Defining Planktonic Protist Functional Groups on Mechanisms for Energy and Nutrient Acquisition: Incorporation of Diverse Mixotrophic Strategies

Arranging organisms into functional groups aids ecological research by grouping organisms (irrespective of phylogenetic origin) that interact with environmental factors in similar ways. Planktonic protists traditionally have been split between photoautotrophic “phytoplankton” and phagotrophic “microzoo-plankton”. However, there is a growing recognition of the importance of mixotrophy in euphotic aquatic systems, where many protists often combine photoautotrophic and phagotrophic modes of nutrition. Such organisms do not align with the traditional dichotomy of phytoplankton and microzooplankton. To reflect this understanding,we propose a new functional grouping of planktonic protists in an eco- physiological context: (i) phagoheterotrophs lacking phototrophic capacity, (ii) photoautotrophs lacking phagotrophic capacity,(iii) constitutive mixotrophs (CMs) as phagotrophs with an inherent capacity for phototrophy, and (iv) non-constitutive mixotrophs (NCMs) that acquire their phototrophic capacity by ingesting specific (SNCM) or general non-specific (GNCM) prey. For the first time, we incorporate these functional groups within a foodweb structure and show, using model outputs, that there is scope for significant changes in trophic dynamics depending on the protist functional type description. Accord- ingly, to better reflect the role of mixotrophy, we recommend that as important tools for explanatory and predictive research, aquatic food-web and biogeochemical models need to redefine the protist groups within their frameworks

Intraspecific variability in Karlodinium veneficum:Growth rates, mixotrophy and lipid composition

Postprin

Modeling the seasonal autochthonous sources of dissolved organic carbon and nitrogen in the upper Chesapeake Bay

In this paper we investigate the seasonal autochthonous sources of dissolved organic carbon (DOC) and nitrogen (DON) in the euphotic zone at a station in the upper Chesapeake Bay using a new mass-based ecosystem model. Important features of the model are: (1) carbon and nitrogen are incorporated by means of a set of fixed and varying C:N ratios; (2) dissolved organic matter (DOM) is separated into labile, semi-labile, and refractory pools for both C and N; (3) the production and consumption of DOM is treated in detail; and (4) seasonal observations of light, temperature, nutrients, and surface layer circulation are used to physically force the model. The model reasonably reproduces the mean observed seasonal concentrations of nutrients, DOM, plankton biomass, and chlorophyll a. The results suggest that estuarine DOM production is intricately tied to the biomass concentration, ratio, and productivity of phytoplankton, zooplankton, viruses, and bacteria. During peak spring productivity phytoplankton exudation and zooplankton sloppy feeding are the most important autochthonous sources of DOM. In the summer when productivity peaks again, autochthonous sources of DOM are more diverse and, in addition to phytoplankton exudation, important ones include viral lysis and the decay of detritus. The potential importance of viral decay as a source of bioavailable DOM from within the bulk DOM pool is also discussed. The results also highlight the importance of some poorly constrained processes and parameters. Some potential improvements and remedies are suggested. Sensitivity studies on selected parameters are also reported and discussed

Harmful algal blooms and eutrophication : examining linkages from selected coastal regions of the United States

Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Harmful Algae 8 (2008): 39-53, doi:10.1016/j.hal.2008.08.017.Coastal waters of the United States (U.S.) are subject to many of the major harmful algal bloom (HAB) poisoning syndromes and impacts. These include paralytic shellfish poisoning (PSP), neurotoxic shellfish poisoning (NSP), amnesic shellfish poisoning (ASP), ciguatera fish poisoning (CFP) and various other HAB phenomena such as fish kills, loss of submerged vegetation, shellfish mortalities, and widespread marine mammal mortalities. Here, the occurrences of selected HABs in a selected set of regions are described in terms of their relationship to eutrophication, illustrating a range of responses. Evidence suggestive of changes in the frequency, extent or magnitude of HABs in these areas is explored in the context of the nutrient sources underlying those blooms, both natural and anthropogenic. In some regions of the U.S., the linkages between HABs and eutrophication are clear and well documented, whereas in others, information is limited, thereby highlighting important areas for further research.Support was provided through the Woods Hole Center for Oceans and Human Health (to DMA), National Science Foundation (NSF) grants OCE-9808173 and OCE-0430724 (to DMA), OCE-0234587 (to WPC), OCE04-32479 (to MLP), OCE-0138544 (to RMK), OCE-9981617 (to PMG); National Institute of Environmental Health Sciences (NIEHS) grants P50ES012742-01 (to DMA) and P50ES012740 (to MLP); NOAA Grants NA96OP0099 (to DMA), NA16OP1450 (to VLT), NA96P00084 (to GAV and CAH), NA160C2936 and NA108H-C (to RMK), NA860P0493 and NA04NOS4780241 (to PMG), NA04NOS4780239-02 (to RMK), NA06NOS4780245 (to DWT). Support was also provided from the West Coast Center for Oceans and Human Health (to VLT and WPC), USEPA Grant CR826792-01-0 (to GAV and CAH), and the State of Florida Grant S7701617826 (to GAV and CAH)

Christliche Wissenschaft (christian science) und Glaubensheilung : zwei Aufsätze

Layoutgetreues Digitalsiat der Ausg.: Berlin : Berliner Stadtmission, 1902 Zentralbibliothek Sign.: XIXd C 1780 fc (Raubgut

Das moderne Judenthum in Deutschland, besonders in Berlin : 2 Reden in der christlich-socialen Arbeiterpartei gehalten

von Adolf Stöcke

Das moderne Judenthum in Deutschland, besonders in Berlin : zwei Reden in der christlich-socialen Arbeiterpartei gehalten

von Adolf Stöcke

Stöcker : [Rede] in Darmstadt : stenographischer Bericht über die Versammlung des Deutschen Volksvereins, Abt. Darmstadt, im Städtischen Saalbau am 23. Juni 1891

hrsg. vom Deutschen VolksvereinStöcker in Darmstad

Unsere soziale Lage

Rede des Herrn Stöcker im Kreisverbande Evgl. Arbeitervereine zu Rheydt am 5. April 1892Ohne Titelseite, nur KopftitelSonderdruck aus: Flugblatt N. 110 des Vereins für christliche Volksbildung in Rheinland & Westphale

Seasonal dynamics of Mesodinium rubrum in Chesapeake Bay

Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Oxford University Press for personal use, not for redistribution. The definitive version was published in Journal of Plankton Research 35 (2013): 877-893, doi:10.1093/plankt/fbt028.The photosynthetic ciliate Mesodinium rubrum is a common member of coastal phytoplankton communities that is well adapted to low-light, turbid ecosystems. It supports the growth of or competes with harmful dinoflagellate species for cryptophyte prey, as well as being a trophic link to copepods and larval fish. We have compiled data from various sources (n = 1063), on the abundance and distribution of M. rubrum in Chesapeake Bay and its tributaries. Because M. rubrum relies on obtaining organelles from cryptophyte algae to maintain rapid growth, we also enumerated cryptophyte algae in the portion of these samples that we collected (n = 386). M. rubrum occurred in oligohaline to polyhaline regions of Chesapeake Bay and throughout the year. Blooms (>100 cells ml-1) of M. rubrum primarily occurred during spring, followed by autumn. When compared across all seasons, M. rubrum abundance was positively correlated to temperature and cryptophytes, and negatively correlated with salinity. However, more focused analyses revealed that M. rubrum abundance during spring was associated with surface layer warming and decreased salinity, while early autumn assemblages were associated with surface cooling. These results imply there are distinct seasonal niches for M. rubrum blooms. Blooms of M. rubrum were more common in tributaries than in the main stem Bay and tended to be restricted to salinities under 10 PSU. Despite the rarity of “red water” events, M. rubrum is a ubiquitous mixotroph in Chesapeake Bay and at times likely exerts a strong influence on cryptophyte algal abundance and hence planktonic food web structure.MDJ and DKS would like to acknowledge funding from NSF 1031718 and 1031344.2014-04-0