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Showing papers in "Virginia journal of science in 1996"


Journal Article
TL;DR: Hallegraeff et al. as mentioned in this paper identified three diatoms and nine dinoflagellates, known to be associated with toxin production, have been identified within Chesapeake Bay.
Abstract: Three diatoms and nine dinoflagellates, known to be associated with toxin production, have been identified within Chesapeake Bay. Over the past several decades this number has increased to its present level so that they now represent approximately 1. 7% the total number of phytoplankton species reported for the Bay. INTRODUCTION Hallegraeff (1993) and Smayda (1989) indicate there is a global increase in the occurrence and geographical distribution of marine phytoplankton blooms, including blooms produced by species that are toxin producers. Hallegraeff offers several reasons to explain the increased reports of bloom events. These are: 1) the scientific community is more alert regarding the presence of bloom producers and is now reporting blooms more frequently, 2) the greater use of coastal waters for aquaculture has provided additional favorable sites for blooms to develop, and represent additional sources for reporting toxic events, 3) there has occurred in recent years greater nutrient enrichment of coastal and estuarine waters that fosters increased phytoplankton abundance, including bloom events, and 4) the resting cysts of many algae can be transported in ballast water of ships that move from one global port to another, providing a mechanism for expanding the distribution range for species, including those that produce blooms. For the past three decades the author has reported on the phytoplankton from Chesapeake Bay, plus many of the regional tributaries associated with this estuary, identifying 708 taxa from Chesapeake Bay (Marshall, 1994a). Since 1985, monthly phytoplankton collections have been taken at 7 stations within Chesapeake Bay. Reports based on the analysis of these collections have identified phytoplankton composition, productivity, plus spatial and temporal relationships to water quality variables and algal composition (Marshall, 1994a; Marshall and Alden 1990). The data obtained in this monitoring program, personal records, and othe.r publications, have provided the information on toxin and bloom producing taxa used in this report. The purpose of this paper is to identify species in Chesapeake Bay that have been linked to toxin production in either field or laboratory studies. Historical Records: The earliest listing of phytoplankton taxa in Chesapeake Bay is by Wolfe et al. (1926), who reported on several seasonal collections within the Bay taken between 1916 and 1922. From these samples they noted 99 species. Subsequent systematic studies by Cowles (1930), Griffith (1961 ), Patten et al. (1963), Mulford (1967), and Marshall ( 1967) gradually added to the phytoplankton species identified in Chesapeake Bay . From these earlier papers the diatoms Amphora coffeaeformis, Nitzschia (Pseudo-nitzschia) f. multiseries, and the dinoflagellates Cochlodinium heterolobatum, Dinophysis acuminata, D. acuta, D. caudata, Prorocentrum minimum, have 30 VIRGINIA JOURNAL OF SCIENCE since been recognized as potential toxin producers (Steidinger, 1993). Also noted by Morse (1947) and Mulford (1967) is Gonyaulax catenella Whedon-Kofoid (now classified as Alexandrium catenella (Whedon-Kofoid) Balech) and Gonyaulax polyedra Stein in the Patuxent River, and a single record of G. polyedra at the Chesapeake Bay entrance by Marshall (personal records). They both produce toxins, with A. catenella one of the causative agents for paralytic shellfish poisoning (Steidinger, 1993). Phytoplankton Blooms: The term phytoplankton bloom is generally applied to a rapid increase in abundance within the phytoplankton community. There are seasonal blooms where cell concentrations increase annually within entire bodies of water usually during spring, summer, or fall. In contrast, there are blooms that are more limited in their scope and composition. The term bloom used in this paper refers to a situation where over a relatively short period of time, there is a major increase in the cell concentrations of usually one primary species, with this growth more localized, and limited in its development and duration ( e.g. days, few weeks). The water color during these events will typically have a red, brown, or green coloration, depending on the species producing the bloom, and its abundance. Cell concentrations of the primary bloom producer will vary with the taxon, and its cell size. Some of the large dinoflagellates will reach bloom concentrations at 105 cells r1, whereas with other taxa, bloom concentrations may level off at 10 to 10 cells r . Blooms are commonly recognized as isolated surface patches of various sizes, or be concentrated along tidal fronts, appearing as streaks of discolored water. Marshall ( 1989) reviewed the records of bloom events in the Chesapeake Bay from 1963 through 1989. The majority (67%) of these blooms occurred in tributaries to the Bay (near their river mouths), and 25% were located within the Bay, with the remaining (8%) in adjacent ponds and outside the Bay entrance. Blooms were recorded in each season, but the majority occurred during Summer (54%), followed by Fall (26%), Spring (15%), and Winter (5%). These blooms were not associated with toxin production, major fish kills, or shellfish poisoning, and may be produced by toxin or non-toxin producing species. Yet, there is wide variation in the ability of toxin producing species to produce toxins, and in the strength of toxins they produce (Hallegraff, 1993). The presence of a species reported to produce a toxin does not mean a potent toxin will be produced. Dinoflagellates: The following are dinoflagellates recorded since 1985 from Chesapeake Bay that have been associated with toxin production. During mid-summer to early fall in 1992, a bloom of the dinoflagellate Cochlodinium heterolobatum Silva ( =Coch/odinium polykrikoides Margalef) spread from the mouth of the York River into and out of the lower Chesapeake Bay, and was then transported in near shore waters southward to North Carolina. Concentrations reached 1 o 10 cells 1 and at one time was spread over 215. 7 km of the central and western Chesapeake Bay (Marshall, 1994b ). Prior to this event, blooms of this species were generally localized in the York River (Mackieman, 1968; Zubkoff and Warinner, 1975; Zubkoff et al., 1979; Zubkoff, 1982). Since 1992, Cochlodinium heterolobatum has CHESAPEAK BAY TOXIC PHYTOPLANKTON 31 apparently expanded its regional range, and has become established as an annual bloom producer in several rivers of the lower Chesapeake Bay, where previously it had not been reported ( e.g. James, Elizabeth, Pagan, and LaFayette Rivers). The cells reproduce rapidly, often occurring in rows of2,4, or 8 connected cells. The blooms generally last several days and often extend into nearby inlets. This species is expected to produce summer blooms annually in the local rivers, and a more frequent appearance in the lower Chesapeake Bay is expected to occur. Although no major toxic events were associated with these blooms in Chesapeake Bay, Yuki and Yoshimatsu (1989) have linked this species with deaths in fish culturing grounds in Japan, and Steidinger ( 1993) lists this dinoflagellate as a toxin producer. This species will reach bloom concentrations at river sites generally in late July with major development typically occurring in August. It is often accompanied by several non-toxin producing dinotlagellates in lesser abundance, including Scrippsiella trochoidea and Gymnodinium sp/endens, along with cryptomonads and several diatom taxa. Prorocentrum minimum (Pavillard) Schiller is well documented in the early reports of Bay phytoplankton, in addition to an account of a small Prorocentrum mentioned by Cowles (1930), that was probably P. minimum. Prorocentrum minimum is reported to produce a toxic substance directly responsible for fish and shellfish kills (Okaichi and Imatomi, 1979; Steidinger, 1993). Tyler and Seliger (1978) have associated this species with seasonal blooms in the upper Chesapeake Bay and its transport to these sites within sub-pycnocline waters. In the lower Bay this species is generally ubiquitous, and increases in abundance in spring, reaching higher levels in summer and fall. It is also a frequent sub-dominant species during bloom events and is one of the most common dinoflagellates in the Bay (Marshall, 1994a). The genus Dinophysis is represented in the Chesapeake Bay by five species that are known to produce okadaic acid, or other toxins causing diarrhetic shellfish poisoning (Yasumoto, 1990; Steidinger, 1993). These substances when concentrated in clams, oysters, etc. may cause this illness in humans who eat the infected shellfish. These include Dinophysis acuminata Claparede and Lachmann, D. acuta Eherenberg, D. caudata Saville-Kent, D. fortii Pavillard, and D. norvegica Claparede and Lachmann. These species are present within Atlantic coastal waters and their cells may be found frequently in sub-pycnocline waters entering Chesapeake Bay. Major outbreaks of diarrhetic shellfish poisoning have occurred in european waters due to D. acuminata and off Nova Scotia by D. norvegica (Kat, 1985; Rao et al., 1993). Although not abundant, and often rarely noted, each of these Dinophysis spp. have been recorded in the lower Chesapeake Bay. In addition, Dinophysis tripos Gourret, reported by Yasumoto (1990) as a toxin producer, has also been identified from shelf waters in the vicinity of the Chesapeake Bay entrance (Marshall, 1982). Gyrodinium aureo/um Hulburt has a broad geographic distribution and is known as a toxin producing bloom species that has been associated with massive fish and invertebrate mortality (Tangen, 1977; Jones et al., 1982). This species was first reported in Chesapeake Bay by Marshall (1980a), but was not noted again till over a decade later in an isolated inlet at the U.S. Naval Amphibious Base in Virginia Beach (Marshall, 1994b ). Its presence there was possibly due to ballast water discharged in the harbor. The most recent event regarding a poten

12 citations