Influence of Subantartic and Subtropical Oceanic Water on the Zooplankton and Hydrology of Waters Adjacent to the Derwent River Estuary, South-eastern Tasmania

1979 ◽  
Vol 30 (2) ◽  
pp. 179 ◽  
Author(s):  
N Taw ◽  
DA Ritz
Keyword(s):  
Indicator Species ◽  
Strong Evidence ◽  
Coastal Waters ◽  
River Estuary ◽  
Water Masses ◽  
Seasonal Abundance ◽  
Oceanic Water ◽  
Subtropical Water ◽  
South Eastern ◽  
Subantarctic Water

The oceanic influence on coastal waters adjacent to the mouth of the Derwent River estuary was examined over a season using zooplankton samples. There is strong evidence to indicate the influence of oceanic water in Storm Bay and the mouth of the Derwent River estuary. The occurrence of indicator species suggests that the area is invaded by subantarctic water from August to January and by subtropical water most strongly in February and March. The seasonal abundance and distribu- tion of the major copepods (12 species), chaetognaths (three species), one euphausiid and one tunicate species are described in detail and the importance of these species as indicators of intrusion and mixing of water masses in this region is evaluated.

Zooplankton Distribution in Relation to the Hydrology of the Derwent River Estuary

1978 ◽  
Vol 29 (6) ◽  
pp. 763 ◽  
Author(s):  
N Taw ◽  
DA Ritz
Keyword(s):  
Indicator Species ◽  
Coastal Waters ◽  
River Estuary ◽  
Marine Species ◽  
Copepod Species ◽  
Estuarine System ◽  
Freshwater Flow ◽  
Tidal Zone ◽  
Zooplankton Distribution ◽  
Plankton Distribution

The zooplankton of the Derwent River estuary was sampled during periods of high freshwater flow (October) and low freshwater flow (April). Zooplankton distribution was found to be similar at both times with only minor shifts in location. Observed plankton distribution is shown to correlate well with a hydrologically established zonation scheme. Despite continual exchange between oceanic, coastal and inshore coastal waters, there is only occasional estuarine penetration into the inshore region and little penetration of inshore plankton into the estuary. The tidal zone is shown to be stable, well defined and characterized by estuarine and marine species. It is suggested that in a similar estuarine system, where the zooplankton distribution is well known, the hydrological zones can be inferred. The estuary of the Werribee River, Victoria, contains most of the same copepod species and is similar in other ways to the Derwent River estuary. But the occurrence of indicator species in the marine region of the Derwent estuary suggests that it is subject to a stronger influence of open coastal and oceanic waters.

Temperature, Salinity and Plankton in the Eastern North Atlantic and Coastal Waters of Britain, 1957.: I. The Characterisation and Distribution of Surface Waters

1963 ◽  
Vol 20 (3) ◽  
pp. 789-826 ◽  
Author(s):  
B. McK. Bary
Keyword(s):  
North Sea ◽  
North Atlantic ◽  
Coastal Waters ◽  
Water Bodies ◽  
English Channel ◽  
Oceanic Water ◽  
Climatic Fluctuations ◽  
The North ◽  
The North Sea ◽  
Eastern North Atlantic

Monthly temperature-salinity diagrams for 1957 have demonstrated that three surface oceanic "water bodies" were consistently present in the eastern North Atlantic; two are regarded as modified North Atlantic Central water which give rise to the third by mixing. As well in the oceanic areas, large and small, high or low salinity patches of water were common. Effects of seasonal climatic fluctuations differed in the several oceanic water bodies. In coastal waters, differences in properties and in seasonal and annual cycles of the properties distinguish the waters from the North Sea, English Channel and the western entrance to the Channel.The geographic distributions of the oceanic waters are consistent with "northern" and "southern" water bodies mixing to form a "transitional" water. Within this distribution there are short-term changes in boundaries and long-term (seasonal) changes in size of the water bodies.Water in the western approaches to the English Channel appeared to be influenced chiefly by the mixed, oceanic transitional water; oceanic influences in the North Sea appear to have been from northern and transitional waters.

The role of tides on the carbonate chemistry of a coastal polynya in the south-eastern Weddell Sea

2021 ◽  
Author(s):  
Elise Droste ◽  
Melchor González Dávila ◽  
Juana Magdalena Santana Casiano ◽  
Mario Hoppema ◽  
Gerd Rohardt ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Weddell Sea ◽  
Water Masses ◽  
Total Alkalinity ◽  
The South ◽  
Carbonate Chemistry ◽  
Large Variability ◽  
South Eastern ◽  
Coastal Polynya ◽  
Eastern Weddell Sea

<p>Tides have a large impact on coastal polynyas around Antarctica. We investigate the effect of semi-diurnal tidal cycles on the seawater carbonate chemistry in a coastal polynya hugging the Ekström Ice Shelf in the south-eastern Weddell Sea. This region experiences some of the strongest tides in the Southern Ocean. We assess the implications for the contribution of coastal polynyas to the carbon dioxide (CO<sub>2</sub>) air-sea flux of the Weddell Sea.</p><p>Two site visits, in January 2015 and January 2019, are intercompared in terms of the dissolved inorganic carbon (DIC) concentration, total alkalinity, pH, and CO<sub>2</sub> partial pressure (pCO<sub>2</sub>). The tides induce large variability in the carbonate chemistry of the coastal polynya in the austral summer: DIC concentrations vary between 2174 and 2223 umol kg<sup>-1</sup>.</p><p>The tidal fluctuation in the DIC concentration can swing the polynya from a sink to a source of atmospheric CO<sub>2 </sub>on a semi-diurnal timescale. We attribute these changes to the mixing of different water masses. The amount of variability induced by tides depends on – and is associated with – large scale oceanographic and biogeochemical processes that affect the characteristics and presence of the water masses being mixed, such as the rate of sea ice melt.</p><p>Sampling strategies in Antarctic coastal polynyas should always take tidal influences into account. This would help to reduce biases in our understanding of how coastal polynyas contribute to the CO<sub>2</sub> uptake by the Southern Ocean.</p>

scholarly journals Lunar periodicity in catch rate and reproductive condition of adult eastern king prawns, Penaeus plebejus, in coastal waters of south-eastern Queensland, Australia

1996 ◽  
Vol 47 (1) ◽  
pp. 67 ◽  
Author(s):  
AJ Courtney ◽  
DJ Die ◽  
JG McGilvray
Keyword(s):  
Coastal Waters ◽  
Full Moon ◽  
Lunar Cycle ◽  
Catch Rate ◽  
Lunar Phase ◽  
Reproductive Condition ◽  
Ovary Weight ◽  
South Eastern ◽  
New Moon ◽  
Catch Rates

This study examined the lunar and die1 variation in catch rates and reproductive condition of adult eastern king prawns, Penaeus plebejus, in relatively deep (160 m) coastal waters off south- eastern Queensland. Females numerically dominated catches over most of the lunar cycle and constituted 76% of the weight of the catch. Analysis of variance (ANOVA) revealed an interaction between lunar phase and sex; catches peaked during Lunar Phase 3 (full moon � 3 days) and were particularly marked for males. This was the only period during the lunar cycle when the sex ratio approached 1 : 1. There was also an interaction between trawl-time and sex; male catch rates were at a minimum early in the evening, whereas female catch rates were at a maximum then and declined throughout the night. Trawler logbook catch rate data from the same area over a similar period indicated an interaction between lunar cycle and lunar phase. ANOVA revealed an effect of the interaction between phase and sex on the incidence of soft prawns; the incidence of soft males increased during Phase 4 (half moon waning to new moon � 3 days). Ovary weight also varied between phases and was higher during Phases 2 (half moon waxing to full moon � 3 days) and 4 (half moon waning to new moon � 3 days). Trends in the ovary weight and the incidence of histologically mature and ripe females suggested there are two periods of increased spawning activity during each lunar cycle. A cyclic regression fitted to the data explained 93% of the variation in the incidence of ripe females between samples. The influence of these cyclic trends in catch rate and reproductive condition should be considered when monitoring the spawning stock in the fishery and when planning sampling strategies in any future reproductive studies.

Further studies of plankton ecosystems in the eastern Indian Ocean. VI. Ecology of the Euphausiacea

1977 ◽  
Vol 28 (5) ◽  
pp. 627 ◽  
Author(s):  
PS McWilliam
Keyword(s):  
Indian Ocean ◽  
Food Resources ◽  
Water Masses ◽  
Eastern Indian Ocean ◽  
Subtropical Water ◽  
Larvae And Juveniles ◽  
Larval Distribution ◽  
Living Species ◽  
Breeding Condition

Examination of 26 427 euphausiids from 175 samples taken by vertical hauls in the upper 200-m stratum along the 110°E. meridian during 1962-63 indicated that day samples contained mainly larvae and juveniles whereas night samples contained more adults. The following six species of small euphausiids were the most abundant and ubiquitous: Euphausia mutica, E. tenera, E. brevis, Stylocheiron carinatum, S. suhmii, and S. Affine. Their distribution overlapped according to the distribution, in the upper 150 m, of the tropical and subtropical water masses and their mixtures. These species were commonly observed in breeding condition. Their larval distribution was related to the distribution of the breeding adults. The rarer and less ubiquitous species, which were mainly younger stages and deeper living species, showed more pronounced relationships with seasonal water movements. Food resources appeared more important than temperature and salinity in influencing distribution, abundance, and association of species.

scholarly journals Tidal Mixing Signatures in the Hong Kong Coastal Waters from Satellite-Derived Sea Surface Temperature

2018 ◽  
Vol 11 (1) ◽  
pp. 5 ◽  
Author(s):  
R. Susanto ◽  
Jiayi Pan ◽  
Adam Devlin
Keyword(s):  
Hong Kong ◽  
High Resolution ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Coastal Waters ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Sea Surface ◽  
Tidal Mixing ◽  
Diurnal Tides

Tidal mixing in the coastal waters of Hong Kong was investigated using a combination of in situ observations and high-resolution satellite-derived sea surface temperature (SST) data. An indicator of tide-induced mixing is a fortnightly (spring-neap cycle) signature in SST due to nonlinear interactions between the two principal diurnal and the two principal semi-diurnal tides. Both semi-diurnal and diurnal tides have strong tidal amplitudes and currents near Hong Kong. As a result, both the near-fortnightly (Mf) and fortnightly (MSf) tides are enhanced due to nonlinear tidal signal interactions. In addition, these fortnightly tidal signals are modulated by seasonal variability, with the maximum seasonal modulation of fortnightly tides occurring during the monsoon transition periods in May and October. The largest fortnightly signals are found in the southwestern part of the Pearl River estuary. Tidal constituent properties vary by space and depth, and high-resolution SST plays a pivotal role in resolving the spatial characteristics of tidal mixing.

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