Reproduction in Abra Alba (Wood) and Abra Tenuis (Montagu) (Tellinacea: Scrobiculariidae)

1980 ◽  
Vol 60 (2) ◽  
pp. 465-479 ◽  
Author(s):  
P. Laskaridou Nott
Keyword(s):  
Reproductive Cycle ◽  
Coastal Waters ◽  
Seasonal Changes ◽  
Dominant Species ◽  
Benthic Communities ◽  
Great Abundance ◽  
Indirect Methods ◽  
Histological Techniques ◽  
North West ◽  
Marine Bivalves

Abra alba and Abra tenuis are closely related marine bivalves. They both inhabit similar types of sandy-mud sediments but they prefer different localities. The smaller A. tenuis is found in a few scattered intertidal mudflats, whereas A. alba is more widely distributed and in great abundance in the coastal waters of north-west Europe. The latter can be found at any depth between low-water mark and 80 m (Tebble, 1966; Ansell, 1974) and often forms the dominant species of shallow water benthic communities.The reproductive cycle of the two species has been studied and compared as a part of a wider ecological investigation. There is minimal literature concerning the reproduction of A. tenuis but A. alba has received a lot of attention, because it forms a major source of food for flatfish. However, most of the earlier investigations are confined to the time that spawning occurs with the evidence derived from either the time of the year that larvae appear in the plankton (Lebour, 1938; Jorgensen, 1946; Fosshagen, 1965; Muus, 1973; Rasmusen, 1973), or the time of the year that juveniles first appear in the bottom samples (Orton, 1924; Ford, 1925; Stephen, 1932). The inadequacy of such indirect methods has been discussed by Seed (1969,1975, 1976). Ansell (1974) derived the reproductive cycle of A. alba from seasonal changes in the biochemical composition. In the present investigation, histological techniques have been used, since they are considered to offer the most reliable information about the reproductive cycle (Seed, 1969, 1975, 1976).

Seasonal changes of motile polychaetes in the fouling assemblage developed on test panels submerged on a tropical coast

2013 ◽  
Vol 93 (6) ◽  
pp. 1525-1531 ◽  
Author(s):  
S. Satheesh ◽  
S.G. Wesley
Keyword(s):  
Coastal Waters ◽  
Seasonal Changes ◽  
Dominant Species ◽  
East Coast ◽  
Monsoon Season ◽  
Polychaete Species ◽  
Post Monsoon ◽  
Platynereis Dumerilii ◽  
Post Monsoon Season ◽  
Tropical Coast

The diversity and distribution of polychaete species under the families Nereididae, Syllidae and Eunicidae in sub-tidal fouling assemblage was studied by submerging wood as test substratum. Wooden panels were fitted onto a raft and submerged in Kudankulam coastal waters (south east coast of India) in pre-monsoon, monsoon and post-monsoon seasons from May 2003 to July 2005. Panels (in replicate) were retrieved from the raft at 15-day intervals. A total of 24 polychaete species belonging to the three families were identified from the test panels.Perinereis cultrifera,Platynereis dumerilii,Syllis variegata,Syllis truncata, andEunice australiswere the dominant species observed on the test panels. The abundance of major polychaete group was varied considerably between the panel series submerged in May 2003 (post-monsoon), November 2003 (monsoon) and July 2004 (pre-monsoon). The major difference in the polychaete community structure was the low abundance of both nereidids on pre-monsoon season panels and the eunicids on monsoon and post-monsoon season panels.

Wind speed data analysis for predictions of sea waves in Bitung Coastal Waters

2013 ◽  
pp. 35 ◽  
Author(s):  
Joanes E Koagouw ◽  
Gybert E Mamuaya ◽  
Adrie A Tarumingkeng ◽  
P A Angmalisang
Keyword(s):  
Data Analysis ◽  
Wind Speed ◽  
Coastal Waters ◽  
Transition Period ◽  
Marine Resources ◽  
Land Uses ◽  
Sea Waves ◽  
North West ◽  
North Sulawesi ◽  
The Waves

Coastal area of Bitung Municipality is one of the economical activities centers in North Sulawesi Province such as for land-uses and the exploitation of natural resources. Those activities are exaggerating day bay day and tended to be uncontrollable. The excess of those conditions, it has been recorded the change of waves in Bitung waters that has impacts to coastal areas and can affect the utilization of coastal and marine resources. This research was aimed to observe waves altitude variations in Bitung waters with Svedrup Munk and Bretchsneider (SMB) method that had been used to predict waves altitudes. The results showed that the wind speed during West Season was 0.33 m and were dominant to the East, while during East season was 0.91m from South-East to North-West, and then on transition period (March to May) was 1.08m from South-East to East. The results of those wind speed to the waves altitudes in Bitung waters is discussed in this paper© Pesisir pantai Kota Bitung merupakan salah satu pusat aktivitas ekonomi (misalnya pemanfaatan lahan dan eksploitasi sumberdaya) di Provinsi Sulawesi Utara. Aktivitas tersebut semakin hari semakin meningkat dan memiliki kecenderungan tidak terkontrol. Akibat dari keadaan tersebut, telah terjadi perubahan fenomena gelombang di perairan Bitung yang berdampak pada keberadaan daerah pesisir pantai di mana hal ini dapat mengganggu aktivitas pemanfaatan sumberdaya pesisir dan laut tersebut. Penelitian ini bertujuan untuk mengetahui variasi tinggi gelombang di perairan Bitung dengan menggunakan metode Svedrup Munk and Bretchsneider (SMB) yang biasa digunakan untuk peramalan tinggi gelombang signifikan. Hasil penelitian menunjukkan bahwa kecepatan angin pada Musim Barat sebesar 0,33 meter dan dominan ke arah Timur, sementara pada Musim Timur sebesar 0,91 meter dari arah Tenggara ke Barat Laut, serta pada Musim Peralihan (antara bulan Maret-Mei) adalah sebesar 1,08 meter dari arah Tenggara dan Timur. Pengaruh kecepatan angin tersebut terhadap gelombang laut di perairan Bitung dibahas dalam tulisan ini©

Oil pollution studies of the Solbergstrand mesocosms

1987 ◽  
Vol 316 (1181) ◽  
pp. 641-654 ◽  
Keyword(s):  
Dominant Species ◽  
Oil Pollution ◽  
Benthic Communities ◽  
Ascophyllum Nodosum ◽  
Diesel Oil ◽  
Benthic Macrofauna ◽  
Sediment Chemistry ◽  
Littorina Littorea ◽  
Species Structure ◽  
Laminaria Digitata

Two medium-scale ecosystems (mesocosms) were built on the Oslofjord: one a hard-bottom intertidal system and the other a subtidal soft-sediment system. The hard-bottom mesocosm consists of four basins, two controls and two which were dosed with diesel-oil (129 μg 1 -1 a high oil (HO) dose and 29 μg 1 -1 a low oil (LO) dose). Both oil doses caused high mortality of Mytilus edulis and growth was reduced in the macroalgae Ascophyllum nodosum and Laminaria digitata . Recruitment of Littorina littorea was also affected by oil so that populations declined over time. Subtidal benthic communities have been established in the mesocosm and show variations in sediment chemistry within the range found in the field. Although recruitment of benthic macrofauna is reduced, dominant species and species structure remain closely similar to that in the field over six months. Bioturbation effects studied in the mesocosm have shown the important influence of large, rare species in structuring benthic communities, a finding which would not be possible in nature by diving or by the use ofsubmersibles. Preliminary results from a community taken from 200 m depth and established in the mesocosm suggest that it is now possible to do detailed manipulation experiments on communities simulating the whole continental shelf.

scholarly journals Dynamic of decapod crustacean larvae on the entrance of Guanabara bay

2002 ◽  
Vol 45 (4) ◽  
pp. 491-498 ◽  
Author(s):  
Lohengrin Dias de Almeida Fernandes ◽  
Sérgio Luiz Costa Bonecker ◽  
Jean Louis Valentin
Keyword(s):  
Reproductive Cycle ◽  
Seasonal Variations ◽  
Coastal Waters ◽  
Decapod Crustacean ◽  
Late Summer ◽  
Late Winter ◽  
Guanabara Bay ◽  
Tidal Cycles ◽  
Decapod Larvae

In the present study, we observed seasonal variations in the density of decapod larvae as well as changes in density related to diurnal and tidal cycles. Among the decapod larvae collected, portunids and grapsids were the most abundant, especially during nocturnal ebb tides and near the surface. The same results were obtained in late winter (September) and late summer (March). These results demonstrated a flow of decapod larvae from Guanabara Bay to adjacent coastal waters. Luciferid (Lucifer faxoni) was the only group with high densities during flood tides and we suggest this is an evidence of L. faxoni larvae entering Guanabara Bay in late winter. Probably these changes in distribution of Lucifer faxoni among winter and summer were related to reproductive cycle in the bay. For the portunids, grapsids and ocypodids, a similar dispersion strategy was observed towards adjacent coastal waters in the surface during nocturnal ebb tides.

scholarly journals Seasonal Changes in Microbial Dissolved Organic Sulfur Transformations in Coastal Waters

2020 ◽  
Vol 8 (3) ◽  
pp. 337
Author(s):  
Joanna L Dixon ◽  
Frances E Hopkins ◽  
John A Stephens ◽  
Hendrik Schäfer
Keyword(s):  
Coastal Waters ◽  
Seasonal Changes ◽  
Significant Loss ◽  
Trace Gas ◽  
Organic Sulfur ◽  
Consumption Rates ◽  
Atmospheric Sulfur ◽  
Sulfur Transformation ◽  
Microbial Consumption ◽  
Biogenic Source

The marine trace gas dimethylsulfide (DMS) is the single most important biogenic source of atmospheric sulfur, accounting for up to 80% of global biogenic sulfur emissions. Approximately 300 million tons of DMS are produced annually, but the majority is degraded by microbes in seawater. The DMS precursor dimethylsulfoniopropionate (DMSP) and oxidation product dimethylsulphoxide (DMSO) are also important organic sulfur reservoirs. However, the marine sinks of dissolved DMSO remain unknown. We used a novel combination of stable and radiotracers to determine seasonal changes in multiple dissolved organic sulfur transformation rates to ascertain whether microbial uptake of dissolved DMSO was a significant loss pathway. Surface concentrations of DMS ranged from 0.5 to 17.0 nM with biological consumption rates between 2.4 and 40.8 nM·d−1. DMS produced from the reduction of DMSO was not a significant process. Surface concentrations of total DMSO ranged from 2.3 to 102 nM with biological consumption of dissolved DMSO between 2.9 and 111 nM·d−1. Comparisons between 14C2-DMSO assimilation and dissimilation rates suggest that the majority of dissolved DMSO was respired (>94%). Radiotracer microbial consumption rates suggest that dissimilation of dissolved DMSO to CO2 can be a significant loss pathway in coastal waters, illustrating the significance of bacteria in controlling organic sulfur seawater concentrations.

scholarly journals Fish assemblages in a tidal flat

2003 ◽  
Vol 46 (2) ◽  
pp. 233-242 ◽  
Author(s):  
Ana Lúcia Vendel ◽  
Sabine Granado Lopes ◽  
César Santos ◽  
Henry Louis Spach
Keyword(s):  
Cluster Analysis ◽  
Community Structure ◽  
Tidal Flat ◽  
Seasonal Changes ◽  
Dominant Species ◽  
Fish Assemblages ◽  
Seasonal Pattern ◽  
Abundant Species ◽  
Structure Index ◽  
Total Capture

Studies were carried out on fish assemblages in a tidal flat. Samples were obtained monthly at low tide of the half moon in the tidal flat of Paranaguá Bay, Brazil, with two seine nets, one with a 1 mm mesh, 30 m in length and 3 m in height and another with a 10 mm mesh, 65 m in length and 2 m in height. A total of 8,890 fish were captured, comprising 24 families and 53 species. The most abundant species were Harengula clupeola and Atherinella brasiliensis, which represented 63.4% of the total, capture. A seasonal tendency was observed in the abundance of fishes, with less fishes being captured during winter and part of spring. The number of species showed a seasonal pattern, with the gradual decrease through winter and a marked increase in summer. The community structure index indicated seasonal changes in the assemblage. The faunistic similarities between months separated the 12 months into four major groups. The seasonal pattern was apparent in the numerically dominant species and the Cluster Analysis revealed five main groups.

scholarly journals Interannual and Seasonal Changes in the Benthic Algae Flora of Coral Reef in Xiaodong Hai (Hainan Island, China)

2019 ◽  
Vol 7 (8) ◽  
pp. 243
Author(s):  
Eduard A. Titlyanov ◽  
Tamara V. Titlyanova ◽  
Anna V. Scriptsova ◽  
Yuxiao Ren ◽  
Xiubao Li ◽  
...  
Keyword(s):  
Species Diversity ◽  
Seasonal Changes ◽  
Dominant Species ◽  
Benthic Algae ◽  
Hainan Island ◽  
Algal Turf ◽  
Macroalgal Species ◽  
Antarctic Waters ◽  
Maximum Similarity ◽  
The Tropics

Intensive algal sampling conducted in 2016–2019 in the Xiaodong Hai locality (Hainan Island, South China Sea), yielded a total of 198 benthic macroalgal species and their taxonomic forms (54% reds, 20% browns and 26% greens) and 20 species of Cyanobacteria. The largest number of species belonged to the families Rhodomelaceae, Ceramiaceae and Corallinaceae (Rhodophyta); Sargassaceae and Dictyotaceae (Phaeophyceae); Cladophoraceae and Caulerpaceae (Chlorophyta). The majority (79%) of species inhabiting only the tropics or subtropics were previously recorded and 21% of the species were also inhabiting temperate latitudes. Cosmopolitan algae inhabiting from the tropics to Arctic or Antarctic waters amounted to 14%. The level of maximum similarity of macroalgal species diversity in different years was on average more than 70%, interannual species specificity was observed only in the group of dominating species in algal turf communities. The seasonal variability of floras was manifested in a significant decrease in species diversity from the dry season to the rainy and in the change of dominant species in algal turf communities.

Reproductive cycle of purple clam, Amiantis purpurata (Bivalvia: Veneridae) in northern Patagonia (Argentina)

2005 ◽  
Vol 85 (2) ◽  
pp. 367-373 ◽  
Author(s):  
Enrique M. Morsan ◽  
Marina A. Kroeck
Keyword(s):  
Reproductive Cycle ◽  
Continuous Process ◽  
Early Summer ◽  
Maturation Stage ◽  
Reproductive Pattern ◽  
Oocyte Diameter ◽  
Histological Techniques ◽  
Northern Patagonia ◽  
History Of ◽  
Quantitative Indicators

The reproductive cycle of the purple clam (Amiantis purpurata) northern Patagonian population was studied throughout a 19-month period (September 1993–March 1995) using standard histological techniques and quantitative indicators (oocyte diameter distributions, oocytes per ocular field and relative oocyte area). In this species gametogenesis is a continuous process involving a complete gonadal restitution after the end of the reproductive season (no resting period). The proliferation phase occurs during the coldest half of the year (April to September) and maturation takes place during spring (September to December). Several partial emissions of gametes, with subsequent restitution of the gametogenic series, occur during the summer months. During the total maturation stage, oocytes never filled the whole alveolar area: maximum per cent of alveolar sections occupied by oocytes (46%) was observed in late spring–early summer. Implications of the reproductive pattern in the context of palaeogeographic history of northern Patagonia, and the isolation of this population are discussed.

Seasonal Distribution and Abundance of Dugongs in the Western-Gulf-of-Carpentaria

1989 ◽  
Vol 16 (2) ◽  
pp. 141 ◽  
Author(s):  
P Bayliss ◽  
WJ Freeland
Keyword(s):  
Relative Density ◽  
Relative Abundance ◽  
Coastal Waters ◽  
Seasonal Changes ◽  
Aboriginal People ◽  
Dry Season ◽  
Seasonal Distribution ◽  
Wet Season ◽  
Aerial Surveys ◽  
The 1960S

Aerial surveys of coastal waters (27 216 km2) in the western Gulf of Carpentaria during the dry season of 1984 and wet season of 1985 indicated no major seasonal changes in distribution and relative abundance of dugongs. Minimum population size in the dry season was estimated as 16 816 � 2946 (standard error), with a relative density of 0.62 k 0.11 km-2, and that for the wet season 16 846 + 3257, with a relative density of 0.62 � 0.12 km-2. The estimates exclude 5% of observations which could have been either dugongs or Irrawaddy dolphins, and were corrected for submerged dugongs and those missed on the surface. Dugongs were unevenly distributed over the study area, and neither mean group size nor proportion of calves varied between seasons. Dugong abundance was correlated with area of available seagrass. The catch rate of dugongs by Aboriginal people off Numbulwar decreased six-fold between the 1960s and 1985 (60 to 10 p.a.), possibly due to excessive hunting.

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