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

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2133
Author(s):  
Oghenekaro ◽  
Chigbu
Keyword(s):  
Environmental Factors ◽  
Coastal Lagoons ◽  
Hurricane Sandy ◽  
Zooplankton Abundance ◽  
Low Salinity ◽  
Bivalve Larvae ◽  
Abundance And Diversity ◽  
Maryland Coastal Bays ◽  
Veliger Larvae ◽  
Scientific Attention

The mesozooplankton composition and dynamics in coastal lagoons of Maryland, mid-Atlantic region, USA have received little scientific attention despite the fact that the lagoons have undergone changes in water quality in the past two decades. We compared mesozooplankton abundance and community structure among sites and seasons, and between 2012, a year of higher than average salinity (33.4), and 2013 with lower than average salinity (26.6). It was observed that the composition, diversity, and abundance of mesozooplankton in 2012 differed from those of 2013. Barnacle nauplii were abundant in 2012 contributing 31% of the non-copepod mesozooplankton abundance, whereas hydromedusae were more dominant in 2013 and contributed up to 83% of non-copepod zooplankton abundance. Gastropod veliger larvae were more abundant in 2013 than in 2012 while larvae of bivalves, polychaetes, and decapods, in addition to cladocerans and ostracods had higher abundances in 2012. The abundance and diversity of mesozooplankton were explained by variations in environmental factors particularly salinity, and by the abundance of predators such as bay anchovy (Anchoa mitchelli). Diversity was higher in spring and summer 2012 (dry year) than in 2013 (wet year). The reduction of salinity in fall 2012, due to high freshwater discharge associated with Hurricane Sandy, was accompanied by a decrease in mesozooplankton diversity. Spatially, diversity was higher at sites with high salinity near the Ocean City Inlet than at sites near the mouth of tributaries with lower salinity, higher nutrient levels and higher phytoplankton biomass. Perhaps, the relatively low salinity and high temperature in 2013 resulted in an increase in the abundance of hydromedusae, which through predation contributed to the reduction in the abundance of bivalve larvae and other taxa.

scholarly journals Variability of pikeperch Sander lucioperca (L. 1758) cohorts in early life history

2019 ◽  
pp. 43
Author(s):  
Petr Blabolil ◽  
Martin Čech ◽  
Tomáš Jůza ◽  
Jiří Peterka
Keyword(s):  
Life History ◽  
Environmental Factors ◽  
Early Life ◽  
Early Life History ◽  
Zooplankton Abundance ◽  
Common Phenomenon ◽  
Sander Lucioperca ◽  
Fish Cohort ◽  
Slow Growing ◽  
Study Development

Year to year fluctuations in 0+ fish cohort strength are a common phenomenon. Many factors can affect cohort strength during the fish's early life period. In this study, development of a 0+ pikeperch Sander lucioperca cohort in the pelagic zone was studied by trawling for 50 days from first larvae hatching, in two consecutive years. In 2007, an abundant S. lucioperca cohort collapsed suddenly soon after hatching. After the incident, slow-growing S. lucioperca prevailed in the catch. In 2008, the catch gradually increased during the whole study period because of prolonged hatching. Environmental factors differed mainly in a slower temperature increase, higher water level and higher zooplankton abundance in 2008 compared to 2007. Our study revealed that a strong 0+ S. lucioperca cohort at the time of hatching might not result in a strong S. lucioperca cohort in general.

Environmental factors associated with a toxic bloom of Microcystis aeruginosa

2000 ◽  
Vol 57 (1) ◽  
pp. 231-240 ◽  
Author(s):  
Jean M Jacoby ◽  
Diane C Collier ◽  
Eugene B Welch ◽  
F Joan Hardy ◽  
Michele Crayton
Keyword(s):  
Environmental Factors ◽  
Microcystis Aeruginosa ◽  
Toxin Production ◽  
Water Transparency ◽  
Cyanobacterial Blooms ◽  
Zooplankton Abundance ◽  
Factors Associated ◽  
Water Column Stability ◽  
Microcystin Concentration ◽  
Toxic Bloom

Environmental factors associated with the occurrence of toxic cyanobacterial blooms and toxin production were investigated during the summers of 1994 and 1995 in Steilacoom Lake, Washington. A pronounced and prolonged toxic bloom of Microcystis aeruginosa occurred during summer 1994 but not during 1995. Lake characteristics that were associated with the toxic bloom in 1994 were higher total phosphorus, decreased water transparency, high water column stability, high surface water temperature and pH, and decreased lake flushing. Decreased water transparency during 1994 may have been due to significantly lower zooplankton abundance. We hypothesize that this decreased transparency was caused by increased planktivory by higher numbers of coho salmon (Oncorhynchus kisutch) fingerlings during 1994 and (or) inhibition of zooplankton grazing by Microcystis. The success of Microcystis over other cyanobacteria was associated with low nitrogen to phosphorus ratios and low nitrate-nitrogen with sufficient ammonium-nitrogen concentrations. Toxin production (i.e., micrograms of microcystin per gram of plankton biomass) was not constant over the duration of detectable toxicity; hence, no relationship was found between Microcystis abundance and microcystin concentration. However, microcystin concentration was positively correlated with increasing soluble reactive phosphorus concentrations between 1 and 10 µg·L-1, indicating that toxin production may have been limited by phosphorus.

Guidelines to Prepare for Oil Sands Product Spills in Varied Aquatic Environments

2014 ◽  
Vol 2014 (1) ◽  
pp. 426-433
Author(s):  
Benjamin Douglas Silliman
Keyword(s):  
High Risk ◽  
Environmental Factors ◽  
Oil Recovery ◽  
Oil Sands ◽  
Aquatic Environments ◽  
Low Salinity ◽  
High Turbidity ◽  
Different Response ◽  
And Behavior ◽  
Rapid Deployment

ABSTRACT On July 24, 2007, the Westridge Transfer Line in Burnaby, British Columbia, ruptured spilling 1,400 barrels of oil sands product into the area's storm water systems and eventually into the Burrard Inlet at Vancouver Harbor. The response to this spill was considered successful and there is no record of oil sinking. Several years later, in July of 2010, the Line 6B pipeline operated by Enbridge Energy Partners LLP ruptured spilling 20,082 barrels of oil sands product into the Kalamazoo River. In contrast to the Burnaby spill, this response was extremely difficult due to the sinking of large quantities of oil. The variance in fate and behavior of the oil sands products in these two spills demonstrates how environmental factors can result in different response challenges. Many environmental factors affect the fate of spilled oil sands products in aquatic environments because bitumen, a large component of oil sands products, has a density greater than freshwater. By analyzing specific factors in areas at risk, responders can better prepare for, and expect, submergence in oil sands product spills. Areas identified to have low salinity, rough sedimentation, high turbidity, strong sunlight exposure, high temperatures, and strong currents have a high risk of submergence. Response teams in these areas of high risk should have submerged oil recovery equipment readily available for rapid deployment.

Seasonal variations in the structure of copepod assemblages in tropical marine and estuarine waters, Coleroon, south-east India

2013 ◽  
Vol 94 (3) ◽  
pp. 521-535 ◽  
Author(s):  
M. Rajkumar ◽  
Jun Sun ◽  
I. R. Jenkinson ◽  
M.M. Rahman
Keyword(s):  
Community Structure ◽  
Species Diversity ◽  
Environmental Factors ◽  
Seasonal Patterns ◽  
Dissolved Oxygen Concentration ◽  
Copepod Community ◽  
Factors Affecting ◽  
Abundance And Diversity ◽  
High Diversity ◽  
Coleroon Estuary

A twelve-month investigation was undertaken on how copepod community structure varied in relation to environmental factors in the Coleroon estuary, south-east India. Sampling was monthly, from Station 1 in the sea to Station 4 in the Vettar backwaters. Canonical correspondence analysis (CCA) was applied to elucidate the environmental factors affecting the copepod community. A total of 104 copepod species in 38 genera and 26 families were recorded, with the Calanoids, Acartia erythraea and Oithona brevicornis being the most dominant. At all four stations, both these species loaded near the intercept of CCA axes 1 and 2, perhaps reflecting that they were autochthonous. Most species occurred in distinct seasonal patterns. Abundances ranged from 13 × 103 to 215 × 103 (ind. m−3). Coleroon waters showed high diversity (bits/ind.), from 5.29 at Station 3 to 4.97 at Station 4. Abundance correlated positively with temperature and salinity and negatively with rainfall, dissolved oxygen concentration (DO) and pH. Species diversity correlated strongly with abundance (P < 0.01). Abundance and diversity were highest during the summer, and both correlated positively with salinity. Temperatures (air and water), salinity, pH and DO varied in the ranges 26–36°C, 25–34.2°C, 9–38, 7.0–8.7 and 3.0–6.8 ml l-1, respectively. Nitrate, nitrite, phosphate and silicate (µM) varied in the ranges: 4.7–64.5, 0.4–14.1, 0.2–12.9 and 9.3–148, respectively.

Edge patterns in aquatic invertebrates explained by predictive models

2010 ◽  
Vol 61 (2) ◽  
pp. 214 ◽  
Author(s):  
Peter I. Macreadie ◽  
Rod M. Connolly ◽  
Gregory P. Jenkins ◽  
Jeremy S. Hindell ◽  
Michael J. Keough
Keyword(s):  
Edge Effects ◽  
Predictive Models ◽  
Aquatic Invertebrates ◽  
Zooplankton Abundance ◽  
Calanoid Copepods ◽  
Distribution Models ◽  
Position Effects ◽  
Bare Sand ◽  
Bivalve Larvae ◽  
Harpacticoid Copepods

Predictive frameworks for understanding and describing how animals respond to habitat fragmentation, particularly across edges, have been largely restricted to terrestrial systems. Abundances of zooplankton and meiofauna were measured across seagrass–sand edges and the patterns compared with predictive models of edge effects. Artificial seagrass patches were placed on bare sand, and zooplankton and meiofauna were sampled with tube traps at five positions (from patch edges: 12, 60 and 130 cm into seagrass; and 12 and 60 cm onto sand). Position effects consisted of the following three general patterns: (1) increases in abundance around the seagrass–sand edge (total abundance and cumaceans); (2) declining abundance from seagrass onto sand (calanoid copepods, harpacticoid copepods and amphipods); and (3) increasing abundance from seagrass onto sand (crustacean nauplii and bivalve larvae). The first two patterns are consistent with resource-distribution models, either as higher resources at the confluence of adjacent habitats or supplementation of resources from high-quality to low-quality habitat. The third pattern is consistent with reductions in zooplankton abundance as a consequence of predation or attenuation of currents by seagrass. The results show that predictive models of edge effects can apply to aquatic animals and that edges are important in structuring zooplankton and meiofauna assemblages in seagrass.

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