{"title":"A quantitative study of the trophic relationships within the fish community of the Mhlanga estuary, South Africa","authors":"A.K. Whitfield","doi":"10.1016/S0302-3524(80)80121-6","DOIUrl":"10.1016/S0302-3524(80)80121-6","url":null,"abstract":"<div><p>The importance of benthic floc, zoobenthos, zooplankton and epiphytic flora and fauna as energy sources for the fishes of the Mhlanga estuary was studied between January and December 1978. Benthic floc (detritus and associated microorganisms) was the most important food resource with an annual standing crop of 161 kJ m<sup>−2</sup> (9·46 g m<sup>−2</sup>). More than 90% of the fish biomass utilized this energy source compared to 1·8% feeding on zoobenthos (26·4 kJ m<sup>−2</sup>, 1·5 g m<sup>−2</sup>), 1·7% on zooplankton (1·7 kJ m<sup>−3</sup>, 0·08 g m<sup>−3</sup>) and 3·1% on epiphytic flora and fauna (4·0 kJ m<sup>−2</sup>, 0·27 g m<sup>−2</sup>). Since much of the detritus entered the Mhlanga estuary from the fringing <em>Phragmites</em> swamp, the biological productivity of the estuary was closely linked to that of the reed beds. During the closed phase of the estuary the standing crops of the fish food resources increased due to the relative stability of the physical environment. The highest biomasses of zooplankton, zoobenthos, epiflora and epifauna were recorded after extended periods of closure and decreased significantly when the estuary opened. This was due to two main factors: firstly prolonged exposure of vast areas of the lagoon and reed swamp, and secondly large scale substrate movement caused by floodwaters leaving the estuary.</p></div>","PeriodicalId":100492,"journal":{"name":"Estuarine and Coastal Marine Science","volume":"10 4","pages":"Pages 417-435"},"PeriodicalIF":0.0,"publicationDate":"1980-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-3524(80)80121-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88482764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Groundwater seepage into Great South Bay, New York","authors":"Henry Bokuniewicz","doi":"10.1016/S0302-3524(80)80122-8","DOIUrl":"10.1016/S0302-3524(80)80122-8","url":null,"abstract":"<div><p>Great South Bay (New York) is a large lagoon on the northeast coast of the United States. The flow of groundwater across the floor of Great South Bay has been reported to account for as much as 2/3 of the total freshwater inflow. <em>In situ</em> measurements of this seepage flow have been made along four offshore transects in the Bay. These measurements show that the flow rate decreases rapidly offshore; within 30 m of the shoreline, the submarine outflow rates were typically 40 l (day m<sup>2</sup>)<sup>−1</sup> and decreased to less than 10 l (day m<sup>2</sup>)<sup>−1</sup> at a distance of 100 m from shore. The Bay floor at the study locations was sand or silty sand with vertical intrinsic permeabilities ranging from 14 to 78 darcys.</p><p>The flow rate across the Bay floor may be described by an exponentially decreasing function. The flow distribution may, therefore, be specified with two parameters—the flow value at the shoreline, <em>A</em>, and a ‘decay’ constant, <em>c</em>, that governs the rate of decrease of the flow offshore. The calculated total flows along the four transects were 2·1 × 10<sup>3</sup>, 1·1 × 10<sup>3</sup>, 8·5 × 10<sup>3</sup> and 3·9 × 10<sup>3</sup> l (day m)<sup>−1</sup>. Between 40% and 98% of this flow enters the Bay within 100 m from shore. The total flow of groundwater across the Bay floor was calculated to be about 2 × 10<sup>8</sup> l day<sup>−1</sup> or 10–20% of the total freshwater inflow.</p></div>","PeriodicalId":100492,"journal":{"name":"Estuarine and Coastal Marine Science","volume":"10 4","pages":"Pages 437-444"},"PeriodicalIF":0.0,"publicationDate":"1980-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-3524(80)80122-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76176275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Occurrence and predation by Mnemiopsis leidyi in Barnegat Bay, New Jersey","authors":"Kent Mountford","doi":"10.1016/S0302-3524(80)80119-8","DOIUrl":"10.1016/S0302-3524(80)80119-8","url":null,"abstract":"<div><p>A late-May seed population of the ctenophore, <em>Mnemiposis leidyi</em>, monitored by net tow at four stations, increased from an average 0.15 m<sup>−3</sup> to 68 m<sup>−3</sup> in 15 days. This increase was coupled with almost complete removal of the adult copepod population, and a general depression of net zooplankton biomass. In eight days following peak density the ctenophore population had declined to 21.9 m<sup>−3</sup>, 32% of its peak level. Oscillations in ctenophore and zooplankton density suggested an equilibrium process toward late June.</p><p>With zooplankton biomass as dependent variable, data on the ctenophore population, taxonomic composition of the zooplankton and hydrography were subjected to multiple regression analysis. Calculated zooplankton biomass agreed closely with the observed means. Log<sub>10</sub> ctenophore abundance, a measure of predator pressure, produced the greatest reduction in unexplained variation (0.01<<em>P</em><0.025). The recruitment of bottom invertebrate larvae into the plankton was next most important (0.01<<em>P</em><0.025). Plankton data from other years suggests this dynamic predatorprey interaction is an annual event in this barrier built estuary which is an excellent site to study the phenomenon because of a low flushing rate and the absence of ctenophore predators.</p></div>","PeriodicalId":100492,"journal":{"name":"Estuarine and Coastal Marine Science","volume":"10 4","pages":"Pages 393-402"},"PeriodicalIF":0.0,"publicationDate":"1980-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-3524(80)80119-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87459847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Tidal induced regulation of nitrogen fixation activity (C2H4 production) in a Georgia Salt Marsh","authors":"M.S. Ubben , R.B. Hanson","doi":"10.1016/S0302-3524(80)80123-X","DOIUrl":"10.1016/S0302-3524(80)80123-X","url":null,"abstract":"<div><p>Nitrogen fixation potential, determined by the acetylene reduction technique, was measured at fourteen sites across a Georgia salt marsh. The transect spanned (1) tall and short <em>Spartina alterniflora</em>, and natural <em>Juncus</em> and <em>Salicornia</em> monocultures and (2) small tidal creek which usually floods over a levee into a short <em>Spartina</em> marsh during high tides. Spring tides usually flood the entire marsh and enter the <em>Juncus</em> zone. Nitrogen fixation potential in the soil was related to sites of daily tidal inundation and not to interstitial salinity. We also artificially altered the salinity in cores from short and tall <em>Spartina</em> zones to investigate whether nitrogen-fixing populations were tolerant to fluctuations in salt concentration. Results indicate that populations in the marsh are diverse and fluctuate monthly with respect to salinity tolerance in Sapelo Island salt marsh soils.</p></div>","PeriodicalId":100492,"journal":{"name":"Estuarine and Coastal Marine Science","volume":"10 4","pages":"Pages 445-453"},"PeriodicalIF":0.0,"publicationDate":"1980-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-3524(80)80123-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76848667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Sensitivity of marine ciliates (Protozoa, ciliophora) to high thermal stress","authors":"Edwin A. Martinez","doi":"10.1016/S0302-3524(80)80117-4","DOIUrl":"10.1016/S0302-3524(80)80117-4","url":null,"abstract":"<div><p>The range of sensitivity of marine ciliates to temperatures approaching lethal maxima was determined under a variety of biotic and abiotic conditions. Twelve species of ciliates representing different taxa, sizes and modes of locomotion were examined. A simple heating apparatus consisting of a heated microscope stage was employed to subject the organisms to acute heat stress.</p><p>Heat resistance in the ciliates was influenced by cultivation temperature, salinity and nutrition. Temperatures of LD<sub>50</sub> ranged from 31.5 °C for <em>Uronema marinum</em> Dujardin to 39 °C for <em>Condylostoma arenarium</em> Spiegel. When cultivated at low temperatures (10 °C), <em>Euplotes crassus</em> (Dujardin) was more resistant to heat shock at high salinities (35‰) than at low salinities (15‰). The effect of salinity on thermal resistance diminished as the ciliates were cultivated at higher temperatures (30 °C). Thermal sensitivity depended also on the temperature of acclimation. <em>E. crassus</em> was more sensitive to heat stress when it was cultivated on single strains of bacteria than when it was cultivated on a mixture of bacteria. Furthermore the type of bacteria offered as food also influenced its sensitivity to heat shock.</p></div>","PeriodicalId":100492,"journal":{"name":"Estuarine and Coastal Marine Science","volume":"10 4","pages":"Pages 369-381, IN1"},"PeriodicalIF":0.0,"publicationDate":"1980-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-3524(80)80117-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77283855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A comparison of tidal harmonic constants computed at and near an inlet","authors":"Ned P. Smith","doi":"10.1016/S0302-3524(80)80118-6","DOIUrl":"10.1016/S0302-3524(80)80118-6","url":null,"abstract":"<div><p>Time series of bottom pressure and surface water level are used to compute harmonic constants and thus compare tidal conditions at and near an inlet along Florida's Atlantic coast. Supportive hydrographic and surface atmospheric pressure data are incorporated to estimate the probable maximum errors in comparing pressure fluctuations with water level variations. The M<sub>2</sub> tidal amplitude decreases from 0.45 decibar (0.45 m±0.02 m) over the inner shelf to 0.28 m in the nearby inlet. There is an 11° phase lag of the M<sub>2</sub> tide in the inlet. The K<sub>1</sub> and O<sub>1</sub> constituent amplitudes show essentially no decrease from the shelf to the inlet, though the tidal wave form is delayed by 9° and 18° respectively. Locally damped amplitudes and phase lags are attributed to estuarine-shelf exchanges through the inlet. Local perturbations in the tidal harmonic constants may have a significant effect on the construction of co-tidal and co-range charts for the adjacent ocean basin.</p></div>","PeriodicalId":100492,"journal":{"name":"Estuarine and Coastal Marine Science","volume":"10 4","pages":"Pages 383-391"},"PeriodicalIF":0.0,"publicationDate":"1980-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-3524(80)80118-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90689656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Deposition of dredged sediment at open water sites","authors":"Henry J. Bokuniewicz , Robert B. Gordon","doi":"10.1016/S0302-3524(80)80102-2","DOIUrl":"https://doi.org/10.1016/S0302-3524(80)80102-2","url":null,"abstract":"<div><p>Silt-clay dredge spoil released at the surface of near-shore waters is deposited on the sea floor within a few hundred meters of its impact point. Only a few percent of the spoil is lost into the water column in most disposal operations. Surveys of the deposits formed by the controlled release of dredged sediment show some to be compact (presenting minimum surface area to the ambient water) and others dispersed (extending over a large area as a thin layer). The principal factor controlling the degree of dispersion during placement is the cohesion of the spoil. Disaggregated spoil is deposited from a turbidity current in a thin annulus, aggregated or cohesive spoil, in a compact pile of discrete blocks or ‘clods’. Formation of a compact deposit of spoil requires that the clods survive impact with the bottom; their kinetic energy must be absorbed in plastic deformation without clod rupture. The impact speed and the kinetic energy density are calculated for free fall of clods in water. Laboratory measurements are made of the deformation-rate dependence of the mechanical work done to rupture clods of silt-clay marine sediment in impact. These show that plastic deformation will dissipate the impact energy for clods less than 0·8 m in diameter; larger clods will break up upon impact. Field observations confirm the presence of clods smaller than this in deposits of cohesive spoil. The disposal processes responsible for the formation of spoil deposits are insensitive to the water depth and current speed. A compact spoil deposit is most likely to result when cohesive sediment is dredged with a clam shell bucket and released in small quantities at low speed over a soft-bottomed disposal area.</p></div>","PeriodicalId":100492,"journal":{"name":"Estuarine and Coastal Marine Science","volume":"10 3","pages":"Pages 289-303, IN1-IN2"},"PeriodicalIF":0.0,"publicationDate":"1980-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-3524(80)80102-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72277661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Daily, seasonal, and annual fluctuations among zooplankton populations in an unpolluted tropical embayment","authors":"Marsh J. Youngbluth","doi":"10.1016/S0302-3524(80)80101-0","DOIUrl":"10.1016/S0302-3524(80)80101-0","url":null,"abstract":"<div><p>During 1973–74 biweekly collections of zooplankton in Jobos Bay, Puerto Rico revealed that major differences in the abundance and variety of several populations were related to water circulation, seasonal rainfall, and diel behavior. Total densities of zooplankton ranged from 225 to 9050/m<sup>3</sup> for night and 30 to 4700/m<sup>3</sup> for day samples. Abundance levels increased about twofold from coastal to isolated regions of the bay but at least twice as many species occurred in the coastal areas. Rapid, short-term changes in abundance, pulses of about one order of magnitude, occurred shortly before and during the wet season. Diel differences in density, most notable among the copepod, <em>Acartia tonsa</em>, coincided with a seasonal increase in abundance.</p><p>The size and composition of the zooplankton communities in Jobos Bay were similar to those found in one polluted, tropical embayment (Guayanilla Bay, Puerto Rico) but differed greatly from those described in another (Kingston Harbour, Jamaica).</p></div>","PeriodicalId":100492,"journal":{"name":"Estuarine and Coastal Marine Science","volume":"10 3","pages":"Pages 265-287"},"PeriodicalIF":0.0,"publicationDate":"1980-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-3524(80)80101-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79562183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amanda Wilding, Michael Collins, George Ferentinos
{"title":"Analyses of sea level fluctuations in Thermaicos Gulf and Salonica Bay, northwestern Aegean Sea","authors":"Amanda Wilding, Michael Collins, George Ferentinos","doi":"10.1016/S0302-3524(80)80105-8","DOIUrl":"https://doi.org/10.1016/S0302-3524(80)80105-8","url":null,"abstract":"<div><p>Short period (2·4 to 2·7 h) and long period (several days) oscillations of non-tidal origin have been identified in the analysis of a short series of sea level records from stations in Salonica Bay and Thermaicos Gulf.</p><p>Oscillations of short period can be attributed to seiche-like motions; those of long period correspond with variations in barometric pressure. The harmonic constituents are generally indicative of a standing tidal wave over the whole of the area.</p></div>","PeriodicalId":100492,"journal":{"name":"Estuarine and Coastal Marine Science","volume":"10 3","pages":"Pages 325-334"},"PeriodicalIF":0.0,"publicationDate":"1980-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-3524(80)80105-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72277662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effects of moderate sewage input on benthic polychaete populations","authors":"Daniel M. Dauer, William G. Conner","doi":"10.1016/S0302-3524(80)80106-X","DOIUrl":"10.1016/S0302-3524(80)80106-X","url":null,"abstract":"<div><p>The polychaete fauna of a sandy intertidal habitat receiving effluent from a sewage treatment plant was compared to that of a control site. The total number of individuals, total biomass, and average species numbers were significantly greater at the sewage-affected site. The response of individual species to nutrient enrichment varied. Some species showed significantly greater numbers of individuals at the sewage-affected site while other species' densities showed no difference. All species maintained greater biomass at the enriched site, most biomass differences were significant. Those species which did not show density differences between sites tended to have the greatest difference in average weight per individual. In general, species with either benthic development or some form of brooding behavior were best able to exploit the enriched condition by increased densities, or greater average biomass per individual. It was concluded that for moderate increases in nutrient concentrations, benthic productivity will be most enhanced in those sediments with very low concentrations of fine sized particles.</p></div>","PeriodicalId":100492,"journal":{"name":"Estuarine and Coastal Marine Science","volume":"10 3","pages":"Pages 335-346"},"PeriodicalIF":0.0,"publicationDate":"1980-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-3524(80)80106-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72581613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}