Adnan Al-Azri

Ocean urea fertilization for carbon credits poses high ecological risks

The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to the deep sea are classically leaky, and the inefficient burial of new biomass makes the estimation of a net loss of carbon from the atmosphere questionable at best. The potential for growth of toxic dinoflagellates is also high, as many grow well on urea and some even increase their toxicity when grown on urea. Many toxic dinoflagellates form cysts which can settle to the sediment and germinate in subsequent years, forming new blooms even without further fertilization. If large-scale blooms do occur, it is likely that they will contribute to hypoxia in the bottom waters upon decomposition. Lastly, urea production requires fossil fuel usage, further limiting the potential for net carbon sequestration. The environmental and economic impacts are potentially great and need to be rigorously assessed.

Seasonal and interannual variability of chlorophyll-a in the Gulf of Oman compared to the open Arabian Sea regions

Field sampling, remote sensing and modelling were employed to understand the seasonal and interannual changes of chlorophyll-a concentrations in the Gulf of Oman in comparison to open sea regions. In these regions, maximal chlorophyll concentrations were reported during the summer monsoon (with peaks in June and August), while in the Gulf of Oman, the chlorophyll maximum was observed during the winter monsoon (February–March). From 1997 through to 2008, the interannual variability in chlorophyll-a concentrations in the Gulf of Oman has not exhibited pronounced trends and neither have the other two (oceanic) regions in the western Arabian Sea. However, an increase of the annual variation in chlorophyll concentrations over the years was noticed. The diatom biomass decreased two-fold from 1997 to 2007. Nitrate concentration and mixed-layer depth also declined. In comparison to the seasonal blooms driven in the Gulf of Oman by the dinoflagellate Noctiluca scintillans, the year 2008 was markedly different. The summer bloom was shifted to September; it was gradually extended in time and formed by the other species. An applicability of the concept of ecosystem regime shift is discussed.

Interannual Changes in the Sea of Oman Ecosystem

Historical data were used to estimate interannual tendencies for the Sea of Oman over the past 50 years. Declining trends were shown for the atmospheric surface level pressure in the region affected by the Siberian High atmospheric anomaly, the zonal component of wind speed, concentration of nitrates, biomass of diatoms and sardine landings. Changes in Zooplankton biomass showed no clear trend. These trends were associated with and accompanied by rising atmospheric temperature, sea surface temperature, annual variability of the kinetic energy of mesoscale eddies, frequency of fish kills (along with the death of other animals- dolphins, turtles, and sea birds) and harmful algal bloom incidents. In terms of interannual coupling between physical and biological processes, the evaluated trends imply that the weakening of the Siberian High atmospheric anomaly results in the decline of the zonal wind speed and a regional increase of air temperature. This in turn increases the temperature in the mixed layer which strengthens thermo-haline stratification of the water column. Increasing stratification prevents the penetration of nutrients into the mixed layer and does not favor the interannual increase of biological productivity, although annual variation of biological productivity has increased, from 1997 to 2008.

Unusual Blooms of Green Noctiluca Miliaris (Dinophyceae) in the Arabian Sea During the Winter Monsoon

A large-scale, ongoing study conducted by the National Institute of Oceanography, India, from 2003 onward in support of Indias ocean color program, has documented for the first time ever the appearance of extensive blooms of Noctiluca miliaris Suriray in late winter and early spring for several consecutive years. Until the late 1990s, N. miliaris Suriray (synonym Noctiluca scintillans Macartney), a large dinoflagellate, was a minor component of phytoplankton populations in the Arabian Sea, appearing sporadically in bloom form in coastal regions during the summer southwest monsoon (June―September). Recently, N. miliaris blooms have begun to appear with increased frequency and intensity following the winter northeast monsoon (November―mid-February). These findings contradict established notions of the predominance of diatoms in winter blooms based on large-scale studies such as the Joint Global Ocean Flux Study (JGOFS) in the early 1990s and the International Indian Ocean Expeditions (IIOEs) of 1959―1965. A field program in the Gulf of Oman since February 2003 has also documented the appearance of blooms of N. miliaris blooms with increased intensity in early winter. The present study investigates the temporal evolution and spatial extent of the N miliaris blooms using phytoplankton taxonomic and pigment data from cruises undertaken in 2003― 2004 and 2007 as well as ocean color satellite data. Our findings indicate that N. miliaris blooms are becoming an annual and widespread feature in the Arabian Sea. Aqua-Moderate Resolution Imaging Spectroradiometer (MODIS) sea surface temperature and altimetry data suggest that mesoscale eddies that populate the western Arabian Sea may play a significant role in the production and dispersal of these blooms from the Gulf of Oman into the northern Arabian Sea.

Key Questions and Recent Research Advances on Harmful Algal Blooms in Relation to Nutrients and Eutrophication

The Core Research Project on HABs in Eutrophic Systems was one of the projects implemented under the Global Ecology and Oceanography of Harmful Algal Blooms (GEOHAB) program. Building on several Open Science Meetings and associated international efforts, this project focused on a number of key questions that related to the types of harmful algal species found in eutrophic systems, the drivers of nutrient changes and their effects, as well as interactions with community composition of all members of the food web. Substantial progress was made on all of the identified key questions and that progress is reviewed in this chapter. In all, the evidence is unequivocal that harmful algae can be directly and/or indirectly stimulated by nutrient over-enrichment and that chronic, subtle effects, such as changes in nutrient proportion or form, can be equally important or even more important than the obvious, acute effects. Furthermore, nutrient enrichment interacts with other major drivers, such as hydrology, food web interactions, and climate change, in both direct and indirect ways. Many questions remain, however. Much needs to be done in parameterizing rates, characterizing traits, and how they are both externally driven and internally dynamically regulated. Many species are understudied. Work needs to advance in understanding the physiological responses to excess nutrient availability and relationships with toxicity, among other physiological processes. A new emphasis on improved model formulations is needed, linking land-use models with regional ocean models and that incorporate dynamic physiological behavior. Given the pace at which nutrient loads continue to pollute the global landscape and the global expansion of HABs, continued international collaborative efforts in understanding changing nutrients and their relationships with HABs are not only necessary, but urgently needed.

The occurrence of algal blooms in Omani coastal waters

Monthly sampling of phytoplankton, chlorophyll a, temperature, salinity and nutrients was carried out in the Sea of Oman and in the Arabian Sea, from 2004 and onwards. In addition to time series data, historical data from 1976 to 2003 were collected from the Ministry of Agriculture and Fisheries Wealth reports. Annual averages of algal blooms occurrence along the coast of Oman showed three major components of seasonal and interannual fluctuations- the seasonal cycle, interannual fluctuations with approximate period of 8 years, and the interannual rising tendency. The dominant algal blooms species comprise both diatoms and dinoflagellates, with obvious dominance of Noctiluca scintillans followed by Cochlodinium polykrikoides and Prorocentrum sp.

Mesoscale eddies and variability of chlorophyll-a in the Sea of Oman

Satellite-derived (TOPEX/Poseidon, Jason-1, Jason-2, SeaWIFS (Sea-Viewing Wide Field-of-View Sensor) and MODIS (Moderate Resolution Imaging Spectroradiometer) Aqua) weekly and monthly products for sea surface height, sea surface temperature (SST) and chlorophyll-a (CHL) concentration were used to analyse the trends of physical–biological coupling. In the variability of chlorophyll, no interannual trends were found for the Sea of Oman (1997–2008). However, the variation of chlorophyll within the annual cycle has increased. A similar tendency was evaluated for the variability of the energy of mesoscale eddies. The median level of kinetic energy and the coefficient of variation of this energy within the annual cycle both increased from 1997 through 2008.

Influence of a Tropical Cyclone Gonu on Phytoplankton Biomass (Chlorophyll a) in the Arabian Sea

Tropical cyclones could gradually affect the physical, chemical, and biological processes in the upper layer of the ocean. In terms of biological consequences, the cyclone wind field causes local mixing which results in the injection of nutrients into the upper layer of the ocean and triggering phytoplankton bloom (Subrahmanyam et al. 2002). In some cases, the magnitude of the hurricane-induced bloom could reach a gradual (30-fold) increase in the surface chlorophyll a concentration, as well as an increase in the primary production (Lin et al. 2003; Smitha et al. 2006). In the regions where cyclones often occur, their propagation could chiefly influence the annual productivity of the ocean. For example, an average of 14 cyclones pass over the South China Sea annually, which suggests the contribution of cyclones to annual production to be as much as 20-30% (Lin et al. 2003).

Comparative evaluation of EIA systems in the Gulf Cooperation Council States

This review paper details the current status of environmental impact assessment (EIA) legislation framework and procedures of implementation of EIA systems in the Gulf Cooperation Council States. The paper discusses the similarities and the different practice approaches of EIA studies between the States through assessment criteria of EIA systems. Performance evaluation criteria consisting of systematic and foundation measures are used for comparative assessment. This paper hence, seeks to develop a compilation on these EIA systems with regard to its legislation, practices and performance in the respective countries. A set of recommendations on how such practices can be enhanced and improved is presented.

Recent Outbreaks of Harmful Algal Blooms Along the Coast of Oman: Possible Response to Climate Change?

The Sultanate of Oman has an extensive coastline of 3,615 km, which includes the Gulf of Oman (GOO) in the north and the Arabian Sea (NAS) in the south (Fig. 1). In comparison to the extensive research on phytoplankton productivity processes carried out in the offshore oceanic waters of the Arabian Sea during the International Joint Global Fluxes program (Wiggert et al. 2000; Smith 2001; Barber et al. 2001), phytoplankton variability in the coastal waters of Oman is poorly known. One of the limitations has been the lack of a dedicated program with systematic sampling along the coast at regular time intervals. Consequently, no information is available on plankton variability on an annual cycle. Based on the extensive array of investigations designed to observe the physical and biochemical processes in the Arabian sea, we can infer that physical-biological coupling in the coastal ecosystem of the GOO and NAS is largely driven by meteorological forcing, termed the monsoon, which manifests itself as strong, seasonally reversing winds (Wiggert et al. 2000). The two components of this annual cycle are referred to as the northeast monsoon (NEM) and the southwest monsoon (SWM).