 3 bottom pressure sensors (Aanderaa WLR7, SAIV TD301A and Aqualogger 210PT) at different periods of time (spanning a total of six years). Second location is Arrecife (AR) station, which is 23 km south of JA station. In this case, the sea level data come from a float tide gauge belonging to the Instituto Español de Oceanografía, installed at the beginning of the loading bay, and a radar tide gauge from the

Tide-surge Interaction Intensified by the Taiwan Strait

Science.gov (United States)

Zhang, Wen-Zhou; Shi, Fengyan; Hong, Hua-Sheng; Shang, Shao-Ping; Kirby, James T.

2010-06-01

The Taiwan Strait is a long and wide shelf-channel where the hydrodynamics is extremely complex, being characterized by strong tides, and where storm surges frequently occur during the typhoon season. Obvious oscillations due to tide-surge interaction were observed by tide gauges along the northern Fujian coast, the west bank of the Taiwan Strait, during Typhoon Dan (1999). Numerical experiments indicate that nonlinear bottom friction (described by the quadratic formula) is a major factor to predict these oscillations while the nonlinear advective terms and the shallow water effect have little contribution. It is found that the tide-surge interaction in the northern portion of the Taiwan Strait is intensified by the strait. Simulations based on simplified topographies with and without the island of Taiwan show that, in the presence of the island, the channel effect strengthens tidal currents and tends to align the major axes of tidal ellipses along the channel direction. Storm-induced currents are also strengthened by the channel. The pattern of strong tidal currents and storm-induced currents along the channel direction enhances tide-surge interaction via the nonlinear bottom friction, resulting in the obvious oscillations along the northern Fujian coast.

Sea level reconstruction from satellite altimetry and tide gauge data

DEFF Research Database (Denmark)

Svendsen, Peter Limkilde; Andersen, Ole Baltazar; Nielsen, Allan Aasbjerg

2012-01-01

Ocean satellite altimetry has provided global sets of sea level data for the last two decades, allowing determination of spatial patterns in global sea level. For reconstructions going back further than this period, tide gauge data can be used as a proxy. We examine different methods of combining...... for better sensitivity analysis with respect to spatial distribution, and tide gauge data are available around the Arctic Ocean, which may be important for a later high-latitude reconstruction....... satellite altimetry and tide gauge data using optimal weighting of tide gauge data, linear regression and EOFs, including automatic quality checks of the tide gauge time series. We attempt to augment the model using various proxies such as climate indices like the NAO and PDO, and investigate alternative...

Ocean acidification reduces growth and calcification in a marine dinoflagellate

NARCIS (Netherlands)

Van de Waal, D.B.; John, U.; Ziveri, P.; Reichart, G.J.; Hoins, M.; Sluijs, A.; Rost, B.

2013-01-01

Ocean acidification is considered a major threat to marine ecosystems and may particularly affect calcifying organisms such as corals, foraminifera and coccolithophores. Here we investigate the impact of elevated pCO2 and lowered pH on growth and calcification in the common calcareous dinoflagellate

Heat-stress and light-stress induce different cellular pathologies in the symbiotic dinoflagellate during coral bleaching.

Science.gov (United States)

Downs, C A; McDougall, Kathleen E; Woodley, Cheryl M; Fauth, John E; Richmond, Robert H; Kushmaro, Ariel; Gibb, Stuart W; Loya, Yossi; Ostrander, Gary K; Kramarsky-Winter, Esti

2013-01-01

Coral bleaching is a significant contributor to the worldwide degradation of coral reefs and is indicative of the termination of symbiosis between the coral host and its symbiotic algae (dinoflagellate; Symbiodinium sp. complex), usually by expulsion or xenophagy (symbiophagy) of its dinoflagellates. Herein, we provide evidence that during the earliest stages of environmentally induced bleaching, heat stress and light stress generate distinctly different pathomorphological changes in the chloroplasts, while a combined heat- and light-stress exposure induces both pathomorphologies; suggesting that these stressors act on the dinoflagellate by different mechanisms. Within the first 48 hours of a heat stress (32°C) under low-light conditions, heat stress induced decomposition of thylakoid structures before observation of extensive oxidative damage; thus it is the disorganization of the thylakoids that creates the conditions allowing photo-oxidative-stress. Conversely, during the first 48 hours of a light stress (2007 µmoles m(-2) s(-1) PAR) at 25°C, condensation or fusion of multiple thylakoid lamellae occurred coincidently with levels of oxidative damage products, implying that photo-oxidative stress causes the structural membrane damage within the chloroplasts. Exposure to combined heat- and light-stresses induced both pathomorphologies, confirming that these stressors acted on the dinoflagellate via different mechanisms. Within 72 hours of exposure to heat and/or light stresses, homeostatic processes (e.g., heat-shock protein and anti-oxidant enzyme response) were evident in the remaining intact dinoflagellates, regardless of the initiating stressor. Understanding the sequence of events during bleaching when triggered by different environmental stressors is important for predicting both severity and consequences of coral bleaching.

Heat-stress and light-stress induce different cellular pathologies in the symbiotic dinoflagellate during coral bleaching.

Directory of Open Access Journals (Sweden)

C A Downs

Full Text Available Coral bleaching is a significant contributor to the worldwide degradation of coral reefs and is indicative of the termination of symbiosis between the coral host and its symbiotic algae (dinoflagellate; Symbiodinium sp. complex, usually by expulsion or xenophagy (symbiophagy of its dinoflagellates. Herein, we provide evidence that during the earliest stages of environmentally induced bleaching, heat stress and light stress generate distinctly different pathomorphological changes in the chloroplasts, while a combined heat- and light-stress exposure induces both pathomorphologies; suggesting that these stressors act on the dinoflagellate by different mechanisms. Within the first 48 hours of a heat stress (32°C under low-light conditions, heat stress induced decomposition of thylakoid structures before observation of extensive oxidative damage; thus it is the disorganization of the thylakoids that creates the conditions allowing photo-oxidative-stress. Conversely, during the first 48 hours of a light stress (2007 µmoles m(-2 s(-1 PAR at 25°C, condensation or fusion of multiple thylakoid lamellae occurred coincidently with levels of oxidative damage products, implying that photo-oxidative stress causes the structural membrane damage within the chloroplasts. Exposure to combined heat- and light-stresses induced both pathomorphologies, confirming that these stressors acted on the dinoflagellate via different mechanisms. Within 72 hours of exposure to heat and/or light stresses, homeostatic processes (e.g., heat-shock protein and anti-oxidant enzyme response were evident in the remaining intact dinoflagellates, regardless of the initiating stressor. Understanding the sequence of events during bleaching when triggered by different environmental stressors is important for predicting both severity and consequences of coral bleaching.

Ocean tide models for satellite geodesy and Earth rotation

Science.gov (United States)

Dickman, Steven R.

1991-01-01

A theory is presented which predicts tides in turbulent, self-gravitating, and loading oceans possessing linearized bottom friction, realistic bathymetry, and continents (at coastal boundaries no-flow conditions are imposed). The theory is phrased in terms of spherical harmonics, which allows the tide equations to be reduced to linear matrix equations. This approach also allows an ocean-wide mass conservation constraint to be applied. Solutions were obtained for 32 long and short period luni-solar tidal constituents (and the pole tide), including the tidal velocities in addition to the tide height. Calibrating the intensity of bottom friction produces reasonable phase lags for all constituents; however, tidal amplitudes compare well with those from observation and other theories only for long-period constituents. In the most recent stage of grant research, traditional theory (Liouville equations) for determining the effects of angular momentum exchange on Earth's rotation were extended to encompass high-frequency excitations (such as short-period tides).

Non-Migrating Tides, with Zonally Symmetric Component, Generated in the Mesosphere

Science.gov (United States)

Mayr, H. G.; Mengel, J. G.; Talaat, E. R.; Porter, H. S.; Hines, C. O.

2003-01-01

For comparison with measurements from the TIMED satellite and coordinated ground based observations, we discuss results from our Numerical Spectral Model (NSM) that incorporates the Doppler Spread Parameterization (Hines, 1997) for small-scale gravity waves (GWs). The NSM extends from the ground into the thermosphere and describes the major dynamical features of the atmosphere including the wave driven equatorial oscillations (QBO and SAO), and the seasonal variations of tides and planetary waves. With emphasis on the non-migrating tides, having periods of 24 and 12 hours, we discuss our modeling results that account for the classical migrating solar excitation sources only. As reported earlier, the NSM reproduces the observed seasonal variations and in particular the large equinoctial maxima in the amplitude of the migrating diurnal tide at altitudes around 90 km. Filtering of the tide by the zonal circulation and GW momentum deposition was identified as the cause. The GWs were also shown to produce a strong non-linear interaction between the diurnal and semi-diurnal tides. Confined largely to the mesosphere, the NSM produces through dynamical interactions a relatively large contribution of non-migrating tides. A striking feature is seen in the diurnal and semi-diurnal oscillations of the zonal mean (m = 0). Eastward propagating tides are also generated for zonal wave numbers m = 1 to 4. When the NSM is run without GWs, the amplitudes for the non-migrating tides, including m = 0, are generally small. Planetary wave interaction and non-linear coupling that involves the filtering of GWs and related height integration of dynamical features are discussed as possible mechanisms for generating these non-migrating tides in the NSM. As is the case for the solar migrating tides, the non-migrating tides reveal persistent seasonal variations. Under the influence of the QBO and SAO, interannual variations are produced.

Dynamic Tides and the Evolution of Stars in Close Binaries

OpenAIRE

Willems, B.; Claret, A.

2004-01-01

In this talk, we review some recent advances in the theory of dynamic tides in close binaries. We particularly focus on the effects of resonances of dynamic tides with free oscillation modes and on the role of dynamic tides in the comparison of theoretically predicted and observationally inferred apsidal-motion rates.

A fast-response shallow-water tide gauge

International Nuclear Information System (INIS)

Cavaleri, L.; Curiotto, S.

1979-01-01

The authors describe the characteristics of a fast-response tide gauge suitable for shallow-water conditions. Its time constant is of the order of minutes. Wind waves are filtered better than 99% in the (0/10) s interval. The tide gauge has now been operative for three years on an oceanographic tower in the open sea. (author)

NONLINEAR TIDES IN CLOSE BINARY SYSTEMS

International Nuclear Information System (INIS)

Weinberg, Nevin N.; Arras, Phil; Quataert, Eliot; Burkart, Josh

2012-01-01

We study the excitation and damping of tides in close binary systems, accounting for the leading-order nonlinear corrections to linear tidal theory. These nonlinear corrections include two distinct physical effects: three-mode nonlinear interactions, i.e., the redistribution of energy among stellar modes of oscillation, and nonlinear excitation of stellar normal modes by the time-varying gravitational potential of the companion. This paper, the first in a series, presents the formalism for studying nonlinear tides and studies the nonlinear stability of the linear tidal flow. Although the formalism we present is applicable to binaries containing stars, planets, and/or compact objects, we focus on non-rotating solar-type stars with stellar or planetary companions. Our primary results include the following: (1) The linear tidal solution almost universally used in studies of binary evolution is unstable over much of the parameter space in which it is employed. More specifically, resonantly excited internal gravity waves in solar-type stars are nonlinearly unstable to parametric resonance for companion masses M' ∼> 10-100 M ⊕ at orbital periods P ≈ 1-10 days. The nearly static 'equilibrium' tidal distortion is, however, stable to parametric resonance except for solar binaries with P ∼ 3 [P/10 days] for a solar-type star) and drives them as a single coherent unit with growth rates that are a factor of ≈N faster than the standard three-wave parametric instability. These are local instabilities viewed through the lens of global analysis; the coherent global growth rate follows local rates in the regions where the shear is strongest. In solar-type stars, the dynamical tide is unstable to this collective version of the parametric instability for even sub-Jupiter companion masses with P ∼< a month. (4) Independent of the parametric instability, the dynamical and equilibrium tides excite a wide range of stellar p-modes and g-modes by nonlinear inhomogeneous forcing

Storm Surge and Tide Interaction: A Complete Paradigm

Science.gov (United States)

Horsburgh, K.

2014-12-01

Estimates show that in 2005, in the largest 136 coastal cities, there were 40 million people and 3,000 billion of assets exposed to 1 in 100 year coastal flood events. Mean sea level rise will increase this exposure to 150 million people and 35,000 billion of assets by 2070. Any further change in the statistics of flood frequency or severity would impact severely on economic and social systems. It is therefore crucial to understand the physical drivers of extreme storm surges, and to have confidence in datasets used for extreme sea level statistics. Much previous research has focussed on the process of tide-surge interaction, and it is now widely accepted that the physical basis of tide-surge interaction is that a phase shift of the tidal signal represents the effect of the surge on the tide. The second aspect of interaction is that shallow water momentum considerations imply that differing tidal states should modulate surge generation: wind stress should have greater surge-generating potential on lower tides. We present results from a storm surge model of the European shelf that demonstrate that tidal range does have an effect on the surges generated. The cycle-integrated effects of wind stress (i.e. the skew surge) are greater when tidal range is low. Our results contradict the absence of any such correlation in tide gauge records. This suggests that whilst the modulating effect of the tide on the skew surge (the time-independent difference between peak prediction and observations) is significant, the difference between individual storms is dominant. This implies that forecasting systems must predict salient detail of the most intense storms. A further implication is that flood forecasting models need to simulate tides with acceptable accuracy at all coastal locations. We extend our model analysis to show that the same modulation of storm surges (by tidal conditions) applies to tropical cyclones. We conduct simulations using a mature operational storm surge model

Lake-level variations and tides in Lago Argentino, Patagonia: insights from pressure tide gauge records

Directory of Open Access Journals (Sweden)

Andreas Richter

2015-08-01

Full Text Available Based on precise pressure tide gauge observations lake-level records are derived for two sites in Lago Argentino, southern Patagonia, of 2.5 and 1 years of duration. Applying the tools of time series analysis, the principal processes affecting the lake level are identified and quantified. Lake-level changes reflecting variations in lake volume are dominated by a seasonal cycle of 1.2 m in amplitude. Lake-volume changes occur in addition with a daily period in response to melt water influx from surrounding glaciers. Sporadic lake-volume jumps are caused by bursting of the ice dam of Perito Moreno glacier. Water movements in Lago Argentino are dominated by surface seiches reaching 20 cm in amplitude. Lake tides reach a maximum amplitude of 3 mm. The comparison of the tidal signal extracted from the lake-level observations with a model composed of the contributions of body tide and ocean tidal loading indicates a phase shift of 23° which is most likely explained by an 1 hour phase lag of global ocean tide models in the region of the highly fragmented Pacific coast. The comparison of the obtained results with those of a previous study of Lago Fagnano, Tierra del Fuego, allows to relate differences in the hydrological and hydrodynamic processes between both lakes to morphological properties. This leads to a tentative prediction of the lake-level variability to be expected from other great Patagonian lakes. The presented geodetic results shall serve as a starting point for a detailed limnological investigation of these aquatic ecosystems.

Influence analysis of Arctic tide gauges using leverages

DEFF Research Database (Denmark)

Svendsen, Peter Limkilde; Andersen, Ole Baltazar; Nielsen, Allan Aasbjerg

2014-01-01

a calibration period, in this preliminary case Drakkar ocean model data, which are forced using historical tide gauge data from the PSMSL database. The resulting leverage for each tide gauge may indicate that it represents a distinct mode of variability, or that its time series is perturbed in a way......Reconstructions of historical sea level in the Arctic Ocean are fraught with difficulties related to lack of data, uneven distribution of tide gauges and seasonal ice cover. Considering the period from 1950 to the present, we attempt to identify conspicuous tide gauges in an automated way, using...... the statistical leverage of each individual gauge. This may be of help in determining appropriate procedures for data preprocessing, of particular importance for the Arctic area as the GIA is hard to constrain and many gauges are located on rivers. We use a model based on empirical orthogonal functions from...

Survey on germination and species composition of dinoflagellates from ballast tanks and recent sediments in ports on the South Coast of Finland, North-Eastern Baltic Sea

International Nuclear Information System (INIS)

Pertola, Sari . E-mail sari.pertola@fimr.fi; Faust, Maria A.; Kuosa, Harri

2006-01-01

Cyst beds in ships and ports in Finland have previously been unstudied. Therefore, sediments from ships' ballast water tanks and four Finnish ports were sampled for dinoflagellate cysts and other phytoplankton. Untreated sediments were incubated at 10 o C and 20 o C in the local 6 psu salinity for 1, 4 and 7 days, and vegetative cells were examined with light and scanning electron microscope. Sediments were inhabited by various dinoflagellates, diatoms, chlorophytes, cyanophytes and small flagellates. Germinated dinoflagellates were found in 90% of ballast tanks and in all ports. Gymnodiniales spp. and Heterocapsa rotundata formed a major proportion of the proliferating dinoflagellate cells. One species, Peridinium quinquecorne, not previously reported from the Baltic Sea, was identified with SEM. The study emphasises that ships are potential transport vehicles for dinoflagellate cysts even in the low salinity Finnish waters, and small-sized dinoflagellates should be focused upon in ballast water studies

Symbiodinium transcriptomes: genome insights into the dinoflagellate symbionts of reef-building corals.

KAUST Repository

Bayer, Till; Aranda, Manuel; Sunagawa, Shinichi; Yum, Lauren K; Desalvo, Michael K; Lindquist, Erika; Coffroth, Mary Alice; Voolstra, Christian R.; Medina, Mó nica

2012-01-01

Dinoflagellates are unicellular algae that are ubiquitously abundant in aquatic environments. Species of the genus Symbiodinium form symbiotic relationships with reef-building corals and other marine invertebrates. Despite their ecologic importance

Molecular phylogeny of ocelloid-bearing dinoflagellates (Warnowiaceae) as inferred from SSU and LSU rDNA sequences.

Science.gov (United States)

Hoppenrath, Mona; Bachvaroff, Tsvetan R; Handy, Sara M; Delwiche, Charles F; Leander, Brian S

2009-05-25

Dinoflagellates represent a major lineage of unicellular eukaryotes with unparalleled diversity and complexity in morphological features. The monophyly of dinoflagellates has been convincingly demonstrated, but the interrelationships among dinoflagellate lineages still remain largely unresolved. Warnowiid dinoflagellates are among the most remarkable eukaryotes known because of their possession of highly elaborate ultrastructural systems: pistons, nematocysts, and ocelloids. Complex organelles like these are evolutionary innovations found only in a few athecate dinoflagellates. Moreover, the taxonomy of warnowiids is extremely confusing and inferences about the evolutionary history of this lineage are mired by the absence of molecular phylogenetic data from any member of the group. In this study, we provide the first molecular phylogenetic data for warnowiids and couple them with a review of warnowiid morphological features in order to formulate a hypothetical framework for understanding character evolution within the group. These data also enabled us to evaluate the evolutionary relationship(s) between warnowiids and the other group of dinoflagellates with complex organelles: polykrikoids. Molecular phylogenetic analyses of SSU and LSU rDNA sequences demonstrated that warnowiids form a well-supported clade that falls within the more inclusive Gymnodinium sensu stricto clade. These data also confirmed that polykrikoids are members of the Gymnodinium sensu stricto clade as well; however, a specific sister relationship between the warnowiid clade and the polykrikoid clade was unresolved in all of our analyses. Nonetheless, the new DNA sequences from different isolates of warnowiids provided organismal anchors for several previously unidentified sequences derived from environmental DNA surveys of marine biodiversity. Comparative morphological data and molecular phylogenetic data demonstrate that the polykrikoid and the warnowiid clade are closely related to each other

Molecular phylogeny of ocelloid-bearing dinoflagellates (Warnowiaceae as inferred from SSU and LSU rDNA sequences

Directory of Open Access Journals (Sweden)

Handy Sara M

2009-05-01

Full Text Available Abstract Background Dinoflagellates represent a major lineage of unicellular eukaryotes with unparalleled diversity and complexity in morphological features. The monophyly of dinoflagellates has been convincingly demonstrated, but the interrelationships among dinoflagellate lineages still remain largely unresolved. Warnowiid dinoflagellates are among the most remarkable eukaryotes known because of their possession of highly elaborate ultrastructural systems: pistons, nematocysts, and ocelloids. Complex organelles like these are evolutionary innovations found only in a few athecate dinoflagellates. Moreover, the taxonomy of warnowiids is extremely confusing and inferences about the evolutionary history of this lineage are mired by the absence of molecular phylogenetic data from any member of the group. In this study, we provide the first molecular phylogenetic data for warnowiids and couple them with a review of warnowiid morphological features in order to formulate a hypothetical framework for understanding character evolution within the group. These data also enabled us to evaluate the evolutionary relationship(s between warnowiids and the other group of dinoflagellates with complex organelles: polykrikoids. Results Molecular phylogenetic analyses of SSU and LSU rDNA sequences demonstrated that warnowiids form a well-supported clade that falls within the more inclusive Gymnodinium sensu stricto clade. These data also confirmed that polykrikoids are members of the Gymnodinium sensu stricto clade as well; however, a specific sister relationship between the warnowiid clade and the polykrikoid clade was unresolved in all of our analyses. Nonetheless, the new DNA sequences from different isolates of warnowiids provided organismal anchors for several previously unidentified sequences derived from environmental DNA surveys of marine biodiversity. Conclusion Comparative morphological data and molecular phylogenetic data demonstrate that the polykrikoid

The self-consistent dynamic pole tide in non-global oceans

Science.gov (United States)

Dickman, S. R.

1988-01-01

The dynamic pole tide is determined by solving Laplace tide equations which take into account the presence of continents in oceans, oceanic self-gravitation and loading, and mantle elasticity. Dynamical effects are found to be only mild. It is shown that the dynamical pole tide contributes about one day more to the Chandler period than a static pole tide would, and dissipates wobble energy at a very weak rate. It is noted that, depending on the wobble period predicted for an oceanless elastic earth, mantle anelasticity at low frequencies may nevertheless contribute negligibly to the Chandler period.

Loktanella spp. Gb03 as an algicidal bacterium, isolated from the culture of Dinoflagellate Gambierdiscus belizeanus.

Science.gov (United States)

Bloh, Anmar Hameed; Usup, Gires; Ahmad, Asmat

2016-02-01

Bacteria associated with harmful algal blooms can play a crucial role in regulating algal blooms in the environment. This study aimed at isolating and identifying algicidal bacteria in Dinoflagellate culture and to determine the optimum growth requirement of the algicidal bacteria, Loktanella sp. Gb-03. The Dinoflagellate culture used in this study was supplied by Professor Gires Usup's Laboratory, School of Environmental and Natural Resources Sciences, Faculty of Science and Technology, University Kebangsaan Malaysia, Malaysia. The culture was used for the isolation of Loktanella sp., using biochemical tests, API 20 ONE kits. The fatty acid content of the isolates and the algicidal activity were further evaluated, and the phenotype was determined through the phylogenetic tree. Gram-negative, non-motile, non-spore-forming, short rod-shaped, aerobic bacteria (Gb01, Gb02, Gb03, Gb04, Gb05, and Gb06) were isolated from the Dinoflagellate culture. The colonies were pink in color, convex with a smooth surface and entire edge. The optimum growth temperature for the Loktanella sp. Gb03 isolate was determined to be 30°C, in 1% of NaCl and pH7. Phylogenetic analysis based on 16S rRNA gene sequences showed that the bacterium belonged to the genus Loktanella of the class Alphaproteobacteria and formed a tight cluster with the type strain of Loktanella pyoseonensis (97.0% sequence similarity). On the basis of phenotypic, phylogenetic data and genetic distinctiveness, strain Gb-03, were placed in the genus Loktanella as the type strain of species. Moreover, it has algicidal activity against seven toxic Dinoflagellate. The algicidal property of the isolated Loktanella is vital, especially where biological control is needed to mitigate algal bloom or targeted Dinoflagellates.

Internal tides and deep diel fades in acoustic intensity.

Science.gov (United States)

White, Andrew W; Henyey, Frank S; Andrew, Rex K; Mercer, James A; Worcester, Peter F; Dzieciuch, Matthew A; Colosi, John A

2016-11-01

A mechanism is presented by which the observed acoustic intensity is made to vary due to changes in the acoustic path that are caused by internal-tide vertical fluid displacements. The position in range and depth of large-scale caustic structure is determined by the background sound-speed profile. Internal tides cause a deformation of the background profile, changing the positions of the caustic structures-which can introduce intensity changes at a distant receiver. Gradual fades in the acoustic intensity occurring over timescales similar to those of the tides were measured during a low-frequency (284-Hz) acoustic scattering experiment in the Philippine Sea in 2009 [White et al., J. Acoust. Soc. Am. 134(4), 3347-3358 (2013)]. Parabolic equation and Hamiltonian ray-tracing calculations of acoustic propagation through a plane-wave internal tide environmental model employing sound-speed profiles taken during the experiment indicate that internal tides could cause significant gradual changes in the received intensity. Furthermore, the calculations demonstrate how large-scale perturbations to the index of refraction can result in variation in the received intensity.

Annual Variation and Global Structures of The DE3 Tide

International Nuclear Information System (INIS)

Ze-Yu, Chen; Da-Ren, Lu

2008-01-01

The SABER/TIMED temperatures taken in 2002–2006 are used to delineate the tidal signals in the middle and upper atmosphere. Then the Hough mode decomposition is applied with the DE3 tide, and the overall features of the seasonal variations and the complete global structures of the tide are observed. Investigation results show that the tide is most prominent at 110 km with the maximal amplitude of > 9K, and exhibits significant seasonal variation with its maximum amplitude always occurring in July every year. Results from the Hough mode decomposition reveal that the tide is composed primarily of two leading propagating Hough modes, i.e., the (−3,3) and the (−3,4) modes, thus is equatorially trapped. Estimation of the mean amplitude of the Hough modes show that the (−3,3) mode and (−3,4) mode exhibit maxima at 110km and 90 km, respectively. The (−3,3) mode plays a predominant role in shaping the global latitude-height structure of the tide, e.g., the vertical scale of > 50km at the equator, and the annual course. Significant influence of the (−3,4) mode is found below 90km, where the tide exhibits anti-symmetric structure about the equator; meanwhile the tide at northern tropical latitudes exhibits smaller vertical wavelength of about 30 km. (geophysics, astronomy, and astrophysics)

The synthesis of mycosporine-like amino acids (MAAs) by cultured, symbiotic dinoflagellates.

Science.gov (United States)

T Banaszak1 A; LaJeunesse; Trench

2000-06-28

We tested the hypothesis that there is a relation between phylotypes (phylogenetic types, as determined by restriction fragment length polymorphism (RFLP) and partial sequence analysis of the small subunit ribosomal RNA gene (SSUrDNA)) and the synthesis of mycosporine-like amino acids (MAAs) by symbiotic dinoflagellates under the influence of ultraviolet radiation (UV-B/A) and photosynthetically active radiation (PAR). We exposed 27 isolates of symbiotic dinoflagellates simultaneously to UV-B/A and PAR, and subsequently determined the MAAs present in cell extracts and in the media. The algae used included 24 isolates of Symbiodinium spp. originating from jellyfishes, sea anemones, zoanthids, scleractinians, octocorals, and bivalves, and three others in the genera Gymnodinium, Gloeodinium and Amphidinium from a jellyfish, an hydrocoral and a flatworm, respectively. In this study, all of the phylotype A Symbiodinium spp. synthesized up to three identified MAAs. None of the 11 cultured phylotypes B and C Symbiodinium spp. synthesized MAAs. The three non-Symbiodinium symbionts also synthesized up to three MAAs. The results support a conclusion that phylotype A Symbiodinium spp. have a high predilection for the synthesis of MAAs, while phylotypes B and C do not. Synthesis of MAAs by symbiotic dinoflagellates in culture does not appear to relate directly to depths or to the UV exposure regimes from which the consortia were collected.

Aquifer response to earth tides

International Nuclear Information System (INIS)

Kanehiro, B.Y.; Narasimhan, T.N.

1981-01-01

The relation presented in the first part of this paper are applicable to packed-off wells and other situations where appreciable flow to the well does not exist. Comparisons of aquifer properties determined from the response to earth tides and from the more standard pumping tests for the two California fields are reasonably good. The case of an open well makes the problem more complicated, since there may be an appreciable amount of flow to the well. This flow to the well is seen as either a phase lag or as a difference in the ratio of the well signal to the tide for the semidiurnal and diurnal components of the tide. The latter is probably the better and more accurate indicator of flow to the well. Analyses of such situations, however, become involved and are probably best done as case-by-case studies. The numerical solutions show that treating the inverse problem through numerical modeling is at least feasible for any individual situation. It may be possible to simplify the inverse problem through the generation of type curves, but general type curves that are applicable to diverse situations are not likely to be practical. 7 figures

Construction of Green Tide Monitoring System and Research on its Key Techniques

Science.gov (United States)

Xing, B.; Li, J.; Zhu, H.; Wei, P.; Zhao, Y.

2018-04-01

As a kind of marine natural disaster, Green Tide has been appearing every year along the Qingdao Coast, bringing great loss to this region, since the large-scale bloom in 2008. Therefore, it is of great value to obtain the real time dynamic information about green tide distribution. In this study, methods of optical remote sensing and microwave remote sensing are employed in Green Tide Monitoring Research. A specific remote sensing data processing flow and a green tide information extraction algorithm are designed, according to the optical and microwave data of different characteristics. In the aspect of green tide spatial distribution information extraction, an automatic extraction algorithm of green tide distribution boundaries is designed based on the principle of mathematical morphology dilation/erosion. And key issues in information extraction, including the division of green tide regions, the obtaining of basic distributions, the limitation of distribution boundary, and the elimination of islands, have been solved. The automatic generation of green tide distribution boundaries from the results of remote sensing information extraction is realized. Finally, a green tide monitoring system is built based on IDL/GIS secondary development in the integrated environment of RS and GIS, achieving the integration of RS monitoring and information extraction.

Effects of the toxic dinoflagellate, Gymnodinium catenatum on hydrolytic and antioxidant enzymes, in tissues of the giant lions-paw scallop Nodipecten subnodosus.

Science.gov (United States)

Estrada, Norma; de Jesús Romero, Maria; Campa-Córdova, Angel; Luna, Antonio; Ascencio, Felipe

2007-11-01

This study documents effects of the toxic dinoflagellate Gymnodinium catenatum, a producer of paralytic shellfish poison, on juvenile farmed (5.9+/-0.39 cm) giant lions-paw scallop Nodipecten subnodosus. Scallops were fed bloom concentrations of toxic dinoflagellate G. catenatum for 7 h. The effect of the toxic dinoflagellate in different tissues was determined by analysis of antioxidant enzymes (catalase, superoxide dismutase, gluthathione peroxidase), thiobarbituric acid reactive substances (lipid peroxidation), and hydrolytic enzymes (proteases, glycosidases, phosphatases, lipases, and esterases). Histopathological photos record the effects of the toxic dinoflagellate in various tissues. The results show that juvenile lions-paw scallops produce pseudo-feces, partially close their shell, increase melanization, and aggregate hemocytes. Several enzymes were affected and could serve as biological markers. In general, the adductor muscle was not affected. In the digestive gland, some enzymes could be the result of defensive and digestive processes. Gills and mantle tissue were markedly affected because these sites respond first to toxic dinoflagellates, leading to the idea that proteolytic cascades could be involved.

Survey on germination and species composition of dinoflagellates from ballast tanks and recent sediments in ports on the South Coast of Finland, North-Eastern Baltic Sea

Energy Technology Data Exchange (ETDEWEB)

Pertola, Sari [Finnish Institute of Marine Research, Department of Biological Research, P.O. Box 2, FI-00561 Helsinki (Finland)]. E-mail sari.pertola@fimr.fi; Faust, Maria A. [Department of Botany, US National Herbarium, Smithsonian Institution, 4210 Silver Hill Road, Suitland, Maryland 20746 (United States); Kuosa, Harri [Tvaerminne Zoological Station, University of Helsinki, FI-10900 Hanko (Finland)

2006-08-15

Cyst beds in ships and ports in Finland have previously been unstudied. Therefore, sediments from ships' ballast water tanks and four Finnish ports were sampled for dinoflagellate cysts and other phytoplankton. Untreated sediments were incubated at 10 {sup o}C and 20 {sup o}C in the local 6 psu salinity for 1, 4 and 7 days, and vegetative cells were examined with light and scanning electron microscope. Sediments were inhabited by various dinoflagellates, diatoms, chlorophytes, cyanophytes and small flagellates. Germinated dinoflagellates were found in 90% of ballast tanks and in all ports. Gymnodiniales spp. and Heterocapsa rotundata formed a major proportion of the proliferating dinoflagellate cells. One species, Peridinium quinquecorne, not previously reported from the Baltic Sea, was identified with SEM. The study emphasises that ships are potential transport vehicles for dinoflagellate cysts even in the low salinity Finnish waters, and small-sized dinoflagellates should be focused upon in ballast water studies.

Spatial distribution of symbiont-bearing dinoflagellates in the Indian Ocean in relation to oceanographic regimes

DEFF Research Database (Denmark)

Tarangkoon, Woraporn; Hansen, Gert; Hansen, Per Juel

2010-01-01

, and the highest species diversity and cell concentrations were found at temperatures around 20 to 30°C. The symbiont-bearing dinoflagellates were always associated with water masses with low nutrient (N-limited) and chl a concentrations. Special attention was given to the ectosymbiont-bearing dinoflagellates....... Under light microscopy, some of the food vacuoles of Ornithocercus spp. resembled ectosymbionts in size, shape and colour. Transmission electron microscopy of O. magnificus and O. quadratus revealed the presence of a peduncle and many rhabdosomes; both may serve in prey capture. Also, numerous food...

Accuracy Assessment of Global Barotropic Ocean Tide Models

Science.gov (United States)

2014-08-07

Altimetry, Venice . Cartwright, D. E. (1999), Tides: A Scientific History , Cambridge Univ. Press, New York. Cartwright, D. E., and R. D. Ray (1990), Oceanic...E. Harrison, and D. Stammer, p. 4, ESA Publication WPP-306, Venice , Italy. Book, J. W., H. Perkins, and M. Wimbush (2009), North Adriatic tides

Mapping ocean tides with satellites - A computer simulation

Science.gov (United States)

Won, I. J.; Kuo, J. T.; Jachens, R. C.

1978-01-01

As a preliminary study for the future worldwide direct mapping of the open ocean tide with satellites equipped with precision altimeters we conducted a simulated study using sets of artificially generated altimeter data constructed from a realistic geoid and four pairs of major tides in the northeastern Pacific Ocean. Recovery of the original geoid and eight tidal maps is accomplished by a space-time, least squares harmonic analysis scheme. The resultant maps appear fairly satisfactory even when random noises up to + or - 100 cm are added to the altimeter data of sufficient space-time density. The method also produces a refined geoid which is rigorously corrected for the dynamic tides.

Novel insight into the role of heterotrophic dinoflagellates in the fate of crude oil in the sea

DEFF Research Database (Denmark)

Almeda, Rodrigo; Connelly, Tara L.; Buskey, Edward J.

2014-01-01

Although planktonic protozoans are likely to interact with dispersed crude oil after a spill, protozoan-mediated processes affecting crude oil pollution in the sea are still not well known. Here, we present the first evidence of ingestion and defecation of physically or chemically dispersed crude...... to 0.37 mu g-oil mg-C-dino (-1) d(-1), which could represent similar to 17% to 100% of dispersed oil in surface waters when heterotrophic dinoflagellates are abundant or bloom. Egestion of faecal pellets containing crude oil by heterotrophic dinoflagellates could contribute to the sinking and flux...... of toxic petroleum hydrocarbons in coastal waters. Our study indicates that crude oil ingestion by heterotrophic dinoflagellates is a noteworthy route by which petroleum enters marine food webs and a previously overlooked biological process influencing the fate of crude oil in the sea after spills....

Bioluminescence and the Actin Cytoskeleton in the Dinoflagellate Pyrocystis fusiformis: An Examination of Organelle Transport and Mechanotransduction

OpenAIRE

McDougall, Carrie A.

2002-01-01

Bioluminescence (BL), light produced by organisms, is a diverse and widespread marine phenomenon. yet little studied by researchers. Major contributors to sea surface BL displays are dinoflagellates, which produce rapid BL flashes upon fluid motion; mechanical stimulation triggers a 200-ms flash within 20 ms, representing one of the most rapid sensor-effector transduction systems described. In some dinoflagellate species the sensor-effector link is not constant throughout a 24-hour period. Me...

Ship traffic and the introduction of diatoms and dinoflagellates via ballast water in the port of Annaba, Algeria

Science.gov (United States)

Cheniti, Radhia; Rochon, André; Frihi, Hocine

2018-03-01

We present here the first study on the role of ship traffic in the introduction of potentially harmful and/or non-indigenous species in the port of Annaba (Algeria). A total of 25 ships of two different types (general cargo and bulk carriers) were sampled and separated into two categories: oceanic and Mediterranean ships. We estimated propagule pressure of high-risk coastal phytoplankton delivered in ballast water to the port of Annaba. We identified 40 diatom and 38 dinoflagellate taxa, among which, 11 harmful/toxic taxa: Pseudo-nitzschia spp., Alexandrium tamarense, Alexandrium sp., Dinophysis acuminata, Dinophysis rotundata, Dinophysis sp., Gonyaulax spinifera, Gymnodinium catenatum, Lingulodinium polyedrum, Protoceratium reticulatum and cyst of Alexandrium sp. In addition, 8 taxa (5 diatoms, 1 dinoflagellate and 2 dinoflagellate cysts) never observed in the Annaba region were considered as potentially non-indigenous: Actinoptychus splendens, Coscinodiscus asteromphalus, Coscinodiscus lineatus, Odentella granulata, Thalassiosira cf. decipiens, Prorocentrum scutellum, cyst of Polykrikos kofoidii and Islandinium minutum. Several factors were examined, including ship routes, ballast water age and the volume of ballast water discharged. Our analyses revealed that diatom and dinoflagellate abundances decreased with ballast water age, possibly as a result of mortality of species due to voyage length and lack of light in ballast tanks. Estimates of actual propagule pressure, diatoms and dinoflagellates abundances varied from 1 to 4 × 108 cells/ship. The results of this study could serve as the baseline for the development and implementation of monitoring and ballast water management programs in ports of Algeria.

Never Riding the Tide

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 13; Issue 10. Never Riding the Tide - Seymour Benzer–The Founder of Neurogenetics. K VijayRaghavan Veronica Rodrigues. General Article Volume 13 Issue 10 October 2008 pp 909-915 ...

Influence of tides on the gravitational field of Jupiter

International Nuclear Information System (INIS)

Gavrilov, S.V.; Zharkov, V.N.; Leont'ev, V.V.

1975-01-01

The influence of tides on the gravitational field of giant planets is considered quantitatively. The ''gravitational noise'' due to tides can affect the determination of J 8 and J 10 for Jupiter. Tidal sounding of the giant planets is suggested. (author)

Ocean Tide Influences on the Antarctic and Greenland Ice Sheets

Science.gov (United States)

Padman, Laurie; Siegfried, Matthew R.; Fricker, Helen A.

2018-03-01

Ocean tides are the main source of high-frequency variability in the vertical and horizontal motion of ice sheets near their marine margins. Floating ice shelves, which occupy about three quarters of the perimeter of Antarctica and the termini of four outlet glaciers in northern Greenland, rise and fall in synchrony with the ocean tide. Lateral motion of floating and grounded portions of ice sheets near their marine margins can also include a tidal component. These tide-induced signals provide insight into the processes by which the oceans can affect ice sheet mass balance and dynamics. In this review, we summarize in situ and satellite-based measurements of the tidal response of ice shelves and grounded ice, and spatial variability of ocean tide heights and currents around the ice sheets. We review sensitivity of tide heights and currents as ocean geometry responds to variations in sea level, ice shelf thickness, and ice sheet mass and extent. We then describe coupled ice-ocean models and analytical glacier models that quantify the effect of ocean tides on lower-frequency ice sheet mass loss and motion. We suggest new observations and model developments to improve the representation of tides in coupled models that are used to predict future ice sheet mass loss and the associated contribution to sea level change. The most critical need is for new data to improve maps of bathymetry, ice shelf draft, spatial variability of the drag coefficient at the ice-ocean interface, and higher-resolution models with improved representation of tidal energy sinks.

Description of Tyrannodinium gen. nov., a freshwater dinoflagellate closely related to the marine Pfiesteria-like species

DEFF Research Database (Denmark)

Calado, Antonio J.; Craveiro, Sandra; Daugbjerg, Niels

2009-01-01

On the basis of morphological (light and electron microscopy) as well molecular data, we show that the widely distributed freshwater dinoflagellate presently known as Peridiniopsis berolinensis is a member of the family Pfiesteriaceae, an otherwise marine and estuarine family of dinoflagellates. ...

Tides in three enclosed basins: the Baltic, Black and Caspian seas

Directory of Open Access Journals (Sweden)

Igor P Medvedev

2016-04-01

Full Text Available Tides are the main type of sea level variability in the world ocean. However, oceanic tides penetrate weakly, or do not penetrate at all, into enclosed basins such as the Baltic, Black and Caspian seas. Consequently, only directly forced tides are formed in these basins. Long observation time series (up to 123 years in the Baltic Sea and 38 years in the Black and Caspian seas at numerous stations were used to precisely estimate tidal constituents. High-resolution spectra revealed fine structure of discrete peaks at tidal frequencies. The diurnal radiational constituent S1 (1 cpd, apparently associated with breeze winds, was found to play an important role in general tidal dynamics in these seas. Harmonic analysis of tides for individual yearly series with consecutive vector averaging over the entire observational period was applied to estimate mean amplitudes and phases of tidal constituents. Our findings indicate that the formation and predominance of diurnal or semidiurnal tides in these seas appears to depend on the frequency-selective properties of the basins. Thus, in the Baltic Sea with fundamental modal period of about 27 h, diurnal tides dominate in the major eastern gulfs. In the Black Sea resonant amplification of semidiurnal tides is observed in the northwestern part. The predominance of semidiurnal tides in the Caspian Sea has also probably a resonant nature. Maximum tidal heights estimated for a 100-year period are 23 cm in the Baltic Sea, 18 cm in the Black Sea and 21 cm in the southern Caspian Sea.

Estimating absolute sea level variations by combining GNSS and Tide gauge data

Digital Repository Service at National Institute of Oceanography (India)

Bos, M.S.; Fernandes, R.M.S; Vethamony, P.; Mehra, P.

Indian tide gauges can be used to estimate sea level rise. To separate relative sea level rise from vertical land motion at the tide gauges, various GNSS stations have been installed in the last years at, or nearby, tide gauges. Using the PSMSL...

Earth tide effects on kinematic/static GPS positioning in Denmark and Greenland

DEFF Research Database (Denmark)

Xu, G.C.; Knudsen, Per

2000-01-01

A detailed Study of the Earth tide effects on the GPS kinematic/static positioning is presented in this paper by using theoretical Earth tide computation and practical GPS data processing. Tidal effects could reach up to 30 cm in Denmark and Greenland depending on the measuring time...... and the position of reference station. With a baseline less than 80 km, the difference of the Earth tide effects could reach more than 5 mm. So, in precise applications of GPS positioning, the Earth tide effect has to be taken into account even for a relative small local GPS network. Several examples are given...... for demonstrating that the Earth tide effects can be viewed by GPS surveying. They are given through static GPS data static processing, static GPS data kinematic processing, and airborne kinematic GPS data processing. In these cases, the Earth tide effects can be subtracted from the GPS results. The determination...

The self-consistent dynamic pole tide in global oceans

Science.gov (United States)

Dickman, S. R.

1985-01-01

The dynamic pole tide is characterized in a self-consistent manner by means of introducing a single nondifferential matrix equation compatible with the Liouville equation, modelling the ocean as global and of uniform depth. The deviations of the theory from the realistic ocean, associated with the nonglobality of the latter, are also given consideration, with an inference that in realistic oceans long-period modes of resonances would be increasingly likely to exist. The analysis of the nature of the pole tide and its effects on the Chandler wobble indicate that departures of the pole tide from the equilibrium may indeed be minimal.

Seasonal variation of semidiurnal internal tides in the East/Japan Sea

Science.gov (United States)

Jeon, Chanhyung; Park, Jae-Hun; Varlamov, Sergey M.; Yoon, Jong-Hwan; Kim, Young Ho; Seo, Seongbong; Park, Young-Gyu; Min, Hong Sik; Lee, Jae Hak; Kim, Cheol-Ho

2014-05-01

The seasonal variation of semidiurnal internal tides in the East/Japan Sea was investigated using 25 month long output from a real-time ocean forecasting system. The z coordinate eddy-resolving high-resolution numerical model, called the RIAM ocean model, incorporates data assimilation that nudges temperature and salinity fields together with volume transport through the Korea Strait to produce realistic oceanic currents and stratification. In addition to atmospheric forcing, it includes tidal forcing of 16 major components along open boundaries. The model generates energetic semidiurnal internal tides around the northern entrance of the Korea Strait. Energy conversion from barotropic to baroclinic (internal) tides varies seasonally with maxima in September (ranging 0.48-0.52 GW) and minima in March (ranging 0.11-0.16 GW). This seasonal variation is induced by the seasonality in stratification near the southwestern East/Japan Sea. The propagation distance of the internal tides is associated with generation intensity and wavelength. From late summer to early winter, the semidiurnal internal tides travel relatively far from the generation region due to stratification changes; its energy dissipates less as a result of longer wavelengths. Our results suggest that spatiotemporal variation of internal-tide-induced mixing due to the seasonality in the generation, propagation, and dissipation of internal tides should be considered for a more realistic simulation of water masses and circulation in models of the East/Japan Sea.

Fight and flight in dinoflagellates?

DEFF Research Database (Denmark)

Selander, Erik; Fagerberg, Tony; Wohlrab, Sylke

2012-01-01

We monitored the kinetics of grazer-induced responses in the marine dinoflagellate Alexandrium tamarense. Chemical cues from each of three calanoid copepods (Calanus sp., Centropages typicus, and Acartia tonsa) induced increased toxicity and suppressed chain formation in A. tamarense. Both chemical...... and morphological responses augmented over 3 d. Toxicity subsequently averaged 299% higher than controls, and average biovolume 24% lower than controls because of suppression of chain formation in grazed treatments. Grazer-induced toxicity returned to control levels after approximately 11 d, equivalent to five cell...... that the inducing cue(s) attenuate rapidly in seawater, which allows A. tamarense to adjust resource allocation to grazer-induced responses to follow fluctuations in grazer density. Grazer-induced responses, however, develop too slowly to be accounted for in short-term grazing experiments with laboratory cultures...

INVESTIGATION THE BEHAVIOR OF MODIS OCEAN COLOR PRODUCTS UNDER THE 2008 RED TIDE IN THE EASTERN PERSIAN GULF

Directory of Open Access Journals (Sweden)

M. Ghanea

2015-12-01

Full Text Available Biophysical properties of water undergo serious variations under red tide (RT outbreak. During RT conditions, algal blooms spread out in the estuarine, marine and fresh waters due to different triggering factors such as nutrient loading, marine currents, and monsoonal winds. The Persian Gulf (PG was a talent region subjected to different RTs in recent decade. A massive RT started from the Strait of Hormuz in October 2008 and extended towards the northern parts of the PG covering more than 1200 km of coastlines. The bloom of microorganism C. Polykrikoides was the main specie that generated large fish mortalities, and hampered marine industries, and water desalination appliances. Ocean color satellite data have many advantages to monitor and alarm RT occurrences, such as wide and continuous extent, short time of imagery, high accessibility, and appropriate estimation of ocean color parameters. Since 1999, MODerate Resolution Imaging Spectroradiometer (MODIS satellite sensor has estimated satellite derived chlorophyll-a (Chl-a, normalized fluorescence line height (nFLH, and diffuse attenuation coefficient at 490nm (kd490. It provides a capability to study the behavior of these parameters during RT and normal conditions. This study monitors variations in satellite derived Chl-a, nFLH, and kd490 under both RT and normal conditions of the PG between 2002 and 2008. Up to now, daily and monthly variations in these products were no synchronously investigated under RT conditions in the PG. In doing so, the MODIS L1B products were provided from NASA data archive. They were corrected for Rayleigh scattering and gaseous absorption, and atmospheric interference in turbid coastal waters, and then converted to level 2 data. In addition, Enhanced Red Green Blue (ERGB image was used to illustrate better water variations. ERGB image was built with three normalized leaving water radiance between 443 to 560nm. All the above data processes were applied by SeaDAS 7

The Use of Stimulable Bioluminescence from Marine Dinoflagellates as a Means of Detecting Toxicity in the Marine Environment

Science.gov (United States)

1993-04-01

FROM MARINE PR: ME65 DINOFLAGELLATES AS A MEANS OF DETECTING TOXICITY IN THE PE: 060372N MARINE ENVIRONMENT WU: DN288604 6ý AUTHOR(S) Accesion For I...measure the acute and sublethal effects of heavy metals ( tributyltin , copper, and zinc) and storm drain effluent on the light output from marine...Grovhoug 3 THE USE OF STIM1ULABLE BIOLUMINESCENCE FROM MARINE DINOFLAGELLATES AS A MEANS OF DETECTING TOXICITY IN THE MARINE ENVIRONMENT. REFERENCE

Role of TRP Channels in Dinoflagellate Mechanotransduction.

Science.gov (United States)

Lindström, J B; Pierce, N T; Latz, M I

2017-10-01

Transient receptor potential (TRP) ion channels are common components of mechanosensing pathways, mainly described in mammals and other multicellular organisms. To gain insight into the evolutionary origins of eukaryotic mechanosensory proteins, we investigated the involvement of TRP channels in mechanosensing in a unicellular eukaryotic protist, the dinoflagellate Lingulodinium polyedra. BLASTP analysis of the protein sequences predicted from the L. polyedra transcriptome revealed six sequences with high similarity to human TRPM2, TRPM8, TRPML2, TRPP1, and TRPP2; and characteristic TRP domains were identified in all sequences. In a phylogenetic tree including all mammalian TRP subfamilies and TRP channel sequences from unicellular and multicellular organisms, the L. polyedra sequences grouped with the TRPM, TPPML, and TRPP clades. In pharmacological experiments, we used the intrinsic bioluminescence of L. polyedra as a reporter of mechanoresponsivity. Capsaicin and RN1734, agonists of mammalian TRPV, and arachidonic acid, an agonist of mammalian TRPV, TRPA, TRPM, and Drosophila TRP, all stimulated bioluminescence in L. polyedra. Mechanical stimulation of bioluminescence, but not capsaicin-stimulated bioluminescence, was inhibited by gadolinium (Gd 3+ ), a general inhibitor of mechanosensitive ion channels, and the phospholipase C (PLC) inhibitor U73122. These pharmacological results are consistent with the involvement of TRP-like channels in mechanosensing by L. polyedra. The TRP channels do not appear to be mechanoreceptors but rather are components of the mechanotransduction signaling pathway and may be activated via a PLC-dependent mechanism. The presence and function of TRP channels in a dinoflagellate emphasize the evolutionary conservation of both the channel structures and their functions.

Tidal asymmetry in a funnel-shaped estuary with mixed semidiurnal tides

Science.gov (United States)

Gong, Wenping; Schuttelaars, Henk; Zhang, Heng

2016-05-01

Different types of tidal asymmetry (see review of de Swart and Zimmerman Annu Rev Fluid Mech 41: 203-229, 2009) are examined in this study. We distinguish three types of tidal asymmetry: duration and magnitude differences between flood and ebb tidal flow, duration difference between the rising and falling tides. For waterborne substance transport, the first two asymmetries are important while the last one is not. In this study, we take the Huangmaohai Estuary (HE), Pearl River Delta, China as an example to examine the spatio-temporal variations of the tidal asymmetry in a mixed semidiurnal tidal regime and to explain them by investigating the associated mechanisms. The methodology defining the tidal duration asymmetry and velocity skewness, proposed by Nidzieko (J Geophys Res 115: C08006. doi: 10.1029/2009JC005864 , 2010) and synthesized by Song et al. (J Geophys Res 116: C12007. doi: 10.1029/2011JC007270 , 2011), is utilized here and referred to as tidal duration asymmetry (TDA) and flow velocity asymmetry (FVA), respectively. The methodology is further used to quantify the flow duration asymmetry (FDA). A positive asymmetry means a shorter duration of low water slack for FDA, a shorter duration of the rising tide for TDA, and a flood dominance for FVA and vice versa. The Regional Ocean Modeling System (ROMS) model is used to provide relatively long-term water elevation and velocity data and to conduct diagnostic experiments. In the HE, the main tidal constituents are diurnal tides K 1, O 1 and semidiurnal tides M 2 and S 2. The interaction among the diurnal and semidiurnal tides generates a negative tidal asymmetry, while the interactions among semidiurnal tides and their overtides or compound tides result in a positive tidal asymmetry. The competition among the above interactions determines the FDA and TDA, whereas for the FVA, aside from the interaction among different tidal constituents, an extra component, the residual flow, plays an important role. The

The Effect of Warming Oceans at a Tide Gauge Station

OpenAIRE

Bâki Iz H.

2016-01-01

This study proposes a new paradigm for assessing thermosteric effects of warming oceans at a tide gauge station. For demonstration, the trend due to the global thermosteric sea level at the Key West, FL tide gauge station was estimated using the tide gauge measurements and the global sea surface temperature anomalies that were represented by yearly distributed lags. A comparison of the estimate with the trend estimate from a descriptive model revealed that 0.7±0.1 mm/y...

NOS CO-OPS Water Level Data, High Low Tide Prediction

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has High Low Tide Predictions from NOAA NOS Center for Operational Oceanographic Products and Services (CO-OPS). The official Tide and Tidal Current...

NOS CO-OPS Water Level Data, Tide Prediction, 60-Minute

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has High Low Tide Predictions from NOAA NOS Center for Operational Oceanographic Products and Services (CO-OPS). The official Tide and Tidal Current...

NOS CO-OPS Water Level Data, Tide Prediction, 6-Minute

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has High Low Tide Predictions from NOAA NOS Center for Operational Oceanographic Products and Services (CO-OPS). The official Tide and Tidal Current...

Inhibitory effects of copper on marine dinoflagellates

Energy Technology Data Exchange (ETDEWEB)

Saifullah, S.M.

1978-01-01

The effect of copper on three species of marine dinoflagellates (Scrippsiella faeroense (Paulsen) Balech et Soares, Prorocentrum micans Ehrenberg, Gymnodinium splendens Lebour) was studied. It inhibited the growth of all species and was lethal to one species in batch cultures. The effect was more pronounced in semicontinuous culture than in batch cultures. Chlorophyll concentrations and rate of uptake of radioactive carbon by cells of S. faeroense were affected in a manner similar to cell numbers. Copper inhibited growth of cells, most probably either by arresting cell division or by penetrating inside the cell and affecting metabolism.

Weight, gravitation, inertia, and tides

Science.gov (United States)

Pujol, Olivier; Lagoute, Christophe; Pérez, José-Philippe

2015-11-01

This paper deals with the factors that influence the weight of an object near the Earth's surface. They are: (1) the Earth's gravitational force, (2) the centrifugal force due to the Earth's diurnal rotation, and (3) tidal forces due to the gravitational field of the Moon and Sun, and other solar system bodies to a lesser extent. Each of these three contributions is discussed and expressions are derived. The relationship between weight and gravitation is thus established in a direct and pedagogical manner readily understandable by undergraduate students. The analysis applies to the Newtonian limit of gravitation. The derivation is based on an experimental (or operational) definition of weight, and it is shown that it coincides with the Earth’s gravitational force modified by diurnal rotation around a polar axis and non-uniformity of external gravitational bodies (tidal term). Two examples illustrate and quantify these modifications, respectively the Eötvös effect and the oceanic tides; tidal forces due to differential gravitation on a spacecraft and an asteroid are also proposed as examples. Considerations about inertia are also given and some comments are made about a widespread, yet confusing, explanation of tides based on a centrifugal force. Finally, the expression of the potential energy of the tide-generating force is established rigorously in the appendix.

Weight, gravitation, inertia, and tides

International Nuclear Information System (INIS)

Pujol, Olivier; Lagoute, Christophe; Pérez, José-Philippe

2015-01-01

This paper deals with the factors that influence the weight of an object near the Earth's surface. They are: (1) the Earth's gravitational force, (2) the centrifugal force due to the Earth's diurnal rotation, and (3) tidal forces due to the gravitational field of the Moon and Sun, and other solar system bodies to a lesser extent. Each of these three contributions is discussed and expressions are derived. The relationship between weight and gravitation is thus established in a direct and pedagogical manner readily understandable by undergraduate students. The analysis applies to the Newtonian limit of gravitation. The derivation is based on an experimental (or operational) definition of weight, and it is shown that it coincides with the Earth’s gravitational force modified by diurnal rotation around a polar axis and non-uniformity of external gravitational bodies (tidal term). Two examples illustrate and quantify these modifications, respectively the Eötvös effect and the oceanic tides; tidal forces due to differential gravitation on a spacecraft and an asteroid are also proposed as examples. Considerations about inertia are also given and some comments are made about a widespread, yet confusing, explanation of tides based on a centrifugal force. Finally, the expression of the potential energy of the tide-generating force is established rigorously in the appendix. (paper)

The dinoflagellates Durinskia baltica and Kryptoperidinium foliaceum retain functionally overlapping mitochondria from two evolutionarily distinct lineages

Directory of Open Access Journals (Sweden)

Keeling Patrick J

2007-09-01

Full Text Available Abtract Background The dinoflagellates Durinskia baltica and Kryptoperidinium foliaceum are distinguished by the presence of a tertiary plastid derived from a diatom endosymbiont. The diatom is fully integrated with the host cell cycle and is so altered in structure as to be difficult to recognize it as a diatom, and yet it retains a number of features normally lost in tertiary and secondary endosymbionts, most notably mitochondria. The dinoflagellate host is also reported to retain mitochondrion-like structures, making these cells unique in retaining two evolutionarily distinct mitochondria. This redundancy raises the question of whether the organelles share any functions in common or have distributed functions between them. Results We show that both host and endosymbiont mitochondrial genomes encode genes for electron transport proteins. We have characterized cytochrome c oxidase 1 (cox1, cytochrome oxidase 2 (cox2, cytochrome oxidase 3 (cox3, cytochrome b (cob, and large subunit of ribosomal RNA (LSUrRNA of endosymbiont mitochondrial ancestry, and cox1 and cob of host mitochondrial ancestry. We show that all genes are transcribed and that those ascribed to the host mitochondrial genome are extensively edited at the RNA level, as expected for a dinoflagellate mitochondrion-encoded gene. We also found evidence for extensive recombination in the host mitochondrial genes and that recombination products are also transcribed, as expected for a dinoflagellate. Conclusion Durinskia baltica and K. foliaceum retain two mitochondria from evolutionarily distinct lineages, and the functions of these organelles are at least partially overlapping, since both express genes for proteins in electron transport.

Global Earth Response to Loading by Ocean Tide Models

Science.gov (United States)

Estes, R. H.; Strayer, J. M.

1979-01-01

Mathematical and programming techniques to numerically calculate Earth response to global semidiurnal and diurnal ocean tide models were developed. Global vertical crustal deformations were evaluated for M sub 2, S sub 2, N sub 2, K sub 2, K sub 1, O sub 1, and P sub 1 ocean tide loading, while horizontal deformations were evaluated for the M sub 2 tidal load. Tidal gravity calculations were performed for M sub 2 tidal loads, and strain tensor elements were evaluated for M sub 2 loads. The M sub 2 solution used for the ocean tide included the effects of self-gravitation and crustal loading.

Impacts of exotic mangroves and mangrove control on tide pool fish assemblages

Science.gov (United States)

Richard A. MacKenzie; Cailtin L. Kryss

2013-01-01

Fish were sampled from tide pools in Hawaii to determine how exotic mangroves Rhizophora mangle and the use of herbicides to chemically eradicate them are impacting tide pool fish assemblages. Ecological parameters were compared among mangrove-invaded, native vegetated, and non-vegetated tide pools before and after mangroves had been chemically...

The Effect of Barotropic and Baroclinic Tides on Coastal Stratification and Mixing

Science.gov (United States)

Suanda, S. H.; Feddersen, F.; Kumar, N.

2017-12-01

The effects of barotropic and baroclinic tides on subtidal stratification and vertical mixing are examined with high-resolution, three-dimensional numerical simulations of the Central Californian coastal upwelling region. A base simulation with realistic atmospheric and regional-scale boundary forcing but no tides (NT) is compared to two simulations with the addition of predominantly barotropic local tides (LT) and with combined barotropic and remotely generated, baroclinic tides (WT) with ≈ 100 W m-1 onshore baroclinic energy flux. During a 10 day period of coastal upwelling when the domain volume-averaged temperature is similar in all three simulations, LT has little difference in subtidal temperature and stratification compared to NT. In contrast, the addition of remote baroclinic tides (WT) reduces the subtidal continental shelf stratification up to 50% relative to NT. Idealized simulations to isolate barotropic and baroclinic effects demonstrate that within a parameter space of typical U.S. West Coast continental shelf slopes, barotropic tidal currents, incident energy flux, and subtidal stratification, the dissipating baroclinic tide destroys stratification an order of magnitude faster than barotropic tides. In WT, the modeled vertical temperature diffusivity at the top (base) of the bottom (surface) boundary layer is increased up to 20 times relative to NT. Therefore, the width of the inner-shelf (region of surface and bottom boundary layer overlap) is increased approximately 4 times relative to NT. The change in stratification due to dissipating baroclinic tides is comparable to the magnitude of the observed seasonal cycle of stratification.

Satellite remote sensing of harmful algal blooms: A new multi-algorithm method for detecting the Florida Red Tide (Karenia brevis)

Science.gov (United States)

Carvalho, Gustavo A.; Minnett, Peter J.; Fleming, Lora E.; Banzon, Viva F.; Baringer, Warner

2010-01-01

In a continuing effort to develop suitable methods for the surveillance of Harmful Algal Blooms (HABs) of Karenia brevis using satellite radiometers, a new multi-algorithm method was developed to explore whether improvements in the remote sensing detection of the Florida Red Tide was possible. A Hybrid Scheme was introduced that sequentially applies the optimized versions of two pre-existing satellite-based algorithms: an Empirical Approach (using water-leaving radiance as a function of chlorophyll concentration) and a Bio-optical Technique (using particulate backscatter along with chlorophyll concentration). The long-term evaluation of the new multi-algorithm method was performed using a multi-year MODIS dataset (2002 to 2006; during the boreal Summer-Fall periods – July to December) along the Central West Florida Shelf between 25.75°N and 28.25°N. Algorithm validation was done with in situ measurements of the abundances of K. brevis; cell counts ≥1.5×104 cells l−1 defined a detectable HAB. Encouraging statistical results were derived when either or both algorithms correctly flagged known samples. The majority of the valid match-ups were correctly identified (~80% of both HABs and non-blooming conditions) and few false negatives or false positives were produced (~20% of each). Additionally, most of the HAB-positive identifications in the satellite data were indeed HAB samples (positive predictive value: ~70%) and those classified as HAB-negative were almost all non-bloom cases (negative predictive value: ~86%). These results demonstrate an excellent detection capability, on average ~10% more accurate than the individual algorithms used separately. Thus, the new Hybrid Scheme could become a powerful tool for environmental monitoring of K. brevis blooms, with valuable consequences including leading to the more rapid and efficient use of ships to make in situ measurements of HABs. PMID:21037979

Genomics study of the exposure effect of Gymnodinium catenatum, a paralyzing toxin producer, on Crassostrea gigas' defense system and detoxification genes.

Directory of Open Access Journals (Sweden)

Norma García-Lagunas

Full Text Available BACKGROUND: Crassostrea gigas accumulates paralytic shellfish toxins (PST associated with red tide species as Gymnodinium catenatum. Previous studies demonstrated bivalves show variable feeding responses to toxic algae at physiological level; recently, only one study has reported biochemical changes in the transcript level of the genes involved in C. gigas stress response. PRINCIPAL FINDINGS: We found that 24 h feeding on toxic dinoflagellate cells (acute exposure induced a significant decrease in clearance rate and expression level changes of the genes involved in antioxidant defense (copper/zinc superoxide dismutase, Cu/Zn-SOD, cell detoxification (glutathione S-transferase, GST and cytochrome P450, CPY450, intermediate immune response activation (lipopolysaccharide and beta glucan binding protein, LGBP, and stress responses (glutamine synthetase, GS in Pacific oysters compared to the effects with the non-toxic microalga Isochrysis galbana. A sub-chronic exposure feeding on toxic dinoflagellate cells for seven and fourteen days (30×10³ cells mL⁻¹ showed higher gene expression levels. A significant increase was observed in Cu/Zn-SOD, GST, and LGBP at day 7 and a major increase in GS and CPY450 at day 14. We also observed that oysters fed only with G. catenatum (3×10³ cells mL⁻¹ produced a significant increase on the transcription level than in a mixed diet (3×10³ cells mL⁻¹ of G. catenatum+0.75×10⁶ cells mL⁻¹ I. galbana in all the analyzed genes. CONCLUSIONS: Our results provide gene expression data of PST producer dinoflagellate G. catenatum toxic effects on C. gigas, a commercially important bivalve. Over expressed genes indicate the activation of a potent protective mechanism, whose response depends on both cell concentration and exposure time against these toxic microalgae. Given the importance of dinoflagellate blooms in coastal environments, these results provide a more comprehensive overview of how oysters respond to

Genomics study of the exposure effect of Gymnodinium catenatum, a paralyzing toxin producer, on Crassostrea gigas' defense system and detoxification genes.

Science.gov (United States)

García-Lagunas, Norma; Romero-Geraldo, Reyna; Hernández-Saavedra, Norma Y

2013-01-01

Crassostrea gigas accumulates paralytic shellfish toxins (PST) associated with red tide species as Gymnodinium catenatum. Previous studies demonstrated bivalves show variable feeding responses to toxic algae at physiological level; recently, only one study has reported biochemical changes in the transcript level of the genes involved in C. gigas stress response. We found that 24 h feeding on toxic dinoflagellate cells (acute exposure) induced a significant decrease in clearance rate and expression level changes of the genes involved in antioxidant defense (copper/zinc superoxide dismutase, Cu/Zn-SOD), cell detoxification (glutathione S-transferase, GST and cytochrome P450, CPY450), intermediate immune response activation (lipopolysaccharide and beta glucan binding protein, LGBP), and stress responses (glutamine synthetase, GS) in Pacific oysters compared to the effects with the non-toxic microalga Isochrysis galbana. A sub-chronic exposure feeding on toxic dinoflagellate cells for seven and fourteen days (30×10³ cells mL⁻¹) showed higher gene expression levels. A significant increase was observed in Cu/Zn-SOD, GST, and LGBP at day 7 and a major increase in GS and CPY450 at day 14. We also observed that oysters fed only with G. catenatum (3×10³ cells mL⁻¹ produced a significant increase on the transcription level than in a mixed diet (3×10³ cells mL⁻¹ of G. catenatum+0.75×10⁶ cells mL⁻¹ I. galbana) in all the analyzed genes. Our results provide gene expression data of PST producer dinoflagellate G. catenatum toxic effects on C. gigas, a commercially important bivalve. Over expressed genes indicate the activation of a potent protective mechanism, whose response depends on both cell concentration and exposure time against these toxic microalgae. Given the importance of dinoflagellate blooms in coastal environments, these results provide a more comprehensive overview of how oysters respond to stress generated by toxic dinoflagellate exposure.

Effects of in vitro Brevetoxin Exposure on Apoptosis and Cellular Metabolism in a Leukemic T Cell Line (Jurkat

Directory of Open Access Journals (Sweden)

John W. Sleasman

2008-06-01

Full Text Available Harmful algal blooms (HABs of the toxic dinoflagellate, Karenia brevis, produce red tide toxins, or brevetoxins. Significant health effects associated with red tide toxin exposure have been reported in sea life and in humans, with brevetoxins documented within immune cells from many species. The objective of this research was to investigate potential immunotoxic effects of brevetoxins using a leukemic T cell line (Jurkat as an in vitro model system. Viability, cell proliferation, and apoptosis assays were conducted using brevetoxin congeners PbTx-2, PbTx-3, and PbTx-6. The effects of in vitro brevetoxin exposure on cell viability and cellular metabolism or proliferation were determined using trypan blue and MTT (1-(4,5-dimethylthiazol-2-yl-3,5- diphenylformazan, respectively. Using MTT, cellular metabolic activity was decreased in Jurkat cells exposed to 5 - 10 μg/ml PbTx-2 or PbTx-6. After 3 h, no significant effects on cell viability were observed with any toxin congener in concentrations up to 10 μg/ml. Viability decreased dramatically after 24 h in cells treated with PbTx-2 or -6. Apoptosis, as measured by caspase-3 activity, was significantly increased in cells exposed to PbTx-2 or PbTx-6. In summary, brevetoxin congeners varied in effects on Jurkat cells, with PbTx-2 and PbTx-6 eliciting greater cellular effects compared to PbTx-3.

Modelling and parameterizing the influence of tides on ice-shelf melt rates

Science.gov (United States)

Jourdain, N.; Molines, J. M.; Le Sommer, J.; Mathiot, P.; de Lavergne, C.; Gurvan, M.; Durand, G.

2017-12-01

Significant Antarctic ice sheet thinning is observed in several sectors of Antarctica, in particular in the Amundsen Sea sector, where warm circumpolar deep waters affect basal melting. The later has the potential to trigger marine ice sheet instabilities, with an associated potential for rapid sea level rise. It is therefore crucial to simulate and understand the processes associated with ice-shelf melt rates. In particular, the absence of tides representation in ocean models remains a caveat of numerous ocean hindcasts and climate projections. In the Amundsen Sea, tides are relatively weak and the melt-induced circulation is stronger than the tidal circulation. Using a regional 1/12° ocean model of the Amundsen Sea, we nonetheless find that tides can increase melt rates by up to 36% in some ice-shelf cavities. Among the processes that can possibly affect melt rates, the most important is an increased exchange at the ice/ocean interface resulting from the presence of strong tidal currents along the ice drafts. Approximately a third of this effect is compensated by a decrease in thermal forcing along the ice draft, which is related to an enhanced vertical mixing in the ocean interior in presence of tides. Parameterizing the effect of tides is an alternative to the representation of explicit tides in an ocean model, and has the advantage not to require any filtering of ocean model outputs. We therefore explore different ways to parameterize the effects of tides on ice shelf melt. First, we compare several methods to impose tidal velocities along the ice draft. We show that getting a realistic spatial distribution of tidal velocities in important, and can be deduced from the barotropic velocities of a tide model. Then, we explore several aspects of parameterized tidal mixing to reproduce the tide-induced decrease in thermal forcing along the ice drafts.

Accumulation, Biotransformation, Histopathology and Paralysis in the Pacific Calico Scallop Argopecten ventricosus by the Paralyzing Toxins of the Dinoflagellate Gymnodinium catenatum

OpenAIRE

Escobedo-Lozano, Amada Y.; Estrada, Norma; Ascencio, Felipe; Contreras, Gerardo; Alonso-Rodriguez, Rosalba

2012-01-01

The dinoflagellate Gymnodinium catenatum produces paralyzing shellfish poisons that are consumed and accumulated by bivalves. We performed short-term feeding experiments to examine ingestion, accumulation, biotransformation, histopathology, and paralysis in the juvenile Pacific calico scallop Argopecten ventricosus that consume this dinoflagellate. Depletion of algal cells was measured in closed systems. Histopathological preparations were microscopic...

Feeding, prey selection and prey encounter mechanisms in the heterotrophic dinoflagellate Noctiluca scintillans

DEFF Research Database (Denmark)

Kiørboe, Thomas; Titelman, J.

1998-01-01

/or that microscale shear brings it into contact with prey. Noctiluca scintillans has a specific carbon content 1-2 orders of magnitude less than that typical for protists and, thus, an inflated volume. It also has a density slightly less than that of the ambient water and therefore ascends at high velocities...... (similar to 1 m h(- 1)). In stagnant water, clearance rates of latex spheres (5-80 mu m) increased approximately with prey particle size squared. This scaling is consistent with N.scintillans being an interception feeder. However, absolute clearance rates were substantially lower than those predicted...... higher rates than latex beads and other phytoplankters, particularly dinoflagellates. We propose that diatoms stick more efficiently than latex beads to the mucus of N.scintillans and that dinoflagellates reduce fatal contact behaviorally. We conclude that N.scintillans is an interception feeder...

Arctic Tides from GPS on sea-ice

DEFF Research Database (Denmark)

Kildegaard Rose, Stine; Skourup, Henriette; Forsberg, René

2013-01-01

The presence of sea-ice in the Arctic Ocean plays a significant role in the Arctic climate. Sea-ice dampens the ocean tide amplitude with the result that global tidal models perform less accurately in the polar regions. This paper presents, a kinematic processing of global positioning system (GPS....... The results show coherence between the GPS buoy measurements, and the tide model. Furthermore, we have proved that the reference ellipsoid of WGS84, can be interpolated to the tidal defined zero level by applying geophysical corrections to the GPS data....

Preliminary study on the influence of the tides of planet earth on hydrostatic leveling system

International Nuclear Information System (INIS)

He Xiaoye; Xu Shaofeng; Wang Peng

2012-01-01

Hydrostatic leveling system, used mainly in survey and alignment technology in particle accelerator and monitoring the tides is introduced in this paper. Based on the theory about the ocean tide and earth tide, we analyze effects of the earth tides on a hydrostatic leveling system. From the data obtained from an HLS, and their F are, and finally we verify the influence of the tides of planet earth. (authors)

Evidence for miRNA-mediated modulation of the host transcriptome in cnidarian-dinoflagellate symbiosis

KAUST Repository

Baumgarten, Sebastian

2017-12-08

Reef-building corals and other cnidarians living in symbiotic relationships with intracellular, photosynthetic dinoflagellates in the genus Symbiodinium undergo transcriptomic changes during infection with the algae and maintenance of the endosymbiont population. However, the precise regulatory mechanisms modulating the host transcriptome are unknown. Here we report apparent post-transcriptional gene regulation by miRNAs in the sea anemone Aiptasia, a model system for cnidarian-dinoflagellate endosymbiosis. Aiptasia encodes mainly species-specific miRNAs, and there appears to have been recent differentiation within the Aiptasia genome of miRNAs that are commonly conserved among anthozoan cnidarians. Analysis of miRNA expression showed that both conserved and species-specific miRNAs are differentially expressed in response to endosymbiont infection. Using cross-linking immunoprecipitation of Argonaute, the central protein of the miRNA-induced silencing complex, we identified miRNA binding sites on a transcriptome-wide scale and found that the targets of the miRNAs regulated in response to symbiosis include genes previously implicated in biological processes related to Symbiodinium infection. Our study shows that cnidarian miRNAs recognize their mRNA targets via high-complementarity target binding and suggests that miRNA-mediated modulations of genes and pathways are important during the onset and maintenance of cnidarian-dinoflagellate endosymbiosis. This article is protected by copyright. All rights reserved.

Evidence for miRNA-mediated modulation of the host transcriptome in cnidarian-dinoflagellate symbiosis

KAUST Repository

Baumgarten, Sebastian; Cziesielski, Maha J.; Thomas, Ludivine; Michell, Craig; Esherick, Lisl Y.; Pringle, John R.; Aranda, Manuel; Voolstra, Christian R.

2017-01-01

Reef-building corals and other cnidarians living in symbiotic relationships with intracellular, photosynthetic dinoflagellates in the genus Symbiodinium undergo transcriptomic changes during infection with the algae and maintenance of the endosymbiont population. However, the precise regulatory mechanisms modulating the host transcriptome are unknown. Here we report apparent post-transcriptional gene regulation by miRNAs in the sea anemone Aiptasia, a model system for cnidarian-dinoflagellate endosymbiosis. Aiptasia encodes mainly species-specific miRNAs, and there appears to have been recent differentiation within the Aiptasia genome of miRNAs that are commonly conserved among anthozoan cnidarians. Analysis of miRNA expression showed that both conserved and species-specific miRNAs are differentially expressed in response to endosymbiont infection. Using cross-linking immunoprecipitation of Argonaute, the central protein of the miRNA-induced silencing complex, we identified miRNA binding sites on a transcriptome-wide scale and found that the targets of the miRNAs regulated in response to symbiosis include genes previously implicated in biological processes related to Symbiodinium infection. Our study shows that cnidarian miRNAs recognize their mRNA targets via high-complementarity target binding and suggests that miRNA-mediated modulations of genes and pathways are important during the onset and maintenance of cnidarian-dinoflagellate endosymbiosis. This article is protected by copyright. All rights reserved.

Future Nuisance Flooding at Boston Caused by Astronomical Tides Alone

Science.gov (United States)

Ray, Richard D.; Foster, Grant

2016-01-01

Sea level rise necessarily triggers more occurrences of minor, or nuisance, flooding events along coastlines, a fact well documented in recent studies. At some locations nuisance flooding can be brought about merely by high spring tides, independent of storms, winds, or other atmospheric conditions. Analysis of observed water levels at Boston indicates that tidal flooding began to occur there in 2011 and will become more frequent in subsequent years. A compilation of all predicted nuisance-flooding events, induced by astronomical tides alone, is presented through year 2050. The accuracy of the tide prediction is improved when several unusual properties of Gulf of Maine tides, including secular changes, are properly accounted for. Future mean sea-level rise at Boston cannot be predicted with comparable confidence, so two very different climate scenarios are adopted; both predict a large increase in the frequency and the magnitude of tidal flooding events.

Dinoflagellate cysts and the paleoenvironment of Late-Pliocene early-pleistocene deposits of Brittany, Northwest France

Science.gov (United States)

Morzadec-Kerfourn, Marie Thérèse

The marine Pliocene facies of the Redon clay is widely distributed in the western part of Brittany. the decrease in the abundance of Tertiary pollen towards the top of the deposits, coupled with the increase of pollen of boreal forest taxa and the development of Ericaceae and Poaceae indicates a Late-Pliocene age. The occurrence of the transgression maximum is recorded in calcareous beds which contain the highest concentration of microforaminiferal linings and dinoflagellate cysts. Hystrichokolpoma rigaudae and Melitasphaeridium choanophorum, along with Achomosphaera andalousiensis and Operculodinium israelianum make up these aseemblages. The presence of dinoflagellate cyst assemblages with estuarine and neritic affinities but with an occasional oceanic form, indicates sedimentation in coastal waters with a neritic influence. The paleotopography exerts a control on the altitudinal distribution of the Redon clays in the western part of Brittany to the west of the Rennes Basin. The Pliocene-Pleistocene dinoflagelate cyst assemblages of southern England and northwestern france show a remarkable degree of homogeneity in their composition, chiefly expressed in the apparent contradictory association of A. andalousensis and O. israelianum that suggest sedimentation in an unusual type of environment which arose in the context of climatic change and sea-level variations at that time.

Polyuridylylation and processing of transcripts from multiple gene minicircles in chloroplasts of the dinoflagellate Amphidinium carterae

KAUST Repository

Barbrook, Adrian C.

2012-05-05

Although transcription and transcript processing in the chloroplasts of plants have been extensively characterised, the RNA metabolism of other chloroplast lineages across the eukaryotes remains poorly understood. In this paper, we use RT-PCR to study transcription and transcript processing in the chloroplasts of Amphidinium carterae, a model peridinin-containing dinoflagellate. These organisms have a highly unusual chloroplast genome, with genes located on multiple small \\'minicircle\\' elements, and a number of idiosyncratic features of RNA metabolism including transcription via a rolling circle mechanism, and 3′ terminal polyuridylylation of transcripts. We demonstrate that transcription occurs in A. carterae via a rolling circle mechanism, as previously shown in the dinoflagellate Heterocapsa, and present evidence for the production of both polycistronic and monocistronic transcripts from A. carterae minicircles, including several regions containing ORFs previously not known to be expressed. We demonstrate the presence of both polyuridylylated and non-polyuridylylated transcripts in A. carterae, and show that polycistronic transcripts can be terminally polyuridylylated. We present a model for RNA metabolism in dinoflagellate chloroplasts where long polycistronic precursors are processed to form mature transcripts. Terminal polyuridylylation may mark transcripts with the correct 3′ end. © 2012 Springer Science+Business Media B.V.

Life-cycle, ultrastructure, and phylogeny of Parvilucifera corolla sp. nov. (Alveolata, Perkinsozoa), a parasitoid of dinoflagellates.

Science.gov (United States)

Reñé, Albert; Alacid, Elisabet; Figueroa, Rosa Isabel; Rodríguez, Francisco; Garcés, Esther

2017-04-01

Recent studies of marine protists have revealed parasites to be key components of marine communities. Here we describe a new species of the parasitoid genus Parvilucifera that was observed infecting the dinoflagellate Durinskia baltica in salt marshes of the Catalan coast (NW Mediterranean). In parallel, the same species was detected after the incubation of seawater from the Canary Islands (Lanzarote, NE Atlantic). The successful isolation of strains from both localities allowed description of the life cycle, ultrastructure, and phylogeny of the species. Its infection mechanism consists of a free-living zoospore that penetrates a dinoflagellate cell. The resulting trophont gradually degrades the dinoflagellate cytoplasm while growing in size. Once the host is consumed, schizogony of the parasitoid yields a sporocyte. After cytokinesis is complete, the newly formed zoospores are released into the environment and are ready to infect new host cells. A distinguishing feature of the species is the radial arrangement of its zoospores around the central area of the sporocyte during their formation. The species shows a close morphological similarity with other species of the genus, including P. infectans, P. sinerae, and P. rostrata. Copyright © 2016 Elsevier GmbH. All rights reserved.

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

Directory of Open Access Journals (Sweden)

Barrie Dale

2001-12-01

Full Text Available 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

Climatologies of tides at mid-latitudes in the lower termosphere

International Nuclear Information System (INIS)

Cevolani, G.

1991-01-01

Time variations of the semi-diurnal and diurnal tides observed at Budrio (45N, 12E) in the wind structure of the lower termosphere ((80-110) km) throughout the period 1976-1990 are herewith represented as monthly contours of both amplitudes and phases vs. height. The semi-diurnal tide has more marked seasonal variations, showing amplitudes generally larger than the diurnal ones ((10-30) m/s vs. (5-15) m/s). The vertical wavelengths are longer in summer than in winter, at least below 100 km. Agreement with new numerical models for semi-diurnal tide at 50N appears to be satisfactory

Putative N₂-fixing heterotrophic bacteria associated with dinoflagellate-Cyanobacteria consortia in the low-nitrogen Indian Ocean

DEFF Research Database (Denmark)

Farnelid, H.; Tarangkoon, Woraporn; Hansen, Gert

2010-01-01

that the symbionts fix gaseous nitrogen (N2). Individual heterotrophic dinoflagellates containing cyanobacterial symbionts were isolated from the open Indian Ocean and off Western Australia, and characterized using light microscopy, transmission electron microscopy (TEM), and nitrogenase (nifH) gene amplification......, cloning, and sequencing. Cyanobacteria, heterotrophic bacteria and eukaryotic algae were recognized as symbionts of the heterotrophic dinoflagellates. nifH gene sequences were obtained from 23 of 37 (62%) specimens of dinoflagellates (Ornithocercus spp. and Amphisolenia spp.). Interestingly, only 2...... specimens contained cyanobacterial nifH sequences, while 21 specimens contained nifH genes related to heterotrophic bacteria. Of the 137 nifH sequences obtained 68% were most similar to Alpha-, Beta-, and Gammaproteobacteria, 8% clustered with anaerobic bacteria, and 5% were related to second alternative...

Genetic diversity of giant clams (Tridacna spp.) and their associated Symbiodinium in the central Red Sea

KAUST Repository

Pappas, Melissa

2017-05-19

The biodiversity of the Red Sea remains relatively understudied, particularly for invertebrate taxa. Documenting present patterns of biodiversity is essential for better understanding Red Sea reef ecosystems and how these ecosystems may be impacted by stressors (such as fishing and climate change). Several species of giant clams (genus Tridacna) are reported from the Red Sea, although the majority of research effort has occurred in the Gulf of Aqaba. We investigated the genetic diversity (16S rDNA) of the Tridacna species found in the central Saudi Arabian Red Sea. We also investigated the genetic diversity (ITS rDNA) of symbiotic dinoflagellates Symbiodinium associated with these clams. Samples were collected from nine reefs on a cross-shelf gradient near Thuwal, Saudi Arabia. Two species, T. squamosa and T. maxima, were recorded, with the latter being the most abundant. Tridacna squamosina, a species recently reported in the northern Red Sea, was not found, suggesting that this species is not present or is very rare in our study region. All tridacnids sampled were found to harbor Symbiodinium grouped in Clade A, considered an opportunistic, heat-tolerant symbiont group in anemones and corals. The consistent association with Clade A Symbiodinium in central Red Sea tridacnids may reflect the consequence of adaptation to the relatively extreme conditions of the Red Sea. This study contributes to an ever-growing catalog of Red Sea biodiversity and serves as important baseline information for a region experiencing dynamic pressures.

Genetic diversity of giant clams (Tridacna spp.) and their associated Symbiodinium in the central Red Sea

KAUST Repository

Pappas, Melissa; He, Song; Hardenstine, Royale; Kanee, Hana; Berumen, Michael L.

2017-01-01

The biodiversity of the Red Sea remains relatively understudied, particularly for invertebrate taxa. Documenting present patterns of biodiversity is essential for better understanding Red Sea reef ecosystems and how these ecosystems may be impacted by stressors (such as fishing and climate change). Several species of giant clams (genus Tridacna) are reported from the Red Sea, although the majority of research effort has occurred in the Gulf of Aqaba. We investigated the genetic diversity (16S rDNA) of the Tridacna species found in the central Saudi Arabian Red Sea. We also investigated the genetic diversity (ITS rDNA) of symbiotic dinoflagellates Symbiodinium associated with these clams. Samples were collected from nine reefs on a cross-shelf gradient near Thuwal, Saudi Arabia. Two species, T. squamosa and T. maxima, were recorded, with the latter being the most abundant. Tridacna squamosina, a species recently reported in the northern Red Sea, was not found, suggesting that this species is not present or is very rare in our study region. All tridacnids sampled were found to harbor Symbiodinium grouped in Clade A, considered an opportunistic, heat-tolerant symbiont group in anemones and corals. The consistent association with Clade A Symbiodinium in central Red Sea tridacnids may reflect the consequence of adaptation to the relatively extreme conditions of the Red Sea. This study contributes to an ever-growing catalog of Red Sea biodiversity and serves as important baseline information for a region experiencing dynamic pressures.

Effect of Tide Elevation on Extratropical Storm Surge in Northwest Europe

Science.gov (United States)

Keshtpoor, M.; Carnacina, I.; Yablonsky, R. M.

2016-12-01

Extratropical cyclones (ETCs) are the major storm surge-generating meteorological events in northwest Europe. The total water level increase induced by these ETCs is significantly influenced by the local tidal range, which exceeds 8 meters along the southwestern UK coastline. In particular, a surge-generating ETC during high tide may put coastal assets and infrastructure in risk. Also, during low tide, the risk of surge induced by extreme ETC events is diminished. Here, the effect of tidal elevation on storm surge is investigated at 196 tide gauges in northwest Europe. A numerical, hydrodynamic model was developed using Delft3D-FM framework to simulate the coastal hydrodynamics during ETCs. Then, 1750 historical events were simulated to investigate the pattern of coastal inundation. Results suggest that in areas with a large tidal range ( 8 meters) and during the time period surrounding high or low tide, the pattern of coastal hydrodynamics is governed by tide and not storm surge. This result is most evident near the English Channel and Bristol Channel, where low frequency maximum water levels are observed when storm surge is combined with high tide. In contrast, near the tidal phase reversal, coastal hydrodynamics responds primarily to the storm surge, and low frequency maximum water elevation largely depends on the surge. In the areas with a small tidal range, ETC strength determines the pattern of coastal inundation.

Constant pH Accelerated Molecular Dynamics Investigation of the pH Regulation Mechanism of Dinoflagellate Luciferase.

Science.gov (United States)

Donnan, Patrick H; Ngo, Phong D; Mansoorabadi, Steven O

2018-01-23

The bioluminescence reaction in dinoflagellates involves the oxidation of an open-chain tetrapyrrole by the enzyme dinoflagellate luciferase (LCF). The activity of LCF is tightly regulated by pH, where the enzyme is essentially inactive at pH ∼8 and optimally active at pH ∼6. Little is known about the mechanism of LCF or the structure of the active form of the enzyme, although it has been proposed that several intramolecularly conserved histidine residues in the N-terminal region are important for the pH regulation mechanism. Here, constant pH accelerated molecular dynamics was employed to gain insight into the conformational activation of LCF induced by acidification.

M2, S2, K1 models of the global ocean tide

Science.gov (United States)

Parke, M. E.; Hendershott, M. C.

1979-01-01

Ocean tidal signals appear in many geophysical measurements. Geophysicists need realistic tidal models to aid in interpretation of their data. Because of the closeness to resonance of dissipationless ocean tides, it is difficult for numerical models to correctly represent the actual open ocean tide. As an approximate solution to this problem, test functions derived by solving Laplace's Tidal Equations with ocean loading and self gravitation are used as a basis for least squares dynamic interpolation of coastal and island tidal data for the constituents M2, S2, and Kl. The resulting representations of the global tide are stable over at least a ?5% variation in the mean depth of the model basin, and they conserve mass. Maps of the geocentric tide, the induced free space potential, the induced vertical component of the solid earth tide, and the induced vertical component of the gravitational field for each contituent are presented.

Ocean tides in GRACE monthly averaged gravity fields

DEFF Research Database (Denmark)

Knudsen, Per

2003-01-01

The GRACE mission will map the Earth's gravity fields and its variations with unprecedented accuracy during its 5-year lifetime. Unless ocean tide signals and their load upon the solid earth are removed from the GRACE data, their long period aliases obscure more subtle climate signals which GRACE...... aims at. In this analysis the results of Knudsen and Andersen (2002) have been verified using actual post-launch orbit parameter of the GRACE mission. The current ocean tide models are not accurate enough to correct GRACE data at harmonic degrees lower than 47. The accumulated tidal errors may affect...... the GRACE data up to harmonic degree 60. A study of the revised alias frequencies confirm that the ocean tide errors will not cancel in the GRACE monthly averaged temporal gravity fields. The S-2 and the K-2 terms have alias frequencies much longer than 30 days, so they remain almost unreduced...

Interannual and Intraseasonal Variability of the Diurnal Tide

Science.gov (United States)

Riggin, D. M.; Ortland, D. A.; Lieberman, R. S.; Oberheide, J.; Murayama, Y.; Hocking, W. K.; Vincent, R. A.; Reid, I. M.; Kumar, G. K.; Batista, P. P.; Clemesha, B. R.

2013-12-01

Temporal variations in the amplitude of the diurnal tide (DT) have been observed by radars with a seasonal dependence that is typically semiannual in the tropics. During some years the wind variation departs from the normal seasonal behavior with anomalously large amplitudes compared to most other years. This anomaly often takes the form of a greatly enhanced boreal spring equinoctal maximum. The boreal spring of 2008 is a example of this behavior. Diurnal amplitudes in the meridional winds are shown in the figure below for the first 6 months of 2008. Note that the diurnal tide undergoes a sharp increase in amplitude up to 80 ms-1 during this event. The characteristics of this event are diagnosed in a variety of global data sets. These include our own physics-based assimilation of SABER temperatures, and gridded analyses from the national weather services (NCAR/NCEP and ECMWF). Tidal amplitude variations are sometimes attributed to nonlinear interaction. However, this type of interaction would be expected to produce non-migrating tides, e.g., westward-2 or standing. SABER data show that the amplitude anomaly is mainly in the migrating DT. The global data sets allow us to explore properties of the anomaly, such as its origin, evolution in time, and associated momentum flux. In addition to this case study, we also investigate the general characteristics of DT interannual variability during the years of the SABER mission (2002-present). Diurnal tide momentum deposition plays a significant role in controlling the zonal mean wind in the mesosphere, We demonstrate its importance in driving the mesospheric semiannual oscillation (MSAO). Diurnal tide wind amplitudes in the meridional component observed at two radar sites, Rarotonga, Cook Islands (22.1°S, 159.8°W), and at Guanacaste, Costa Rica (10.3°N, 85.6°W).

Accumulation, biotransformation, histopathology and paralysis in the Pacific calico scallop Argopecten ventricosus by the paralyzing toxins of the dinoflagellate Gymnodinium catenatum.

Science.gov (United States)

Escobedo-Lozano, Amada Y; Estrada, Norma; Ascencio, Felipe; Contreras, Gerardo; Alonso-Rodriguez, Rosalba

2012-05-01

The dinoflagellate Gymnodinium catenatum produces paralyzing shellfish poisons that are consumed and accumulated by bivalves. We performed short-term feeding experiments to examine ingestion, accumulation, biotransformation, histopathology, and paralysis in the juvenile Pacific calico scallop Argopecten ventricosus that consume this dinoflagellate. Depletion of algal cells was measured in closed systems. Histopathological preparations were microscopically analyzed. Paralysis was observed and the time of recovery recorded. Accumulation and possible biotransformation of toxins were measured by HPLC analysis. Feeding activity in treated scallops showed that scallops produced pseudofeces, ingestion rates decreased at 8 h; approximately 60% of the scallops were paralyzed and melanin production and hemocyte aggregation were observed in several tissues at 15 h. HPLC analysis showed that the only toxins present in the dinoflagellates and scallops were the N-sulfo-carbamoyl toxins (C1, C2); after hydrolysis, the carbamate toxins (epimers GTX2/3) were present. C1 and C2 toxins were most common in the mantle, followed by the digestive gland and stomach-complex, adductor muscle, kidney and rectum group, and finally, gills. Toxin profiles in scallop tissue were similar to the dinoflagellate; biotransformations were not present in the scallops in this short-term feeding experiment.

Subsurface Ocean Tides in Enceladus and Other Icy Moons

Science.gov (United States)

Beuthe, M.

2016-12-01

Could tidal dissipation within Enceladus' subsurface ocean account for the observed heat flow? Earthlike models of dynamical tides give no definitive answer because they neglect the influence of the crust. I propose here the first model of dissipative tides in a subsurface ocean, by combining the Laplace Tidal Equations with the membrane approach. For the first time, it is possible to compute tidal dissipation rates within the crust, ocean, and mantle in one go. I show that oceanic dissipation is strongly reduced by the crustal constraint, and thus contributes little to Enceladus' present heat budget. Tidal resonances could have played a role in a forming or freezing ocean less than 100 meters deep. The model is general: it applies to all icy satellites with a thin crust and a shallow or stratified ocean. Scaling rules relate the resonances and dissipation rate of a subsurface ocean to the ones of a surface ocean. If the ocean has low viscosity, the westward obliquity tide does not move the crust. Therefore, crustal dissipation due to dynamical obliquity tides can differ from the static prediction by up to a factor of two.

Tide-surge interaction along the east coast of the Leizhou Peninsula, South China Sea

Science.gov (United States)

Zhang, Heng; Cheng, Weicong; Qiu, Xixi; Feng, Xiangbo; Gong, Wenping

2017-06-01

A triply-nested two-dimensional (2D) ocean circulation model along with observed sea level records are used to study tide-surge interaction along the east coast of the Leizhou Peninsula (LP) which is characterized by extensive mudflats, large tidal ranges and a complex coastline. The dependency of surge maxima on the water level and the phase of tide are respectively investigated using two statistical approaches. Results show that tide-surge interaction along the east coast of the LP is significant, where surges peak 3-6 h before or after the nearest high water. The triply-nested 2D ocean circulation model is used to quantify tide-surge interaction in this region and to investigate its physical cause. The largest amplitudes of tide-surge interaction are found in the shallow water region of the Leizhou Bay, with values up to 1 m during typhoon events. Numerical experiments reveal that nonlinear bottom friction is the main contributor to tide-surge interaction, while the contribution of the nonlinear advective effect can be neglected. The shallow water effect enhances the role of nonlinear bottom friction in determining tide-surge modulation, leaving the surge peaks usually occur on the rising or falling tide. It is also found that the relative contribution of local wind and remote wind is different depending on the storm track and storm intensity, which would finally affect the temporal and spatial distribution of tide-surge interaction during typhoon events. These findings confirm the importance of coupling storm surges and tides for the prediction of storm surge events in regions which are characterized by shallow water depths and large tidal ranges.

Survey of benthic dinoflagellates associated to beds of Thalassia testudinumin San Andres Island, Seaflower biosphere reserve, Caribbean Colombia

International Nuclear Information System (INIS)

Rodriguez E, Angelica; Mancera Pineda, J Ernesto; Gavio, Brigitte

2010-01-01

In order to determine the occurrence of epiphytic toxic dinoflagellates in the coastal waters of San Andres Island, Caribbean Colombia, we analyzed the sea grass beds on the northern and eastern sides of the island. We found seven species of toxicogenic dinoflagellates, belonging to the genera Prorocentrum and Ostreopsis. The cell densities were generally low if compared with previous studies in other Caribbean sites, ranging from 0 to 836 cells/dry weights. The species encountered are known to produce toxins causing the diarrheic shellfish poisoning and ciguatera, poisonings which have been documented in the island.

Dynamical significance of tides over the Bay of Bengal

Science.gov (United States)

Bhagawati, Chirantan; Pandey, Suchita; Dandapat, Sumit; Chakraborty, Arun

2018-06-01

Tides play a significant role in the ocean surface circulations and vertical mixing thereby influencing the Sea Surface Temperatures (SST) as well. This, in turn, plays an important role in the global circulation when used as a lower boundary condition in a global atmospheric general circulation model. Therefore in the present study, the dynamics of tides over the Bay of Bengal (BoB) is investigated through numerical simulations using a high resolution (1/12°) Regional Ocean Modeling System (ROMS). Based on statistical analysis it is observed that incorporation of explicit tidal forcing improves the model performance in simulating the basin averaged monthly surface circulation features by 64% compared to the simulation without tides. The model simulates also Mixed Layer Depth (MLD) and SST realistically. The energy exchange between tidal oscillations and eddies leads to redistribution of surface kinetic energy density with a net decrease of 0.012 J m-3 in the western Bay and a net increase of 0.007 J m-3 in the eastern Bay. The tidal forcing also affects the potential energy anomaly and vertical mixing thereby leading to a fall in monthly MLD over the BoB. The mixing due to tides leads to a subsequent reduction in monthly SST and a corresponding reduction in surface heat exchange. These results from the numerical simulation using ROMS reveal that tides have a significant influence over the air-sea heat exchange which is the most important parameter for prediction of Tropical Cyclone frequency and its future variability over the BoB.

Secular Changes in the Solar Semidiurnal Tide of the Western North Atlantic Ocean

Science.gov (United States)

Ray, Richard D.

2009-01-01

An analysis of twentieth century tide gauge records reveals that the solar semidiurnal tide S, has been decreasing in amplitude along the eastern coast of North America and at the mid-ocean site Bermuda. In relative terms the observed rates are unusually large, of order 10% per century. Periods of greatest change, however, are inconsistent among the stations, and roughly half the stations show increasing amplitude since the late 1990s. Excepting the Gulf of Maine, lunar tides are either static or slightly increasing in amplitude; a few stations show decreases. Large changes in solar, but not lunar, tides suggest causes related to variable radiational forcing, but the hypothesis is at present unproven. Citation: Ray, R. D. (2009), Secular changes in the solar semidiurnal tide of the western North Atlantic Ocean

Distribution and Evolution of Peroxisomes in Alveolates (Apicomplexa, Dinoflagellates, Ciliates)

Science.gov (United States)

Ludewig-Klingner, Ann-Kathrin; Michael, Victoria; Jarek, Michael; Brinkmann, Henner

2018-01-01

Abstract The peroxisome was the last organelle to be discovered and five decades later it is still the Cinderella of eukaryotic compartments. Peroxisomes have a crucial role in the detoxification of reactive oxygen species, the beta-oxidation of fatty acids, and the biosynthesis of etherphospholipids, and they are assumed to be present in virtually all aerobic eukaryotes. Apicomplexan parasites including the malaria and toxoplasmosis agents were described as the first group of mitochondriate protists devoid of peroxisomes. This study was initiated to reassess the distribution and evolution of peroxisomes in the superensemble Alveolata (apicomplexans, dinoflagellates, ciliates). We established transcriptome data from two chromerid algae (Chromera velia, Vitrella brassicaformis), and two dinoflagellates (Prorocentrum minimum, Perkinsus olseni) and identified the complete set of essential peroxins in all four reference species. Our comparative genome analysis provides unequivocal evidence for the presence of peroxisomes in Toxoplasma gondii and related genera. Our working hypothesis of a common peroxisomal origin of all alveolates is supported by phylogenetic analyses of essential markers such as the import receptor Pex5. Vitrella harbors the most comprehensive set of peroxisomal proteins including the catalase and the glyoxylate cycle and it is thus a promising model organism to investigate the functional role of this organelle in Apicomplexa. PMID:29202176

TIDE: Lightweight Device Composition for Enhancing Tabletop Environments with Smartphone Applications

DEFF Research Database (Denmark)

Sicard, Leo; Tabard, Aurelien; Ramos, Juan David Hincapie

2013-01-01

platforms have to be re-developed. At the same time, smartphones are pervasive computers that users carry around and with a large pool of applications. This paper presents TIDE, a lightweight device composition middleware to bring existing smartphone applica- tions onto the tabletop. Through TIDE......, applications running on the smartphone are displayed on the tabletop computer, and users can interact with them through the tabletop’s interactive surface. TIDE contributes to the areas of device compo- sition and tabletops by providing an OS-level middleware that is transparent to the smartphone applications...

Effects of the toxic benthic dinoflagellate Ostreopsis cf. ovata on fertilization and early development of the sea urchin Lytechinus variegatus.

Science.gov (United States)

Neves, Raquel A F; Contins, Mariana; Nascimento, Silvia M

2018-04-01

Blooms of the benthic dinoflagellate Ostreopsis cf. ovata have been recorded with increasing frequency, intensity and geographic distribution. This dinoflagellate produces potent toxins that may cause mortality of marine invertebrates. Adults of sea urchins are commonly affected by O. cf. ovata exposure with evidence of spines loss and high mortality during periods of high dinoflagellate abundances. Here, we report on the effects of the toxic dinoflagellate O. cf. ovata on fertilization and early development of the sea urchin Lytechinus variegatus, a key ecological herbivore. Lytechinus variegatus eggs and sperm were experimentally exposed to different concentrations of Ostreopsis cf. ovata (4, 40, 400, and 4000 cells ml -1 ) to test the hypothesis that fertilization success, embryonic and larval development of the sea urchin are negatively affected by the toxic dinoflagellate even at low abundances. Reduced fertilization, developmental failures, embryo and larval mortality, and occurrence of abnormal offspring were evident after exposure to O. cf. ovata. Fertilization decreased when gametes were exposed to high O. cf. ovata abundances (400 and 4000 cells ml -1 ), but just the exposure to the highest abundance significantly reduced fertilization success. Sea urchin early development was affected by O. cf. ovata in a dose-dependent way, high dinoflagellate abundances fully inhibited the early development of L. variegatus. Ostreopsis cf. ovata significantly increased the mortality of sea urchin eggs and embryos in the first hours of exposure (∼1-3 h), regardless of dinoflagellate abundance. Abundances of 400 and 4000 O. cf. ovata cells ml -1 induced significantly higher mortality on sea urchin initial stages in the first hours, and no egg or embryo was found in these treatments after 18 h of incubation. The early echinopluteus larva was only reached in the control and in treatments with low Ostreopsis cf. ovata abundances (4 and 40 cells ml -1 ). The

Modelling the tides and their impacts on the vertical stratification ...

African Journals Online (AJOL)

The Sofala Bank, a wide shelf located along the central coast of Mozambique, hosts tides with high amplitudes. The Regional Ocean Modelling System (ROMS) was used to analyse the tidal currents on the bank and to investigate their effects on the stratification and generation of tidal fronts. During spring tides, barotropic ...

Histone occurrence in chromatin from Peridinium balticum, a binucleate dinoflagellate.

Science.gov (United States)

Rizzo, P J; Cox, E R

1977-12-23

Peridinium balticum is one of two dinoflagellates known to have dissimilar nuclei together in the same cell. One nucleus (dinokaryotic) has permanently condensed chromosomes, while the other (eukaryotic) does not have morphologically distinct chromosomes. Acid extracts of chromatin prepared from a mixture of dinokaryotic and eukaryotic nuclei and purified eukaryotic nuclei give four bands that co-migrate with four of the five histones from calf thymus when analyzed in urea-containing polyacrylamide gels.

Geographical representation of radial orbit perturbations due to ocean tides: Implications for satellite altimetry

Science.gov (United States)

Bettadpur, Srinivas V.; Eanes, Richard J.

1994-01-01

In analogy to the geographical representation of the zeroth-order radial orbit perturbations due to the static geopotential, similar relationships have been derived for radial orbit perturbations due to the ocean tides. At each location these perturbations are seen to be coherent with the tide height variations. The study of this singularity is of obvious importance to the estimation of ocean tides from satellite altimeter data. We derive analytical expressions for the sensitivity of altimeter derived ocean tide models to the ocean tide force model induced errors in the orbits of the altimeter satellite. In particular, we focus on characterizing and quantifying the nonresonant tidal orbit perturbations, which cannot be adjusted into the empirical accelerations or radial perturbation adjustments commonly used during orbit determination and in altimeter data processing. As an illustration of the utility of this technique, we study the differences between a TOPEX/POSEIDON-derived ocean tide model and the Cartwright and Ray 1991 Geosat model. This analysis shows that nearly 60% of the variance of this difference for M(sub 2) can be explained by the Geosat radial orbit eror due to the omission of coefficients from the GEM-T2 background ocean tide model. For O(sub 1), K(sub 1), S(sub 2), and K(sub 2) the orbital effects account for approximately 10 to 40% of the variances of these differences. The utility of this technique to assessment of the ocean tide induced errors in the TOPEX/POSEIDON-derived tide models is also discussed.

The Maastrichtiense Daniense and Middle Eocene age transgression in the Punta del Este basin and it regional correlation established by dinoflagellate

International Nuclear Information System (INIS)

Daners, G.; Veroslavsky, G.; Guerstein, G.; Guler, M.

2004-01-01

In the Punta del Este Basin (Uruguay), two transgressions were recognized through the study of dinoflagellate associations of Gaviotin Formation. The transgression cycles were assigned to Maastrichtian-Danian and Middle Eocene ages, separated by a paracomformity established through biostratigraphic criteria. A regional correlation for these transgressive cycles was stablished by the comparisson of these dinoflagellate associations with those of other Atlantic and Austral basins (Colorado, Neuquina and Austral) [es

Karmitoxin: An amine containing polyhydroxy-polyene toxin from the marine dinoflagellate Karlodinium armiger

DEFF Research Database (Denmark)

Rasmussen, Silas Anselm; Binzer, Sofie Bjørnholt; Hoeck, Casper

2017-01-01

Marine algae from the genus Karlodinium are known to be involved in fish-killing events worldwide. Here we report for the first time the chemistry and bioactivity of a natural product from the newly described mixotrophic dinoflagellate Karlodinium armiger. Our work describes the isolation and str...

Nonlinear terms in storm surge predictions: Effect of tide and shelf geometry with case study from Hurricane Rita

Science.gov (United States)

Rego, JoãO. L.; Li, Chunyan

2010-06-01

This study applied the finite volume coastal ocean model (FVCOM) to the storm surge induced by Hurricane Rita along the Louisiana-Texas coast. The model was calibrated for tides and validated with observed water levels. Peak water levels were shown to be lower than expected for a landfall at high tide. For low- and high-tide landfalls, nonlinear effects due to tide-surge coupling were constructive and destructive to total storm tide, respectively, and their magnitude reached up to 70% of the tidal amplitude in the Rita application. Tide-surge interaction was further examined using a standard hurricane under idealized scenarios to evaluate the effects of various shelf geometries, tides, and landfall timings (relative to tide). Nonlinearity was important between landfall position and locations within 2.5 × radius of maximum winds. On an idealized wide continental shelf, nonlinear effects reached up to 80% of the tidal amplitude with an S2 tide and up to 47% with a K1 tide. Increasing average depths by 4 m reduced nonlinear effects to 41% of the tidal amplitude; increasing the slope by a factor of 3 produced nonlinearities of just 26% of tide (both with a K1 tide). The nonlinear effect was greatest for landfalls at low tide, followed by landfalls at high tide and then by landfalls at midebb or midflood.

Fatty acid composition of bacteria associated with the toxic dinoflagellate Ostreopsis lenticularis and with Caribbean Palythoa species.

Science.gov (United States)

Carballeira, N M; Emiliano, A; Sostre, A; Restituyo, J A; González, I M; Colón, G M; Tosteson, C G; Tosteson, T R

1998-06-01

The fatty acid composition of a Pseudomonas sp. (Alteromonas) and its host, the dinoflagellate Ostreopsis lenticularis, vectors in ciguatera fish poisoning, has been studied. The major fatty acids in O. lenticularis were 16:0, 20:5n-3, and 22:6n-3, but 18:2n-6, 18:3n-3, and 18:n-3 were also identified. In contrast to other dinoflagellates, 1 8:5n-3 was not detected in O. lenticularis. Even-chain fatty acids such as 9-16:1, 11-18:1, and 13-20:1 predominated in the Pseudomonas sp. from O. lenticularis, but 1 6-20% of (E)-11-methyl-12-octadecenoic acid was also identified. The chirality of the latter was confirmed by total synthesis (28% overall yield) starting from oxacyclotridecan-2-one. The fatty acid compositions of two other Pseudomonas species, from the palytoxin-producing zoanthids Palythoa mamillosa and P. caribdea, were also studied and were similar to that of the Pseudomonas sp. from O. lenticularis. The possibility of using some of these fatty acids as chemotaxonomic lipids in identifying marine animals that consume toxic dinoflagellates or zoanthids is discussed.

Consortial brown tide - picocyanobacteria blooms in Guantánamo Bay, Cuba.

Science.gov (United States)

Hall, Nathan S; Litaker, R Wayne; Kenworthy, W Judson; Vandersea, Mark W; Sunda, William G; Reid, James P; Slone, Daniel H; Butler, Susan

2018-03-01

A brown tide bloom of Aureoumbra lagunensis developed in Guantánamo Bay, Cuba during a period of drought in 2013 that followed heavy winds and rainfall from Hurricane Sandy in late October 2012. Based on satellite images and water turbidity measurements, the bloom appeared to initiate in January 2013. The causative species (A. lagunensis) was confirmed by microscopic observation, and pigment and genetic analyses of bloom samples collected on May 28 of that year. During that time, A. lagunensis reached concentrations of 900,000 cells ml -1 (28 ppm by biovolume) in the middle portion of the Bay. Samples could not be collected from the northern (Cuban) half of the Bay because of political considerations. Subsequent sampling of the southern half of the Bay in November 2013, April 2014, and October 2014 showed persistent lower concentrations of A. lagunensis, with dominance shifting to the cyanobacterium Synechococcus (up to 33 ppm in April), an algal group that comprised a minor bloom component on May 28. Thus, unlike the brown tide bloom in Laguna Madre, which lasted 8 years, the bloom in Guantánamo Bay was short-lived, much like recent blooms in the Indian River, Florida. Although hypersaline conditions have been linked to brown tide development in the lagoons of Texas and Florida, observed euhaline conditions in Guantánamo Bay (salinity 35-36) indicate that strong hypersalinity is not a requirement for A. lagunensis bloom formation. Microzooplankton biomass dominated by ciliates was high during the observed peak of the brown tide, and ciliate abundance was high compared to other systems not impacted by brown tide. Preferential grazing by zooplankton on non-brown tide species, as shown in A. lagunensis blooms in Texas and Florida, may have been a factor in the development of the Cuban brown tide bloom. However, subsequent selection of microzooplankton capable of utilizing A. lagunensis as a primary food source may have contributed to the short-lived duration

A technique to circumvent lower density water trapping by tide-wells

Digital Repository Service at National Institute of Oceanography (India)

Joseph, A.; VijayKumar, K.; Desa, E.S.; Desa, E.; Peshwe, V.B.

A 3-year study of water density differences inside and outside of a conventional tide-well indicated that the average water density within the well is consistently lower than the external ambient waters. The tide-well at Goa is situated at the mouth...

The role of photosynthesis and food uptake for the growth of marine mixotrophic dinoflagellates

DEFF Research Database (Denmark)

Hansen, Per Juel

2011-01-01

Mixotrophy (i.e. combined use of photosynthesis and food uptake for growth) is widespread among marine dinoflagellates. Species with permanent chloroplasts generally display a growth response towards irradiance like an ordinary autotrophic alga. However, some species cannot grow in the light...

Earthquake swarms and the semidiurnal solid earth tide

Energy Technology Data Exchange (ETDEWEB)

Klein, F W

1976-01-01

Several correlations between peak earthquake activity during swarms and the phase and stress orientation of the calculated solid earth tide are described. The events correlating with the tide are clusters of swarm earthquakes. Swarm clusters from many sequences recorded over several years are used. Significant tidal correlations (which have less than a 5% chance of being observed if earthquakes were random) are found in the Reykjanes Peninsula in Iceland, the central Mid-Atlantic Ridge, the Imperial Valley and northern Gulf of California, and larger (m/sub b/ greater than or equal to 5.0) aftershocks of the 1965 Rat Islands earthquake. In addition, sets of larger single earthquakes on Atlantic and north-east Pacific fracture zones are significantly correlated with the calculated solid tide. No tidal correlation, however, could be found for the Matsushiro Japan swarm of 1965 to 1967. The earthquake-tide correlations other than those of the Reykjanes Peninsula and Mid-Atlantic Ridge can be interpreted as triggering caused by enhancement of the tectonic stress by tidal stress, i.e. the alignment of fault and tidal principal stresses. All tidal correlations except in the Aleutians are associated with oceanic rifts or their landward extensions. If lithospheric plates are decoupled at active rifts, then tidal stresses channeled along the lithospheric stress guide may be concentrated at ridge-type plate boundaries. Tidal triggering of earthquakes at rifts may reflect this possible amplification of tidal strains in the weakened lithosphere at ridges. 25 figures, 2 tables.

Characteristics of Phytoplankton Biomass, Primary Production and Community Structure in the Modaomen Channel, Pearl River Estuary, with Special Reference to the Influence of Saltwater Intrusion during Neap and Spring Tides.

Science.gov (United States)

Zhou, Weihua; Gao, Jie; Liao, Jianzu; Shi, Ronggui; Li, Tao; Guo, Yajuan; Long, Aimin

2016-01-01

In recent decades, increasing frequency and intensity of saltwater intrusion in the Modaomen Channel has threatened the freshwater supply in the surrounding cities of the Pearl River Estuary, and ulteriorly changed the environmental conditions of the estuarine waters. Phytoplankton biomass, primary production (PP) and species composition, as well as hydrological and chemical parameters were examined along a downstream transect in the Modaomen Channel during neap tide (NT) and spring tide (ST), when a strong saltwater intrusion event occurred in late September, 2011. A total of 46 species phytoplankton were identified, including Bacillariophyta (25 species), Dinoflagellate (14 species), Chlorophyta (4 species), Cyanophyta (2 species) and Euglenozoa (1 species). The dominant species were shifted from freshwater diatoms (e.g., Melosira granulata and Melosira granulata var. angustissima) in the upper reaches to saline water diatoms (e.g., Skeletonema costatum and Coscinodiscus sp.) in the river mouth. Generally, phytoplankton density, biomass (chl-a) and PP decreased from the upper to lower reaches along the channel, and were significantly higher in NT than those of ST. There was a shift from large-sized phytoplankton (>20 μm) in the upper reaches to relative small-sized cells (5-20 μm) in the lower reaches. Compared to NT, low discharge and flow velocity, coupled with strong easterly winds during ST specially aggravated saltwater intrusion further to the upstream (~50 km from the estuary). The intruded saltwater diluted nutrients, N/P ratios, chl-a, and phytoplankton abundances, and thereby led to a decline in PP during ST.

Interactions between the mixotrophic dinoflagellate Takayama helix and common heterotrophic protists.

Science.gov (United States)

Ok, Jin Hee; Jeong, Hae Jin; Lim, An Suk; Lee, Kyung Ha

2017-09-01

The phototrophic dinoflagellate Takayama helix that is known to be harmful to abalone larvae has recently been revealed to be mixotrophic. Although mixotrophy elevates the growth rate of T. helix by 79%-185%, its absolute growth rate is still as low as 0.3d -1 . Thus, if the mortality rate of T. helix due to predation is high, this dinoflagellate may not easily prevail. To investigate potential effective protistan grazers on T. helix, feeding by diverse heterotrophic dinoflagellates such as engulfment-feeding Oxyrrhis marina, Gyrodinium dominans, Gyrodinium moestrupii, Polykrikos kofoidii, and Noctiluca scintillans, peduncle-feeding Aduncodinium glandula, Gyrodiniellum shiwhaense, Luciella masanensis, and Pfiesteria piscicida, pallium-feeding Oblea rotunda and Protoperidinium pellucidum, and the naked ciliates Pelagostrobilidium sp. (ca. 40μm in cell length) and Strombidinopsis sp. (ca. 150μm in cell length) on T. helix was explored. Among the tested heterotrophic protists, O. marina, G. dominans, G. moestrupii, A. glandula, L. masanensis, P. kofoidii, P. piscicida, and Strombidinopsis sp. were able to feed on T. helix. The growth rates of all these predators except Strombidinopsis sp. with T. helix prey were lower than those without the prey. The growth rate of Strombidinopsis sp. on T. helix was almost zero although the growth rate of Strombidinopsis sp. with T. helix prey was higher than those without the prey. Moreover, T. helix fed on O. marina and P. pellucidum and lysed the cells of P. kofoidii and G. shiwhaense. With increasing the concentrations of T. helix, the growth rates of O. marina and P. kofoidii decreased, but those of G. dominans and L. masanensis largely did not change. Therefore, reciprocal predation, lysis, no feeding, and the low ingestion rates of the common protists preying on T. helix may result in a low mortality rate due to predation, thereby compensating for this species' low growth rate. Copyright © 2017 Elsevier B.V. All rights

TideWatch: Fingerprinting the cyclicality of big data workloads

KAUST Repository

Williams, Daniel W.

2014-04-01

Intrinsic to \\'big data\\' processing workloads (e.g., iterative MapReduce, Pregel, etc.) are cyclical resource utilization patterns that are highly synchronized across different resource types as well as the workers in a cluster. In Infrastructure as a Service settings, cloud providers do not exploit this characteristic to better manage VMs because they view VMs as \\'black boxes.\\' We present TideWatch, a system that automatically identifies cyclicality and similarity in running VMs. TideWatch predicts period lengths of most VMs in Hadoop workloads within 9% of actual iteration boundaries and successfully classifies up to 95% of running VMs as participating in the appropriate Hadoop cluster. Furthermore, we show how TideWatch can be used to improve the timing of VM migrations, reducing both migration time and network impact by over 50% when compared to a random approach. © 2014 IEEE.

Correcting GRACE gravity fields for ocean tide effects

DEFF Research Database (Denmark)

Knudsen, Per; Andersen, Ole Baltazar

2002-01-01

[1] The GRACE mission will be launch in early 2002 and will map the Earth's gravity fields and its variations with unprecedented accuracy during its 5-year lifetime. Unless ocean tide signals and their load upon the solid earth are removed from the GRACE data, their long period aliases obscure more...... tide model if altimetry corrected for inverted barometer effects was used in its derivation. To study the temporal characteristics of the ocean tidal constituents when sampled by GRACE, approximate alias frequencies were derived assuming a sampling of half a sidereal day. Those results show...

Tides and sea-level variability

Digital Repository Service at National Institute of Oceanography (India)

Shetye, S.R.; Suresh, I.; Sundar, D.

of the gravitational pull of the Moon and the Sun exerted on the waters of the ocean as the three-body system consisting of the Earth, Moon, and Sun moves in a stable configuration under the influence of the gravitational pull of one another. Tides at any location...

Collective Motion of Micro-organisms from Field Theoretical Viewpoint

OpenAIRE

Nojiri, Shin'ichi; Kawamura, Masako; Sugamoto, Akio

1995-01-01

We analyze the collective motion of micro-organisms in the fluid and consider the problem of the red tide. The red tide is produced by the condensation of the micro-organisms, which might be a similar phenomenon to the condensation of the strings. We propose a model of the generation of the red tide. By considering the interaction between the micro- organisms mediated by the velocity fields in the fluid, we derive the Van der Waals type equation of state, where the generation of the red tide ...

Seasonality and toxin production of Pyrodinium bahamense in a Red Sea lagoon

KAUST Repository

Banguera Hinestroza, Eulalia

2016-03-19

Harmful algal blooms of the dinoflagellate Pyrodinium bahamense have caused human and economic losses in the last decades. This study, for the first time, documents a bloom of P. bahamense in the Red Sea. The alga was recurrently present in a semi-enclosed lagoon throughout nearly 2 years of observations. The highest cell densities (104-105 cells L-1) were recorded from September to beginning of December at temperatures and salinities of ~26-32 °C and ~41, respectively. The peak of the bloom was recorded mid-November, before a sharp decrease in cell numbers at the end of December. Minimum concentrations in summer were at ~103 cells L-1. A saxitoxin ELISA immunoassay of cultures and water samples confirmed the toxicity of the strain found in the Red Sea. Moreover, a gene expression analysis of the saxitoxin gene domain SxtA4 showed that transcript production peaked at the culmination of the bloom, suggesting a relation between transcript production, sudden cells increment-decline, and environmental factors. © 2016 Elsevier B.V.

Seasonality and toxin production of Pyrodinium bahamense in a Red Sea lagoon.

Science.gov (United States)

Banguera-Hinestroza, E; Eikrem, W; Mansour, H; Solberg, I; Cúrdia, J; Holtermann, K; Edvardsen, B; Kaartvedt, S

2016-05-01

Harmful algal blooms of the dinoflagellate Pyrodinium bahamense have caused human and economic losses in the last decades. This study, for the first time, documents a bloom of P. bahamense in the Red Sea. The alga was recurrently present in a semi-enclosed lagoon throughout nearly 2 years of observations. The highest cell densities (10 4 -10 5 cellsL -1 ) were recorded from September to beginning of December at temperatures and salinities of ∼26-32°C and ∼41, respectively. The peak of the bloom was recorded mid-November, before a sharp decrease in cell numbers at the end of December. Minimum concentrations in summer were at ∼10 3 cellsL -1 . A saxitoxin ELISA immunoassay of cultures and water samples confirmed the toxicity of the strain found in the Red Sea. Moreover, a gene expression analysis of the saxitoxin gene domain SxtA4 showed that transcript production peaked at the culmination of the bloom, suggesting a relation between transcript production, sudden cells increment-decline, and environmental factors. Copyright © 2016 Elsevier B.V. All rights reserved.

Twenty Years of Progress on Global Ocean Tides: The Impact of Satellite Altimetry

Science.gov (United States)

Egbert, Gary; Ray, Richard

2012-01-01

At the dawn of the era of high-precision altimetry, before the launch of TOPEX/Poseidon, ocean tides were properly viewed as a source of noise--tidal variations in ocean height would represent a very substantial fraction of what the altimeter measures, and would have to be accurately predicted and subtracted if altimetry were to achieve its potential for ocean and climate studies. But to the extent that the altimetry could be severely contaminated by tides, it also represented an unprecedented global-scale tidal data set. These new data, together with research stimulated by the need for accurate tidal corrections, led to a renaissance in tidal studies in the oceanographic community. In this paper we review contributions of altimetry to tidal science over the past 20 years, emphasizing recent progress. Mapping of tides has now been extended from the early focus on major constituents in the open ocean to include minor constituents, (e.g., long-period tides; non-linear tides in shelf waters, and in the open ocean), and into shallow and coastal waters. Global and spatially local estimates of tidal energy balance have been refined, and the role of internal tide conversion in dissipating barotropic tidal energy is now well established through modeling, altimetry, and in situ observations. However, energy budgets for internal tides, and the role of tidal dissipation in vertical ocean mixing remain controversial topics. Altimetry may contribute to resolving some of these important questions through improved mapping of low-mode internal tides. This area has advanced significantly in recent years, with several global maps now available, and progress on constraining temporally incoherent components. For the future, new applications of altimetry (e.g., in the coastal ocean, where barotropic tidal models remain inadequate), and new mission concepts (studies of the submesoscale with SWOT, which will require correction for internal tides) may bring us full circle, again pushing

Eutrophication signals in the sedimentary record of dinoflagellate cysts in coastal waters

Science.gov (United States)

Dale, Barrie

2009-01-01

A brief review is presented of the current status of eutrophication signals from the sedimentary records of dinoflagellate cysts in coastal waters, particularly of NW Europe. There is a dearth of the multi-decadal time series data from plankton needed to document eutrophication, and the cysts may provide an alternative source of information. Two different eutrophication signals have been described so far from cyst records: 1) from the Oslofjord, comprising a marked increase in total cyst concentrations (interpreted as probably reflecting increased phytoplankton productivity), with Lingulodinium polyedrum cysts accounting for most of the increase (interpreted as a species particularly benefiting from added nutrients from cultural eutrophication in late summer when nutrients otherwise may be limiting); and 2) the heterotroph signal, from several other Norwegian fjords and Tokyo Bay, Japan, involving both cases of increased cyst concentrations and others with no particular increase, but with a marked proportional increase in cysts of heterotrophic species (interpreted as reflecting increased diatoms and possibly other prey for the heterotrophic dinoflagellates and/or more unfavourable conditions for autotrophs, e.g. from shading). These signals should be used critically, and there is a particular need to distinguish between eutrophication signals and climate signals that may be co-occurring at a given time. Work by various authors has generally supported the concept of these cyst-based signals since they were first published, including both further records from cored sediments from other parts of the world and studies relating cyst distributions in surface sediments to gradients of pollution and nutrients from sewage discharge. Recent, unpublished work by Dale and Sætre, linked cyst signals in cored sediments to the timing of collapse of local fisheries at different times within the past fifty years in four fjord systems along the Norwegian Skagerrak coast

Allelopathic effects of Alexandrium tamarense on other algae: evidence from mixed growth experiments

DEFF Research Database (Denmark)

Tillmann, Urban; Hansen, Per Juel

2009-01-01

period, even though cell concentrations of Alex5 became very high (2 × 104 cells ml-1). As both strains contained comparable amounts of PST, this confirmed previous suggestions that so far unidentified compounds are causing the negative effects on other algae. Sensitivity of the tested algae to Alex2......The effect of 2 strains (Alex2 and Alex5) of the marine red tide dinoflagellate Alexandrium tamarense on 10 other planktonic algal target species common in temperate waters was studied in mixed growth experiments under nutrient-rich conditions. In a comparative approach, the 2 strains of A....... tamarense, similar in their cellular paralytic shellfish toxin (PST) content, were selected because of their fundamentally different lytic potencies. The Alex2 strain clearly affected all target algae while the Alex5 strain had no negative effect on the growth of any of the target species during the study...

Tracking the history of dinoflagellate cyst assemblages in sediments from the west coast of India

Digital Repository Service at National Institute of Oceanography (India)

DeSilva, M.S.; Anil, A.C.; Borole, D.V.; Nath, B.N.; Singhal, R.K.

In order to trace the history of dinoflagellate cyst assemblages and provide new insights in to Harmful Algal Bloom (HAB) dynamics in monsoon influenced tropical environments, sediment cores were collected from four different coastal locations along...

On the Temporal Variability of Low-Mode Internal Tides in the Deep Ocean

Science.gov (United States)

Ray, Richard D.; Zaron, E. D.

2010-01-01

In situ measurements of internal tides are typically characterized by high temporal variability, with strong dependence on stratification, mesoscale eddies, and background currents commonly observed. Thus, it is surprising to find phase-locked internal tides detectable by satellite altimetry. An important question is how much tidal variability is missed by altimetry. We address this question in several ways. We subset the altimetry by season and find only very small changes -- an important exception being internal tides in the South China Sea where we observe strong seasonal dependence. A wavenumber-domain analysis confirms that throughout most of the global ocean there is little temporal variability in altimetric internal-tide signals, at least in the first baroclinic mode, which is the mode that dominates surface elevation. The analysis shows higher order modes to be significantly more variable. The results of this study have important practical implications for the anticipated SWOT wide-swath altimeter mission, for which removal of internal tide signals is critical for observing non-tidal submesoscale phenomena.

Molecular characterization and morphology of the photosynthetic dinoflagellate Bysmatrum caponii from two solar saltons in western Korea

Science.gov (United States)

Jeong, Hae Jin; Jang, Se Hyeon; Kang, Nam Seon; Yoo, Yeong Du; Kim, Min Jeong; Lee, Kyung Ha; Yoon, Eun Young; Potvin, Éric; Hwang, Yeong Jong; Kim, Jong Im; Seong, Kyeong Ah

2012-03-01

Species belonging to the genus Bysmatrum are peridinoid, thecate, photosynthetic dinoflagellates. The plate formula of Bysmatrum spp., arranged in a Kofoidian series, is almost identical to that of Scrippsiella spp. Bysmatrum spp., which were originally classified as Scrippsiella spp., but were transferred to the genus Bysmatrum spp. because of separation of the intercalary plates 2a and 3a by plate 3'. Whether this transfer from Scrippsiella spp. to Bysmatrum spp. is reasonable should be genetically confirmed. Dinoflagellates were isolated from 2 solar saltons located in western Korea in 2009-2010 and 3 clonal cultures from Sooseong solar saltons and 2 clonal cultures from Garolim solar saltons were successfully established. All of these dinoflagellates were identified as Bysmatrum caponii based on morphology analysis by light and electron microscopy. The plates of all Korean strains of B. caponii were arranged in a Kofoidian series of Po, X, 4', 3a, 7″, 6c, 4s, 5‴, 0 (p), and 24'. When properly aligned, the ribosomal DNA (rDNA) sequences of the 3 Sooseong strains of B. caponii were identical, as were those of the 2 Garolim strains. Furthermore, the sequences of the 3 Sooseong strains were 0.01% different from those of the Garolim strains. However, the sequences of SSU rDNA of these Korean B. caponii strains were 9% different from that of Bysmatrum subsalsum and > 10% from that of any other dinoflagellate thus far reported. In the phylogenetic trees generated using SSU and LSU rDNA sequences, these Korean B. caponii strains formed a clade with B. subsalsum which was clearly divergent from the Scrippsiella clade. However, this Bysmatrum clade was phylogenetically close to the Protoperidinium and/or Peridinium clades. The results of the present study suggest that Bysmatrum spp. are markedly different genetically from Scrippsiella spp..

Partly standing internal tides in a dendritic submarine canyon observed by an ocean glider

Science.gov (United States)

Hall, Rob A.; Aslam, Tahmeena; Huvenne, Veerle A. I.

2017-08-01

An autonomous ocean glider is used to make the first direct measurements of internal tides within Whittard Canyon, a large, dendritic submarine canyon system that incises the Celtic Sea continental slope and a site of high benthic biodiversity. This is the first time a glider has been used for targeted observations of internal tides in a submarine canyon. Vertical isopycnal displacement observations at different stations fit a one-dimensional model of partly standing semidiurnal internal tides - comprised of a major, incident wave propagating up the canyon limbs and a minor wave reflected back down-canyon by steep, supercritical bathymetry near the canyon heads. The up-canyon internal tide energy flux in the primary study limb decreases from 9.2 to 2.0 kW m-1 over 28 km (a dissipation rate of 1 - 2.5 ×10-7 Wkg-1), comparable to elevated energy fluxes and internal tide driven mixing measured in other canyon systems. Within Whittard Canyon, enhanced mixing is inferred from collapsed temperature-salinity curves and weakened dissolved oxygen concentration gradients near the canyon heads. It has previously been hypothesised that internal tides impact benthic fauna through elevated near-bottom current velocities and particle resuspension. In support of this, we infer order 20 cm s-1 near-bottom current velocities in the canyon and observe high concentrations of suspended particulate matter. The glider observations are also used to estimate a 1 °C temperature range and 12 μmol kg-1 dissolved oxygen concentration range, experienced twice a day by organisms on the canyon walls, due to the presence of internal tides. This study highlights how a well-designed glider mission, incorporating a series of tide-resolving stations at key locations, can be used to understand internal tide dynamics in a region of complex topography, a sampling strategy that is applicable to continental shelves and slopes worldwide.

Three-Dimensional Structures of Thermal Tides Simulated by a Venus GCM

Science.gov (United States)

Takagi, Masahiro; Sugimoto, Norihiko; Ando, Hiroki; Matsuda, Yoshihisa

2018-02-01

Thermal tides in the Venus atmosphere are investigated by using a GCM named as AFES-Venus. The three-dimensional structures of wind and temperature associated with the thermal tides obtained in our model are fully examined and compared with observations. The result shows that the wind and temperature distributions of the thermal tides depend complexly on latitude and altitude in the cloud layer, mainly because they consist of vertically propagating and trapped modes with zonal wave numbers of 1-4, each of which predominates in different latitudes and altitudes under the influence of mid- and high-latitude jets. A strong circulation between the subsolar and antisolar (SS-AS) points, which is equivalent to a diurnal component of the thermal tides, is superposed on the superrotation. The vertical velocity of SS-AS circulation is about 10 times larger than that of the zonal-mean meridional circulation (ZMMC) in 60-70 km altitudes. It is suggested that the SS-AS circulation could contribute to the material transport, and its upward motion might be related to the UV dark region observed in the subsolar and early afternoon regions in low latitudes. The terdiurnal and quaterdiurnal tides, which may be excited by the nonlinear interactions among the diurnal and semidiurnal tides in middle and high latitudes, are detected in the solar-fixed Y-shape structure formed in the vertical wind field in the upper cloud layer. The ZMMC is weak and has a complex structure in the cloud layer; the Hadley circulation is confined to latitudes equatorward of 30°, and the Ferrel-like one appears in middle and high latitudes.

Effects of three macroalgae, Ulva linza (Chlorophyta), Corallina pilulifera (Rhodophyta) and Sargassum thunbergii (Phaeophyta) on the growth of the red tide microalga Prorocentrum donghaiense under laboratory conditions

Science.gov (United States)

Wang, Renjun; Xiao, Hui; Wang, You; Zhou, Wenli; Tang, Xuexi

2007-10-01

Allelopathic effects of several concentrations of fresh tissue and dry powder of three macroalgae, Ulva linza, Corallina pilulifera and Sargassum thunbergii, on the red tide microalga Prorocentrum donghaiense were evaluated in microcosms. Preliminary studies on the algicidal effects of one aqueous and four organic solvent extracts from the macroalgae on the microalga were carried out to confirm the existence of allelochemicals in the tissues of the macroalgae. The effects of macroalgal culture medium filtrate on P. donghaiense were investigated using initial or semi-continuous filtrate addition. Furthermore, the potential effects of the microalga on these three macroalgae were also tested. The results of the microcosm assay showed that the growth of P. donghaiense was strongly inhibited by using fresh tissues and dry powder of the three macroalgae. Both aqueous and methanol extracts of the macroalgae had strong growth inhibitory effects on P. donghaiense, while the other three organic solvent extracts (acetone, ether and chloroform) had no apparent effect on its growth; this suggested that the allelochemicals from these three macroalga had relatively high polarities. The three macroalgal culture medium filtrates exhibited apparent growth inhibitory effect on the microalgae under initial or semi-continuous addition, which suggested that the cells of P. donghaiense are sensitive to the allelochemicals. In contrast, P. donghaiense had no apparent effect on the growth of the macroalgae in coexistence experiment.

Differential effects of ocean acidification on carbon acquisition in two bloom-forming dinoflagellate species

NARCIS (Netherlands)

Eberlein, T.; Van de Waal, D.B.; Rost, B.

2014-01-01

Dinoflagellates represent a cosmopolitan group of phytoplankton with the ability to form harmful algal blooms. Featuring a Ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) with very low CO2-affinities, photosynthesis of this group may be particularly prone to carbon limitation and thus

Exploring Marine Science through the University of Delaware's TIDE camp

Science.gov (United States)

Veron, D. E.; Newton, F. A.; Veron, F.; Trembanis, A. C.; Miller, D. C.

2012-12-01

For the past five years, the University of Delaware has offered a two-week, residential, summer camp to rising sophomores, juniors, and seniors who are interested in marine science. The camp, named TIDE (Taking an Interest in Delaware's Estuary) camp, is designed to introduce students to the breadth of marine science while providing them with a college experience. Campers participate in a variety of academic activities which include classroom, laboratory, and field experiences, as well as numerous social activities. Two unique features of this small, focused camp is the large number of university faculty that are involved, and the ability of students to participate in ongoing research projects. At various times students have participated in fish and dolphin counts, AUV deployment, wind-wave tank experiments, coastal water and beach studies, and ROV activities. In addition, each year campers have participated in a local service project. Through communication with former TIDE participants, it is clear that this two-week, formative experience plays a large role in students choice of major when entering college.2012 Tide Camp - Salt marsh in southern Delaware 2012 Tide Camp - Field trip on a small boat

Atmospheric tides on Neptune

International Nuclear Information System (INIS)

Dement'ev, M.S.; Morozhenko, A.V.

1989-01-01

The dependence of the equivalent width of the methane absorption band at 619 nm in the Neptune's spectrum upon the Triton's orbital position is discovered. It is assumed that observed changes of the equivalent width of the band and colour index (J - K) (Belton et al., 1981; Brown et al., 1981; Cruikshank, 1978) are due to atmospheric tides (period 2 d .9375) and Neptune's rotation (period 10 h .14)

Palynological investigation of the sediment cores from the Arabian Sea 2: Dinoflagellate cysts and acritarchs

Digital Repository Service at National Institute of Oceanography (India)

Saxena, R.K.; Chandra, A.; Setty, M.G.A.P.

The present paper incorporates the study of dinoflagellate cysts and acritarchs recovered from five sediment cores from the Arabian Sea This assemblage is represented by 15 genera and 22 species Of these, 14 species belonging to 11 genera...

Evaluation of Ocean Tide Models Used for Jason-2 Altimetry Corrections

DEFF Research Database (Denmark)

Fok, H.S.; Baki Iz, H.; Shum, C. K.

2010-01-01

It has been more than a decade since the last comprehensive accuracy assessment of global ocean tide models. Here, we conduct an evaluation of the barotropic ocean tide corrections, which were computed using FES2004 and GOT00.2, and other models on the Jason-2 altimetry Geophysical Data Record (G...

On Measurements of the Tide at Churchill, Hudson Bay

Science.gov (United States)

Ray, Richard D.

2016-01-01

Since the late 1990s the semi-diurnal tide at Churchill, on the western shore of Hudson Bay, has been decreasing in amplitude, with M(sub 2) amplitudes falling from approximately 154 cm in 1998 to 146 cm in 2012 and 142 cm in 2014. There has been a corresponding small increase in phase lag. Mean low water, decreasing throughout most of the twentieth century, has levelled off. Although the tidal changes could reflect merely a malfunctioning tide gauge, the fact that there are no other measurements in the region and the possibility that the tide is revealing important environmental changes calls for serious investigation. Satellite altimeter measurements of the tide in Hudson Bay are complicated by the seasonal ice cover; at most locations less than 40% of satellite passes return valid ocean heights and even those can be impacted by errors from sea ice. Because the combined TOPEX/Poseidon, Jason-1, and Jason-2 time series is more than 23 years long, it is now possible to obtain sufficient data at crossover locations near Churchill to search for tidal changes. The satellites sense no changes in M(sub 2) that are comparable to the changes seen at the Churchill gauge. The changes appear to be localized to the harbour, or to the Churchill River, or to the gauge itself.

Thermal Tides During the 2001 Martian Global-Scale Dust Storm

Science.gov (United States)

Guzewich, Scott D.; Wilson, R. John; McConnochie, Timothy H.; Toigo, Anthony D.; Bandfield, Donald J.; Smith, Michael D.

2014-01-01

The 2001 (Mars Year 25) global dust storm radically altered the dynamics of the Martian atmosphere. Using observations from the Thermal Emission Spectrometer onboard the Mars Global Surveyor spacecraft and Mars WRF general circulation model simulations, we examine the changes to thermal tides and planetary waves caused by the storm. We find that the extratropical diurnal migrating tide is dramatically enhanced during the storm, particularly in the southern hemisphere, reaching amplitudes of more than 20 K. The tropical diurnal migrating tide is weakened to almost undetectable levels. The diurnal Kelvin waves are also significantly weakened, particularly during the period of global expansion at Ls=200deg-210deg. In contrast, the westward propagating diurnal wavenumber 2 tide strengthens to 4-8 K at altitudes above 30km. The wavenumber 1 stationary wave reaches amplitudes of 10-12 K at 50deg-70degN, far larger than is typically seen during this time of year. The phase of this stationary wave and the enhancement of the diurnal wavenumber 2 tide appear to be responses to the high-altitude westward propagating equatorial wavenumber 1 structure in dust mixing ratio observed during the storm in previous works. This work provides a global picture of dust storm wave dynamics that reveals the coupling between the tropics and high-latitude wave responses. We conclude that the zonal distribution of thermotidal forcing from atmospheric aerosol concentration is as important to understanding the atmospheric wave response as the total global mean aerosol optical depth.

Effects of Long Period Ocean Tides on the Earth's Rotation

Science.gov (United States)

Gross, Richard S.; Chao, Ben F.; Desai, Shailen D.

1996-01-01

The spectra of polar motion excitation functions exhibit enhanced power in the fortnightly tidal band. This enhanced power is attributed to ocean tidal excitation. Ocean tide models predict polar motion excitation effects that differ with each other, and with observations, by factors as large as 2-3. There is a need for inproved models for the effect of long-period ocean tides on Earth's rotation.

Propagation of the Semidiurnal Internal Tide: Phase Velocity Versus Group Velocity

Science.gov (United States)

Zhao, Zhongxiang

2017-12-01

The superposition of two waves of slightly different wavelengths has long been used to illustrate the distinction between phase velocity and group velocity. The first-mode M2 and S2 internal tides exemplify such a two-wave model in the natural ocean. The M2 and S2 tidal frequencies are 1.932 and 2 cycles per day, respectively, and their superposition forms a spring-neap cycle in the semidiurnal band. The spring-neap cycle acts like a wave, with its frequency, wave number, and phase being the differences of the M2 and S2 internal tides. The spring-neap cycle and energy of the semidiurnal internal tide propagate at the group velocity. Long-range propagation of M2 and S2 internal tides in the North Pacific is observed by satellite altimetry. Along a 3,400 km beam spanning 24°-54°N, the M2 and S2 travel times are 10.9 and 11.2 days, respectively. For comparison, it takes the spring-neap cycle 21.1 days to travel over this distance. Spatial maps of the M2 phase velocity, the S2 phase velocity, and the group velocity are determined from phase gradients of the corresponding satellite observed internal tide fields. The observed phase and group velocities agree with theoretical values estimated using the World Ocean Atlas 2013 annual-mean ocean stratification.

Mapping nonlinear shallow-water tides: a look at the past and future

DEFF Research Database (Denmark)

Andersen, Ole Baltazar; Egbert, G.D.; Erofeeva, S.Y.

2006-01-01

advanced by the pioneering researches of Christian Le Provost who employed analytical theory, physical modeling, and numerical modeling in many extensive studies, especially of the tides of the English Channel. Le Provost's complementary work with satellite altimetry motivates our attempts to merge...... these two interests. After a brief review, we describe initial steps toward the assimilation of altimetry into models of nonlinear tides via generalized inverse methods. A series of barotropic inverse solutions is computed for the M-4 tide over the northwest European Shelf. Future applications of altimetry...

Gonyaulax taylorii, a new yessotoxins-producer dinoflagellate species from Chilean waters.

Science.gov (United States)

Álvarez, Gonzalo; Uribe, Eduardo; Regueiro, Jorge; Blanco, Juan; Fraga, Santiago

2016-09-01

In summer 2009, during a survey in Bahía Mejillones, a dense bloom of a dinoflagellate from the genus Gonyaulax was detected, as well as the presence of yessotoxin. Phytoplankton samples were analyzed in detail by light and scanning electron microscopy (SEM), revealing the presence of Gonyaulax taylorii. Morphological examination showed that the cells in the bloom fit in Gonyaulax jollifei Murray et Whitting sensu Dodge, subsequently classified as Gonyaulax taylorii by Carbonell-Moore. In this context, some inconsistencies have been found in regard to the holotype; the plate 1"' appears as two plates, 1‴ and 2‴, showing a suture that does not exist in Dodge's figure of G. jollifei, from where the holotype was drawn, nor within the samples collected. Therefore, this plate has been originally described erroneously as two plates named 1"' and 2"' instead of only one named 1‴. After this correction, this species has five instead of six postcingular plates. For this reason, the description of this species must be emended. Phytoplankton net samples were found to contain yessotoxin and homoyessotoxin, with concentrations below 1pgcell -1 . The present study identifies, therefore, the dinoflagellate G. taylorii as a new source of yessotoxins. Copyright © 2016 Elsevier B.V. All rights reserved.

Ribosomal RNA analysis indicates a benthic pennate diatom ancestry for the endosymbionts of the dinoflagellates Peridinium foliaceum and Peridinium balticum (Pyrrhophyta).

Science.gov (United States)

Chesnick, J M; Kooistra, W H; Wellbrock, U; Medlin, L K

1997-01-01

The establishment of chloroplasts as cellular organelles in the dinoflagellate, heterokont (stramenopile), haptophyte, and cryptophyte algae is widely accepted to have been the result of secondary endosymbiotic events, that is, the uptake of a photosynthetic eukaryote by a phagotrophic eukaryote. However, the circumstances that promote such associations between two phylogenetically distinct organisms and result in the integration of their genomes to form a single functional photosynthetic cell is unclear. The dinoflagellates Peridinium foliaceum and Peridinium balticum are unusual in that each contains a membrane-bound eukaryotic heterokont endosymbiont. These symbioses have been interpreted, through data derived from ultrastructural and biochemical investigations, to represent an intermediate stage of secondary endosymbiotic chloroplast acquisition. In this study we have examined the phylogenetic origin of the P. foliaceum and P. balticum heterokont endosymbionts through analysis of their nuclear small subunit ribosomal RNA genes. Our analyses clearly demonstrate both endosymbionts are pennate diatoms belonging to the family Bacillariaceae. Since members of the Bacillariaceae are usually benthic, living on shallow marine sediments, the manner in which establishment of a symbiosis between a planktonic flagellated dinoflagellate and a bottom-dwelling diatom is discussed. In particular, specific environmentally-associated life strategy stages of the host and symbiont, coupled with diatom food preferences by the dinoflagellate, may have been vital to the formation of this association.

Modelling explicit tides in the Indonesian seas: An important process for surface sea water properties.

Science.gov (United States)

Nugroho, Dwiyoga; Koch-Larrouy, Ariane; Gaspar, Philippe; Lyard, Florent; Reffray, Guillaume; Tranchant, Benoit

2017-06-16

Very intense internal tides take place in Indonesian seas. They dissipate and affect the vertical distribution of temperature and currents, which in turn influence the survival rates and transports of most planktonic organisms at the base of the whole marine ecosystem. This study uses the INDESO physical model to characterize the internal tides spatio-temporal patterns in the Indonesian Seas. The model reproduced internal tide dissipation in agreement with previous fine structure and microstructure observed in-situ in the sites of generation. The model also produced similar water mass transformation as the previous parameterization of Koch-Larrouy et al. (2007), and show good agreement with observations. The resulting cooling at the surface is 0.3°C, with maxima of 0.8°C at the location of internal tides energy, with stronger cooling in austral winter. The cycle of spring tides and neap tides modulates this impact by 0.1°C to 0.3°C. These results suggest that mixing due to internal tides might also upwell nutrients at the surface at a frequency similar to the tidal frequencies. Implications for biogeochemical modelling are important. Copyright © 2017 Elsevier Ltd. All rights reserved.

Warm mid-Cretaceous high-latitude sea-surface temperatures from the southern Tethys Ocean and cool high-latitude sea-surface temperatures from the Arctic Ocean: asymmetric worldwide distribution of dinoflagellates

Science.gov (United States)

Masure, Edwige; Desmares, Delphine; Vrielynck, Bruno

2014-05-01

Dealing with 87 articles and using a Geographical Information System, Masure and Vrielynck (2009) have mapped worldwide biogeography of 38 Late Albian dinoflagellate cysts and have demonstrated Cretaceous oceanic bioclimatic belts. For comparison 30 Aptian species derived from 49 studies (Masure et al., 2013) and 49 Cenomanian species recorded from 33 articles have been encountered. Tropical, Subtropical, Boreal, Austral, bipolar and cosmopolitan species have been identified and Cretaceous dinoflagellate biomes are introduced. Asymmetric distribution of Aptian and Late Albian/Cenomanian subtropical Tethyan species, from 40°N to 70°S, demonstrates asymmetric Aptian and Late Albian/Cenomanian Sea Surface Temperature (SST) gradients with warm water masses in high latitudes of Southern Ocean. The SST gradients were stronger in the Northern Hemisphere than in the Southern Hemisphere. We note that Aptian and Late Albian/Cenomanian dinoflagellates restricted to subtropical and subpolar latitudes met and mixed at 35-40°N, while they mixed from 30°S to 70°S and from 50°S to 70°S respectively in the Southern Hemisphere. Mixing belts extend on 5° in the Northern Hemisphere and along 40° (Aptian) and 20° (Late Albian/Cenomanian) in the Southern one. The board southern mixing belt of Tethyan and Austral dinoflagellates suggest co-occurrence of warm and cold currents. We record climatic changes such as the Early Aptian cooler period and Late Aptian and Albian warming through the poleward migration of species constrained to cool water masses. These species sensitive to temperature migrated from 35°N to 55°N through the shallow Greenland-Norwergian Seaway connecting the Central Atlantic and the Arctic Ocean. While Tethyan species did not migrate staying at 40°N. We suggest that the Greenland-Norwergian Seaway might has been a barrier until Late Albian/Cenomanian for oceanic Tethyan dinoflagellates stopped either by the shallow water column or temperature and salinity

River flow controls on tides an tide-mean water level profiles in a tidel freshwater river

NARCIS (Netherlands)

Sassi, M.G.; Hoitink, A.J.F.

2013-01-01

[1] Tidal rivers feature oscillatory and steady gradients in the water surface, controlled by interactions between river flow and tides. The river discharge attenuates the tidal motion, and tidal motion increases tidal-mean friction in the river, which may act as a barrier to the river discharge.

Multi-satellite ocean tide modelling - the K-1 constituent

DEFF Research Database (Denmark)

Andersen, Ole Baltazar; Knudsen, Per

1997-01-01

All major ocean tide constituents are aliased into signals with periods less than 90 days from TOPEX/POSEIDON altimetry, except the K-1 constituent. The aliased K-1 has a period of 173 days. Consequently, it might be confounded with height variations caused by the semiannual cycle having a period......, where the presence of crossing tracks cannot separate K-1 from the semiannual signal from TOPEX/POSEIDON, the importance of including ERS-1 and GEOSAT observations was demonstrated. A comparison with 29 pelagic and coastal tide gauges in the Southern Ocean south of 50 degrees S gave 5.59 (M-2), 2.27 (S......-2) and 5.04 (K-1) cm RMS agreement for FES95.1 ocean tide model. The same comparison for the best empirical estimated constituents based on TOPEX/POSEIDON + ERS-1 + GEOSAT gave 4.32, 2.21, and 4.29 cm for M-2, S-2 and K-1, respectively....

Tides Stabilize Deltas until Humans Interfere

Science.gov (United States)

Hoitink, T.; Zheng Bing, W.; Vermeulen, B.; Huismans, Y.; Kastner, K.

2017-12-01

Despite global concerns about river delta degradation caused by extraction of natural resources, sediment retention by reservoirs and sea-level rise, human activity in the world's largest deltas intensifies. In this review, we argue that tides tend to stabilize deltas until humans interfere. Under natural circumstances, delta channels subject to tides are more stable than their fluvial-dominated counterparts. The oscillatory tidal flow counteracts the processes responsible for bank erosion, which explains why unprotected tidal channels migrate only slowly. Peak river discharges attenuate the tides, which creates storage space to accommodate the extra river discharge during extreme events and as a consequence, reduce flood risk. With stronger tides, the river discharge is being distributed more evenly over the various branches in a delta, preventing silting up of smaller channels. Human interference in deltas is massive. Storm surge barriers are constructed, new land is being reclaimed and large-scale sand excavation takes place, to collect building material. Evidence from deltas around the globe shows that in human-controlled deltas the tidal motion often plays a destabilizing role. In channels of the Rhine-Meuse Delta, some 100 scour holes are identified, which relates to the altered tidal motion after completion of a storm surge barrier. Sand mining has led to widespread river bank failures in the tidally-influenced Mekong Delta. The catastrophic flood event in the Gauges-Brahmaputra Delta by Cyclone Aila, which caused the inundation of an embanked polder area for over two years, was preceded by river bank erosion at the mouths of formal tidal channels that were blocked by the embankment. Efforts to predict the developments of degrading deltas are few. Existing delta models are capable of reproducing expanding deltas, which is essentially a matter of simulating the transport of sediment from source in a catchment to the sink in a delta. Processes of soil

Polyuridylylation and processing of transcripts from multiple gene minicircles in chloroplasts of the dinoflagellate Amphidinium carterae

KAUST Repository

Barbrook, Adrian C.; Dorrell, Richard G.; Burrows, Jennifer; Plenderleith, Lindsey J.; Nisbet, R. Ellen R.; Howe, Christopher J.

2012-01-01

-PCR to study transcription and transcript processing in the chloroplasts of Amphidinium carterae, a model peridinin-containing dinoflagellate. These organisms have a highly unusual chloroplast genome, with genes located on multiple small 'minicircle' elements

Consortial brown tide − picocyanobacteria blooms in Guantánamo Bay, Cuba

Science.gov (United States)

Hall, Nathan S; Litaker, R. Wayne; Kenworthy, W. Judson; Vandersea, Mark W.; Sunda, William G.; Reid, James P.; Slone, Daniel H.; Butler, Susan M.

2018-01-01

A brown tide bloom of Aureoumbra lagunensis developed in Guantánamo Bay, Cuba during a period of drought in 2013 that followed heavy winds and rainfall from Hurricane Sandy in late October 2012. Based on satellite images and water turbidity measurements, the bloom appeared to initiate in January 2013. The causative species (A. lagunensis) was confirmed by microscopic observation, and pigment and genetic analyses of bloom samples collected on May 28 of that year. During that time, A. lagunensis reached concentrations of 900,000 cells ml−1 (28 ppm by biovolume) in the middle portion of the Bay. Samples could not be collected from the northern (Cuban) half of the Bay because of political considerations. Subsequent sampling of the southern half of the Bay in November 2013, April 2014, and October 2014 showed persistent lower concentrations of A. lagunensis, with dominance shifting to the cyanobacterium Synechococcus (up to 33 ppm in April), an algal group that comprised a minor bloom component on May 28. Thus, unlike the brown tide bloom in Laguna Madre, which lasted 8 years, the bloom in Guantánamo Bay was short-lived, much like recent blooms in the Indian River, Florida. Although hypersaline conditions have been linked to brown tide development in the lagoons of Texas and Florida, observed euhaline conditions in Guantánamo Bay (salinity 35–36) indicate that strong hypersalinity is not a requirement for A. lagunensis bloom formation. Microzooplankton biomass dominated by ciliates was high during the observed peak of the brown tide, and ciliate abundance was high compared to other systems not impacted by brown tide. Preferential grazing by zooplankton on non-brown tide species, as shown in A. lagunensis blooms in Texas and Florida, may have been a factor in the development of the Cuban brown tide bloom. However, subsequent selection of microzooplankton capable of utilizing A. lagunensis as a primary food source may have contributed to the

Development and Use of Tide Models in Alaska Supporting VDatum and Hydrographic Surveying

Directory of Open Access Journals (Sweden)

Lei Shi

2014-03-01

Full Text Available National Oceanic and Atmospheric Administration’s National Ocean Service uses observations, hydrodynamic models and interpolation techniques to develop many of its products and services. We examine how two projects, computation of tidal datums for vertical datum transformation and the estimation of tidal characteristics for hydrographic surveys, are being developed in Alaska and how they may be more seamlessly integrated. Preliminary VDatum development for Alaska is in progress for the Alaska Panhandle through the setup of a high resolution tide model that will be used to compute spatially varying tidal datums. Tide models such as these can be used for other projects that traditionally rely on estimation of tides in between data locations, such as the planning for hydrographic surveys that need correctors to adjust bathymetry to the chart datum. We therefore also examine how an existing model in western Alaska can be used for better supporting hydrographic survey planning. The results show that integration of tide models with nearshore observations can provide improved information for these correctors and future work will further evaluate this methodology with existing VDatum tide models.

Numerical study of the effect of earth tides on recurring short-term slow slip events

Science.gov (United States)

Matsuzawa, T.; Tanaka, Y.; Shibazaki, B.

2017-12-01

Short-term slow slip events (SSEs) in the Nankai region are affected by earth tides (e.g., Nakata et al., 2008; Ide and Tanaka, 2014; Yabe et al., 2015). The effect of tidal stress on the SSEs is also examined numerically (e.g., Hawthorne and Rubin, 2013). In our previous study (Matsuzawa et al., 2017, JpGU-AGU), we numerically simulated SSEs in the Shikoku region, and reported that tidal stress makes the variance of recurrence intervals of SSEs smaller in relatively isolated SSE regions. However, the reason of such stable recurrence was not clear. In this study, we examine the tidal effect on short-term SSEs based on a flat plate and a realistic plate model (e.g., Matsuzawa et al., 2013, GRL). We adopt a rate- and state-dependent friction law (RS-law) with cutoff velocities as in our previous studies (Matsuzawa et al., 2013). We assume that (a-b) value in the RS-law is negative within the short-term SSE region, and positive outside the region. In a flat plate model, the short-term SSE region is a circular patch with the radius of 6 km. In a realistic plate model, the short-term SSE region is based on the actual distribution of low-frequency tremor. Low effective normal stress is assumed at the depth of SSEs. Calculating stress change by earth tides as in Yabe et al., (2015), we examine the stress perturbation by two different earth tides with the period of semidiurnal (M2) and fortnight (Mf) tide in this study. In the result of a flat plate case, amplitude of SSEs becomes smaller just after the slip at whole simulated area. Recurring SSEs become clear again within one year in the case with tides (M2 or Mf), while the recurrence becomes clear after seven years in the case without tides. Interestingly, the effect of the Mf tide is similar to the case with the M2 tide, even though the amplitude of the Mf tide (0.01 kPa) is two-order smaller than that of the M2 tide. In the realistic plate model of Shikoku, clear recurrence of short-term SSEs is found earlier than the

The Impact of the 1989 Exxon Valdez Oil Spill on Phytoplankton as Evidenced Through the Sedimentary Dinoflagellate Cyst Records in Prince William Sound (Alaska, USA).

Science.gov (United States)

Genest, M.; Pospelova, V.; Williams, J. R.; Dellapenna, T.; Mertens, K.; Kuehl, S. A.

2016-12-01

Large volumes of crude oil are extracted from marine environments and transported via the sea, putting coastal communities at a greater risk of oils spills. It is therefore crucial for these communities to properly assess the risk. The first step is to understand the effects of such events on the environment, which is limited by the lack of research on the impact of oil spills on phytoplankton. This first-of-its-kind research aims to identify how one of the major groups of phytoplankton, dinoflagellates, have been affected by the 1989 Exxon Valdez oil spill in Prince William Sound (PWS), Alaska. To do this, sedimentary records of dinoflagellate cysts, produced during dinoflagellate reproduction and preserved in the sediment, were analyzed. Two sediment cores were collected from PWS in 2012. The sediments are mainly composed of silt with a small fraction of clay. Both well-dated with 210Pb and 137Cs, the cores have high sedimentation rates, allowing for an annual to biannual resolution. Core 10 has a sedimentation rate of 1.1 cm yr-1 and provides continuous record since 1957, while Core 12 has a sedimentation rate of 1.3 cm yr-1 and spans from 1934. The cores were subsampled every centimeter for a total of 110 samples. Samples were treated using a standard palynological processing technique to extract dinoflagellate cysts and 300 cysts were counted per sample. In both cores, cysts were abundant, diverse and well preserved with the average cyst assemblage being characterized by an equal number of cysts produced by autotrophic and heterotrophic dinoflagellates. Of the 40 dinoflagellate cyst taxa, the most abundant are: Operculodinium centrocarpum and Brigantedinium spp. Other common species are: Spiniferites ramosus, cysts of Pentapharsodinium dalei, Echinidinium delicatum, E. zonneveldiae, E. transparantum, Islandinium minutum, and a thin pale brown Brigantedinium type. Changes in the sedimentary sequence of dinoflagellate cysts were analyzed by determining cyst

Investigations in Marine Chemistry: Tide Pool Ecology.

Science.gov (United States)

Schlenker, Richard M.

Students investigated the salinity of tide pools at different levels in the intertidal zone. Data are analyzed collectively. Students graphed and discussed data. Included are suggestions for evaluation and further study. (Author)

Growth and grazing responses of two chloroplast-retaining dinoflagellates: effect of irradiance and prey species

DEFF Research Database (Denmark)

Jakobsen, Hans Henrik; Hansen, P.J.; Larsen, J.

2000-01-01

The effect of irradiance on growth and grazing responses of 2 phagotrophic dinoflagellates, Gymnodinium gracilentum Campbell 1973 and Amphidinium poecilochroum Larsen 1985, was studied. While G. gracilentum belongs to the plankton, A. poecilochroum is a benthic species that primarily feeds on prey...

New insights into ocean tide loading corrections on tidal gravity data in Canary Islands

Science.gov (United States)

Arnoso, J.; Benavent, M.; Bos, M. S.; Montesinos, F. G.

2009-04-01

The Canary Islands are an interesting area to investigate ocean tides loading effects due to the complex coastline of the islands and the varying bathymetry. We present here the quality of five recent global oceanic tidal models, GOT00.2, GOT4.7, FES2004, TPXO.7.1 and AG2006, by comparing their predicted ocean tide loading values with results from tidal gravity observations made on three islands, Lanzarote, Tenerife and El Hierro, for the four harmonic constituents O1, K1, M2 and S2. In order to improve the accuracy of the loading corrections on the gravity tide measurements, we have used the high resolution regional oceanic model CIAM2 to supplement the global models considered here. This regional model has been obtained by assimilating TOPEX/Poseidon altimetry at crossovers and along-track points and tide gauge observations into a hydrodynamic model. The model has a 5'Ã-5' resolution and covers the area between the coordinates 26°.5N to 30°.0N and 19°.0W to 12°.5W. The gravity tide observing sites have been occupied by three different LaCoste&Romberg (LCR) spring gravimeters during different periods of observation. We considered here the most recent gravity tide observations made with LCR Graviton-EG1194 in El Hierro Island, for a period of 6 months during 2008. In the case of Tenerife and Lanzarote sites we have used observation periods of 6 months and 8 years with LCR-G665 and LCR-G434 gravimeters, respectively. The last two sites have been revisited in order to improve the previous tidal analysis results. Thus, the gravity ocean tide loading corrections, based on the five global ocean tide models supplemented with the regional model CIAM2 allowed us to review the normalization factors (scale factor and phase lag) of both two gravimeters. Also, we investigated the discrepancies of the corrected gravimetric factors with the DDW elastic and inelastic non hydrostatic body tide model (Dehant et al., 1999). The lowest values are found for inelastic model in the

EFFECTS OF OCEAN TIDE MODELS ON GNSS-ESTIMATED ZTD AND PWV IN TURKEY

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G. Gurbuz

2015-12-01

Full Text Available Global Navigation Satellite System (GNSS observations can precisely estimate the total zenith tropospheric delay (ZTD and precipitable water vapour (PWV for weather prediction and atmospheric research as a continuous and all-weather technique. However, apart from GNSS technique itself, estimations of ZTD and PWV are subject to effects of geophysical models with large uncertainties, particularly imprecise ocean tide models in Turkey. In this paper, GNSS data from Jan. 1st to Dec. 31st of 2014 are processed at 4 co-located GNSS stations (GISM, DIYB, GANM, and ADAN with radiosonde from Turkish Met-Office along with several nearby IGS stations. The GAMIT/GLOBK software has been used to process GNSS data of 30-second sample using the Vienna Mapping Function and 10° elevation cut-off angle. Also tidal and non-tidal atmospheric pressure loadings (ATML at the observation level are also applied in GAMIT/GLOBK. Several widely used ocean tide models are used to evaluate their effects on GNSS-estimated ZTD and PWV estimation, such as IERS recommended FES2004, NAO99b from a barotropic hydrodynamic model, CSR4.0 obtained from TOPEX/Poseidon altimetry with the model FES94.1 as the reference model and GOT00 which is again long wavelength adjustments of FES94.1 using TOPEX/Poseidon data at 0.5 by 0.5 degree grid. The ZTD and PWV computed from radiosonde profile observations are regarded as reference values for the comparison and validation. In the processing phase, five different strategies are taken without ocean tide model and with four aforementioned ocean tide models, respectively, which are used to evaluate ocean tide models effects on GNSS-estimated ZTD and PWV estimation through comparing with co-located Radiosonde. Results showed that ocean tide models have greatly affected the estimation of the ZTD in centimeter level and thus the precipitable water vapour in millimeter level, respectively at stations near coasts. The ocean tide model FES2004 that is

Effects of dynamic long-period ocean tides on changes in earth's rotation rate

Science.gov (United States)

Nam, Young; Dickman, S. R.

1990-01-01

As a generalization of the zonal response coefficient first introduced by Agnew and Farrell (1978), the zonal response function kappa of the solid earth-ocean system is defined as the ratio, in the frequency domain, of the tidal change in earth's rotation rate to the tide-generating potential. Amplitudes and phases of kappa for the monthly, fortnightly, and nine-day lunar tides are estimated from 2 1/2 years of VLBI UT1 observations, corrected for atmospheric angular momentum effects using NMC wind and pressure series. Using the dynamic ocean tide model of Dickman (1988, 1989), amplitudes and phases of kappa for an elastic earth-ocean system are predicted. The predictions confirm earlier results which found that dynamic effects of the longer-period ocean tides reduce the amplitude of kappa by about 1 percent.

CO2-dependent carbon isotope fractionation in the dinoflagellate Alexandrium tamarense

Science.gov (United States)

Wilkes, Elise B.; Carter, Susan J.; Pearson, Ann

2017-09-01

The carbon isotopic composition of marine sedimentary organic matter is used to resolve long-term histories of pCO2 based on studies indicating a CO2-dependence of photosynthetic carbon isotope fractionation (εP). It recently was proposed that the δ13C values of dinoflagellates, as recorded in fossil dinocysts, might be used as a proxy for pCO2. However, significant questions remain regarding carbon isotope fractionation in dinoflagellates and how such fractionation may impact sedimentary records throughout the Phanerozoic. Here we investigate εP as a function of CO2 concentration and growth rate in the dinoflagellate Alexandrium tamarense. Experiments were conducted in nitrate-limited chemostat cultures. Values of εP were measured on cells having growth rates (μ) of 0.14-0.35 d-1 and aqueous carbon dioxide concentrations of 10.2-63 μmol kg-1 and were found to correlate linearly with μ/[CO2(aq)] (r2 = 0.94) in accord with prior, analogous chemostat investigations with eukaryotic phytoplankton. A maximum fractionation (εf) value of 27‰ was characterized from the intercept of the experiments, representing the first value of εf determined for an algal species employing Form II RubisCO-a structurally and catalytically distinct form of the carbon-fixing enzyme. This value is larger than theoretical predictions for Form II RubisCO and not significantly different from the ∼25‰ εf values observed for taxa employing Form ID RubisCO. We also measured the carbon isotope contents of dinosterol, hexadecanoic acid, and phytol from each experiment, finding that each class of biomarker exhibits different isotopic behavior. The apparent CO2-dependence of εP values in our experiments strengthens the proposal to use dinocyst δ13C values as a pCO2 proxy. Moreover, the similarity between the εf value for A. tamarense and the consensus value of ∼25‰ indicates that the CO2-sensitivity of carbon isotope fractionation saturates at similar CO2 levels across all three

Comparative Transcriptomics to Identify Novel Genes and Pathways in Dinoflagellates

Science.gov (United States)

Ryan, D.

2016-02-01

The unarmored dinoflagellate Karenia brevis is among the most prominent harmful, bloom-forming phytoplankton species in the Gulf of Mexico. During blooms, the polyketides PbTx-1 and PbTx-2 (brevetoxins) are produced by K. brevis. Brevetoxins negatively impact human health and the Gulf shellfish harvest. However, the genes underlying brevetoxin synthesis are currently unknown. Because the K. brevis genome is extremely large ( 1 × 1011 base pairs long), and with a high proportion of repetitive, non-coding DNA, it has not been sequenced. In fact, large, repetitive genomes are common among the dinoflagellate group. High-throughput RNA sequencing technology enabled us to assemble Karenia transcriptomes de novo and investigate potential genes in the brevetoxin pathway through comparative transcriptomics. The brevetoxin profile varies among K. brevis clonal cultures. For example, well-documented Wilson-CCFWC268 typically produces 8-10 pg PbTx per cell, whereas SP1 produces differences in gene expression. Of the 85,000 transcripts in the K. brevis transcriptome, 4,600 transcripts, including novel unannotated orthologs and putative polyketide synthases (PKSs), were only expressed by brevetoxin-producing K. brevis and K. papilionacea, not K. mikimotoi. Examination of gene expression between the typical- and low-toxin Wilson clones identified about 3,500 genes with significantly different expression levels, including 2 putative PKSs. One of the 2 PKSs was only found in the brevetoxin-producing Karenia species. These transcriptomes could not have been characterized without high-throughput RNA sequencing.

Gyrodiniellum shiwhaense n. gen., n. sp., A New Planktonic Heterotrophic Dinoflagellate from the Coastal Waters of Western Korea 

DEFF Research Database (Denmark)

Kang, Nam Seon; Jeong, Hae Jin; Moestrup, O.

2011-01-01

The heterotrophic dinoflagellate Gyrodiniellum shiwhaense n. gen., n. sp. is described from live cells and from cells prepared for light, scanning electron, and transmission electron microscopy. Also, sequences of the small subunit (SSU) and large subunit (LSU) of rDNA have been analyzed. The epi......The heterotrophic dinoflagellate Gyrodiniellum shiwhaense n. gen., n. sp. is described from live cells and from cells prepared for light, scanning electron, and transmission electron microscopy. Also, sequences of the small subunit (SSU) and large subunit (LSU) of rDNA have been analyzed.......3-0.5 x cell length. Cells that were feeding on the dinoflagellate Amphidinium carterae Hulburt were 9.1-21.6 mu m long and 6.6-15.7 mu m wide. Cells of G. shiwhaense contain nematocysts, trichocysts, a peduncle, and pusule systems, but they lack chloroplasts. The SSU rDNA sequence is > 3% different from......., cells of which possess a taeniocyst-nematocyst complex, G. shiwhaense has nematocysts but lacks taeniocysts. It differs from Paragymnodinium shiwhaense Kang, Jeong, Moestrup & Shin by possessing nematocysts with stylets and filaments. Gyrodiniellum shiwhaense n. gen., n. sp. furthermore lacks ocelloids...

Effects of nitrate on the diurnal vertical migration, carbon to nitrogen ratio, and the photosynthetic capacity of the dinoflagellate Gymnodinium splendens

Energy Technology Data Exchange (ETDEWEB)

Cullen, J.J.; Horrigan, S.G.

1981-01-01

A non-thecate dinoflagellate, Gymnodinium splendens, was studied in a 12 d laboratory experiment in 2.0 x 0.25 m containers in which light, temperature, and nutrients could be manipulated. Under a 12 h light:12 h dark cycle, the dinoflagellates exhibited diurnal vertical migrations, swimming downward before the dark period began and upward before the end of the dark period. This vertical migration probably involved geotaxis and a diel rhythm, as well as light-mediated behavior. The vertical distribution of nitrate affected the behavior and physiology of the dinoflagellate. When nitrate was present throughout the container, the organisms resembled those in exponential batch culture both in C:N ratios and photosynthetic capacity (P/sub max/); moreover, they migrated to the surface during the day. In contrast, when nitrate was depleted, C:N ratios increased, P/sub max/ decreased, and the organisms formed a subsurface layer at a depth corresponding to the light level at which photosynthesis saturated. When nitrate was present only at the bottom of the tank, C:N ratios of the population decreased until similar to those of nutrient-saturated cells and P/sub max/ increased; however, the dinoflagellates behaved the same as nutient-depleted cells, forming a subsurface layer during the light period. Field measurements revealed a migratory subsurface chlorophyll maximum layer dominated by G. splendens. It was just above the nitracline during the day, and in the nitracline during the night, which concurs with our laboratory observations.

POET: Planetary Orbital Evolution due to Tides

Science.gov (United States)

Penev, Kaloyan

2014-08-01

POET (Planetary Orbital Evolution due to Tides) calculates the orbital evolution of a system consisting of a single star with a single planet in orbit under the influence of tides. The following effects are The evolutions of the semimajor axis of the orbit due to the tidal dissipation in the star and the angular momentum of the stellar convective envelope by the tidal coupling are taken into account. In addition, the evolution includes the transfer of angular momentum between the stellar convective and radiative zones, effect of the stellar evolution on the tidal dissipation efficiency, and stellar core and envelope spins and loss of stellar convective zone angular momentum to a magnetically launched wind. POET can be used out of the box, and can also be extended and modified.

Acoustic observations of internal tides and tidal currents in shallow water.

Science.gov (United States)

Turgut, Altan; Mignerey, Peter C; Goldstein, David J; Schindall, Jeffrey A

2013-04-01

Significant acoustic travel-time variability and frequency shifts of acoustic intensity level curves in broadband signal spectrograms were measured in the East China Sea during the summer of 2008. The broadband pulses (270-330 Hz) were transmitted from a fixed source and received at a bottomed horizontal array, located at the 33 km range. The acoustic intensity level curves of the received signals indicate regular frequency shifts that are well correlated with the measured internal tides. Similarly, regular travel-time shifts of the acoustic mode arrivals correlate well with the barotropic tides and can be explained by tidal currents along the acoustic propagation track. These observations indicate the potential of monitoring internal tides and tidal currents using low-frequency acoustic signals propagating at long ranges.

The Contribution of Io-Raised Tides to Europa's Diurnally-Varying Surface Stresses

Science.gov (United States)

Rhoden, Alyssa Rose; Hurford, Terry A,; Manga, Michael

2011-01-01

Europa's icy surface records a rich history of geologic activity, Several features appear to be tectonic in origin and may have formed in response to Europa's daily-varying tidal stress [I]. Strike-slip faults and arcuate features called cycloids have both been linked to the patterns of stress change caused by eccentricity and obliquity [2J[3]. In fact, as Europa's obliquity has not been directly measured, observed tectonic patterns arc currently the best indicators of a theoretically supported [4] non-negligible obliquity. The diurnal tidal stress due to eccentricity is calculated by subtracting the average (or static) tidal shape of Europa generated by Jupiter's gravitational field from the instantaneous shape, which varies as Europa moves through its eccentric orbit [5]. In other words, it is the change of shape away from average that generates tidal stress. One might expect tidal contributions from the other large moons of Jupiter to be negligible given their size and the height of the tides they raise on Europa versus Jupiter's mass and the height of the tide it raises on Europa, However, what matters for tidally-induced stress is not how large the lo-raised bulge is compared to the Jupiter-raised bulge but rather the differences bet\\Veen the instantaneous and static bulges in each case. For example, when Europa is at apocenter, Jupiter raises a tide 30m lower than its static tide. At the same time, 10 raises a tide about 0.5m higher than its static tide. Hence, the change in Io's tidal distortion is about 2% of the change in the Jovian distortion when Europa is at apocenter

A description of the tides in the Eastern North Atlantic

Science.gov (United States)

Fanjul, Enrique Alvarez; Gómez, Begoña Pérez; Sánchez-Arévalo, Ignacio Rodríguez

A description of the Eastern North Atlantic tidal dynamics (in a region spanning from 20°N to 48°N in latitude and from 34°W to 0° in longitude) is obtained by means of new in situ measurements and numerical modelling based on TOPEX/POSEIDON-derived data sets. The main source of measurements is the tide gauge network REDMAR (RED de MAReógrafos de Puertos del Estado), operative since July 1992 and managed by Clima Marítimo (Puertos del Estado). Results derived from the harmonic analysis of the first years of measurements are presented and compared with model results. In order to obtain a global picture of the tides in the region, a large compilation of harmonic constants obtained from other institutes is included. The availability of new TOPEX/POSEIDON-derived harmonic constants data sets provides a chance to include the benefits derived from satellite altimetry in high resolution regional applications of numerical models. Richard Ray's tidal model (Ray et al., 1994), based on a response type tidal analysis of TOPEX/POSEIDON data, was employed within a model of the studied area. The numerical model employed is HAMSOM, a 3-D finite difference code developed both by the Institut für Meereskunde (Hamburg University) and Clima Marítimo. Results from simulations of seven major harmonics are presented, providing a comprehensive view of tidal dynamics, including current information. The results of tidal simulations show good agreement between semidiurnal harmonic components and the values measured by both coastal and pelagic tidal gauges and by current meters. The modelled diurnal constituents show larger relative differences with measurements than semidiurnal harmonics, especially concerning the phase lags. The non-linear transfer of energy from semidiurnal to higher order harmonics, such as M 4 and M 6, was mapped. Those transfers were found to be important only in two areas: the French continental shelf in the Bay of Biscay and the widest part of the African

Determination of ocean tides from the first year of TOPEX/POSEIDON altimeter measurements

Science.gov (United States)

Ma, X. C.; Shum, C. K.; Eanes, R. J.; Tapley, B. D.

1994-01-01

An improved geocentric global ocean tide model has been determined using 1 year of TOPEX/POSEIDON altimeter measurements to provide corrections to the Cartwright and Ray (1991) model (CR91). The corrections were determined on a 3 deg x 3 deg grid using both the harmonic analysis method and the response method. The two approaches produce similar solutions. The effect on the tide solution of simultaneously adjusting radial orbit correction parameters using altimeter measurements was examined. Four semidiurnal (N(sub 2), M(sub 2), S(sub 2) and K(sub 2)), four diurnal (Q(sdub 1), O(sub 1), P(sub 1), and K(sub 1)), and three long-period (S(sub sa), M(sub m), and M(sub f)) constituents, along with the variations at the annual frequency, were included in the harmomnic analysis solution. The observed annual variations represents the first global measurement describing accurate seasonal changes of the ocean during an El Nino year. The corrections to the M(sub 2) constituent have an root mean square (RMS) of 3.6 cm and display a clear banding pattern with regional highs and lows reaching 8 cm. The improved tide model reduces the weighted altimeter crossover residual from 9.8 cm RMS, when the CR91 tide model is used, to 8.2 cm on RMS. Comparison of the improved model to pelagic tidal constants determined from 80 tide gauges gives RMS differences of 2.7 cm for M(sub 2) and 1.7 cm for K(sub 1). Comparable values when the CR91 model is used are 3.9 cm and 2.0 cm, respectively. Examination of TOPEX/POSEIDON sea level anomaly variations using the new tide model further confirms that the tide model has been improved.

Impact of large-scale tides on cosmological distortions via redshift-space power spectrum

Science.gov (United States)

Akitsu, Kazuyuki; Takada, Masahiro

2018-03-01

Although large-scale perturbations beyond a finite-volume survey region are not direct observables, these affect measurements of clustering statistics of small-scale (subsurvey) perturbations in large-scale structure, compared with the ensemble average, via the mode-coupling effect. In this paper we show that a large-scale tide induced by scalar perturbations causes apparent anisotropic distortions in the redshift-space power spectrum of galaxies in a way depending on an alignment between the tide, wave vector of small-scale modes and line-of-sight direction. Using the perturbation theory of structure formation, we derive a response function of the redshift-space power spectrum to large-scale tide. We then investigate the impact of large-scale tide on estimation of cosmological distances and the redshift-space distortion parameter via the measured redshift-space power spectrum for a hypothetical large-volume survey, based on the Fisher matrix formalism. To do this, we treat the large-scale tide as a signal, rather than an additional source of the statistical errors, and show that a degradation in the parameter is restored if we can employ the prior on the rms amplitude expected for the standard cold dark matter (CDM) model. We also discuss whether the large-scale tide can be constrained at an accuracy better than the CDM prediction, if the effects up to a larger wave number in the nonlinear regime can be included.

SURVEY OF BENTHIC DINOFLAGELLATES ASSOCIATED TO BEDS OF Thalassia testudinum IN SAN ANDRÉS ISLAND, SEAFLOWER BIOSPHERE RESERVE, CARIBBEAN COLOMBIA

Directory of Open Access Journals (Sweden)

Brigitte Gavio

2010-05-01

Full Text Available In order to determine the occurrence of epiphytic toxic dinoflagellates in the coastal waters of San Andrés Island, Caribbean Colombia, we analyzed the seagrass beds on the northern and eastern sides of the island. We found seven species of toxicogenic dinoflagellates, belonging to the genera Prorocentrum and Ostreopsis. The cell densities were generally low if compared with previous studies in other Caribbean sites, ranging from 0 to 836 cells/dry weight. The species encountered are known to produce toxins causing the Diarrehic Shellfish Poisoning and Ciguatera, poisonings which have been documented in the island.

Cascades of convergent evolution: The corresponding evolutionary histories of euglenozoans and dinoflagellates

Czech Academy of Sciences Publication Activity Database

Lukeš, Julius; Leander, B. S.; Keeling, P. J.

2009-01-01

Roč. 106, č. 1 (2009), s. 9963-9970 ISSN 0027-8424 R&D Projects: GA ČR GA204/09/1667; GA MŠk LC07032; GA MŠk 2B06129 Institutional research plan: CEZ:AV0Z60220518 Keywords : comparative genomics * convergent evolution * dinoflagellates * Euglenozoa * mitochondria * molecular evolution * plastids * RNA editing * RNA editing Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 9.432, year: 2009

Vertical land motion along the coast of Louisiana: Integrating satellite altimetry, tide gauge and GPS

Science.gov (United States)

Dixon, T. H.; A Karegar, M.; Uebbing, B.; Kusche, J.; Fenoglio-Marc, L.

2017-12-01

Coastal Louisiana is experiencing the highest rate of relative sea-level rise in North America due to the combination of sea-level rise and subsidence of the deltaic plain. The land subsidence in this region is studied using various techniques, with continuous GPS site providing high temporal resolution. Here, we use high resolution tide-gauge data and advanced processing of satellite altimetry to derive vertical displacements time series at NOAA tide-gauge stations along the coast (Figure 1). We apply state-of-the-art retracking techniques to process raw altimetry data, allowing high accuracy on range measurements close to the coast. Data from Jason-1, -2 and -3, Envisat, Saral and Cryosat-2 are used, corrected for solid Earth tide, pole tide and tidal ocean loading, using background models consistent with the GPS processing technique. We reprocess the available GPS data using precise point positioning and estimate the rate uncertainty accounting for correlated noise. The displacement time series are derived by directly subtracting tide-gauge data from the altimetry sea-level anomaly data. The quality of the derived displacement rates is evaluated in Grand Isle, Amerada Pass and Shell Beach where GPS data are available adjacent to the tide gauges. We use this technique to infer vertical displacement at tide gauges in New Orleans (New Canal Station) and Port Fourchon and Southwest Pass along the coastline.

Minutes of TOPEX/POSEIDON Science Working Team Meeting and Ocean Tides Workshop

Science.gov (United States)

Fu, Lee-Lueng (Editor)

1995-01-01

This third TOPEX/POSEIDON Science Working Team meeting was held on December 4, 1994 to review progress in defining ocean tide models, precision Earth orbits, and various science algorithms. A related workshop on ocean tides convened to select the best models to be used by scientists in the Geophysical Data Records.

Measuring storm tide and high-water marks caused by Hurricane Sandy in New York: Chapter 2

Science.gov (United States)

Simonson, Amy E.; Behrens, Riley

2015-01-01

In response to Hurricane Sandy, personnel from the U.S. Geological Survey (USGS) deployed a temporary network of storm-tide sensors from Virginia to Maine. During the storm, real-time water levels were available from tide gages and rapid-deployment gages (RDGs). After the storm, USGS scientists retrieved the storm-tide sensors and RDGs and surveyed high-water marks. These data demonstrate that the timing of peak storm surge relative to astronomical tide was extremely important in southeastern New York. For example, along the south shores of New York City and western Suffolk County, the peak storm surge of 6–9 ft generally coincided with the astronomical high tide, which resulted in substantial coastal flooding. In the Peconic Estuary and northern Nassau County, however, the peak storm surge of 9 ft and nearly 12 ft, respectively, nearly coincided with normal low tide, which helped spare these communities from more severe coastal flooding.

THERMAL TIDES IN FLUID EXTRASOLAR PLANETS

International Nuclear Information System (INIS)

Arras, Phil; Socrates, Aristotle

2010-01-01

Asynchronous rotation and orbital eccentricity lead to time-dependent irradiation of the close-in gas giant exoplanets-the hot Jupiters. This time-dependent surface heating gives rise to fluid motions which propagate throughout the planet. We investigate the ability of this 'thermal tide' to produce a quadrupole moment which can couple to the stellar gravitational tidal force. While previous investigations discussed planets with solid surfaces, here we focus on entirely fluid planets in order to understand gas giants with small cores. The Coriolis force, thermal diffusion, and self-gravity of the perturbations are ignored for simplicity. First, we examine the response to thermal forcing through analytic solutions of the fluid equations which treat the forcing frequency as a small parameter. In the 'equilibrium tide' limit of zero frequency, fluid motion is present but does not induce a quadrupole moment. In the next approximation, finite frequency corrections to the equilibrium tide do lead to a nonzero quadrupole moment, the sign of which torques the planet away from synchronous spin. We then numerically solve the boundary value problem for the thermally forced, linear response of a planet with neutrally stratified interior and a stably stratified envelope. The numerical results find quadrupole moments in agreement with the analytic non-resonant result at a sufficiently long forcing period. Surprisingly, in the range of forcing periods of 1-30 days, the induced quadrupole moments can be far larger than the analytic result due to response of internal gravity waves which propagate in the radiative envelope. We discuss the relevance of our results for the spin, eccentricity, and thermal evolution of hot Jupiters.

Immuno-flow cytometric detection of the ichthyotoxic dinoflagellates Gyrodinium aureolum and Gymnodinium nagasakiense : Independence of physiological state

NARCIS (Netherlands)

Vrieling, EG; vandePoll, WH; Vriezekolk, G; Gieskes, WWC

The ichthyotoxic dinoflagellates Gyrodinium aureolum and Gymnodinium nagasakiense were cultured under different environmental conditions to test possible variability in immunochemical labelling intensity of cell-surface antigens using species-specific monoclonal antibodies. Variation of antigen

The isolation and purification of a caribbean maitotoxin

Energy Technology Data Exchange (ETDEWEB)

Davis, S.E.; Knoepp, S.M.; Lanoue, B.A. [and others

1994-12-31

The phenomenon known as red tide has been a topic of great interest in that there is concern that the scale and complexity of this natural phenomenon are expanding. It is known that the benthic dinoflagellate, Gambierdiscus toxicus, produces a variety of polyether toxins that contaminate seafood and result in human illness. Maitotoxin (MTX) is one of the toxins that have been implicated in ciguatera seafood poisoning. There is a need for the development of a much broader understanding of the nature of the poisoning toxins. MTX cogeners can be difficult to isolate due to its size and chemical nature. A major goal is to obtain a purified standard of a Caribbean MTX so that more efficient assays can be developed to test seafood for the presence of toxins and thus avoid human harm. The primary goal of this project is to obtain large amounts of pure maitotoxin. The procedure described is also useful as a starting point for the purification of other toxins.

Phytoplankton IF-FISH: Species-specific labeling of cellular proteins by immunofluorescence (IF) with simultaneous species identification by fluorescence immunohybridization (FISH).

Science.gov (United States)

Meek, Megan E; Van Dolah, Frances M

2016-05-01

Phytoplankton rarely occur as unialgal populations. Therefore, to study species-specific protein expression, indicative of physiological status in natural populations, methods are needed that will both assay for a protein of interest and identify the species expressing it. Here we describe a protocol for IF-FISH, a dual labeling procedure using immunofluorescence (IF) labeling of a protein of interest followed by fluorescence in situ hybridization (FISH) to identify the species expressing that protein. The protocol was developed to monitor expression of the cell cycle marker proliferating cell nuclear antigen (PCNA) in the red tide dinoflagellate, Karenia brevis, using a large subunit (LSU) rRNA probe to identify K. brevis in a mixed population of morphologically similar Karenia species. We present this protocol as proof of concept that IF-FISH can be successfully applied to phytoplankton cells. This method is widely applicable for the analysis of single-cell protein expression of any protein of interest within phytoplankton communities. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of macronutrient additions on nickel uptake and distribution in the dinoflagellate Prorocentrum donghaiense Lu

Energy Technology Data Exchange (ETDEWEB)

Hong Huasheng; Wang Minghua; Huang Xuguang [State Key Laboratory of Marine Environmental Science, Xiamen University/Environmental Science Research Center, Xiamen University, No. 192, Daxue Road, Siming Zone, Xiamen 361005 (China); Wang Dazhi, E-mail: dzwang@xmu.edu.c [State Key Laboratory of Marine Environmental Science, Xiamen University/Environmental Science Research Center, Xiamen University, No. 192, Daxue Road, Siming Zone, Xiamen 361005 (China)

2009-06-15

The influences of macronutrient additions on nickel (Ni) uptake and distribution in the subcellular structures and macromolecular components of the dinoflagellate Prorocentrum donghaiense Lu were examined using a radioisotope tracer method. The results showed that nitrate addition enhanced the uptake of Ni by P. donghaiense, whereas phosphate addition inhibited Ni uptake at high-Ni concentration. Nitrate or phosphate addition significantly affected Ni distribution in the subcellular structures and components. The majority of Ni was found in the soluble substances (>70%) and in the proteins (55.0-79.6%) of the algal cells. Urea reduced the Ni content in the amino acid-carbohydrate but elevated its content in proteins, and shown significantly correlated with the protein content of the algal cells. Thus, nutrient enrichment could influence both metal uptake and its distribution in the subcellular structures and components of the phytoplankton, as well as its subsequent transfer in marine food chains. - Macronutrient additions significantly affected nickel uptake and distribution in the subcellular substructures and components of the dinoflagellate.

Effects of macronutrient additions on nickel uptake and distribution in the dinoflagellate Prorocentrum donghaiense Lu

International Nuclear Information System (INIS)

Hong Huasheng; Wang Minghua; Huang Xuguang; Wang Dazhi

2009-01-01

The influences of macronutrient additions on nickel (Ni) uptake and distribution in the subcellular structures and macromolecular components of the dinoflagellate Prorocentrum donghaiense Lu were examined using a radioisotope tracer method. The results showed that nitrate addition enhanced the uptake of Ni by P. donghaiense, whereas phosphate addition inhibited Ni uptake at high-Ni concentration. Nitrate or phosphate addition significantly affected Ni distribution in the subcellular structures and components. The majority of Ni was found in the soluble substances (>70%) and in the proteins (55.0-79.6%) of the algal cells. Urea reduced the Ni content in the amino acid-carbohydrate but elevated its content in proteins, and shown significantly correlated with the protein content of the algal cells. Thus, nutrient enrichment could influence both metal uptake and its distribution in the subcellular structures and components of the phytoplankton, as well as its subsequent transfer in marine food chains. - Macronutrient additions significantly affected nickel uptake and distribution in the subcellular substructures and components of the dinoflagellate.

A dual-species co-cultivation system to study the interactions between Roseobacters and Dinoflagellates

Directory of Open Access Journals (Sweden)

Hui eWang

2014-06-01

Full Text Available Some microalgae in nature live in symbiosis with microorganisms that can enhance or inhibit growth, thus influencing the dynamics of phytoplankton blooms. In spite of the great ecological importance of these interactions, very few defined laboratory systems are available to study them in detail. Here we present a co-cultivation system consisting of the toxic phototrophic dinoflagellate Prorocentrum minimum and the photoheterotrophic alphaproteobacterium Dinoroseobacter shibae. In a mineral medium lacking a carbon source, vitamins for the bacterium and the essential vitamin B12 for the dinoflagellate, growth dynamics reproducibly went from a mutualistic phase, where both algae and bacteria grow, to a pathogenic phase, where the algae are killed by the bacteria. The data show a Jekyll and Hyde lifestyle that had been proposed but not previously demonstrated. We used RNAseq and microarray analysis to determine which genes of D. shibae are transcribed and differentially expressed in a light dependent way at an early time-point of the co-culture when the bacterium grows very slowly. Enrichment of bacterial mRNA for transcriptome analysis was optimized, but none of the available methods proved capable of removing dinoflagellate ribosomal RNA completely. RNAseq showed that a phasin encoding gene (phaP1 which is part of the polyhydroxyalkanoate (PHA metabolism operon represented approximately 10 % of all transcripts. Five genes for aerobic anoxygenic photosynthesis were down-regulated in the light, indicating that the photosynthesis apparatus was functional. A betaine-choline-carnitine-transporter (BCCT that may be used for dimethylsulfoniopropionate (DMSP uptake was the highest up-regulated gene in the light. The data suggest that at this early mutualistic phase of the symbiosis, PHA degradation might be the main carbon and energy source of D. shibae, supplemented in the light by degradation of DMSP and aerobic anoxygenic photosynthesis.

Tides and the evolution of planetary habitability.

Science.gov (United States)

Barnes, Rory; Raymond, Sean N; Jackson, Brian; Greenberg, Richard

2008-06-01

Tides raised on a planet by the gravity of its host star can reduce the planet's orbital semi-major axis and eccentricity. This effect is only relevant for planets orbiting very close to their host stars. The habitable zones of low-mass stars are also close in, and tides can alter the orbits of planets in these locations. We calculate the tidal evolution of hypothetical terrestrial planets around low-mass stars and show that tides can evolve planets past the inner edge of the habitable zone, sometimes in less than 1 billion years. This migration requires large eccentricities (>0.5) and low-mass stars ( less or similar to 0.35 M(circle)). Such migration may have important implications for the evolution of the atmosphere, internal heating, and the Gaia hypothesis. Similarly, a planet that is detected interior to the habitable zone could have been habitable in the past. We consider the past habitability of the recently discovered, approximately 5 M(circle) planet, Gliese 581 c. We find that it could have been habitable for reasonable choices of orbital and physical properties as recently as 2 Gyr ago. However, when constraints derived from the additional companions are included, most parameter choices that indicate past habitability require the two inner planets of the system to have crossed their mutual 3:1 mean motion resonance. As this crossing would likely have resulted in resonance capture, which is not observed, we conclude that Gl 581 c was probably never habitable.

Tides and tidal harmonics at Umbharat, Gujarat

Digital Repository Service at National Institute of Oceanography (India)

Suryanarayana, A.; Swamy, G.N.

A part of the data on tides recorded at Machiwada near Umbharat, Gulf of Cambay during April 1978 was subjected to harmonic analysis following the Admiralty procedure. The general tidal characteristics and the value of four major harmonic...

Observations of the Mf ocean tide from Geosat altimetry

Science.gov (United States)

Cartwright, David E.; Ray, Richard D.

1990-01-01

Zonal averages of the 13.66-day Mf tide are derived from one year of Geosat altimetry records. The orbit errors are reduced by 1/revolution corrections taken over long (several day) arcs. The short-period tides are removed using a model previously derived from the same data. The Mf zonal averages indicate definite nonequilibrium character at nearly all latitudes. The imaginary admittances indicate a Q of at least 8; such a value is consistent with a simplified theory of coupled gravitational and vorticity modes and suggests a value for Proudman's 'friction period' about 123 days.

Accurate Modelling of Surface Currents and Internal Tides in a Semi-enclosed Coastal Sea

Science.gov (United States)

Allen, S. E.; Soontiens, N. K.; Dunn, M. B. H.; Liu, J.; Olson, E.; Halverson, M. J.; Pawlowicz, R.

2016-02-01

The Strait of Georgia is a deep (400 m), strongly stratified, semi-enclosed coastal sea on the west coast of North America. We have configured a baroclinic model of the Strait of Georgia and surrounding coastal waters using the NEMO ocean community model. We run daily nowcasts and forecasts and publish our sea-surface results (including storm surge warnings) to the web (salishsea.eos.ubc.ca/storm-surge). Tides in the Strait of Georgia are mixed and large. The baroclinic model and previous barotropic models accurately represent tidal sea-level variations and depth mean currents. The baroclinic model reproduces accurately the diurnal but not the semi-diurnal baroclinic tidal currents. In the Southern Strait of Georgia, strong internal tidal currents at the semi-diurnal frequency are observed. Strong semi-diurnal tides are also produced in the model, but are almost 180 degrees out of phase with the observations. In the model, in the surface, the barotropic and baroclinic tides reinforce, whereas the observations show that at the surface the baroclinic tides oppose the barotropic. As such the surface currents are very poorly modelled. Here we will present evidence of the internal tidal field from observations. We will discuss the generation regions of the tides, the necessary modifications to the model required to correct the phase, the resulting baroclinic tides and the improvements in the surface currents.

SMLTM simulations of the diurnal tide: comparison with UARS observations

Directory of Open Access Journals (Sweden)

R. A. Akmaev

1997-09-01

Full Text Available Wind and temperature observations in the mesosphere and lower thermosphere (MLT from the Upper Atmosphere Research Satellite (UARS reveal strong seasonal variations of tides, a dominant component of the MLT dynamics. Simulations with the Spectral mesosphere/lower thermosphere model (SMLTM for equinox and solstice conditions are presented and compared with the observations. The diurnal tide is generated by forcing specified at the model lower boundary and by in situ absorption of solar radiation. The model incorporates realistic parameterizations of physical processes including various dissipation processes important for propagation of tidal waves in the MLT. A discrete multi-component gravity-wave parameterization has been modified to account for seasonal variations of the background temperature. Eddy diffusion is calculated depending on the gravity-wave energy deposition rate and stability of the background flow. It is shown that seasonal variations of the diurnal-tide amplitudes are consistent with observed variations of gravity-wave sources in the lower atmosphere.

A revised northern European Turonian (Upper Cretaceous) dinoflagellate cyst biostratigraphy: Integrating palynology and carbon isotope events

Czech Academy of Sciences Publication Activity Database

Olde, K.; Jarvis, I.; Pearce, M.; Uličný, David; Tocher, B.; Trabucho-Alexandre, J.; Gröcke, D. R.

2015-01-01

Roč. 213, February (2015), s. 1-16 ISSN 0034-6667 R&D Projects: GA ČR GAP210/10/1991 Institutional support: RVO:67985530 Keywords : palynology * dinoflagellate cyst * Czech Republic Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.158, year: 2015

Triplet-triplet energy transfer from chlorophylls to carotenoids in two antenna complexes from dinoflagellate Amphidinium carterae

Czech Academy of Sciences Publication Activity Database

Kvíčalová, Z.; Alster, J.; Hofmann, E.; Khoroshyy, P.; Litvín, Radek; Bína, David; Polívka, Tomáš; Pšenčík, J.

2016-01-01

Roč. 1857, č. 4 (2016), s. 341-349 ISSN 0005-2728 R&D Projects: GA ČR GBP501/12/G055 Institutional support: RVO:60077344 Keywords : Dinoflagellate * Chlorophyll * Carotenoid * Triplet state Subject RIV: BO - Biophysics Impact factor: 4.932, year: 2016

A winter dinoflagellate bloom drives high rates of primary production in a Patagonian fjord ecosystem

Science.gov (United States)

Montero, P.; Pérez-Santos, I.; Daneri, G.; Gutiérrez, M. H.; Igor, G.; Seguel, R.; Purdie, D.; Crawford, D. W.

2017-12-01

A dense winter bloom of the dinoflagellate Heterocapsa triquetra was observed at a fixed station (44°35.3‧S; 72°43.6‧W) in the Puyuhuapi Fjord in Chilean Patagonia during July 2015. H. triquetra dominated the phytoplankton community in the surface waters between 2 and 15 m (13-58 × 109 cell m-2), with abundances some 3 to 15 times higher than the total abundance of the diatom assemblage, which was dominated by Skeletonema spp. The high abundance of dinoflagellates was reflected in high rates of gross primary production (GPP; 0.6-1.6 g C m-2 d-1) and chlorophyll-a concentration (Chl-a; 70-199.2 mg m-2) that are comparable to levels reported in spring diatom blooms in similar Patagonian fjords. We identify the main forcing factors behind a pulse of organic matter production during the non-productive winter season, and test the hypothesis that low irradiance levels are a key factor limiting phytoplankton blooms and subsequent productivity during winter. Principal Component Analysis (PCA) indicated that GPP rates were significantly correlated (r = -0.8, p bloom. The bloom occurred under low surface irradiance levels characteristic of austral winter and was accompanied by strong northern winds, associated with the passage of a low-pressure system, and a water column dominated by double diffusive layering. To our knowledge, this is the first report of a dense dinoflagellate bloom during deep austral winter in a Patagonian fjord, and our data challenge the paradigm of light limitation as a factor controlling phytoplankton blooms in this region in winter.

 Marine derived dinoflagellates in Antarctic saline lakes: Community composition and annual dynamics

DEFF Research Database (Denmark)

Rengefors, K.; Layborn-Parry, L.; Logares, R.

2008-01-01

polar dinoflagellate community, and not freshwater species. Polarella glacialis Montresor, Procaccini et Stoecker, a bipolar marine species, was for the first time described in a lake habitat and was an important phototrophic component in the higher salinity lakes. In the brackish lakes, we found a new...... sibling species to the brackish-water species Scrippsiella hangoei (J. Schiller) J. Larsen, previously observed only in the Baltic Sea....

Impacts of tides on tsunami propagation due to potential Nankai Trough earthquakes in the Seto Inland Sea, Japan

Science.gov (United States)

Lee, Han Soo; Shimoyama, Tomohisa; Popinet, Stéphane

2015-10-01

The impacts of tides on extreme tsunami propagation due to potential Nankai Trough earthquakes in the Seto Inland Sea (SIS), Japan, are investigated through numerical experiments. Tsunami experiments are conducted based on five scenarios that consider tides at four different phases, such as flood, high, ebb, and low tides. The probes that were selected arbitrarily in the Bungo and Kii Channels show less significant effects of tides on tsunami heights and the arrival times of the first waves than those that experience large tidal ranges in inner basins and bays of the SIS. For instance, the maximum tsunami height and the arrival time at Toyomaesi differ by more than 0.5 m and nearly 1 h, respectively, depending on the tidal phase. The uncertainties defined in terms of calculated maximum tsunami heights due to tides illustrate that the calculated maximum tsunami heights in the inner SIS with standing tides have much larger uncertainties than those of two channels with propagating tides. Particularly in Harima Nada, the uncertainties due to the impacts of tides are greater than 50% of the tsunami heights without tidal interaction. The results recommend simulate tsunamis together with tides in shallow water environments to reduce the uncertainties involved with tsunami modeling and predictions for tsunami hazards preparedness. This article was corrected on 26 OCT 2015. See the end of the full text for details.

75 FR 20371 - Certificate of Alternative Compliance for the Offshore Supply Vessel LEBOUEF TIDE

Science.gov (United States)

2010-04-19

... Compliance for the Offshore Supply Vessel LEBOUEF TIDE AGENCY: Coast Guard, DHS. ACTION: Notice. SUMMARY: The... vessel LEBOUEF TIDE as required by 33 U.S.C. 1605(c) and 33 CFR 81.18. [[Page 20372

The variability of SE2 tide extracted from TIMED/SABER observations

Science.gov (United States)

Li, X.; Wan, W.; Ren, Z.

2017-12-01

Based on the temperature observations of the TIMED/SABER in mesosphere/lower thermosphere region (70-110 km altitudes) and at the low latitude and midlatitude (45°S-45°N) from 2002 to 2012, the variability of the nonmigrating tide SE2 with 1 day resolution is analyzed. It is found that the climatological features (large-scale variability) of the semidiurnal nonmigrating tide with zonal wave number 2 (SE2) tide are similar with the results from the previous research works. The SE2 tide manifests mainly at the low-mid latitudes around ±30°. The northern hemisphere tidal amplitudes below 110 km are larger than the southern hemisphere tide. SE2 peaks below 110 km mainly present between 100 and 110 km altitude. The tidal amplitudes below 110 km occur a north-south asymmetry about the equator in the annual variation: in the southern hemisphere, SE2 occurs with an obvious annual variation with a maximum of tidal amplitudes in December, while in the northern one, the semiannual variations with maximum at the equinoxes. Herein, owing to the high-resolution tidal data, we could research the short-term (day-to-day) variations of SE2. We found that the day-to-day variations manifest mainly at between 100 and 110 km altitudes; it increases gradually with latitudes, and it is stronger at the low-mid latitudes; it is relatively slightly stronger around solstices than equinoxes; and it does not present a remarkably interannual variation. The SE2 day-to-day variations may be composed by the absolute amplitudes' variance and the impact of the wave phases, and the latter ones are more important.

Tides and seiches in gulfs

International Nuclear Information System (INIS)

Pierini, S.

1981-01-01

In this paper Garrett's theory of tides in gulfs is extended so that its formalism includes the free oscillations (seiches) of the gulf. The elevation of the free surface zeta and the velocity field u are obtained in a rectangular, one-dimensional gulf opening into an infinite ocean. An application of the results to the Adriatic sea can explain qualitatively the long life of the uninodal seiche of that basin. (author)

Acute toxicity assessment of N,N-diethyl-m-toluamide (DEET) on the oxygen flux of the dinoflagellate Gymnodinium instriatum.

Science.gov (United States)

Martinez, Eloy; Vélez, Sylvia M; Mayo, Marietta; Sastre, Miguel P

2016-01-01

Despite the ubiquitous occurrence of N,N-diethyl-m-toluamide (DEET) in aquatic systems, assessments evaluating the toxicity of DEET on phytoplankton species are summed to a single study on a unicellular green alga. In particular, the toxicological effects of DEET in dinoflagellates are unknown. In this study, we employed the mixotrophic dinoflagellate Gymnodinium instriatum as a study system to evaluate acute effects of DEET on the oxygen flux of laboratory cultures. This study reports an inhibitory reaction model of DEET described by the equation y = 4.99x(0.54), where y represents the percent inhibition of oxygen flux and x represents DEET concentration in mg L(−1) (r(2) = 0.98). Based on this model, the effective concentration of DEET needed to reduce O2 flux by 50% (EC50) for this species was found to be at 72.9 mg L(−1). The reported EC50 is more than five times lower than the EC50 reported previously for the unicellular green algae Chlorella protothecoides. This study raises the question of the potential toxicological effects of DEET in dinoflagellates, in particular those populations inhabiting systems characterized by low water circulation such as enclosed bays and lagoons.

Neutron star/red giant encounters in globular clusters

International Nuclear Information System (INIS)

Bailyn, C.D.

1988-01-01

The author presents a simple expression for the amount by which xsub(crit) is diminished as a star evolves xsub(crit) Rsub(crit)/R*, where Rsub(crit) is the maximum distance of closest approach between two stars for which the tidal energy is sufficient to bind the system, and R* is the radius of the star on which tides are being raised. Also it is concluded that tidal capture of giants by neutron stars resulting in binary systems is unlikely in globular clusters. However, collisions between neutron stars and red giants, or an alternative process involving tidal capture of a main-sequence star into an initially detached binary system, may result either in rapidly rotating neutron stars or in white dwarf/neutron star binaries. (author)

Distinct gene number-genome size relationships for eukaryotes and non-eukaryotes: gene content estimation for dinoflagellate genomes.

Directory of Open Access Journals (Sweden)

Yubo Hou

Full Text Available The ability to predict gene content is highly desirable for characterization of not-yet sequenced genomes like those of dinoflagellates. Using data from completely sequenced and annotated genomes from phylogenetically diverse lineages, we investigated the relationship between gene content and genome size using regression analyses. Distinct relationships between log(10-transformed protein-coding gene number (Y' versus log(10-transformed genome size (X', genome size in kbp were found for eukaryotes and non-eukaryotes. Eukaryotes best fit a logarithmic model, Y' = ln(-46.200+22.678X', whereas non-eukaryotes a linear model, Y' = 0.045+0.977X', both with high significance (p0.91. Total gene number shows similar trends in both groups to their respective protein coding regressions. The distinct correlations reflect lower and decreasing gene-coding percentages as genome size increases in eukaryotes (82%-1% compared to higher and relatively stable percentages in prokaryotes and viruses (97%-47%. The eukaryotic regression models project that the smallest dinoflagellate genome (3x10(6 kbp contains 38,188 protein-coding (40,086 total genes and the largest (245x10(6 kbp 87,688 protein-coding (92,013 total genes, corresponding to 1.8% and 0.05% gene-coding percentages. These estimates do not likely represent extraordinarily high functional diversity of the encoded proteome but rather highly redundant genomes as evidenced by high gene copy numbers documented for various dinoflagellate species.

Sea surface conditions in the southern Nordic Seas during the Holocene based on dinoflagellate cyst assemblages

DEFF Research Database (Denmark)

Van Nieuwenhove, Nicolas; Baumann, Astrid; Matthiessen, Jens

2016-01-01

Dinoflagellate cyst (dinocyst) records from the southern Nordic Seas were compiled in order to evaluate the evolution of upper ocean conditions, on a millennial timescale and supported by a highly resolved record from the Vøring Plateau. After the transitional phase from the last deglaciation...

Seasonal variations of the semi-diurnal and diurnal tides in the MLT: multi-year MF radar observations from 2–70° N, modelled tides (GSWM, CMAM

Directory of Open Access Journals (Sweden)

A. H. Manson

2002-05-01

Full Text Available In an earlier paper (Manson et al., 1999a tidal data (1990–1997 from six Medium Frequency Radars (MFR were compared with the Global Scale Wave Model (GSWM, original 1995 version. The radars are located between the equator and high northern latitudes: Christmas Island (2° N, Hawaii (22° N, Urbana (40° N, London (43° N, Saskatoon (52° N and Tromsø (70° N. Common harmonic analysis was applied, to ensure consistency of amplitudes and phases in the 75–95 km height range. For the diurnal tide, seasonal agreements between observations and model were excellent while for the semi-diurnal tide the seasonal transitions between clear solstitial states were less well captured by the model. Here the data set is increased by the addition of two locations in the Pacific-North American sector: Yamagawa 31° N, and Wakkanai 45° N. The GSWM model has undergone two additional developments (1998, 2000 to include an improved gravity wave (GW stress parameterization, background winds from UARS systems and monthly tidal forcing for better characterization of seasonal change. The other model, the Canadian Middle Atmosphere Model (CMAM which is a General Circulation Model, provides internally generated forcing (due to ozone and water vapour for the tides. The two GSWM versions show distinct differences, with the 2000 version being either closer to, or further away from, the observations than the original 1995 version. CMAM provides results dependent upon the GW parameterization scheme inserted, but one of the schemes provides very useful tides, especially for the semi-diurnal component.Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides

Accumulation, Biotransformation, Histopathology and Paralysis in the Pacific Calico Scallop Argopecten ventricosus by the Paralyzing Toxins of the Dinoflagellate Gymnodinium catenatum

Directory of Open Access Journals (Sweden)

Rosalba Alonso-Rodriguez

2012-05-01

Full Text Available The dinoflagellate Gymnodinium catenatum produces paralyzing shellfish poisons that are consumed and accumulated by bivalves. We performed short-term feeding experiments to examine ingestion, accumulation, biotransformation, histopathology, and paralysis in the juvenile Pacific calico scallop Argopecten ventricosus that consume this dinoflagellate. Depletion of algal cells was measured in closed systems. Histopathological preparations were microscopically analyzed. Paralysis was observed and the time of recovery recorded. Accumulation and possible biotransformation of toxins were measured by HPLC analysis. Feeding activity in treated scallops showed that scallops produced pseudofeces, ingestion rates decreased at 8 h; approximately 60% of the scallops were paralyzed and melanin production and hemocyte aggregation were observed in several tissues at 15 h. HPLC analysis showed that the only toxins present in the dinoflagellates and scallops were the N-sulfo-carbamoyl toxins (C1, C2; after hydrolysis, the carbamate toxins (epimers GTX2/3 were present. C1 and C2 toxins were most common in the mantle, followed by the digestive gland and stomach-complex, adductor muscle, kidney and rectum group, and finally, gills. Toxin profiles in scallop tissue were similar to the dinoflagellate; biotransformations were not present in the scallops in this short-term feeding experiment.

Near-surface energy transfers from internal tide beams to smaller vertical scale motions

Science.gov (United States)

Chou, S.; Staquet, C.; Carter, G. S.; Luther, D. S.

2016-02-01

Mechanical energy capable of causing diapycnal mixing in the ocean is transferred to the internal wave field when barotropic tides pass over underwater topography and generate internal tides. The resulting internal tide energy is confined in vertically limited structures, or beams. As internal tide beams (ITBs) propagate through regions of non-uniform stratification in the upper ocean, wave energy can be scattered through multiple reflections and refractions, be vertically trapped, or transferred to non-tidal frequencies through different nonlinear processes. Various observations have shown that ITBs are no longer detectable in horizontal kinetic energy beyond the first surface reflection. Importantly, this implies that some of the internal tide energy no longer propagates in to the abyssal ocean and consequently will not be available to maintain the density stratification. Using the NHM, a nonlinear and nonhydrostatic model based on the MITgcm, simulations of an ITB propagating up to the sea surface are examined in order to quantify the transformation of ITB energy to other motions. We compare and contrast the transformations enabled by idealized, smoothly-varying stratification with transformations enabled by realistic stratification containing a broad-band vertical wavenumber spectrum of variations. Preliminary two-dimensional results show that scattering due to small-scale structure in realistic stratification profiles from Hawaii can lead to energy being vertically trapped near the surface. Idealized simulations of "locally" generated internal solitary waves are analyzed in terms of energy flux transfers from the ITB to solitary waves, higher harmonics, and mean flow. The amount of internal tide energy which propagates back down after near-surface reflection of the ITB in different environments is quantified.

Modelling alongshore flow in a semi-enclosed lagoon strongly forced by tides and waves

Science.gov (United States)

Taskjelle, Torbjørn; Barthel, Knut; Christensen, Kai H.; Furaca, Noca; Gammelsrød, Tor; Hoguane, António M.; Nharreluga, Bilardo

2014-08-01

Alongshore flows strongly driven by tides and waves is studied in the context of a one-dimensional numerical model. Observations from field surveys performed in a semi-enclosed lagoon (1.7 km×0.2 km) outside Xai-Xai, Mozambique, are used to validate the model results. The model is able to capture most of the observed temporal variability of the current, but sea surface height tends to be overestimated at high tide, especially during high wave events. Inside the lagoon we observed a mainly uni-directional alongshore current, with speeds up to 1 ms-1. The current varies primarily with the tide, being close to zero near low tide, generally increasing during flood and decreasing during ebb. The observations revealed a local minimum in the alongshore flow at high tide, which the model was successful in reproducing. Residence times in the lagoon were calculated to be less than one hour with wave forcing dominating the flushing. At this beach a high number of drowning casualties have occurred, but no connection was found between them and strong current events in a simulation covering the period 2011-2012.

Environmental Chemistry and Chemical Ecology of "Green Tide" Seaweed Blooms.

Science.gov (United States)

Van Alstyne, Kathryn L; Nelson, Timothy A; Ridgway, Richard L

2015-09-01

Green tides are large growths or accumulations of green seaweeds that have been increasing in magnitude and frequency around the world. Because green tides consist of vast biomasses of algae in a limited area and are often seasonal or episodic, they go through periods of rapid growth in which they take up large amounts of nutrients and dissolved gases and generate bioactive natural products that may be stored in the plants, released into the environment, or broken down during decomposition. As a result of the use and production of inorganic and organic compounds, the algae in these blooms can have detrimental impacts on other organisms. Here, we review some of the effects that green tides have on the chemistry of seawater and the effects of the natural products that they produce. As blooms are developing and expanding, algae in green tides take up inorganic nutrients, such as nitrate and ortho-phosphate, which can limit their availability to other photosynthetic organisms. Their uptake of dissolved inorganic carbon for use in photosynthesis can cause localized spikes in the pH of seawater during the day with concomitant drops in the pH at night when the algae are respiring. Many of the algae that form green-tide blooms produce allelopathic compounds, which are metabolites that affect other species. The best documented allelopathic compounds include dimethylsulfoniopropionate (DMSP), dopamine, and reactive oxygen species (ROS) and their breakdown products. DMSP and dopamine are involved in defenses against herbivores. Dopamine and ROS are released into seawater where they can be allelopathic or toxic to other organisms. Thus, these macroalgal blooms can have harmful effects on nearby organisms by altering concentrations of nutrients and dissolved gas in seawater and by producing and releasing allelopathic or toxic compounds. © The Author 2015. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved

High tide in the Delta

International Nuclear Information System (INIS)

Vellinga, P.

2008-01-01

This inaugural speech takes a closer look at the relation of the Netherlands with water and sea. The author pleas for better connections of land and water and better connections of fresh and salt water. The oration discusses the influence of man on the climate, recent discoveries in the field of climate, urgency in the field of energy, opportunities for high tide protection in the Netherlands and plans for filling the new chair [nl

A Global Ocean Tide Model From TOPEX/POSEIDON Altimetry: GOT99.2

Science.gov (United States)

Ray, Richard D.

1999-01-01

Goddard Ocean Tide model GOT99.2 is a new solution for the amplitudes and phases of the global oceanic tides, based on over six years of sea-surface height measurements by the TOPEX/POSEIDON satellite altimeter. Comparison with deep-ocean tide-gauge measurements show that this new tidal solution is an improvement over previous global models, with accuracies for the main semidiurnal lunar constituent M2 now below 1.5 cm (deep water only). The new solution benefits from use of prior hydrodynamic models, several in shallow and inland seas as well as the global finite-element model FES94.1. This report describes some of the data processing details involved in handling the altimetry, and it provides a comprehensive set of global cotidal charts of the resulting solutions. Various derived tidal charts are also provided, including tidal loading deformation charts, tidal gravimetric charts, and tidal current velocity (or transport) charts. Finally, low-degree spherical harmonic coefficients are computed by numerical quadrature and are tabulated for the major short-period tides; these are useful for a variety of geodetic and geophysical purposes, especially in combination with similar estimates from satellite laser ranging.

Crustal control of dissipative ocean tides in Enceladus and other icy moons

Science.gov (United States)

Beuthe, Mikael

2016-12-01

Could tidal dissipation within Enceladus' subsurface ocean account for the observed heat flow? Earthlike models of dynamical tides give no definitive answer because they neglect the influence of the crust. I propose here the first model of dissipative tides in a subsurface ocean, by combining the Laplace Tidal Equations with the membrane approach. For the first time, it is possible to compute tidal dissipation rates within the crust, ocean, and mantle in one go. I show that oceanic dissipation is strongly reduced by the crustal constraint, and thus contributes little to Enceladus' present heat budget. Tidal resonances could have played a role in a forming or freezing ocean less than 100 m deep. The model is general: it applies to all icy satellites with a thin crust and a shallow ocean. Scaling rules relate the resonances and dissipation rate of a subsurface ocean to the ones of a surface ocean. If the ocean has low viscosity, the westward obliquity tide does not move the crust. Therefore, crustal dissipation due to dynamical obliquity tides can differ from the static prediction by up to a factor of two.

Verifying the body tide at the Canary Islands using tidal gravimetry observations

Science.gov (United States)

Arnoso, J.; Benavent, M.; Bos, M. S.; Montesinos, F. G.; Vieira, R.

2011-05-01

Gravity tide records from El Hierro, Tenerife and Lanzarote Islands (Canarian Archipelago) have been analyzed and compared to the theoretical body tide model (DDW) of Dehant el al. (1999). The use of more stringent criterion of tidal analysis using VAV program allowed us to reduce the error bars by a factor of two of the gravimetric factors at Tenerife and Lanzarote compared with previous published values. Also, the calibration values have been revisited at those sites. Precise ocean tide loading (OTL) corrections based on up-to-date global ocean models and improved regional ocean model have been obtained for the main tidal harmonics O 1, K 1, M 2, S 2. We also point out the importance of using the most accurate coastline definition for OTL calculations in the Canaries. The remaining observational errors depend on the accuracy of the calibration of the gravimeters and/or on the length of the observed data series. Finally, the comparison of the tidal observations with the theoretical body tide models has been done with an accuracy level of 0.1% at El Hierro, 0.4% at Tenerife and 0.5% at Lanzarote.

Modeling the diurnal tide with dissipation derived from UARS/HRDI measurements

Directory of Open Access Journals (Sweden)

M. A. Geller

1997-09-01

Full Text Available This paper uses dissipation values derived from UARS/HRDI observations in a recently published diurnal-tide model. These model structures compare quite well with the UARS/HRDI observations with respect to the annual variation of the diurnal tidal amplitudes and the size of the amplitudes themselves. It is suggested that the annual variation of atmospheric dissipation in the mesosphere-lower thermosphere is a major controlling factor in determining the annual variation of the diurnal tide.

COST Action ES1401 TIDES: a European network on TIme DEpendent Seismology

Science.gov (United States)

Morelli, Andrea

2016-04-01

Using the full-length records of seismic events and background ambient noise, today seismology is going beyond still-life snapshots of the interior of the Earth, and look into time-dependent changes of its properties. Data availability has grown dramatically with the expansion of seismographic networks and data centers, so as to enable much more detailed and accurate analyses. COST Action ES1401 TIDES (TIme DEpendent Seismology; http://tides-cost.eu) aims at structuring the EU seismological community to enable development of data-intensive, time-dependent techniques for monitoring Earth active processes (e.g., earthquakes, volcanic eruptions, landslides, glacial earthquakes) as well as oil/gas reservoirs. The main structure of TIDES is organised around working groups on: Workflow integration of data and computing resources; Seismic interferometry and ambient noise; Forward problems and High-performance computing applications; Seismic tomography, full waveform inversion and uncertainties; Applications in the natural environment and industry. TIDES is an open network of European laboratories with complementary skills, and is organising a series of events - workshops and advanced training schools - as well as supporting short-duration scientific stays. The first advanced training school was held in Bertinoro (Italy) on June 2015, with attendance of about 100 participants from 20 European countries, was devoted to how to manage and model seismic data with modern tools. The next school, devoted to ambient noise, will be held in 2016 Portugal: the program will be announced at the time of this conference. TIDES will strengthen Europe's role in a critical field for natural hazards and natural resource management.

INTRODUCING CAFein, A NEW COMPUTATIONAL TOOL FOR STELLAR PULSATIONS AND DYNAMIC TIDES

International Nuclear Information System (INIS)

Valsecchi, F.; Farr, W. M.; Willems, B.; Rasio, F. A.; Kalogera, V.

2013-01-01

Here we present CAFein, a new computational tool for investigating radiative dissipation of dynamic tides in close binaries and of non-adiabatic, non-radial stellar oscillations in isolated stars in the linear regime. For the latter, CAFein computes the non-adiabatic eigenfrequencies and eigenfunctions of detailed stellar models. The code is based on the so-called Riccati method, a numerical algorithm that has been successfully applied to a variety of stellar pulsators, and which does not suffer from the major drawbacks of commonly used shooting and relaxation schemes. Here we present an extension of the Riccati method to investigate dynamic tides in close binaries. We demonstrate CAFein's capabilities as a stellar pulsation code both in the adiabatic and non-adiabatic regimes, by reproducing previously published eigenfrequencies of a polytrope, and by successfully identifying the unstable modes of a stellar model in the β Cephei/SPB region of the Hertzsprung-Russell diagram. Finally, we verify CAFein's behavior in the dynamic tides regime by investigating the effects of dynamic tides on the eigenfunctions and orbital and spin evolution of massive main sequence stars in eccentric binaries, and of hot Jupiter host stars. The plethora of asteroseismic data provided by NASA's Kepler satellite, some of which include the direct detection of tidally excited stellar oscillations, make CAFein quite timely. Furthermore, the increasing number of observed short-period detached double white dwarfs (WDs) and the observed orbital decay in the tightest of such binaries open up a new possibility of investigating WD interiors through the effects of tides on their orbital evolution

Quantitative proteomic analysis of cell cycle of the dinoflagellate Prorocentrum donghaiense (Dinophyceae.

Directory of Open Access Journals (Sweden)

Da-Zhi Wang

Full Text Available Dinoflagellates are the major causative agents of harmful algal blooms in the coastal zone, which has resulted in adverse effects on the marine ecosystem and public health, and has become a global concern. Knowledge of cell cycle regulation in proliferating cells is essential for understanding bloom dynamics, and so this study compared the protein profiles of Prorocentrum donghaiense at different cell cycle phases and identified differentially expressed proteins using 2-D fluorescence difference gel electrophoresis combined with MALDI-TOF-TOF mass spectrometry. The results showed that the synchronized cells of P. donghaiense completed a cell cycle within 24 hours and cell division was phased with the diurnal cycle. Comparison of the protein profiles at four cell cycle phases (G1, S, early and late G2/M showed that 53 protein spots altered significantly in abundance. Among them, 41 were identified to be involved in a variety of biological processes, e.g. cell cycle and division, RNA metabolism, protein and amino acid metabolism, energy and carbon metabolism, oxidation-reduction processes, and ABC transport. The periodic expression of these proteins was critical to maintain the proper order and function of the cell cycle. This study, to our knowledge, for the first time revealed the major biological processes occurring at different cell cycle phases which provided new insights into the mechanisms regulating the cell cycle and growth of dinoflagellates.

Evidence for Excitation of Polar Motion by Fortnightly Ocean Tides

Science.gov (United States)

Gross, Richard S.; Hamdan, Kamal H.; Boggs, Dale H.

1996-01-01

The second-degree zonal tide raising potential, which is responsible for tidal changes in the Earth's rotation rate and length-of-day, is symmetric about the polar axis and hence can excite the Earth's polar motion only through its action upon nonaxisymmetric features of the Earth such as the oceans. Ocean tidal excitation of polar motion in the diurnal and semidiurnal tidal bands has been previously detected and examined. Here, the detection of ocean tidal excitation of polar motion in the long-period tidal band, specifically at the Mf' (13.63-day) and Mf (13.66-day) tidal frequencies, is reported. Spectra of the SPACE94 polar motion excitation series exhibit peaks at the prograde and retrograde fortnightly tidal periods. After removing effects of atmospheric wind and pressure changes, an empirical model for the effect of the fortnightly ocean tides upon polar motion excitation is obtained by least-squares fitting periodic terms at the Mf and Mf' tidal frequencies to the residual polar motion excitation series. The resulting empirical model is then compared with the predictions of two hydrodynamic ocean tide models.

Differential responses of net ecosystem exchange of carbon dioxide to light and temperature between spring and neap tides in subtropical mangrove forests.

Science.gov (United States)

Li, Qing; Lu, Weizhi; Chen, Hui; Luo, Yiqi; Lin, Guanghui

2014-01-01

The eddy flux data with field records of tidal water inundation depths of the year 2010 from two mangroves forests in southern China were analyzed to investigate the tidal effect on mangrove carbon cycle. We compared the net ecosystem exchange (NEE) and its responses to light and temperature, respectively, between spring tide and neap tide inundation periods. For the most time of the year 2010, higher daytime NEE values were found during spring tides than during neap tides at both study sites. Regression analysis of daytime NEE to photosynthetically active radiation (PAR) using the Landsberg model showed increased sensitivity of NEE to PAR with higher maximum photosynthetic rate during spring tides than neap tides. In contrast, the light compensation points acquired from the regression function of the Landsberg model were smaller during spring tides than neap tides in most months. The dependence of nighttime NEE on soil temperature was lower under spring tide than under neap tides. All these results above indicated that ecosystem carbon uptake rates of mangrove forests were strengthened, while ecosystem respirations were inhibited during spring tides in comparison with those during neap tides, which needs to be considered in modeling mangrove ecosystem carbon cycle under future sea level rise scenarios.

An Adaptive Neuro-Fuzzy Inference System for Sea Level Prediction Considering Tide-Generating Forces and Oceanic Thermal Expansion

Directory of Open Access Journals (Sweden)

Li-Ching Lin Hsien-Kuo Chang

2008-01-01

Full Text Available The paper presents an adaptive neuro fuzzy inference system for predicting sea level considering tide-generating forces and oceanic thermal expansion assuming a model of sea level dependence on sea surface temperature. The proposed model named TGFT-FN (Tide-Generating Forces considering sea surface Temperature and Fuzzy Neuro-network system is applied to predict tides at five tide gauge sites located in Taiwan and has the root mean square of error of about 7.3 - 15.0 cm. The capability of TGFT-FN model is superior in sea level prediction than the previous TGF-NN model developed by Chang and Lin (2006 that considers the tide-generating forces only. The TGFT-FN model is employed to train and predict the sea level of Hua-Lien station, and is also appropriate for the same prediction at the tide gauge sites next to Hua-Lien station.

Bottom friction optimization for a better barotropic tide modelling

Science.gov (United States)

Boutet, Martial; Lathuilière, Cyril; Son Hoang, Hong; Baraille, Rémy

2015-04-01

At a regional scale, barotropic tides are the dominant source of variability of currents and water heights. A precise representation of these processes is essential because of their great impacts on human activities (submersion risks, marine renewable energies, ...). Identified sources of error for tide modelling at a regional scale are the followings: bathymetry, boundary forcing and dissipation due to bottom friction. Nevertheless, bathymetric databases are nowadays known with a good accuracy, especially over shelves, and global tide models performances are better than ever. The most promising improvement is thus the bottom friction representation. The method used to estimate bottom friction is the simultaneous perturbation stochastic approximation (SPSA) which consists in the approximation of the gradient based on a fixed number of cost function measurements, regardless of the dimension of the vector to be estimated. Indeed, each cost function measurement is obtained by randomly perturbing every component of the parameter vector. An important feature of SPSA is its relative ease of implementation. In particular, the method does not require the development of tangent linear and adjoint version of the circulation model. Experiments are carried out to estimate bottom friction with the HYbrid Coordinate Ocean Model (HYCOM) in barotropic mode (one isopycnal layer). The study area is the Northeastern Atlantic margin which is characterized by strong currents and an intense dissipation. Bottom friction is parameterized with a quadratic term and friction coefficient is computed with the water height and the bottom roughness. The latter parameter is the one to be estimated. Assimilated data are the available tide gauge observations. First, the bottom roughness is estimated taking into account bottom sediment natures and bathymetric ranges. Then, it is estimated with geographical degrees of freedom. Finally, the impact of the estimation of a mixed quadratic/linear friction

Intraseasonal variability and tides in Makassar Strait

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Susanto, R. Dwi; Gordon, Arnold L.; Sprintall, Janet; Herunadi, Bambang

2000-05-01

Intraseasonal variability and tides along the Makassar Strait, the major route of Indonesian throughflow, are investigated using spectral and time-frequency analyses which are applied to sea level, wind and mooring data. Semidiurnal and diurnal tides are dominant features, with higher (lower) semidiurnal (diurnal) energy in the north compared to the south. Sea levels and mooring data display intraseasonal variability which are probably a response to remotely forced Kelvin waves from the Indian Ocean through Lombok Strait and to Rossby waves from the Pacific Ocean. Sea levels in Tarakan and Balikpapan and Makassar mooring velocities reveal intraseasonal features with periods of 48-62 days associated with Rossby waves from the Sulawesi Sea. Kelvin wave features with periods of 67-100 days are seen in Bali (Lombok Strait), at the mooring sites and in Balikpapan, however, they are not seen in Tarakan, which implies that these waves diminish after passing through the Makassar Strait.

Quantitative estimation of Holocene surface salinity variation in the Black Sea using dinoflagellate cyst process length

DEFF Research Database (Denmark)

Mertens, Kenneth Neil; Bradley, Lee R.; Takano, Yoshihito

2012-01-01

Reconstruction of salinity in the Holocene Black Sea has been an ongoing debate over the past four decades. Here we calibrate summer surface water salinity in the Black Sea, Sea of Azov and Caspian Sea with the process length of the dinoflagellate cyst Lingulodinium machaerophorum. We then apply ...

Solar cycle variability of nonmigrating tides in the infrared cooling of the thermosphere

Science.gov (United States)

Nischal, N.; Oberheide, J.; Mlynczak, M. G.; Marsh, D. R.

2017-12-01

Nitric Oxide (NO) at 5.3 μm and Carbon dioxide (CO2) at 15 μm are the major infrared emissions responsible for the radiative cooling of the thermosphere. We study the impact of two important diurnal nonmigrating tides, the DE2 and DE3, on NO and CO2 infrared emissions over a complete solar cycle (2002-2013) by (i) analyzing NO and CO2 cooling rate data from SABER and (ii) photochemical modeling using dynamical tides from a thermospheric empirical tidal model, CTMT. Both observed and modeled results show that the NO cooling rate amplitudes for DE2 and DE3 exhibit strong solar cycle dependence. NO 5.3 μm cooling rate tides are relatively unimportant for the infrared energy budget during solar minimum but important during solar maximum. On the other hand DE2 and DE3 in CO2 show comparatively small variability over a solar cycle. CO2 15 μm cooling rate tides remain, to a large extent, constant between solar minimum and maximum. This different responses by NO and CO2 emissions to the DE2 and DE3 during a solar cycle comes form the fact that the collisional reaction rate for NO is highly sensitive to the temperature comparative to that for CO2. Moreover, the solar cycle variability of these nonmigrating tides in thermospheric infrared emissions shows a clear QBO signals substantiating the impact of tropospheric weather system on the energy budget of the thermosphere. The relative contribution from the individual tidal drivers; temperature, density and advection to the observed DE2 and DE3 tides does not vary much over the course of the solar cycle, and this is true for both NO and CO2 emissions.

Prediction of tides using back-propagation neural networks

Digital Repository Service at National Institute of Oceanography (India)

Mandal, S.

Prediction of tides is very much essential for human activities and to reduce the construction cost in marine environment. This paper presents an application of the artificial neural network with back-propagation procedures for accurate prediction...

Application of the Convolution Formalism to the Ocean Tide Potential: Results from the Gravity and Recovery and Climate Experiment (GRACE)

Science.gov (United States)

Desai, S. D.; Yuan, D. -N.

2006-01-01

A computationally efficient approach to reducing omission errors in ocean tide potential models is derived and evaluated using data from the Gravity Recovery and Climate Experiment (GRACE) mission. Ocean tide height models are usually explicitly available at a few frequencies, and a smooth unit response is assumed to infer the response across the tidal spectrum. The convolution formalism of Munk and Cartwright (1966) models this response function with a Fourier series. This allows the total ocean tide height, and therefore the total ocean tide potential, to be modeled as a weighted sum of past, present, and future values of the tide-generating potential. Previous applications of the convolution formalism have usually been limited to tide height models, but we extend it to ocean tide potential models. We use luni-solar ephemerides to derive the required tide-generating potential so that the complete spectrum of the ocean tide potential is efficiently represented. In contrast, the traditionally adopted harmonic model of the ocean tide potential requires the explicit sum of the contributions from individual tidal frequencies. It is therefore subject to omission errors from neglected frequencies and is computationally more intensive. Intersatellite range rate data from the GRACE mission are used to compare convolution and harmonic models of the ocean tide potential. The monthly range rate residual variance is smaller by 4-5%, and the daily residual variance is smaller by as much as 15% when using the convolution model than when using a harmonic model that is defined by twice the number of parameters.

Water flux management and phytoplankton communities in a Mediterranean coastal lagoon. Part II: Mixotrophy of dinoflagellates as an adaptive strategy?

International Nuclear Information System (INIS)

Cecchi, P.; Garrido, M.; Collos, Y.; Pasqualini, V.

2016-01-01

Dinoflagellate proliferation is common in coastal waters, and trophic strategies are often advanced to explain the success of these organisms. The Biguglia lagoon is a Mediterranean brackish ecosystem where eutrophication has long been an issue, and where dominance of dinoflagellates has persisted for several years. Monthly monitoring of fluorescence-based properties of phytoplankton communities carried out in 2010 suggested that photosynthesis alone could not support the observed situation all year round. Contrasting food webs developed depending on the hydrological season, with a gradual shift from autotrophy to heterotrophy. Progressively, microphytoplankton assemblages became unequivocally dominated by a Prorocentrum minimum bloom, which exhibited very weak effective photosynthetic performance, whereas paradoxically its theoretical capacities remained fully operational. Different environmental hypotheses explaining this discrepancy were examined, but rejected. We conclude that P. minimum bloom persistence is sustained by mixotrophic strategies, with complex compromises between phototrophy and phagotrophy, as evidenced by fluorescence-based observations. - Highlights: •Dinoflagellate proliferation is now common in Mediterranean coastal waters. •Trophic strategies are advanced to explain the success of these organisms. •Prorocentrum minimum exhaustively dominated in the Biguglia lagoon (Corsica) in 2010. •Photosynthesis alone did not sustain the observed situation all year round. •Mixotrophy is hypothesized as an alternative driver of the process.

The effect of ocean tides on the earth's rotation as predicted by the results of an ocean tide model

Science.gov (United States)

Gross, Richard S.

1993-01-01

The published ocean tidal angular momentum results of Seiler (1991) are used to predict the effects of the most important semidiurnal, diurnal, and long period ocean tides on the earth's rotation. The separate, as well as combined, effects of ocean tidal currents and sea level height changes on the length-of-day, UT1, and polar motion are computed. The predicted polar motion results reported here account for the presence of the free core nutation and are given in terms of the motion of the celestial ephemeris pole so that they can be compared directly to the results of observations. Outside the retrograde diurnal tidal band, the summed effect of the semidiurnal and diurnal ocean tides studied here predict peak-to-peak polar motion amplitudes as large as 2 mas. Within the retrograde diurnal tidal band, the resonant enhancement caused by the free core nutation leads to predicted polar motion amplitudes as large as 9 mas.

Influence of tides and winds on fishing techniques and strategies in the Mamanguape River Estuary, Paraíba State, NE Brazil.

Science.gov (United States)

Bezerra, Dandara M M; Nascimento, Douglas M; Ferreira, Emmanoela N; Rocha, Pollyana D; Mourão, José S

2012-09-01

This work was carried out in two small fishing communities, Barra de Mamanguape and Tramataia, Northeastern Brazil. The aim was to study these traditional fishermen's knowledge and perception about tide and wind classifications, as well as their fishing strategies and techniques. Our research methodology involved various techniques: free interviews and semi-structured ones, guided tours and direct observations. The results obtained show the fishermen's classification of the tides according to the phases of the moon: 'breaking tide', 'flushing tide', 'dead tide' and 'big tide' designated technically these last as neap tide and spring tide, respectively. Wind is also an essential factor for the fishermen to make successful catches, and they classify it according to direction: North, South, East, Southeast, Southwest, Northeast and Northwest. The data show that fishermen's knowledge can also be useful in devising plans for management and conservation studies for this estuary.

Effects of the toxic dinoflagellate Karlodinium sp. (cultured at different N/P ratios on micro and mesozooplankton

Directory of Open Access Journals (Sweden)

Dolors Vaqué

2006-03-01

Full Text Available An experimental study was carried out to investigate whether two potential predators such as Oxyrrhis marina (phagotrophic dinoflagellate and Acartia margalefi (Copepoda: Calanoida had different responses when feeding on toxic (Karlodinium sp.-strain CSIC1- or non-toxic (Gymnodinium sp1 dinoflagellates with a similar shape and size. Both prey were cultured at different N/P ratios (balanced N/P = 15, and P-limited N/P > 15 to test whether P-limitation conditions could lead to depressed grazing rates or have other effects on the predators. Both predators ingested the non-toxic Gymnodinium sp1, and low or non-ingestion rates were observed when incubated with Karlodinium sp. The dinoflagellate O. marina did not graze at all on Karlodinium sp. at N/P > 15 and very little at NP = 15, as its net growth rates were always negative when feeding on Karlodinium sp. cultured under P-limitation conditions. A. margalefi had lower ingestion rates when feeding on Karlodinium sp. grown at N/P = 15 than when feeding on Gymnodinium sp1, and did not graze on P-limited Karlodinium sp. Nevertheless, feeding on Karlodinium sp. grown under N/P =15 or N/P > 15 did not have any paralyzing or lethal effect on A. margalefi after 24 h. Finally, a direct effect on the viability of A. margalefi eggs was detected when healthy eggs were incubated for 5 days in the presence of Karlodinium sp. grown under N/P =15 or N/P > 15, producing a decrease in viability of 20% and 60% respectively.

Latitudinal variation in the symbiotic dinoflagellateSymbiodiniumof the common reef zoantharianPalythoa tuberculosaon the Saudi Arabian coast of the Red Sea

KAUST Repository

Reimer, James D.

2016-08-08

Aim The Red Sea presents an ideal setting to explore the variability of Symbiodinium over environmental, latitudinal and geographical gradients. We used sequences from two molecular markers to examine genetic diversity of Symbiodinium associated with the widely distributed zoantharian Palythoa tuberculosa in the northern and central Red Sea. Location Northern and central Red Sea. Methods Specimens (n = 329) were collected from 15 locations. Sequence data from nuclear ribosomal ITS2 (n = 269) and chloroplast minicircle psbAncr (n = 173) were phylogenetically analysed (maximum likelihood, neighbour joining), and Symbiodinium types identified for each P. tuberculosa colony. To establish whether environment was a strong predictor of Symbiodinium psbAncr lineage, SST, chlorophyll-a, salinity, and depth data were fit into a multinomial logistic regression using the package VGAM in the R statistical environment. Results Based on ITS2 and psbAncr results, P. tuberculosa colonies were shown to be in symbioses with Symbiodinium clade C (n = 172) and clade D (n = 1). Within clade C, four psbAncr lineages were observed; closely related lineages designated Pt-1-a and Pt-1-b, and closely related lineages Pt-3-a and Pt-3-b. By location, Pt-1-a dominated the sites within the Gulf of Aqaba (c. 86%, 37/43 colonies). At the entrance to the Gulf of Aqaba, Pt-3-a dominated (c. 88%, 15/17), while the more southern remaining sites in the Red Sea were dominated by Pt-3-b (c. 78%, 89/113). Main conclusions Multinomial logistic regression analyses established that predictions based on the combination of temperature, chlorophyll-a and salinity accurately reflected symbiont distributions in the central and northern Red Sea. Palythoa tuberculosa host Pt-1-a in the coldest region, the Gulf of Aqaba (annual average SST = 24.5–25.0 °C), while immediately to the south Pt-3-a dominates (SST = 26.0–26.5 °C), with warmest southern sites dominated by Pt-3-b (SST > 26.5 °C). The Gulf of Aqaba is

UVR-induced photosynthetic inhibition dominates over DNA damage in marine dinoflagellates exposed to fluctuating solar radiation regimes

NARCIS (Netherlands)

Helbling, E. Walter; Buma, Anita G. J.; van de Poll, Willem; Fernandez Zenoff, M. Veronica; Villafane, Virginia E.

2008-01-01

The combined effect of solar radiation (UV-B (280-315 nm), UWA (315-400 nm) and PAR (400-700 nm)) and vertical mixing (i.e., fluctuating radiation regimes) on the marine dinoflagellates Gymnodinium chlorophorum, Heterocapsa triquetra and Prorocentrum micans was investigated during the austral spring

Are there tides within trees?

Science.gov (United States)

Fisahn, Joachim

2018-01-24

Tree stem diameters and electrical stem potentials exhibit rhythmic variations with periodicities of 24-25 h. Under free-running conditions of constant light or darkness these rhythms were suggested to be mediated by the lunisolar gravitational force. To further unravel the regulation of tree stem diameter dilatations, many of the published time courses of diameter variations were re-evaluated in conjunction with the contemporaneous time courses of the lunisolar tidal acceleration. This was accomplished by application of the Etide program, which estimates, with high temporal resolution, local gravitational changes as a consequence of the diurnal variations of the lunisolar gravitational force due to the orbits and relative positions of Earth, Moon and Sun. In all instances investigated, it was evident that a synchronism exists between the times of the turning points of both the lunisolar tide and stem diameter variations when the direction of extension changes. This finding of synchrony documents that the lunisolar tide is a regulator of the tree stem diameter dilatations. Under the described experimental conditions, rhythms in tree stem diameter dilations and electrical stem potentials are controlled by the lunisolar gravitational acceleration. © The Author(s) 2018. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Accumulation, transformation and breakdown of DSP toxins from the toxic dinoflagellate Dinophysis acuta in blue mussels, Mytilus edulis

DEFF Research Database (Denmark)

Nielsen, Lasse Tor; Hansen, Per Juel; Krock, Bernd

2016-01-01

Okadaic acid (OA), dinophysistoxins (DTX) and pectenotoxins (PTX) produced by the dinoflagellates Dinophysis spp. can accumulate in shellfish and cause diarrhetic shellfish poisoning upon human consumption. Shellfish toxicity is a result of algal abundance and toxicity as well as accumulation and...

Atmospheric Pressure Corrections in Geodesy and Oceanography: a Strategy for Handling Air Tides

Science.gov (United States)

Ponte, Rui M.; Ray, Richard D.

2003-01-01

Global pressure data are often needed for processing or interpreting modern geodetic and oceanographic measurements. The most common source of these data is the analysis or reanalysis products of various meteorological centers. Tidal signals in these products can be problematic for several reasons, including potentially aliased sampling of the semidiurnal solar tide as well as the presence of various modeling or timing errors. Building on the work of Van den Dool and colleagues, we lay out a strategy for handling atmospheric tides in (re)analysis data. The procedure also offers a method to account for ocean loading corrections in satellite altimeter data that are consistent with standard ocean-tide corrections. The proposed strategy has immediate application to the on-going Jason-1 and GRACE satellite missions.

Integration of coastal inundation modeling from storm tides to individual waves

Science.gov (United States)

Li, Ning; Roeber, Volker; Yamazaki, Yoshiki; Heitmann, Troy W.; Bai, Yefei; Cheung, Kwok Fai

2014-11-01

Modeling of storm-induced coastal inundation has primarily focused on the surge generated by atmospheric pressure and surface winds with phase-averaged effects of the waves as setup. Through an interoperable model package, we investigate the role of phase-resolving wave processes in simulation of coastal flood hazards. A spectral ocean wave model describes generation and propagation of storm waves from deep to intermediate water, while a non-hydrostatic storm-tide model has the option to couple with a spectral coastal wave model for computation of phase-averaged processes in a near-shore region. The ocean wave and storm-tide models can alternatively provide the wave spectrum and the surface elevation as the boundary and initial conditions for a nested Boussinesq model. Additional surface-gradient terms in the Boussinesq equations maintain the quasi-steady, non-uniform storm tide for modeling of phase-resolving surf and swash-zone processes as well as combined tide, surge, and wave inundation. The two nesting schemes are demonstrated through a case study of Hurricane Iniki, which made landfall on the Hawaiian Island of Kauai in 1992. With input from a parametric hurricane model and global reanalysis and tidal datasets, the two approaches produce comparable significant wave heights and phase-averaged surface elevations in the surf zone. The nesting of the Boussinesq model provides a seamless approach to augment the inundation due to the individual waves in matching the recorded debris line along the coast.

Coastal Improvements for Tide Models: The Impact of ALES Retracker

Directory of Open Access Journals (Sweden)

Gaia Piccioni

2018-05-01

Full Text Available Since the launch of the first altimetry satellites, ocean tide models have been improved dramatically for deep and shallow waters. However, issues are still found for areas of great interest for climate change investigations: the coastal regions. The purpose of this study is to analyze the influence of the ALES coastal retracker on tide modeling in these regions with respect to a standard open ocean retracker. The approach used to compute the tidal constituents is an updated and along-track version of the Empirical Ocean Tide model developed at DGFI-TUM. The major constituents are derived from a least-square harmonic analysis of sea level residuals based on the FES2014 tide model. The results obtained with ALES are compared with the ones estimated with the standard product. A lower fitting error is found for the ALES solution, especially for distances closer than 20 km from the coast. In comparison with in situ data, the root mean squared error computed with ALES can reach an improvement larger than 2 cm at single locations, with an average impact of over 10% for tidal constituents K 2 , O 1 , and P 1 . For Q 1 , the improvement is over 25%. It was observed that improvements to the root-sum squares are larger for distances closer than 10 km to the coast, independently on the sea state. Finally, the performance of the solutions changes according to the satellite’s flight direction: for tracks approaching land from open ocean root mean square differences larger than 1 cm are found in comparison to tracks going from land to ocean.

Observed characteristics of tide-surge interaction along the east coast of India and the head of Bay of Bengal

Digital Repository Service at National Institute of Oceanography (India)

Antony, C.; Unnikrishnan, A.S.

before the high tide. Application of a simple model shows the observed surge peak distribution at Hiron Point can be explained in terms of phase alteration of tide due to surge and surge modulation by tide. The degree of interaction tends to increase...

ACCURACY ASSESSMENT OF RECENT GLOBAL OCEAN TIDE MODELS AROUND ANTARCTICA

Directory of Open Access Journals (Sweden)

J. Lei

2017-09-01

Full Text Available Due to the coverage limitation of T/P-series altimeters, the lack of bathymetric data under large ice shelves, and the inaccurate definitions of coastlines and grounding lines, the accuracy of ocean tide models around Antarctica is poorer than those in deep oceans. Using tidal measurements from tide gauges, gravimetric data and GPS records, the accuracy of seven state-of-the-art global ocean tide models (DTU10, EOT11a, GOT4.8, FES2012, FES2014, HAMTIDE12, TPXO8 is assessed, as well as the most widely-used conventional model FES2004. Four regions (Antarctic Peninsula region, Amery ice shelf region, Filchner-Ronne ice shelf region and Ross ice shelf region are separately reported. The standard deviations of eight main constituents between the selected models are large in polar regions, especially under the big ice shelves, suggesting that the uncertainty in these regions remain large. Comparisons with in situ tidal measurements show that the most accurate model is TPXO8, and all models show worst performance in Weddell sea and Filchner-Ronne ice shelf regions. The accuracy of tidal predictions around Antarctica is gradually improving.

Accuracy Assessment of Recent Global Ocean Tide Models around Antarctica

Science.gov (United States)

Lei, J.; Li, F.; Zhang, S.; Ke, H.; Zhang, Q.; Li, W.

2017-09-01

Due to the coverage limitation of T/P-series altimeters, the lack of bathymetric data under large ice shelves, and the inaccurate definitions of coastlines and grounding lines, the accuracy of ocean tide models around Antarctica is poorer than those in deep oceans. Using tidal measurements from tide gauges, gravimetric data and GPS records, the accuracy of seven state-of-the-art global ocean tide models (DTU10, EOT11a, GOT4.8, FES2012, FES2014, HAMTIDE12, TPXO8) is assessed, as well as the most widely-used conventional model FES2004. Four regions (Antarctic Peninsula region, Amery ice shelf region, Filchner-Ronne ice shelf region and Ross ice shelf region) are separately reported. The standard deviations of eight main constituents between the selected models are large in polar regions, especially under the big ice shelves, suggesting that the uncertainty in these regions remain large. Comparisons with in situ tidal measurements show that the most accurate model is TPXO8, and all models show worst performance in Weddell sea and Filchner-Ronne ice shelf regions. The accuracy of tidal predictions around Antarctica is gradually improving.

Review of research in internal-wave and internal-tide deposits of China: Discussion

Directory of Open Access Journals (Sweden)

G. Shanmugam

2014-10-01

Full Text Available This discussion of a review article by [27], published in the Journal of Palaeogeography (2(1: 56– 65, is aimed at illustrating that interpretations of ten ancient examples in China and one in the central Appalachians (USA as deep-water deposits of internal waves and internal tides are unsustainable. This critical assessment is based on an in-depth evaluation of oceanographic and sedimentologic data on internal waves and internal tides derived from 332 print and online published works during 1838–January 2013, which include empirical data on the physical characteristics of modern internal waves and internal tides from 51 regions of the world’s oceans [108]. In addition, core and outcrop descriptions of deep-water strata from 35 case studies worldwide carried out by the author during 1974–2011, and a selected number of case studies published by other researchers are evaluated for identifying the sedimentological challenges associated with distinguishing types of bottom-current reworked sands in the ancient sedimentary record. The emerging conclusion is that any interpretation of ancient strata as deposits of internal waves and internal tides is premature.

Circum-Antarctic Shoreward Heat Transport Derived From an Eddy- and Tide-Resolving Simulation

Science.gov (United States)

Stewart, Andrew L.; Klocker, Andreas; Menemenlis, Dimitris

2018-01-01

Almost all heat reaching the bases of Antarctica's ice shelves originates from warm Circumpolar Deep Water in the open Southern Ocean. This study quantifies the roles of mean and transient flows in transporting heat across almost the entire Antarctic continental slope and shelf using an ocean/sea ice model run at eddy- and tide-resolving (1/48°) horizontal resolution. Heat transfer by transient flows is approximately attributed to eddies and tides via a decomposition into time scales shorter than and longer than 1 day, respectively. It is shown that eddies transfer heat across the continental slope (ocean depths greater than 1,500 m), but tides produce a stronger shoreward heat flux across the shelf break (ocean depths between 500 m and 1,000 m). However, the tidal heat fluxes are approximately compensated by mean flows, leaving the eddy heat flux to balance the net shoreward heat transport. The eddy-driven cross-slope overturning circulation is too weak to account for the eddy heat flux. This suggests that isopycnal eddy stirring is the principal mechanism of shoreward heat transport around Antarctica, though likely modulated by tides and surface forcing.

Heat stress of two tropical seagrass species during low tides

DEFF Research Database (Denmark)

Pedersen, Ole; Colmer, Timothy D.; Borum, Jens

2016-01-01

Seagrasses grow submerged in aerated seawater but often in low O2 sediments. Elevated temperatures and low O2 are stress factors. Internal aeration was measured in two tropical seagrasses, Thalassia hemprichii and Enhalus acoroides, growing with extreme tides and diel temperature amplitudes......), the high temperatures and reduced CO2 would have diminished PN, whereas RD increased (Q10 of 2.0-2.7) above that at 33°C (0.45 and 0.33 μmol O2 m-2 s-1, respectively). During night-time low tides, O2 declined resulting in shoot base anoxia in both species, but incoming water containing c. 20 kPa O2...

Spatial distribution of dinoflagellates from the tropical coastal waters of the South Andaman, India: Implications for coastal pollution monitoring

Digital Repository Service at National Institute of Oceanography (India)

Narale, D.D.; Anil, A.C.

Dinoflagellate community structure from two semi-enclosed areas along the South Andaman region, India, was investigated to assess the anthropogenic impact on coastal water quality. At the densely inhabited Port Blair Bay, the dominance of mixotrophs...

Winter variability in the western Gulf of Maine: Part 1: Internal tides

Science.gov (United States)

Brown, W. S.

2011-09-01

During the winter 1997-1998, a field program was conducted in Wilkinson Basin-western Gulf of Maine-as part of a study of winter convective mixing. The field program consisted of (1) Wilkinson basin-scale hydrographic surveys, (2) a tight three-mooring array with ˜100 m separations measured temperature and conductivity at rates of 2-15 min and (3) a single pair of upward/downward-looking pair acoustic Doppler current profiling (ADCP) instruments measured currents with 8 m vertical resolution over the 270 m water column in north-central Wilkinson basin at a rate of 10 min. The moored array measurements below the mixed layer (˜100 m depth) between 11 January and 6 February 1998 were dominated by a combination of the relatively strong semidiurnal external (depth-independent or barotropic) tide; upon which were superposed a weaker phase-locked semidiurnal internal tide and a very weak water column mean currents of about 1 cm/s southward or approximately across the local isobaths. The harmonic analysis of a vertical average of the relatively uniform ADCP velocities in the well-mixed upper 123 m of the water column, defined the external tidal currents which were dominated by a nearly rectilinear, across-isobath (326°T) M 2 semidiurnal tidal current of about 15 cm/s. The depth-dependent residual current field, which was created by subtracting the external tidal current, consisted of (1) clockwise-rotating semidiurnal internal tidal currents of about 5 cm/s below the mixed layer; (2) clockwise-rotating inertial currents; and (3) a considerably less energetic subtidal current variability. The results from both frequency-domain empirical orthogonal function and tidal harmonic analyses of the of isotherm displacement series at each of the three moorings in the 100 m array mutually confirm an approximate east-northeastward phase propagation of the dominant M 2 semidiurnal internal tide across Wilkinson Basin. Further investigation supports the idea that this winter internal

River-tide dynamics : Exploration of nonstationary and nonlinear tidal behavior in the Yangtze River estuary

NARCIS (Netherlands)

Guo, L.; Van der Wegen, M.; Jay, D.A.; Matte, P.; Wang, Z.B.; Roelvink, J.A.; He, Q.

2015-01-01

River-tide dynamics remain poorly understood, in part because conventional harmonic analysis (HA) does not cope effectively with nonstationary signals. To explore nonstationary behavior of river tides and the modulation effects of river discharge, this work analyzes tidal signals in the Yangtze

GOCE++ Dynamical Coastal Topography and tide gauge unification using altimetry and GOCE

DEFF Research Database (Denmark)

Andersen, Ole Baltazar; Knudsen, Per; Nielsen, Karina

Mean Dynamic Topography (MDT) of the ocean along a coastline which contributes/requires reconciling altimetry, tide gauge and vertical land motion. The fundamental use of the MDT computed using altimetry, ocean models or through the use of tide gauges has values of between -2 and +1 meters at different...... processes and physics responsible for sea level changes on various temporal/spatial scales. The study runs from October 2015 to march 2017 and involves elements like: Develop an approach to estimate a consistent DT at tide gauges, coastal areas, and open ocean; Validate the approach in well-surveyed areas......ESA has recently released a study on the potential of ocean levelling as a novel approach to the study of height system unification taking the recent development in geoid accuracy trough GOCE data into account. The suggested investigation involves the use of measurements and modelling to estimate...

High tide, news from a warming world

International Nuclear Information System (INIS)

Lynas, M.

2005-01-01

While governments debate and scientists test ever-more complicated hypotheses, ordinary people all over the world are starting to notice the effects of global warming. In High Tide, British journalist Mark Lynas visits global hot spots to record people's reactions and sound a clarion call for action. Readers looking for a 'we are the world' approach to climate change may be taken aback by Lynas' flat expression of the uncomfortable truth: 'Every time America votes, the world holds its breath.... Climate change begins and ends in America'. Lynas damns the George W. Bush administration for undermining global efforts such as the Kyoto Protocol as well as actively preventing innovation within the United States that would reduce auto and industrial emissions. But High Tide is not the firs or the best book to do that; instead, its narrative strength is in the riveting stories of how small towns, islands, riverside cities, and rural areas are being slowly destroyed. Gardeners in England will be unable to grow heritage plant species within the next 75 years. The Alaskan permafrost is melting, as temperatures there increase ''ten times faster than in the rest of the world.'' An entire Pacific Island nation--Tuvalu--will soon disappear beneath the rising sea, leaving its people homeless. Lynas visits Alaska, Tuvalu, Peru, China, and the east coast of the United States, documenting the lives, places, and cultures that will be lost in the decades to come. Thankfully, just when hopelessness threatens to overwhelm the reader, High Tide offers a five-step plan to mitigate the most catastrophic effects of global climate change. Every step in the plan involves action by United States citizens and their elected representatives, offering American activists and visionaries a chance to do penance for wrecking parts of the world far from our own driveways

CHEMOSENSORY ATTRACTION OF ZOOSPORES OF THE ESTUARINE DINOFLAGELLATES, PFIESTERIA PISCICIDA AND P. SHUMWAYAE, TO FINFISH MUCUS AND EXCRETA. (R825551)

Science.gov (United States)

Toxic strains of the estuarine dinoflagellates, Pfiesteria piscicida and P. shumwayae, can cause fish death and disease, whereas other estuarine `lookalike' species such as cryptoperidiniopsoids have not been ichthyotoxic under ecologically rel...

Rapid and accurate identification by real-time PCR of biotoxin-producing dinoflagellates from the family gymnodiniaceae.

Science.gov (United States)

Smith, Kirsty F; de Salas, Miguel; Adamson, Janet; Rhodes, Lesley L

2014-03-07

The identification of toxin-producing dinoflagellates for monitoring programmes and bio-compound discovery requires considerable taxonomic expertise. It can also be difficult to morphologically differentiate toxic and non-toxic species or strains. Various molecular methods have been used for dinoflagellate identification and detection, and this study describes the development of eight real-time polymerase chain reaction (PCR) assays targeting the large subunit ribosomal RNA (LSU rRNA) gene of species from the genera Gymnodinium, Karenia, Karlodinium, and Takayama. Assays proved to be highly specific and sensitive, and the assay for G. catenatum was further developed for quantification in response to a bloom in Manukau Harbour, New Zealand. The assay estimated cell densities from environmental samples as low as 0.07 cells per PCR reaction, which equated to three cells per litre. This assay not only enabled conclusive species identification but also detected the presence of cells below the limit of detection for light microscopy. This study demonstrates the usefulness of real-time PCR as a sensitive and rapid molecular technique for the detection and quantification of micro-algae from environmental samples.

Morphological variation and phylogenetic analysis of the dinoflagellate Gymnodinium aureolum from a tributary of Chesapeake Bay.

Science.gov (United States)

Tang, Ying Zhong; Egerton, Todd A; Kong, Lesheng; Marshall, Harold G

2008-01-01

Cultures of four strains of the dinoflagellate Gymnodinium aureolum (Hulburt) G. Hansen were established from the Elizabeth River, a tidal tributary of the Chesapeake Bay, USA. Light microscopy, scanning electron microscopy, nuclear-encoded large sub-unit rDNA sequencing, and culturing observations were conducted to further characterize this species. Observations of morphology included: a multiple structured apical groove; a peduncle located between the emerging points of the two flagella; pentagonal and hexagonal vesicles on the amphiesma; production and germination of resting cysts; variation in the location of the nucleus within the center of the cell; a longitudinal ventral concavity; and considerable variation in cell width/length and overall cell size. A fish bioassay using juvenile sheepshead minnows detected no ichthyotoxicity from any of the strains over a 48-h period. Molecular analysis confirmed the dinoflagellate was conspecific with G. aureolum strains from around the world, and formed a cluster along with several other Gymnodinium species. Morphological evidence suggests that further research is necessary to examine the relationship between G. aureolum and a possibly closely related species Gymnodinium maguelonnense.

Tsunami hazard assessment in the Hudson River Estuary based on dynamic tsunami-tide simulations

Science.gov (United States)

Shelby, Michael; Grilli, Stéphan T.; Grilli, Annette R.

2016-12-01

This work is part of a tsunami inundation mapping activity carried out along the US East Coast since 2010, under the auspice of the National Tsunami Hazard Mitigation program (NTHMP). The US East Coast features two main estuaries with significant tidal forcing, which are bordered by numerous critical facilities (power plants, major harbors,...) as well as densely built low-level areas: Chesapeake Bay and the Hudson River Estuary (HRE). HRE is the object of this work, with specific focus on assessing tsunami hazard in Manhattan, the Hudson and East River areas. In the NTHMP work, inundation maps are computed as envelopes of maximum surface elevation along the coast and inland, by simulating the impact of selected probable maximum tsunamis (PMT) in the Atlantic ocean margin and basin. At present, such simulations assume a static reference level near shore equal to the local mean high water (MHW) level. Here, instead we simulate maximum inundation in the HRE resulting from dynamic interactions between the incident PMTs and a tide, which is calibrated to achieve MHW at its maximum level. To identify conditions leading to maximum tsunami inundation, each PMT is simulated for four different phases of the tide and results are compared to those obtained for a static reference level. We first separately simulate the tide and the three PMTs that were found to be most significant for the HRE. These are caused by: (1) a flank collapse of the Cumbre Vieja Volcano (CVV) in the Canary Islands (with a 80 km3 volume representing the most likely extreme scenario); (2) an M9 coseismic source in the Puerto Rico Trench (PRT); and (3) a large submarine mass failure (SMF) in the Hudson River canyon of parameters similar to the 165 km3 historical Currituck slide, which is used as a local proxy for the maximum possible SMF. Simulations are performed with the nonlinear and dispersive long wave model FUNWAVE-TVD, in a series of nested grids of increasing resolution towards the coast, by one

Last Interglacial (Eemian) hydrographic conditions in the south-eastern Baltic Sea, NE Europe, based on dinoflagellates and pollen

DEFF Research Database (Denmark)

Head, Martin J.; Seidenkrantz, Marit Solveig Louise Schramm; Janczyk-Kopikowa, Zofia

2005-01-01

of arctic waters. Warm and saline conditions of 15–20 psu or more, at least twice present levels, persisted throughout the early Eemian. A rise in sea level at Licze appears to correlate with a similar event in eastern Denmark, as both coincide with the increase in Corylus (ca. 750 years...... into the interglacial). This sea-level rise might therefore have a basinwide extent, and has been attributed to an opening of the Danish Belts. Whereas dinoflagellate cysts reflect sustained high salinites within the upper water column, a concomitant increase in abundance of the chlorococcalean alga Pediastrum within......A rich organic-walled dinoflagellate cyst and pollen record from the Licze borehole in northern Poland has been used to reconstruct the hydrographic history of the southeastern Baltic Sea during the Eemian Stage (Last Interglacial) of the Upper Pleistocene. Warm and saline waters (ca. 10–15 psu...

Stable carbon isotope fractionation of organic cyst-forming dinoflagellates: Evaluating the potential for a CO2 proxy

Science.gov (United States)

Hoins, Mirja; Van de Waal, Dedmer B.; Eberlein, Tim; Reichart, Gert-Jan; Rost, Björn; Sluijs, Appy

2015-07-01

Over the past decades, significant progress has been made regarding the quantification and mechanistic understanding of stable carbon isotope fractionation (13C fractionation) in photosynthetic unicellular organisms in response to changes in the partial pressure of atmospheric CO2 (pCO2). However, hardly any data is available for organic cyst-forming dinoflagellates while this is an ecologically important group with a unique fossil record. We performed dilute batch experiments with four harmful dinoflagellate species known for their ability to form organic cysts: Alexandrium tamarense, Scrippsiella trochoidea, Gonyaulax spinifera and Protoceratium reticulatum. Cells were grown at a range of dissolved CO2 concentrations characterizing past, modern and projected future values (∼5-50 μmol L-1), representing atmospheric pCO2 of 180, 380, 800 and 1200 μatm. In all tested species, 13C fractionation depends on CO2 with a slope of up to 0.17‰ (μmol L)-1. Even more consistent correlations were found between 13C fractionation and the combined effects of particulate organic carbon quota (POC quota; pg C cell-1) and CO2. Carbon isotope fractionation as well as its response to CO2 is species-specific. These results may be interpreted as a first step towards a proxy for past pCO2 based on carbon isotope ratios of fossil organic dinoflagellate cysts. However, additional culture experiments focusing on environmental variables other than pCO2, physiological underpinning of the recorded response, testing for possible offsets in 13C values between cells and cysts, as well as field calibration studies are required to establish a reliable proxy.

The MicroRNA Repertoire of Symbiodinium, the Dinoflagellate Symbiont of Reef-Building Corals

KAUST Repository

Baumgarten, Sebastian

2013-07-01

Animal and plant genomes produce numerous small RNAs (smRNAs) that regulate gene expression post-transcriptionally affecting metabolism, development, and epigenetic inheritance. In order to characterize the repertoire of endogenous microRNAs and potential gene targets, we conducted smRNA and mRNA expression profiling over nine experimental treatments of cultures from the dinoflagellate Symbiodinium sp. A1, a photosynthetic symbiont of scleractinian corals. We identified a total of 75 novel smRNAs in Symbiodinum sp. A1 that share stringent key features with functional microRNAs from other model organisms. A subset of 38 smRNAs was predicted independently over all nine treatments and their putative gene targets were identified. We found 3,187 animal-like target sites in the 3’UTRs of 12,858 mRNAs and 53 plantlike target sites in 51,917 genes. Furthermore, we identified the core RNAi protein machinery in Symbiodinium. Integration of smRNA and mRNA expression profiling identified a variety of processes that could be under microRNA control, e.g. regulation of translation, DNA modification, and chromatin silencing. Given that Symbiodinium seems to have a paucity of transcription factors and differentially expressed genes, identification and characterization of its smRNA repertoire establishes the possibility of a range of gene regulatory mechanisms in dinoflagellates acting post-transcriptionally.

Nuclear and plastid DNAs from the binucleate dinoflagellates Glenodinium (Peridinium) foliaceum and Peridinium balticum.

Science.gov (United States)

Kite, G C; Rothschild, L J; Dodge, J D

1988-01-01

The binucleate dinoflagellates Glenodinium (Peridinium) foliaceum Stein and Peridinium balticum (Levander) Lemmermann were found to contain two major buoyant density classes of DNA. The heavier peak (1.730 g/cm3) was derived from the "dinokaryotic" nucleus and the lighter peak (1.706 g/cm3) from the "endosymbiont" nucleus and this allowed for the fractionation of G. foliaceum DNA in CsCl/EtBr density gradients. An initial CsCl/Hoechst Dye gradient removed a minor A-T rich satellite species which was identified as plastid DNA with a size of about 100-106 kb. Analysis of the nuclear DNA by agarose gel electrophoresis and renaturation studies showed that the endosymbiont nucleus lacked amplified gene-sized DNA molecules, however, this nucleus did have a comparatively high level of DNA. The total amount of DNA per cell and the relative contributions of the two nuclei appeared to vary between two strains of G. foliaceum (75 pg/cell in CCAP strain and 58 pg in UTEX strain). The only strain of P. balticum examined contained 73 pg cell. These results are discussed in relation to the status and possible functioning of the endosymbiont nucleus and the idea that these dinoflagellates provide model systems with which to study the evolution of plastids.

Properties of Red Sea coastal currents

KAUST Repository

Churchill, J.H.

2014-02-14

Properties of coastal flows of the central Red Sea are examined using 2 years of velocity data acquired off the coast of Saudi Arabia near 22 °N. The tidal flow is found to be very weak. The strongest tidal constituent, the M2 tide, has a magnitude of order 4 cm s−1. Energetic near-inertial and diurnal period motions are observed. These are surface-intensified currents, reaching magnitudes of >10 cm s−1. Although the diurnal currents appear to be principally wind-driven, their relationship with the surface wind stress record is complex. Less than 50% of the diurnal current variance is related to the diurnal wind stress through linear correlation. Correlation analysis reveals a classical upwelling/downwelling response to the alongshore wind stress. However, less than 30% of the overall sub-inertial variance can be accounted for by this response. The action of basin-scale eddies, impinging on the coastal zone, is implicated as a primary mechanism for driving coastal flows.

Modeling Tides, Planetary Waves, and Equatorial Oscillations in the MLT

Science.gov (United States)

Mengel, J. G.; Mayr, H. G.; Drob, D. P.; Porter, H. S.; Bhartia, P. K. (Technical Monitor)

2001-01-01

Applying Hines Doppler Spread Parameterization for gravity waves (GW), our 3D model reproduces some essential features that characterize the observed seasonal variations of tides and planetary waves in the upper mesosphere. In 2D, our model also reproduces the large Semi-Annual Oscillation (SAO) and Quasi Biennial Oscillation (QBO) observed in this region at low latitudes. It is more challenging to describe these features combined in a more comprehensive self consistent model, and we give a progress report that outlines the difficulties and reports some success. In 3D, the GW's are partially absorbed by tides and planetary waves to amplify them. Thus the waves are less efficient in generating the QBO and SAO at equatorial latitudes. Some of this deficiency is compensated by the fact that the GW activity is observed to be enhanced at low latitudes. Increasing the GW source has the desired effect to boost the QBO, but the effect is confined primarily to the stratosphere. With increasing altitude, the meridional circulation becomes more important in redistributing the momentum deposited in the background flow by the GW's. Another factor involved is the altitude at which the GW's originate, which we had originally chosen to be the surface. Numerical experiments show that moving this source altitude to the top of the troposphere significantly increases the efficiency for generating the QBO without affecting much the tides and planetary waves in the model. Attention to the details in which the GW source comes into play thus appears to be of critical importance in modeling the phenomenology of the MLT. Among the suite of numerical experiments reported, we present a simulation that produced significant variations of tides and planetary waves in the upper mesosphere. The effect is related to the QBO generated in the model, and GW filtering is the likely cause.

An overview of dinoflagellate cysts in recent sediments along the west coast of India

Digital Repository Service at National Institute of Oceanography (India)

DeSilva, M.S.; Anil, A.C.; DeCosta, P.M.

using SURFER Fig. 1—Location map of sampling stations (26 coastal stations and 3 port areas) along the west coast of India. D’SILVA et al.: AN OVERVIEW OF DINOFLAGELLATE CYSTS IN RECENT SEDIMENTS 699 plots (SURFER 8 program). The relative... Xandarodinium variable Bujak Prot.div Protoperidinium latissimum (Kofoid) Balech – Prot.lat Protoperidinium leonis (Pavillard) Balech Quinquecuspis concreta (Reid) Harland Prot.leo Protoperidinium oblongum (Aurivillius) Balech Votadinium calvum Reid Prot...

Head-of-tide bottleneck of particulate material transport from watersheds to estuaries

Science.gov (United States)

Ensign, Scott H.; Noe, Gregory; Hupp, Cliff R.; Skalak, Katherine

2015-01-01

We measured rates of sediment, C, N, and P accumulation at four floodplain sites spanning the nontidal through oligohaline Choptank and Pocomoke Rivers, Maryland, USA. Ceramic tiles were used to collect sediment for a year and sediment cores were collected to derive decadal sedimentation rates using 137Cs. The results showed highest rates of short- and long-term sediment, C, N, and P accumulation occurred in tidal freshwater forests at the head of tide on the Choptank and the oligohaline marsh of the Pocomoke River, and lowest rates occurred in the downstream tidal freshwater forests in both rivers. Presumably, watershed material was mostly trapped at the head of tide, and estuarine material was trapped in oligohaline marshes. This hydrologic transport bottleneck at the head of tide stores most available watershed sediment, C, N, and P creating a sediment shadow in lower tidal freshwater forests potentially limiting their resilience to sea level rise.

A review of the green tides in the Yellow Sea, China.

Science.gov (United States)

Liu, Xiangqing; Wang, Zongling; Zhang, Xuelei

2016-08-01

The recurrent green tide of Ulva prolifera caused serious ecological problems in the Yellow Sea and attached substantial scientific study. The bloom originated in the Subei Shoal area and drifted to the coast of Shandong Province during the period from May to July, driven by a series of physical processes. Here we reviewed advances in the understanding of green tides in the Yellow Sea and elucidate the developmental model of this phenomenon. This knowledge will help resource managers to take reasonable measures to mitigate the impacts to the Yellow Sea. Copyright © 2016 Elsevier Ltd. All rights reserved.

Theory of second order tide forces and gravitational wave experiment

International Nuclear Information System (INIS)

Tammelo, R.R.

1989-01-01

Theory of tide forces square by vector radius is presented. The mechanism of 10 18 time gravitational wave pressure increase in case of radiation from pulsars and 10 15 time one in case of standard burst of radiation from astrophysical catastrophe is proposed. This leads to secular shifts of longitudinally free receivers by 10 -16 cm during 10 5 s in the first case and by 10 -19 cm during 10 s in the second one. A possibility of increase effect modulation is available. It is indicated that it is possible to construct a device which produces more energy at the expense of square tide forces than at the expense of linear ones. 21 refs

Design, optimization and numerical modelling of a novel floating pendulum wave energy converter with tide adaptation

Science.gov (United States)

Yang, Jing; Zhang, Da-hai; Chen, Ying; Liang, Hui; Tan, Ming; Li, Wei; Ma, Xian-dong

2017-10-01

A novel floating pendulum wave energy converter (WEC) with the ability of tide adaptation is designed and presented in this paper. Aiming to a high efficiency, the buoy's hydrodynamic shape is optimized by enumeration and comparison. Furthermore, in order to keep the buoy's well-designed leading edge always facing the incoming wave straightly, a novel transmission mechanism is then adopted, which is called the tidal adaptation mechanism in this paper. Time domain numerical models of a floating pendulum WEC with or without tide adaptation mechanism are built to compare their performance on various water levels. When comparing these two WECs in terms of their average output based on the linear passive control strategy, the output power of WEC with the tide adaptation mechanism is much steadier with the change of the water level and always larger than that without the tide adaptation mechanism.

Accuracy assessment of global barotropic ocean tide models

DEFF Research Database (Denmark)

Stammer, D.; Ray, R. D.; Andersen, Ole Baltazar

2014-01-01

, but testing in those regions is impeded by the paucity of high-quality in situ tide records. Long-wavelength components of models tested by analyzing satellite laser ranging measurements suggest that several models are comparably accurate for use in precise orbit determination, but analyses of GRACE...

Golden Tides: Problem or Golden Opportunity? The Valorisation of Sargassum from Beach Inundations

Directory of Open Access Journals (Sweden)

John J. Milledge

2016-09-01

Full Text Available In recent years there have been massive inundations of pelagic Sargassum, known as golden tides, on the beaches of the Caribbean, Gulf of Mexico, and West Africa, causing considerable damage to the local economy and environment. Commercial exploration of this biomass for food, fuel, and pharmaceutical products could fund clean-up and offset the economic impact of these golden tides. This paper reviews the potential uses and obstacles for exploitation of pelagic Sargassum. Although Sargassum has considerable potential as a source of biochemicals, feed, food, fertiliser, and fuel, variable and undefined composition together with the possible presence of marine pollutants may make golden tides unsuitable for food, nutraceuticals, and pharmaceuticals and limit their use in feed and fertilisers. Discontinuous and unreliable supply of Sargassum also presents considerable challenges. Low-cost methods of preservation such as solar drying and ensiling may address the problem of discontinuity. The use of processes that can handle a variety of biological and waste feedstocks in addition to Sargassum is a solution to unreliable supply, and anaerobic digestion for the production of biogas is one such process. More research is needed to characterise golden tides and identify and develop commercial products and processes.

Correlations between solid tides and worldwide earthquakes MS ≥ 7.0 since 1900

Directory of Open Access Journals (Sweden)

Q. H. Xu

2012-03-01

Full Text Available Most studies on the correlations between earthquakes and solid tides mainly concluded the syzygies (i.e. new or full moons of each lunar cycle have more earthquakes than other days in the month. We show a correlation between the aftershock sequence of the ML = 6.3 Christchurch, New Zealand, earthquake and the diurnal solid tide. Ms ≥ 7 earthquakes worldwide since 1900 are more likely to occur during the 0°, 90°, 180° or 270° phases (i.e. earthquake-prone phases of the semidiurnal solid earth tidal curve (M2. Thus, the semidiurnal solid tides triggers earthquakes. However, the long-term triggering effect of the lunar periodicity is uncertain. This proposal is helpful in defining possible origin times of aftershocks several days after a mainshock and can be used for warning of subsequent larger shocks.

The comparison of heavy metals (Pb and Cd) in the water and sediment during spring and neap tide tidal periods in Popoh Bay, Indonesia

Science.gov (United States)

Yona, D.; Febriana, R.; Handayani, M.

2018-04-01

This study attempted to investigate different concentration of lead (Pb) dan cadmium (Cd) in the water and sediment during spring and neap tidal periods in the Popoh Bay, Indonesia. Water and sediment samples were taken during spring and neap tides from eight sampling stations in the study area. The result shows higher concentration of Pb than the concentration of Cd in both spring and neap tides due to higher input of Pb from the oil pollution by boat and fisheries activities. Pb concentrations were doubled during neap tide in both water and sediments with the value of 0.51 and 0.28 ml/L in the water during neap and spring tide, respectively; and 0.27 ppm and 0.16 mg/kg in the sediment during neap and spring tide, respectively. On the other hand, Cd concentrations in the water were found in almost similar values between spring and neap tide (0.159 and 0.165 ml/L in spring tide and neap tide, respectively), but in the sediment, the concentration was a little higher during spring tide (0.09 and 0.05 mg/kg during spring and neap tide, respectively). This study shows that water movement during spring and neap tides has significant effect on the distribution of heavy metals.

Possible forcing of global temperature by the oceanic tides

Science.gov (United States)

Keeling, Charles D.; Whorf, Timothy P.

1997-01-01

An approximately decadal periodicity in surface air temperature is discernable in global observations from A.D. 1855 to 1900 and since A.D. 1945, but with a periodicity of only about 6 years during the intervening period. Changes in solar irradiance related to the sunspot cycle have been proposed to account for the former, but cannot account for the latter. To explain both by a single mechanism, we propose that extreme oceanic tides may produce changes in sea surface temperature at repeat periods, which alternate between approximately one-third and one-half of the lunar nodal cycle of 18.6 years. These alternations, recurring at nearly 90-year intervals, reflect varying slight degrees of misalignment and departures from the closest approach of the Earth with the Moon and Sun at times of extreme tide raising forces. Strong forcing, consistent with observed temperature periodicities, occurred at 9-year intervals close to perihelion (solar perigee) for several decades centered on A.D. 1881 and 1974, but at 6-year intervals for several decades centered on A.D. 1923. As a physical explanation for tidal forcing of temperature we propose that the dissipation of extreme tides increases vertical mixing of sea water, thereby causing episodic cooling near the sea surface. If this mechanism correctly explains near-decadal temperature periodicities, it may also apply to variability in temperature and climate on other times-scales, even millennial and longer. PMID:11607740

Acoustic Tomography in the Canary Basin: Meddies and Tides

Science.gov (United States)

Dushaw, Brian D.; Gaillard, Fabienne; Terre, Thierry

2017-11-01

An acoustic propagation experiment over 308 km range conducted in the Canary Basin in 1997-1998 was used to assess the ability of ocean acoustic tomography to measure the flux of Mediterranean water and Meddies. Instruments on a mooring adjacent to the acoustic path measured the southwestward passage of a strong Meddy in temperature, salinity, and current. Over 9 months of transmissions, the acoustic arrival pattern was an initial broad stochastic pulse varying in duration by 250-500 ms, followed eight stable, identified-ray arrivals. Small-scale sound speed fluctuations from Mediterranean water parcels littered around the sound channel axis caused acoustic scattering. Internal waves contributed more modest acoustic scattering. Based on simulations, the main effect of a Meddy passing across the acoustic path is the formation of many early-arriving, near-axis rays, but these rays are thoroughly scattered by the small-scale Mediterranean-water fluctuations. A Meddy decreases the deep-turning ray travel times by 10-30 ms. The dominant acoustic signature of a Meddy is therefore the expansion of the width of the initial stochastic pulse. While this signature appears inseparable from the other effects of Mediterranean water in this region, the acoustic time series indicates the steady passage of Mediterranean water across the acoustic path. Tidal variations caused by the mode-1 internal tides were measured by the acoustic travel times. The observed internal tides were partly predicted using a recent global model for such tides derived from satellite altimetry.

Flood Tide Transport of Blue Crab Postlarvae: Limitations in a Lagoonal Estuary

Science.gov (United States)

Cudaback, C.; Eggleston, D.

2005-05-01

Blue crabs, an important commercial species, spend much of their life in estuaries along the east coast. The larvae spawn at or near the ocean, but the juveniles mature in the lower salinity waters of the estuary. It is generally believed that blue crab postlarvae migrate into near surface waters on flood, possibly cued by increasing salinity, and return to the bottom on ebb. Over several tidal cycles, the postlarvae travel a significant distance up-estuary. This model applies quite well to Chesapeake Bay, which has a strong along-estuary salinity gradient and large tides, but may not apply as well to Pamlico Sound, where circulation and salinity are more wind-driven than tidal. A recently completed study (N. Reyns, PhD), indicates that postlarval blue crabs use flood tides and wind-driven currents to cross Pamlico Sound. This study was based on observations with good spatial coverage, but limited vertical and temporal resolution. We have recently completed a complementary study, sampling crab larvae around the clock at four depths at a single location. Preliminary results from the new study suggest that the crab postlarvae do swim all the way to the surface, on flood only, and that flood currents are strongest slightly below the surface. These observations suggest the utility of flood tide transport in this system. However, near bottom salinity does not seem to be driven by tides; at this point it is unclear what cue might trigger the vertical migration of the postlarvae.