Utilization of nitrogen and carbon by phytoplankton in Moreton Bay, Australia

2000 ◽  
Vol 51 (7) ◽  
pp. 703 ◽  
Author(s):  
M. J. O'Donohue ◽  
P. M. Glibert ◽  
W. C. Dennison
Keyword(s):  
Water Temperature ◽  
Coastal Waters ◽  
Inorganic Nitrogen ◽  
Spatial Scales ◽  
Co2 Uptake ◽  
Phytoplankton Productivity ◽  
Moreton Bay ◽  
Uptake Rates ◽  
Temporal And Spatial ◽  
River Mouths

Water samples were collected within river mouths, at river plume sites and at well flushed ocean-influenced sites within Moreton Bay, a shallow subtropical embayment in south-eastern Queensland. Rates of inorganic nitrogen (NH+4 and NO-3) and carbon uptake were determined across temporal and spatial scales by use of 15N and 14C incorporation. Phytoplankton productivity, measured as CO2 uptake, was highest at the river mouths. Rates of NH+4 uptake exceeded rates of NO-3 uptake at all sites at all times. Relative preference indices demonstrated a consistent preference by phytoplankton for NH+4 uptake, and NH+4 uptake rates were higher at ocean-influenced sites than at river-mouth sites. Inorganic nutrient and chlorophyll a concentrations were highest at river mouths; however, the greatest NH+4 uptake occurred at the ocean-influenced sites, reflecting a greater dependence on ‘recycled’ N than on ‘new’ N. Biomass-independent NH+4 uptake increased with increasing water temperature; however, NO-3 uptake increased with decreasing water temperature, reflecting the lower temperature optimum for nitrate reductase. The range of NH+4 and NO-3 uptake rates was greater than ranges reported for other coastal waters, reflecting the strong temporal and spatial gradients within Moreton Bay. This trend of strong gradients in C and N dynamics from oligotrophic to river-influenced waters with seasonal flows is likely to exist in many tropical and subtropical coastal waters of Australia.

Verification of a conceptual model of water quality for small temporarily open/closed estuaries: East Kleinemonde Estuary, South Africa

2009 ◽  
Vol 60 (3) ◽  
pp. 234 ◽  
Author(s):  
Susan Taljaard ◽  
Gavin Snow ◽  
Phumelele Gama ◽  
Lara van Niekerk
Keyword(s):  
South Africa ◽  
Water Quality ◽  
Conceptual Model ◽  
Complex Dynamics ◽  
Inorganic Nitrogen ◽  
Spatial Scales ◽  
Chemical Parameters ◽  
Physico Chemical ◽  
Temporal And Spatial ◽  
Warm Temperate

The dynamics of the world’s larger permanently open estuaries have been well documented, but much less is known about the complex dynamics of smaller temporarily open/closed estuaries (TOCEs). Seventy per cent of South Africa’s 250 estuaries are classified as TOCEs, and many are less than 50 ha. A conceptual model of the water-quality dynamics of TOCEs has been proposed, primarily considering three hydrodynamic states (closed, semi-closed and open). This paper uses data from the East Kleinemonde Estuary, a small TOCE in the warm-temperate region of South Africa, to verify the model, focusing on physico-chemical parameters (salinity, temperature, pH, dissolved oxygen and turbidity) and inorganic macronutrients (dissolved inorganic nitrogen and dissolved inorganic phosphate) for the open and closed states. The results generally fitted the model in terms of the behaviour of the physico-chemical parameters and macronutrients in the water column. This knowledge provides a first approach to predict the water-quality dynamics in small TOCEs, thereby ensuring that the often limited resources are targeted at resolving uncertainties at appropriate temporal and spatial scales. TOCEs are not unique to South Africa and also occur along other coasts (Mediterranean and south-western Australia) where this type of model could also be applied.

scholarly journals Temporal and Spatial Distribution of the Toxic Epiphytic Dinoflagellate Ostreopsis cf. ovata in the Coastal Waters off Jeju Island, Korea

2020 ◽  
Vol 12 (14) ◽  
pp. 5864
Author(s):  
Jaeyeon Park ◽  
Jinik Hwang ◽  
Jun-Ho Hyung ◽  
Eun Young Yoon
Keyword(s):  
Spatial Distribution ◽  
Water Temperature ◽  
Coastal Waters ◽  
Microscopic Analysis ◽  
Jeju Island ◽  
Northern Coast ◽  
Temporal And Spatial Distribution ◽  
Chain Reactions ◽  
Polymerase Chain Reactions ◽  
Temporal And Spatial

The temporal and spatial distribution of the toxic epiphytic dinoflagellate Ostreopsis cf. ovata was investigated off the Jeju coastal waters, Korea, from July 2016 to January 2019. The results showed that the presence of Ostreopsis cf. ovata in 184 macroalgae was 79.3%, and it was more frequently attached to red algae and brown algae than to green algae. The abundance of Ostreopsis cf. ovata as determined by quantitative real-time polymerase chain reactions (qPCR) and microscopic analysis was 4–3204 cells g−1, and the maximum abundance observed in September 2018, when the water temperature was 24.4 °C. The abundance was higher in summer and autumn than in spring and winter. Spatially, high abundance was observed in autumn on the northern coast of Jeju Island and, in summer, in the southern and eastern coastal waters. The water temperature of Jeju coastal waters in winter remained higher than 15 °C, and this species could be overwintering in the Jeju waters. Therefore, further monitoring and research are needed to evaluate the proliferation of Ostreopsis cf. ovata, which contains a novel toxin with unidentified effects on humans.

High air–sea CO2 uptake rates in nearshore and shelf areas of Southern Greenland: Temporal and spatial variability

2012 ◽  
Vol 128-129 ◽  
pp. 26-33 ◽  
Author(s):  
S. Rysgaard ◽  
J. Mortensen ◽  
T. Juul-Pedersen ◽  
L.L. Sørensen ◽  
K. Lennert ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Co2 Uptake ◽  
Temporal And Spatial Variability ◽  
Uptake Rates ◽  
Temporal And Spatial

Temporal and spatial scales of water temperature variability as an indicator for mixing in a polymictic lake

Inland Waters ◽  
2018 ◽  
Vol 8 (1) ◽  
pp. 82-95 ◽  
Author(s):  
Silke R. Schmidt ◽  
Dieter Gerten ◽  
Thomas Hintze ◽  
Gunnar Lischeid ◽  
David M. Livingstone ◽  
...  
Keyword(s):  
Water Temperature ◽  
Spatial Scales ◽  
Temperature Variability ◽  
Temporal And Spatial ◽  
Polymictic Lake

WAVE CLIMATE OF THE BLACK SEA’S COASTAL WATERS DURING THE LAST THREE DECADES

2017 ◽  
Author(s):  
Fedor Gippius ◽  
Fedor Gippius ◽  
Stanislav Myslenkov ◽  
Stanislav Myslenkov ◽  
Elena Stoliarova ◽  
...  
Keyword(s):  
Wind Speed ◽  
Cell Size ◽  
Coastal Waters ◽  
Wind Wave ◽  
Spatial Scales ◽  
Wave Model ◽  
Wave Climate ◽  
Computational Grid ◽  
Coastal Areas ◽  
Wave Parameters

This study is focused on the alterations and typical features of the wind wave climate of the Black Sea’s coastal waters since 1979 till nowadays. Wind wave parameters were calculated by means of the 3rd-generation numerical spectral wind wave model SWAN, which is widely used on various spatial scales – both coastal waters and open seas. Data on wind speed and direction from the NCEP CFSR reanalysis were used as forcing. The computations were performed on an unstructured computational grid with cell size depending on the distance from the shoreline. Modeling results were applied to evaluate the main characteristics of the wind wave in various coastal areas of the sea.

Larval Feeding: Mechanisms, Rates, and Performance in Nature

2018 ◽  
Keyword(s):  
Marine Invertebrates ◽  
Spatial Scales ◽  
Size Spectrum ◽  
Larval Feeding ◽  
Natural Habitats ◽  
Feeding Mechanism ◽  
Temporal And Spatial ◽  
And Performance ◽  
Bioenergetics Models ◽  
Many Particles

Larvae of many marine invertebrates must capture and ingest particulate food in order to develop to metamorphosis. These larvae use only a few physical processes to capture particles, but implement these processes using diverse morphologies and behaviors. Detailed understanding of larval feeding mechanism permits investigators to make predictions about feeding performance, including the size spectrum of particles larvae can capture and the rates at which they can capture them. In nature, larvae are immersed in complex mixtures of edible particles of varying size, density, flavor, and nutritional quality, as well as many particles that are too large to ingest. Concentrations of all of these components vary on fine temporal and spatial scales. Mechanistic models linking larval feeding mechanism to performance can be combined with data on food availability in nature and integrated into broader bioenergetics models to yield increased understanding of the biology of larvae in complex natural habitats.

Humans and the Environment

2013 ◽  
Keyword(s):  
Spatial Scales ◽  
Empirical Studies ◽  
Human Action ◽  
Cultural Practice ◽  
Environmental Archaeology ◽  
Archaeological Data ◽  
Temporal And Spatial ◽  
Global And Local ◽  
The Relationship ◽  
The Way

The environment has always been a central concept for archaeologists and, although it has been conceived in many ways, its role in archaeological explanation has fluctuated from a mere backdrop to human action, to a primary factor in the understanding of society and social change. Archaeology also has a unique position as its base of interest places it temporally between geological and ethnographic timescales, spatially between global and local dimensions, and epistemologically between empirical studies of environmental change and more heuristic studies of cultural practice. Drawing on data from across the globe at a variety of temporal and spatial scales, this volume resituates the way in which archaeologists use and apply the concept of the environment. Each chapter critically explores the potential for archaeological data and practice to contribute to modern environmental issues, including problems of climate change and environmental degradation. Overall the volume covers four basic themes: archaeological approaches to the way in which both scientists and locals conceive of the relationship between humans and their environment, applied environmental archaeology, the archaeology of disaster, and new interdisciplinary directions.The volume will be of interest to students and established archaeologists, as well as practitioners from a range of applied disciplines.

scholarly journals On the generation of internal waves by river plumes in subcritical initial conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. Mendes ◽  
J. C. B. da Silva ◽  
J. M. Magalhaes ◽  
B. St-Denis ◽  
D. Bourgault ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Internal Waves ◽  
Coastal Waters ◽  
Initial Conditions ◽  
Spatial Scales ◽  
River Plumes ◽  
Wide Range ◽  
Near Shore ◽  
Generation Mechanisms ◽  
Douro River

AbstractInternal waves (IWs) in the ocean span across a wide range of time and spatial scales and are now acknowledged as important sources of turbulence and mixing, with the largest observations having 200 m in amplitude and vertical velocities close to 0.5 m s−1. Their origin is mostly tidal, but an increasing number of non-tidal generation mechanisms have also been observed. For instance, river plumes provide horizontally propagating density fronts, which were observed to generate IWs when transitioning from supercritical to subcritical flow. In this study, satellite imagery and autonomous underwater measurements are combined with numerical modeling to investigate IW generation from an initial subcritical density front originating at the Douro River plume (western Iberian coast). These unprecedented results may have important implications in near-shore dynamics since that suggest that rivers of moderate flow may play an important role in IW generation between fresh riverine and coastal waters.

Sign in / Sign up

Export Citation Format

Share Document