Search results for "Estuary"

Geomorphological evolution of the River Loukkos estuary around the Phoenician city of Lixus on the Atlantic Littoral of Morocco

2009

The ancient city of Lixus, today situated on a hill on the right bank of the River Loukkos, 4km from the coast, was founded on the shore of a brackish lagoon that was sheltered from Atlantic storms. This geographical context provided the city with one of the best Phoenician harbors and abundant fishing resources, and allowed access to the Gharb cattle farming resources and cereal production systems. In this study, the historical evolution of the Loukkos estuarine environment is reconstructed through geomorphological and sedimentological analyses, combined with cartographic, archaeological, and geographical data. The outcomes reveal the progressive infilling of the estuarine lagoon of Lixus …

Controls on strontium and barium incorporation into freshwater bivalve shells ( Corbicula fluminea )

2017

Abstract Trace elements of bivalve shells can potentially serve as proxies of environmental change. However, to reconstruct past environments using the geochemical properties of the shells and determine the degree to which the element levels are biologically influenced, it is essential to experimentally determine the relationship between environmental variables and the element composition of the shells. To disentangle possible controls on the incorporation of strontium and barium into freshwater bivalve shells, we conducted controlled laboratory experiments using the extremely salinity and temperature tolerant Asian clam, Corbicula fluminea as a model species. Bivalves were reared for five …

Epidemiology of tattoo skin disease in bottlenose dolphins Tursiops truncatus from the Sado estuary, Portugal

2003

We report on the epidemiology of tattoo disease in a community of bottlenose dolphins Tursiops truncatus from the Sado estuary, Portugal. The presence of tattoos (T++) and tattoo-like (T+) lesions was examined in 586 photographic records of 35 dolphins taken from 1994 to 1997. Images were rated into 3 categories: good (GI), average (AI) and poor (PI). Dolphins positive for T++ lesions were observed in 19 GI. Dolphins with T+ lesions were seen in 39 GI, 23 AI and 6 PI. For statistical analysis the dolphins were divided into 2 age classes (immature and adult) and the data grouped into 2 periods (1994-1995 and 1996-1997). Minimum prevalence of T++ lesions in 32 dolphins was 21.9% in 1994-1995 …

Individual habitat transitions of Atlantic herring Clupea harengus in a human-modified coastal system

2015

Published version of an article from the journal: Marine Ecology Progress Series. Also available from Inter Research. Http://dx.doi.org/10.3354/meps11103 Pelagic marine fish often display highly dynamic migration patterns. However, such movement behaviour is usually studied at the population or school level, while less is known about individual movement characteristics and habitat transitions. During March 2012 to June 2013, we used acoustic tags and moored receivers to monitor the behaviour of Atlantic herring Clupea harengus L. (N = 47) throughout a range of habitats on the Skagerrak coast in southern Norway. Five of the tagged herring entered a former lake transformed into an artificial …

Changes to processes in estuaries and coastal waters due to intense multiple pressures:an introduction and synthesis

2015

From the 2013 ECSA conference ‘Estuaries and Coastal Areas in Times of Intense Change’ a theme emerged that has ended up being the focus of this Special Issue of Estuarine Coastal and Shelf Science, namely ‘Changes to processes in estuaries and coastal waters due to intense multiple pressures’. Manyparts of the world are continuing to experience unprecedented rates of economic growth, and those responsible for managing coastal and estuarine areas must respond accordingly. At the same time, global climate change and sea level rise are also continuing, placing new or more intense pressures on coastal areas that must be dealt with in ways that are as far as possible managed as a result of good…

Sedimentation in a fluvially infilling, barrier-bound estuary on a wave-dominated, microtidal coast: the Oueme River estuary, Benin, west Africa

2002

The Oueme River estuary is located on the seasonally humid tropical coast of Benin, west Africa. A striking feature of this microtidal estuary is the presence of a large sand barrier bounding a 120 km2 circular central basin, Lake Nokoue, that is being infilled by heterogeneous fluvial deposits supplied by a relatively large catchment (50 000 km2). Borehole cores from the lower estuary show basal Pleistocene lowstand alluvial sediments overlain by Holocene transgressive–highstand lagoonal mud and by transgressive to probably early highstand tidal inlet and flood-tidal delta sand deposited in association with non-preserved transgressive sand barriers. The change in estuary-mouth sedimentatio…

Sedimentation in a tropical, microtidal, wave-dominated coastal-plain estuary

1996

The Mono estuary is an infilled, microtidal estuary located on the wave-dominated Bight of Benin coast which is subject to very strong eastward longshore drift. The estuarine fill comprises a thick unit of lagoonal mud deposited in a ‘central basin’between upland fluvial deposits and estuary-mouth wave-tide deposits. This lagoonal fill is capped by organic-rich tidal flat mud. In addition to tidal flat mud, the superficial facies overlying the ‘central basin’fill include remnants of spits resting on transgressive/washover sand, an estuary-mouth association of beach, shoreface, flood-tidal delta and tidal inlet deposits, and a thin sheet of fluvial sediments deposited over tidal flat mud. Af…

Emergence of the epibiotic barnacle Xenobalanus globicipitis in Guiana dolphins after a morbillivirus outbreak in Sepetiba Bay, Brazil

2021

Abstract We report on the emergence of the epibiotic barnacle Xenobalanus globicipitis in Guiana dolphins (Sotalia guianensis) from Sepetiba Bay, Rio de Janeiro, Brazil, in September 2018, six months after a lethal morbillivirus epidemic. Small boat surveys were conducted at the entrance and in the interior of the bay from January 2018 to February 2021. Dolphins were photo-identified and classified according to overall spatial use of the Bay. We examined the potential influence of the period and habitat on the prevalence of X. globicipitis. The overall prevalence of the barnacle was 38.7% in 214 dolphins. X. globicipitis was not observed in 99 individually identified dolphins from January t…

The effect of variation in developmental mode on the population dynamics of a spionid polychaete (Pygospio elegans) in a heterogeneous environment

2018

Autochthonous organic matter promotes DNRA and suppresses N2O production in sediments of the coastal Baltic Sea

2021

Coastal environments are nitrogen (N) removal hot spots, which regulate the amount of land-derived N reaching the open sea. However, mixing between freshwater and seawater creates gradients of inorganic N and bioavailable organic matter, which affect N cycling. In this study, we compare nitrate reduction processes between estuary and offshore archipelago environments in the coastal Baltic Sea. Denitrification rates were similar in both environments, despite lower nitrate and carbon concentrations in the offshore archipelago. However, DNRA (dissimilatory nitrate reduction to ammonium) rates were higher at the offshore archipelago stations, with a higher proportion of autochthonous carbon. Th…