Optical Satellite Remote Sensing of the Coastal Zone Environment — An Overview

Optical remote-sensing data are a powerful source of information for monitoring the coastal environment. Due to the high complexity of coastal environments, where different natural and anthropogenic phenomenon interact, the selection of the most appropriate sensor(s) is related to the applications required, and the different types of resolutions available (spatial, spectral, radiometric, and temporal) need to be considered. The development of specific techniques and tools based on the processing of optical satellite images makes possible the production of information useful for coastal environment management, without any destructive impacts. This chapter will highlight different subjects related to coastal environments: shoreline change detection, ocean color, water quality, river plumes, coral reef, alga bloom, bathymetry, wetland mapping, and coastal hazards/vulnerability. The main objective of this chapter is not an exhaustive description of the image processing methods/algorithms employed in coastal environmental studies, but focus in the range of applications available. Several limitations were identified. The major challenge still is to have remote-sensing techniques adopted as a routine tool in assessment of change in the coastal zone. Continuing research is required into the techniques employed for assessing change in the coastal environment

Report on water quality data evaluation and program design services for the James and York rivers in conjunction with the 208 planning program for the Tidewater region of Virginia

The study area considered in this report includes the following: The James River from Fort Monroe to the mouth of the Chickahominy River (statute mile 45) including the small tributaries on the north shore but not the Chickahominy; the York River from its mouth to the confluence of the Mattaponi and Pamunkey at West Point (statute mile 33.5) including the small tributaries along the south shore; and the small drainage area adjacent to Chesapeake Bay lying between the York and James basins. The two rivers included in this basin are Poquoson River and Back River

Effects of oil pollution on the saltmarsh grass puccinellia martima (Huds.) parl.

Imperial Users onl

The utilisation of acid sulphate soils for shrimp (Penaeus monodon) culture on the west coast of Sri Lanka

Continued pressure on land resources for shrimp culture has resulted in many shrimp culture developments on acid sulphate soils in South East Asia which are marginal or difficult to manage. The present study included a survey to identify and classify different acid sulphate and potential acid sulphate soils in the areas earmarked for shrimp culture on the West Coast of Sri Lanka. This was supported by on farm investigations into the behavior and kinetics of metals in culture ponds, time series studies on water and soil quality over a culture cycle, plus morphological and histopathological changes in cultured shrimps and monitoring of calcium and magnesium contents in selected tissues. Although the general environment and water quality criteria in the study areas provided promising conditions for culture of Penaeus monodon, survival (35.1%) and production (1240 kg/ha/ crop) wore found to be significantly lower on acid sulphate soils than that on neutral soils. The stability of metals, particularly that of Iron, which is governed by the redox potential-pH relationships of the pond environment, appears to play a significant role in the processes that increase the potential stress to the shrimps cultured in an acid sulphate environment. Under acid sulphate conditions, shrimps showed elevated levels of iron (119.9 pg/g dry wt) and manganese (38.4 pg/g dry wt) in their muscles and unusually high levels of these heavy metals were recorded in gills (1588 and 93.2 pg/g dry wt of iron and manganese respectively) and carapace (778 and 34 pg/g dry wt of iron and manganese respectively) during the latter part of the culture period. Calcium levels in the carapace were relatively low (136 to 260 mg/ g dry wt) throughout the culture period and showed a negative correlation with culture time (r - -0.950; p - .001). Accumulation of hydrated oxides of iron in gills as a result of oxidation of pyrites was confirmed by the Eh-pH relationships monitored in the pond environment and by histochemical, SEM and TEM studies. These insoluble oxides appear to be primarily responsible for gill colour changes and concomitant histological changes in giil, heart and hepatopancreatic tissues. They are clearly detrimental to the normal gill functions of cultured shrimps. Statistically significant correlations were observed between iron in shrimp gills and muscles with iron in the surface sediments (p -.004 and .010 respectively) and the culture period (p >.013 and .010 respectively). Manganese in gills and carapace of cultured shrimps was correlated to the Iron concentration in those tissues (p >.016 and .002 respectively). Traditional management strategies (drying the pond bottom, liming and artificial aeration) although creating promising conditions for shrimp culture under favourable soil conditions, create adverse conditions by favouring the formation of iron (III) oxides in F>onds on acid sulphate soils. Detailed studies on mapping, classification and identification of profile forms in coastal soils provided vital information necessary for land use planning and development of these sediments in shrimp culture. Development of soil classes; sulphidic sand, unripe sulphidic peat, unripe sulphidic muck, acid sulphate muck, raw acid sulphate muck and raw acid sulphate clay have the most serious implications on cultured shrimps and the environment. Ripe clay with sulphidic subsoil, ripe clay with raw acid sulphate sub-soil, half ripe clay with acid sulphate subsoil and sand with acid sulphate sub- soil appear to be the least harmful soil classes for shrimp culture among the sediment types investigated

National Centers for Coastal Ocean Science (NCCOS) research highlights in the Chesapeake Bay

The Chesapeake Bay is the largest estuary in the United States. It is a unique and valuable national treasure because of its ecological, recreational, economic and cultural benefits. The problems facing the Bay are well known and extensively documented, and are largely related to human uses of the watershed and resources within the Bay. Over the past several decades as the origins of the Chesapeake’s problems became clear, citizens groups and Federal, State, and local governments have entered into agreements and worked together to restore the Bay’s productivity and ecological health. In May 2010, President Barack Obama signed Executive Order number 13508 that tasked a team of Federal agencies to develop a way forward in the protection and restoration of the Chesapeake watershed. Success of both State and Federal efforts will depend on having relevant, sound information regarding the ecology and function of the system as the basis of management and decision making. In response to the executive order, the National Oceanic and Atmospheric Administration’s National Centers for Coastal Ocean Science (NCCOS) has compiled an overview of its research in Chesapeake Bay watershed. NCCOS has a long history of Chesapeake Bay research, investigating the causes and consequences of changes throughout the watershed’s ecosystems. This document presents a cross section of research results that have advanced the understanding of the structure and function of the Chesapeake and enabled the accurate and timely prediction of events with the potential to impact both human communities and ecosystems. There are three main focus areas: changes in land use patterns in the watershed and the related impacts on contaminant and pathogen distribution and concentrations; nutrient inputs and algal bloom events; and habitat use and life history patterns of species in the watershed. Land use changes in the Chesapeake Bay watershed have dramatically changed how the system functions. A comparison of several subsystems within the Bay drainages has shown that water quality is directly related to land use and how the land use affects ecosystem health of the rivers and streams that enter the Chesapeake Bay. Across the Chesapeake as a whole, the rivers that drain developed areas, such as the Potomac and James rivers, tend to have much more highly contaminated sediments than does the mainstem of the Bay itself. In addition to what might be considered traditional contaminants, such as hydrocarbons, new contaminants are appearing in measurable amounts. At fourteen sites studied in the Bay, thirteen different pharmaceuticals were detected. The impact of pharmaceuticals on organisms and the people who eat them is still unknown. The effects of water borne infections on people and marine life are known, however, and the exposure to certain bacteria is a significant health risk. A model is now available that predicts the likelihood of occurrence of a strain of bacteria known as Vibrio vulnificus throughout Bay waters

MICROBIALLY-MEDIATED METHYL IODIDE CYCLING IN A PARTICLE-RICH ESTUARY

The dynamics of aquatic systems (e.g. estuarine systems) are known to facilitate the formation of particle aggregates. These nutrient-rich particulate matter provide suitable substrate for bacteria colonization. Although bacteria-aggregate association is known to result in the degradation of particulate organic matter (POM) in aquatic systems, it has never been attributed to the production of methyl iodide (CH3I) (an environmentally important biogas that has the potential to impact on atmospheric chemistry). From literature, there are evidences which suggest that, certain bacteria (methylotrophs) are capable of oxidizing methyl halides including CH3I. Therefore this study investigates microbial production and removal of CH3I in estuarine water through their association with aggregates and assesses the effect of physicochemical variables on bacterial-mediated production and removal of CH3I. From the study, bacteria-aggregate processes were found to elevate the concentration of CH3I between 15-22% of the total observed CH3I concentration over the study period. Aggregate-attached bacteria which were estimated to represent about 17% of the total bacteria population were responsible for about 37% of the overall bacterial activity. To investigate bacterial-mediated removal of CH3I in estuarine systems, a reliable and reproducible method through adaptations and modifications of existing methods was developed. This method involved the use of [14C] radiolabelled CH3I to estimate bacterial utilization of CH3I. The application of the method confirmed the removal of CH3I by methylotrophs in estuarine water with the total recorded amount in bacterial cells and oxidized C02 ranging between 9.3 - 24.5% (depending on the amount of the added substrate). However, this could only represent the potential microbial CH3I removal in the natural aquatic environment. An investigation into spatial and temporal trends in bacterial-mediated removal of CH3I in the Tamar estuary revealed no significant spatial variation but rather a strong seasonality in methylotrophic bacterial CH3I removal. Spatial trends in CH3I removal was found to be mostly influenced by temperature, bacterial abundance and dissolved oxygen concentration whilst the seasonality in the estuary was influenced by temperature, bacterial abundance, suspended particulate matter (SPM) and CH3I concentration. Temperature was identified to be the single most influential physicochemical variable on both spatial and seasonal variation in bacterial CH3I removal in the Tamar estuary. CH3I concentration along the Tamar estuary was also investigated and using this data the total water to air flux of CH3I over the estuary was estimated to be 0.31 x 10³ g yˉ¹. From this study, it was apparent that bacteria activity in estuarine systems is potentially an important source of CH3I in the aquatic environment when associated with aggregates or as sink of CH3I through methylotrophic activity in estuaries.Plymouth Marine Laborator

Demographics, production, and benthic -pelagic coupling by the suspension feeding polychaete Chaetopterus pergamentaceus in the lower Chesapeake Bay

For many shallow water environments, ecosystem function depends on the cycling and flow of materials and energy between benthic and pelagic subsystems. Benthic suspension feeders often are important links between the water column and sediment in coastal ecosystems. Populations of the suspension feeding polychaete Chaetopterus pergamentaceus (previously reported as Chaetopterus variopedatus) are widely distributed along the United States East Coast, ranging from New England to Florida. This species is a structurally and functionally important member of the lower Chesapeake Bay benthic community, where it has maintained stable populations for at least the last 15 years. Little is known regarding the dynamics of this population and its role in benthic-pelagic coupling. For this study, I elucidated demographics, identified the organic matter sources fueling growth and production, determined the in situ behavior, rates and allometry of filtration, and developed an energy budget for this polychaete within the lower Chesapeake Bay estuary. Chaetopterus pergamentaceus exhibited high seasonal and interannual variability in growth, reproduction, and secondary production. High secondary production was mainly due to the rapid growth and maturation of new recruits during summer. Highly variable interannual production was due to inconsistency in recruitment success. Spatial variations in population processes, concordant with major environmental gradients, may influence the population dynamics. Locally produced organic matter, primarily fresh phytoplankton and secondarily recycled material from microbial sources with minimal to no terrestrial input, was utilized for growth and reproduction. Chaetopterus pergamentaceus has a filtration rate comparable to oysters and has the potential to transfer large quantities of matter from the water column to the benthos. This polychaete may filter a large portion of, or an amount equivalent to, the net water column community production on an annual basis. When considered on a daily basis, the potential carbon flux may be greater than net community production. Thus, this organism plays an important role in benthic-pelagic coupling in the lower Chesapeake Bay

The past and present limnology of the Soetendalsvlei wetlands, Agulhas coast, South Africa

As climatic conditions continue to change globally, there is a need to assess past environmental change in relation to changing water balance, temperature and sea-level. By understanding the extent of past environmental change, and how anthropogenic impacts have affected ecosystems, better and more accurate future predictions of change can be made. Through the use of the sedimentary record within coastal wetlands, geochemical, (organic content and stable isotopes) and biological (diatoms) proxies were utilised to determine; (i) the baseline water quality record for Soetendalsvlei, one of only a few coastal lakes in South Africa, (ii) the effect of agriculture and mouth manipulation of the Heuningnes Estuary on the microalgae ecology and (iii) the link between palaeo-salinity and trophic status on a regional basis between Soetendalsvlei and Groenvlei, situated 320 km apart. Present water quality and phytoplankton biomass and community structure were assessed for Soetendalsvlei and its associated wetlands, Voëlvlei and Waskraalsvlei to determine the current health of these systems and to obtain modern diatom analogues to be used in the palaeolimnological reconstruction of the coastal lake. Diatoms were not dominant during this study period. Chlorophytes and flagellates were the dominant phytoplankton groups throughout the different wetlands. With the exception of Voëlvlei, the wetlands were all in good health, although SRP concentrations were within the eutrophic to hypertrophic range and are cause for concern. In Voëlvlei, phytoplankton biomass was within the eutrophic range with chlorophyll a concentrations ranging between 20 – 400 ug.l-1 Cyanobacteria, a further indicator of eutrophic conditions, were dominant during the warmer summer periods. Rainfall and freshwater inflow had a significant effect on the biomass and composition of the phytoplankton and acted as a resetting mechanism for all the wetlands as water quality conditions improved thereafter. Comparisons of the water quality and phytoplankton community between the upper reaches of the Heuningnes Estuary and Soetendalsvlei, indicated that artificial breaching of the estuary mouth significantly impacted the connectivity between these two systems, with marine intrusion extending into the upper reaches, while freshwater conditions dominate in the coastal lake. Unfortunately for the palaeolimnological study diatom preservation was poor, however, geochemistry and stable isotope analyses did provide adequate evidence of marine transgression (~8000 yr BP and 4000-2000 yr BP) and regression events comparable to other South African sea-level models developed for the east and west coast. High organic matter content (i.e. higher trophic state) and estuarine POC (C4 vegetation) were associated with periods of marine regression, i.e. increased freshwater, whereas marine transgression events were associated with low organic content and marine POC and DOC. This is comparable to studies conducted in Uruguay (South America) where palaeo-salinity was related to trophic status, i.e. increased freshwater input was associated with high nutrients. Comparisons of the palaeo-record with recorded historical occurrences of droughts and floods, also provided a means of assessing the sedimentary record and to infer anthropogenic impacts after 1850 AD. Overall it can be concluded that coastal lakes of both continents in the Southern Hemisphere displayed similar trophic responses to sea-level fluctuations during the Holocene. This adds valuable information to global sea-level change models