Composition and Dynamics of Phytoplankton in the Coastal Bays of Maryland, USA, Revealed by Microscopic Counts and Diagnostic Pigments Analyses

Abstract

Maryland Coastal Bays (MCBs) have undergone changes in water quality in the past two decades due to nutrient enrichment but the composition and dynamics of the phytoplankton community have not been adequately described. Microscopic counts and photosynthetic pigments of samples collected monthly in 2012 at selected sites in MCBs that differed with regard to the degree of anthropogenic impacts were examined. Sixty-three (63) phytoplankton genera were recorded, of which 40 species are being reported for the first time in the Bays. Among the dominant species were Dactyliosolen fragilissimus (Bacillariophyta), Paulinella ovalis (Cercozoa) and Cryptomonas sp. (Cryptophyta). Bloom densities of Heterocapsa rotundata (Miozoa), which previously had not been reported in the Bays, were observed bay-wide in December, particularly at the mouth of St. Martin River. Diatoms dominated (>40%) the phytoplankton community in winter and decreased in spring (<40%), while Cercozoa and microphytoflagellates (MPF) co-dominated in summer (July). From August to October, diatoms dominated with maximum contributions from an unidentified small (<10 µM) centric species and co-dominated the assemblage with cryptophytes in late fall (November). Canonical correspondence analysis indicated that diatoms were favored by high salinity and total dissolved phosphorus (TDP), cercozoans and chlorophytes by total dissolved nitrogen (TDN) and cryptophytes by dissolved organic carbon. The spatial and seasonal differences in the composition of phytoplankton species, coupled with the occurrence of potentially toxic species and bloom densities of H. rotundata suggest that important changes have occurred in the phytoplankton assemblage that likely have affected the food web of these eutrophic bays.

Dynamics of Mesozooplankton Assemblage in Relation to Environmental Factors in the Maryland Coastal Bays

“…The most diverse assemblage was observed in areas with high salinity, but low chlorophyll a. The observed negative correlation between chlorophyll a and diversity was because chlorophyll a levels were higher in areas close to MCBs tributaries (Newport Bay and St. Martin River) with lower salinity and high nutrient levels due to freshwater inflow [38,60], which also had lower mesozooplankton diversity than in areas close to the inlets. Howson et al [35] observed higher zooplankton diversity in the southern bay of the Barnegat Bay, NJ, with more oceanic influence and less anthropogenic impact, than in the more nutrient enriched northern bay.…”

“…A minimum of 1 L by volume of water was filtered except in situations when the filter was clogged. Chlorophyll a and 19'-Butanoyloxy-Fucoxanthin (But-fuco) concentrations were determined, as part of the integrated monitoring of the MCBs, using a High Performance Liquid Chromatography [38]. Freshwater discharge data for Birch branch at Showell, Maryland, USA were downloaded from the United States Geological Survey (USGS) website (http://waterdata.usgs.gov/nwis/monthly).…”

Preliminary Assessment of Ecological Status of the Siversky Donets River Basin (Ukraine) Based on Phytoplankton Parameters and Its Verification by Other Biological Data

“…The phytoplankton in the Sirevsky Donets river basin is formed mostly by diatoms. This division prevalence is typical for the riverine phytoplankton [9,[71][72][73][74] and is consistent with the literature data for the considered basin, in particular, the Siversky Donets river itself, which was characterized by predominance of Bacillariophyta (40%) and Chlorophyta (33%) [70]. It should be noted that many tychoplankton species may have been present in the water of studied rivers, which might be caused by high water flow combined with small depth of most and frequent drying out of some of the rivers, the factors not precisely documented in this study.…”

Ubiquitous Patchiness in Chlorophyll a Concentration in Coastal Archipelago of Baltic Sea

“…Accordingly, site-specific internal processes, related to their actual trophic state, may change the N:P stoichiometry, overall nutrient availability, or grazing pressure (Sommer et al, 2012). Moreover, especially in the more enclosed areas, temperature and salinity differences are more pronounced and abrupt, driving changes in the temperature- (Yvon-Durocher et al, 2017) or salinity-sensitive (Oseji et al, 2019) parts of the plankton community. Finally, inherent stochasticity can cause spatial heterogeneity in organism and resource distributions, which leads to temporal heterogeneity in resource access for phytoplankton (Anderies and Beisner, 2000).…”