scholarly journals Zooplankton community structure before and after Mnemiopsis leidyi arrival

2019 ◽  
Vol 41 (6) ◽  
pp. 803-820
Author(s):  
Emanuela Fiori ◽  
Margherita Benzi ◽  
Carla Rita Ferrari ◽  
Cristina Mazziotti
Keyword(s):  
Temporal Dynamics ◽  
Zooplankton Community ◽  
Mnemiopsis Leidyi ◽  
Zooplankton Abundance ◽  
Zooplankton Community Structure ◽  
North West ◽  
The North ◽  
Before And After ◽  
Emilia Romagna Region ◽  
Time Periods

Abstract In the present study, the temporal dynamics of zooplankton community of the North West Adriatic Sea (coastal area of Emilia-Romagna region, Italy) was monitored over 12 years. The distribution and abundance of zooplankton species were investigated in relation to physical and biological parameters (temperature, salinity, dissolved oxygen and chlorophyll-a). Since November 2015 the non-indigenous copepod Pseudodiaptomus marinus, Sato, 1913 has been observed in the study area. During summer 2016, the American comb jelly Mnemiopsis leidyi, A. Agassiz, 1865 was recorded there for the first time and its presence was continuously monitored since that time (weekly observations from August 2016 to December 2017). Our study confirmed that the environmental conditions of the study area were suitable for M. leidyi growth. In addition, due to the combined effects of temperature, salinity and food availability M. leidyi was able to survive during winter months. Particular attention was then given to zooplankton abundance and community changes between two time periods: before and after M. leidyi arrival. Statistical analysis revealed significant differences in zooplankton abundance between the two time periods and a decrease in species diversity and evenness was observed during summer 2016.

Zooplankton Community Structure in the North Sea and Northeast Atlantic: Development and Test of a Biological Model

1983 ◽  
Vol 40 (11) ◽  
pp. 1912-1924 ◽  
Author(s):  
J. Anthony Koslow
Keyword(s):  
North Sea ◽  
Size Structure ◽  
Zooplankton Community ◽  
Major Elements ◽  
Zooplankton Abundance ◽  
Zooplankton Community Structure ◽  
Marine Zooplankton ◽  
Physical Forcing ◽  
The North ◽  
Zooplankton Communities

A simulation model was used to examine whether predatory interactions may regulate the size structure of marine zooplankton communities, as observed in many freshwater systems. Results of the model were consistent with the freshwater studies, such that large increases or decreases in planktivorous fish led to the dominance of small or large zooplankters, respectively. However, model predictions were not consistent with the recent decline in the northeastern Atlantic of most major elements of the pelagic zooplankton community along with North Sea herring and mackerel stocks. The overall decline of the pelagic community throughout this region indicates that zooplankton abundance may be regulated by physical forcing, and that these populations may be food- rather than predator-limited. Realistic ecological simulations of marine pelagic systems may require more complex two-layer models allowing for the effects of vertical migration, and with day–night differences in food availability and selectivity.

scholarly journals The holoplankton of the Santa Catarina coast, southern Brazil

2011 ◽  
Vol 83 (2) ◽  
pp. 575-588 ◽  
Author(s):  
Charrid Resgalla Jr
Keyword(s):  
Coastal Waters ◽  
Zooplankton Community ◽  
The State ◽  
Zooplankton Abundance ◽  
Santa Catarina ◽  
The North ◽  
Or Groups ◽  
Parvocalanus Crassirostris ◽  
Water Species ◽  
Potential Use

This paper presents information from different sampling surveys carried out along the Santa Catarina coast in order to outline the biogeographical characteristics of the zooplankton in this region and identify species or groups of species with potential use as bioindicators. Based on a checklist of species of the zooplankton community in the state, it was observed that, in the warmer months of the year, the fauna is similar to that of the states of Paraná and São Paulo (e.g. Creseis virgula f. virgula, Penilia avirostris; Acartia lilljeborgi and Oithona oswaldocruzi), while in the colder months there are coastal representatives of the fauna of Rio Grande do Sul (e.g. Acartia tonsa). However, the zooplankton consists predominantly of warm water species for most of the year, which is typical of Tropical Shelf Waters. Various species of zooplankton can be used as hydrological indicators, enabling a distinction to be made between coastal waters which are influenced by continental inputs (e.g. Paracalanus quasimodo and Parvocalanus crassirostris), common in the north of the state, and processes of upwelling (e.g. Podon intermedius) and the influence of the Subtropical Shelf Front (e.g. Pleopis polyphemoides), coming from the south. The different environments investigated present a zooplankton abundance that depends on the influence of continental inputs and the possibility of their retaining and contribution for the coastal enrichment, which varies seasonally

scholarly journals ZOOPLANKTON SPATIAL DISTRIBUTION AND COMMUNITY STRUCTURE IN BANGGAI SEA

2012 ◽  
Vol 4 (2) ◽  
Author(s):  
Arief Rachman ◽  
Elly Asniariati
Keyword(s):  
Spatial Distribution ◽  
Community Structure ◽  
Hot Spot ◽  
Zooplankton Community ◽  
Anthropogenic Activity ◽  
Zooplankton Abundance ◽  
Total Density ◽  
Importance Value ◽  
Zooplankton Community Structure ◽  
Specific Distribution

<p>Banggai Sea is an interesting ecosystem due to mixing influences from Banda Sea in the west and Maluccas Sea in the east. Therefore, a unique zooplankton community structure and specific distribution pattern should be found in this area. This research was carried on using Baruna Jaya VIII research vessel and samples were collected in 14 sampling stations. Vertical towing using NORPAC plankton net (300 μm) was conducted to collect zooplankton samples. Result showed that inner Mesamat Bay had the lowest abundance of zooplankton, probably due to low water quality resulted from anthropogenic activity. Meanwhile the strait between Liang and Labobo Island had the highest zooplankton abundance in Banggai Sea. Calanoids was the dominant zooplankton taxa in the ecosystem and contributing 55.7% of total density of zooplankton community. The highest importance value made this taxa to be very important factor that regulates the lower trophic level organisms. Results also showed that zooplankton was distributed nearly uniform in eastern but aggregated to several stations in western Banggai Sea. Zooplankton abundance was higher in the central of Banggai Sea, compared to western and eastern area. According to Bray-Curtis clustering analysis the strait between Liang and Labobo Island has unique zooplankton community structure. This might happened due to mixing of water from two highly productive seas that influenced the Banggai Sea ecosystem. From this research we conclude that this strait probably was the zooplankton hot spot area which might also indicate that this area also a hot spot of fishes in the Banggai Sea.</p><p>Keywords: spatial distribution, zooplankton, community structure, hot spot, Banggai</p>

Life before and after implementation of an acoustic noise reduction enclosure

2005 ◽  
Vol 109 (1092) ◽  
pp. 65-74
Author(s):  
B. Timmins
Keyword(s):  
Wind Tunnel ◽  
Noise Reduction ◽  
Acoustic Noise ◽  
Financial Health ◽  
Two Phase ◽  
North West ◽  
The North ◽  
Close Proximity ◽  
Before And After ◽  
Increase Productivity

Abstract This paper looks back on the designs and ambitions of ARA in resolving a long term acoustic noise problem which threatened ARA with closure. This paper today briefly looks back to the original issues but deals more fully with the later phases of a two phase project implementation and construction. ARA is now a truly ‘silent site’, where closure was once threatened, ARA has achieved the implementation of a bespoke noise reduction enclosure where 24-hour running has proved to be a reality. This paper looks at the design and construction phases, the ‘before and after’ noise footprints and at some of the financial benefits ARA has achieved. The ARA transonic wind tunnel is sited on an industrial estate on the north west perimeter of Bedford. When it was first built it was on an original farm site with no appreciable residential houses in close proximity. Since the early 1950s there has been considerable residential development around the ARA site resulting in the local householders complaining about the wind tunnel acoustic noise. In early 1999 ARA was obliged to consider several options for noise reduction measures to reduce the noise to within UK government statutory requirements. This paper deals briefly with the original noise nuisance characteristics and footprint, the noise reduction design and method that ARA selected and shows the construction phases, the further noise treatment ARA had to do on other major ancillary equipment to make ARA a truly quiet industrial site. The paper shows how ARA has utilised the resulting benefits of these investments to increase productivity and reduce costs, and the influence it has had on ARA’s financial health.

Advancing an Ecosystem Approach in the Gulf of Maine

2012 ◽  
Keyword(s):  
Gulf Of Maine ◽  
Historical Context ◽  
Zooplankton Community ◽  
Ecosystem Approach ◽  
Environmental Indicators ◽  
Zooplankton Abundance ◽  
The North ◽  
Oscillation Result ◽  
The North Atlantic Oscillation ◽  
Ecosystem Changes

<i>Abstract</i>.—Numerous studies have examined the dynamics of zooplankton in the Gulf of Maine. Here the authors reanalyze relationships found in these prior studies, using updated data, with the goal of evaluating previously identified zooplankton– environment linkages. These reanalyses support the finding that major changes occurred in the zooplankton community during the late 1980s and again in the late 1990s. Evidence for a broader change in the ecosystem during these periods and mechanisms responsible for changes in the zooplankton are discussed. In general, the results of previous studies are upheld, but it is shown that the relationship between the environmental indicators and zooplankton change through time. This result implies that all data collected in the Gulf of Maine must be considered within a historical context and that the observed environmental–zooplankton linkages are still not well understood. It is possible that changes in the seasonal cycle or shifts in the pressures systems responsible for the North Atlantic oscillation result in nonstationary environmental–zooplankton relations. These results indicate that a mechanistic understanding is required to explain the documented environment–zooplankton linkages rather than correlative explanations. Since the causes of the late-1980s and late-1990s regime shifts are still unclear, future ecosystem-based management in the Gulf of Maine must be supported by continued observation and analysis to identify ecosystem changes soon after they occur. Scenario-driven modeling also is needed to provide guidance as to how the ecosystem will respond to future changes in zooplankton abundance and community structure.

Macro and mesoscale physical patterns in the Bay of Biscay

2008 ◽  
Vol 88 (2) ◽  
pp. 217-225 ◽  
Author(s):  
Julio Gil
Keyword(s):  
Physical Oceanography ◽  
Bay Of Biscay ◽  
Mortality Reduction ◽  
Physical Processes ◽  
North West ◽  
Life History Stages ◽  
The North ◽  
Southern Half ◽  
Time Periods ◽  
Significant Mortality

The study area for this work includes all the southern edge of the Bay of Biscay, from the north-west Iberian Peninsula to the southern half of the French shelf. The principal aim of this article is to provide a complete overview of the physical oceanography of the area, mainly in its mesoscale aspects, of which there are few published studies, and the implications for early fish life history stages. The results showed the existence of two space and temporal scales for most of the physical processes that occur in the Bay of Biscay, a macroscale for seasonal time periods and a meso and submesoscale for the periods between seasons. The importance of local phenomena, such as upwelling or the variability of the Poleward Current, was observed. The interaction of both scales on these physical processes is discussed and the need for sampling at the submesoscale level to determine the distribution of ichthyoplankton is considered. Moreover, the mesoscale physical oceanography study is essential to improve the knowledge of interactions between strategies and environmental conditions that result in a significant mortality reduction in fish early stages.

PETROLEUM EXPLORATION PREVIEW FOR 1967

1967 ◽  
Vol 7 (1) ◽  
pp. 16
Author(s):  
M. A. Condon
Keyword(s):  
Financial Incentives ◽  
Petroleum Exploration ◽  
North West ◽  
The North ◽  
Oil Markets ◽  
Before And After ◽  
Timor Sea ◽  
The Government ◽  
Average Size ◽  
The Cost

Exploration for petroleum in Australia paused in 1966 and this pause is likely to continue in 1967.The number of wells drilled and seismic activity will both be slightly less in 1967 than in 1966, but the work will generally be directed to more specific targets. The cost of exploration will be somewhat higher than in 1966.During the year off-shore drilling should increase and it is expected that five mobile rigs will be drilling in the offshore areas by the end of the year. The immediate structural targets available for these rigs are in the Gippsland, Bass and Otway Basins (Victoria-Tasmania), the North-West Shelf and Timor Sea-Bonaparte Gulf, and in the Gulf of Papua.Onshore exploration will be concentrated in the western Australian basins, the Surat Basin, the central Great Artesian Basin, and the Gidgealpa region of the southwestern Great Artesian Basin.The success or otherwise of the off-shore drilling will determine the rate of exploration over the next few years. If important discoveries are made off-shore, these may and probably would result in more intensive exploration of the same stratigraphic intervals onshore.The exploration patterns of Australia and several other countries before and after first commercial discovery are compared. This indicates that Australian discovery came early, as compared with other countries, where production has developed since the war, but that post-discovery effort in Australia has been very much less. The main obvious differences appear to be that in Australia the average size of the exploration concession is very much larger and the number of operators (having regard to the areas concerned) is much smaller, than in the other successful countries.There has been a gradual movement towards reducing the size of operating areas in Australia either by obligatory relinquihment or by farmout, but if discoveries are to be made at a satisfactory rate more operators are needed in every basin.The economic environment of Australia vis-a-vis Middle East oil and oil markets is probably the main basic reason for the peculiar exploratory pattern, which has impelled the Government to provide financial incentives to encourage exploration and development.

Golden Shiner (Notemigonus crysoleucas) Population Abundance Correlations with Food and Predators

1989 ◽  
Vol 46 (5) ◽  
pp. 810-817 ◽  
Author(s):  
Mark R. S. Johannes ◽  
Donald J. McQueen ◽  
Tom J. Stewart ◽  
John R. Post
Keyword(s):  
Zooplankton Community ◽  
Zooplankton Abundance ◽  
Predator Density ◽  
Data Set ◽  
Zooplankton Community Structure ◽  
Piscivorous Fish ◽  
Golden Shiner ◽  
Stock Recruitment ◽  
Young Of The Year ◽  
Notemigonus Crysoleucas

A winterkill at Lake St. George, Ontario eliminated most of the piscivorous fish and some of the planktivores and also influenced zooplankton community structure. This disturbance and the subsequent recovery of the populations provided the opportunity to evaluate potential impacts of food and predators on the population structure and abundance of the dominant planktivore; the golden shiner (Notemigonus crysoleucas). interpretation of the 8-yr data set suggested that there was a positive relationship between adult golden shiner condition and zooplankton abundance, but that this did not translate into a significant stock–recruitment relationship between female numbers and young-of-the-year (YOY) recruitment. Also, there was no significant relationship between golden shiner survival and zooplankton abundance. However, there were significant negative correlations between YOY and adult golden shiner survival estimates and predator abundances. We conclude that at Lake St. George, golden shiner recruitment and population density is strongly influenced by predator density and is not influenced by food abundance.

scholarly journals Meso- and macro-zooplankton community structure of the Amundsen Sea Polynya, Antarctica (Summer 2010–2011)

Elem Sci Anth ◽  
2015 ◽  
Vol 3 ◽  
Author(s):  
Stephanie E. Wilson ◽  
Rasmus Swalethorp ◽  
Sanne Kjellerup ◽  
Megan A. Wolverton ◽  
Hugh W. Ducklow ◽  
...  
Keyword(s):  
Community Structure ◽  
Trophic Position ◽  
Mixed Layer Depth ◽  
Zooplankton Community ◽  
Thick Layer ◽  
Trophic Levels ◽  
Zooplankton Abundance ◽  
Amundsen Sea ◽  
Zooplankton Community Structure ◽  
Pigment Ratios

Abstract The Amundsen Sea Polynya (ASP) has, on average, the highest productivity per unit area in Antarctic waters. To investigate community structure and the role that zooplankton may play in utilizing this productivity, animals were collected at six stations inside and outside the ASP using paired “day-night” tows with a 1 m2 MOCNESS. Stations were selected according to productivity based on satellite imagery, distance from the ice edge, and depth of the water column. Depths sampled were stratified from the surface to ∼ 50–100 m above the seafloor. Macrozooplankton were also collected at four stations located in different parts of the ASP using a 2 m2 Metro Net for krill surface trawls (0–120 m). The most abundant groups of zooplankton were copepods, ostracods, and euphausiids. Zooplankton biovolume (0.001 to 1.22 ml m-3) and abundance (0.21 to 97.5 individuals m-3) varied throughout all depth levels, with a midsurface maximum trend at ∼ 60–100 m. A segregation of increasing zooplankton trophic position with depth was observed in the MOCNESS tows. In general, zooplankton abundance was low above the mixed layer depth, a result attributed to a thick layer of the unpalatable colonial haptophyte, Phaeocystis antarctica. Abundances of the ice krill, Euphausia crystallarophias, however, were highest near the edge of the ice sheet within the ASP and larvae:adult ratios correlated with temperature above a depth of 60 m. Total zooplankton abundance correlated positively with chlorophyll a above 150 m, but negative correlations observed for biovolume vs. the proportion of P. antarctica in the phytoplankton estimated from pigment ratios (19’hexanoyloxyfucoxanthin:fucoxanthin) again pointed to avoidance of P. antarctica. Quantifying zooplankton community structure, abundance, and biovolume (biomass) in this highly productive polynya helps shed light on how carbon may be transferred to higher trophic levels and to depth in a region undergoing rapid warming.

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