Michael J Risk

McMaster University | McMaster

The decline of natural coral reefs has spurred interest in artificial reef construction and reef rehabilitation efforts. However, many restoration programs are failing because of poor water quality and localized pollution factors. This paper examines one etiology of coral restoration failure, highlighting the need for careful site selection based o...

The Lahaina urban/wildland fire event is considered the deadliest wildfire in the past century of U.S. history. This fire resulted in over 2200 building structures destroyed or damaged, approximately 4000 automobiles were incinerated and between 450 and 878 ha of grassland burned in areas adjoining the town of Lahaina, Maui County, State of Hawaii,...

Hanauma Bay’s coral reef system is threatened by sunscreen pollution. Understanding the hydrodynamic nature of the bay is crucial for understanding the transport and fate of pollutants within the bay. This study conducted a comprehensive hydrodynamic analysis, revealing significant aspects of current patterns and their influence on sunscreen pollut...

The present study investigates the suitability of the Northern Persian Gulf coastal areas for establishing artificial reefs using three highly effective Hydrodynamic factors, Current magnitude, Distance from Pollutant Sources and pollution residence time. These factors are the outcomes of a reef-scale hydrodynamic model used to make policy decision...

Due to increasing demand for food, intensive mariculture of finfish is a fast developing industry in the Iranian part of the Persian Gulf (PG). The environmental impacts of cage fish fa rming largely involve release of excessive organic matter (biodeposits). Careful monitoring of fish farms to avoid anoxia and bottom "dead zones" is an essential pa...

We examined the occurrence and sources of 16 priority PAHs in the water and sediment samples of the Miankaleh Wetland (Coastal Biosphere Reserve), famous for harbouring huge flocks of migrating birds. The water and sediment samples collected from various locations were visualized and processed using a self-organizing map, positive matrix factorizat...

Based on the existing in-situ data, laboratory experiments, and increasing tourism trends, corals of Kish Island in Iran are seriously in danger. One factor could be Organic and inorganic UV filters (UVfs) which are key ingredients in various sunscreen and personal care products, massively released to natural waters due to the increased marine tour...

Environmental Fluid Dynamics is a branch of coastal engineering that has the ability to interconnect and integrate the many factors that contribute to to-day’s complicated environmental issues. The techniques used are able to provide estimates of residence times and flushing rates for contaminants of concern. We have applied this approach to the is...

Hanauma Bay is a 101-acre bay created by the partial collapse of a volcanic cone and once supported a vibrant coral reef system. It is the most popular swimming area in the Hawaiian Islands and has been reported to have averaged between 2.8 and 3.5 million visitors a year between the 1980s and the 2010s, with visitors averaging between 3000–4000 a...

Around the world, coral reefs are in decline. Recent interest has focussed on the impacts of global warming/climate change, but the decline started long before the influence of climate change became apparent, driven by anthropogenic factors such as sedimentation, nutrient increase, and overfishing. These continue with no real signs of abatement, as...

With increasing demand for fish in the market, large-scale and intensive finfish mariculture seems inevitable in the Persian Gulf. However, this activity poses a serious threat to the environmental integrity of marine ecosystems of this important body of water. This is why fin-fish Mari culture has faced many oppositions .The negative impact to the...

My presentation was about the effects of fish farms on environmental factors

Bioindicator and Marine pullotion

This paper studies the results of multi-disciplinary investigations on different features of evolution of the Mond River delta during the past five decades. Considering the high importance of Mond River and corresponding sediment discharge, physiography and watershed analysis of Mond River is investigated and sediment discharge from the river and i...

Large-scale and intensive mariculture of finfish is inevitable along the Iranian coastline in the Persian and Oman Gulfs. Finfish mariculture at the proposed sites poses a serious threat to the environmental integrity of over Iranian coastal and marine ecosystems. As a measure of Ecological Conservation and protection of coral reefs, sea turtles, a...

Acropora palmata was listed as threatened under the Endangered Species Act in May 2006 (71 FR 26852). In 2012, the National Marine Fisheries Service proposed the reclassification of A. palmata (77 FR 73219) as endangered, but determined in 2014, that they would remain listed as threatened under the ESA (79 FR 53852). This coral is present only in t...

After nearly 20 years of limited natural recovery of intertidal habitats along the Gulf Coast of the Kingdom of Saudi Arabia, large-scale remediation projects were conducted on approximately 1800 ha of tidal flat and salt marsh habitat. In Fall, 2011, multiple passes of mechanical tilling were used to break up oiled cohesive sediment layer across a...

There is an enormous literature on the effects of sediments and nutrients on reefs. Until recently, there were few clear guidelines that could easily be used by management to alleviate these stresses. Recent progress in our understanding of watershed dynamics has brought us much closer to being able to manage catchments so as to minimize sediment s...

Bamboo corals (Order Gorgonacea, Family Isididae) are attractive prospects for deep-sea paleoceanographic reconstruction, capturing trace elements in their calcitic skeletons that may serve as environmental proxies with subdecadal resolution over multi-century timescales. We study the reproducibility and fidelity of trace-element profiles (Ba, Mg,...

Hurricane Beulah (July 1975) and a major storm both caused catastrophic mortalities among intertidal benthos of the Minas Basin. In both events, surface sediment was scoured off the flats, resulting in high mortalities in shallow-burrowing organisms. The storm was a more severe catastrophe than the hurricane. The demonstrated high secondary product...

The causeway-induced mudflat at Windsor, Nova Scotia, was studied to determine the effect of rapid sedimentation on the sedimentological and biological characteristics of an intertidal mudflat. Compared to typical Minas Basin mudflats, the Windsor flat has high water content, (50% vs. 30% wet wt, approximately) small grain sizes, and elevated organ...

Construction of a tidal dam in the upper reaches of the Bay of Fundy is expected to result in deposition of sediment. We investigated the effect of sediment deposition on populations of three major benthic species of the upper reaches: Corophium volutator, Macoma balthica, and Mya arenaria. In fences and boxes that induced deposition on intertidal...

The effect of spionid worm, Polydora websteri, infestation on the strength of shell valves of the sea scallop, Placopecten magellanicus, was investigated in relation to valve weight and degree of bioerosion. Compression tests indicated that the strength of upper valves increased with weight but were weakened in proportion to the degree of P. webste...

Trace-element and stable-isotope analyses were performed on azooxanthellate corals from the North Atlantic, at two different tectonic settings. One set was from Orphan Knoll, near Newfoundland (1700 m depth, 50°25.57'N, 46°22.05'W), the other from the Mid-Atlantic Ridge (1200 m depth, 45°14.12'N, 28°34.12'W). The Mid-Atlantic Ridge corals contain s...

The size distribution and orientation of massive hemispherical tabulate corals and hemispherical stromatoporoids from the Fossil Hill and Manitoulin Formations on Manitoulin Island (Niagaran and Alexandrian, Ontario), and of hemispherical stromatoporoids in the Flume and Upper Cairn Members of the Miette reef complex (Frasnian, Alberta) and the Jam...

Axius serratus, a burrowing shrimp capable of living in areas so polluted that other benthic organisms are excluded, has a probable range along the Atlantic coast of North America from Massachusetts Bay to the Arctic. Results of computer simulation of burrowing patterns and rates, based on field data, suggest the possibility of extensive sediment r...

Several specimens of a new trace fossil, Polycylindrichnus prolifer, n. gen., n. sp., have been collected from the Middle Silurian Thorold Formation in Hamilton, Ontario. Traces are multiple burrows, originating from a common source at depth, budding into several cylindrical to conical, subhorizontal burrows. Burrow openings lie on a common bedding...

The Long Rapids Formation, a sequence of interbedded black shales, green–grey mudstones, and carbonates in the Moose River Basin of northern Ontario, is Late Devonian in age and has counterpart equivalents in the Michigan, Appalachian, and Illinois basins. The Long Rapids Formation has a maximum known thickness of 85 m and can be divided into three...

The process of skeletal micritization by boring thallophytes (algae and fungi) is known from modern carbonate environments and probably occurred as far back as the Ordovician. Boring thallophytes, probably fungi, possibly algae, were the cause of at least some skeletal micritization in Devonian reef complexes in western Canada. In situ endolithic f...

IntroductionThe relationship between reefs and sediments has been observed by humans certainly for centuries, and possibly for millennia. Columbus observed that his ships could take on fresh water by avoiding the fringing reefs of South America and sailing into the mouths of the Orinoco (Morison, 1974). Moreover, that keen observer Charles Darwin n...

Bamboo corals (Family Isididae) are attractive prospects for deep-sea paleoceanographic reconstruction because their simple skeletal architecture simplifies age assignment, while their calcite skeletons capture trace elements that may serve as environmental proxies. For slow growing proxies like deep corals, laser-ablation ICP-MS is an ideal techni...

In May 1960, the largest recorded earthquake in the earth's history struck southern Chile, and lowered the course of the Rio Cruces by approximately 2 m. This created a wetland, which was colonised by the waterweed Egeria densa and, subsequently, by large populations of the black-necked swan, which fed on the weed. Reported catastrophic declines in...

Stable nitrogen isotope (delta(15)N) analysis has proven an effective "fingerprint" of sewage contamination in coral reef environments; however, short-term variability in nitrogen cycling and isotopic fractionation may obscure long-term trends. Here, we examine delta(15)N signatures in the organic endoskeletons of long-lived (20-40 years) gorgonian...

The increasing use of herbicides in agriculture sectors have received great attention with respect to their potential toxic effect on reef-building corals of Indonesia. One chlorinated compound, 2,4-dichlorophenoxyacetat (2,4-D), has been widely used as a herbicide and has become a substantial environmental pollutant. Contamination of 2,4-D was ass...

In 2007, a study was undertaken of the long-term records of the ratios of stable isotopes of carbon (delta C-13) and nitrogen (delta N-15) in the skeletons of antipatharians (black corals) growing on reefs near the city of Jeddah, Saudi Arabia. Antipatharians were collected from more than 100 sites, and detailed records obtained from 31 individuals...

In May, 1960, the largest recorded earthquake in the history of the planet hit southern Chile, dropping part of the course of the Rio Cruces by 2m and creating an extensive wetland. The Brazilian Waterweed Egeria densa colonised the area, and became a primary food source for large populations of the Black-necked Swan, Cygnus melancoryphus. In 2004,...

While coral reefs decline, scientists argue, and effective strategies to manage land-based pollution lag behind the extent of the problem. There is need for objective, cost-effective, assessment methods. The measurement of stable nitrogen isotope ratios, delta(15)N, in tissues of reef organisms shows promise as an indicator of sewage stress. The ch...

Deep-sea gorgonian corals secrete a 2-part skeleton of calcite, derived from dissolved inorganic carbon at depth, and gorgonin, derived from recently fixed and exported particulate organic matter. Radiocarbon contents of the calcite and gorgonin provide direct measures of seawater radiocarbon at depth and in the overlying surface waters, respective...

A marked increase in the biomass of Cliona delitrix infesting Montastrea cavernosa substrate occurred in a portion of the Grand Cayman fringing reef affected by the discharge of untreated fecal sewage. It is suggested that the six-fold increase in bacteria biomass (both “coliforms” and natural marine bacterioplankton) in reef waters receiving the s...

This chapter focuses on the deep-sea corals. Deep-Sea corals provide a widespread archive of oceanographic processes, with annual- to decadal-resolution records spanning several centuries in length. They are ideally suited to the study of rapid changes, such as that which characterized the Pleistocene–Holocene transition. Deep-sea scleractinians ex...

In this study, time-series stable isotope results (δ13C and δ15N) from three deep-water Leiopathes glaberrima (Esper, 1788) specimens Collected off the southeastern Coast of the United States of America and one specimen from the Gulf of Mexico are presented. The specimens were Collected live in 2004 and are estimated to be 200-500 yrs old based on...

Ecologic and taphonomic impacts of volcanic ashfall on a Pleistocene nearshore hard-bottom community and a Cretaceous offshore soft-bottom community are compared and contrasted. The hard-bottom (reef) community, dominated by sessile, epifaunal organisms, was devastated by rapid deposition of volcanic sediment. In contrast, the offshore community, d...

Algal borings in the shells of the articulate brachiopods Plaesiomys subquadrata (Hall) and Hebertella sinuata (Hall) from the Richmond Formation of Ohio are empty, or partially to entirely filled with pyrite. The pyrite occurs as single framboids and other crystal forms, or in chains filling the bores. The borings provide some insight into the ear...

The presence of organisms whose bodies have low preservation potential may be deduced by searching for the traces produced by them. The addition of predatory gastropods and soft-bodied epizoans to Quaternary marine faunas dominated by bivalves was facilitated by an examination of borings in bivalve shells. Borings attributed to predatory gastropods...

Solid-state 13C nuclear magnetic resonance (NMR) spectra were obtained from the insoluble phase of the organic matrices of fossil bivalves from Pleistocene raised beaches on Baffin Island, Champlain Sea localities in eastern Ontario, and modern representatives of the same species from Nova Scotia and Baffin Island. All the spectra show the presence...

Bioerosion intensity has been proposed as a measure of paleoproductivity in fossil reefs, but it is difficult to measure directly because fossil corals are often incomplete and because it is difticult to infer the length of time a given coral was exposed to bioeroding organisms. Both nutrient availability and taphonomic factors can affect bioerosio...

The long-term stability of the carbonate beaches of Mauritius is the result of the net balance of the supply of carbonate sand from the coral reef environment and the loss of sand to adjacent depositional beaches and through passes in the fringing coral reef to off-reef environments. Carbonate sand is supplied from the lagoon and the balance has be...

Deep-water gorgonian corals are long-lived and abundant in the North Pacific Ocean. Gorgonians have annually-resolved skeletal organic bands, making them proxies of environmental changes. Specimens of Primnoa sp. were collected from the Gulf of Alaska in 2001, 2003, and 2004. Organic band counts and Pb-210 dating were combined to produce a growth c...

Skeletal banding has been found in the deep-water scleractinian coral Desmophyllum cristagalli, an important animal in studies of climate change. This banding pattern sheds light on skeletogenesis and suggests methods by which the record of climate change contained within the coral skeletons may be interpreted. A central wall built of trabeculae fo...

The radiocarbon reservoir age of high latitude North Atlantic Ocean surface water is essential for linking the continental and marine climate records, and is expected to vary according to changes in North Atlantic deep water (NADW) production. Measurements from this region also provide important input and/or tests of oceanic radiocarbon using 3-D g...

A marine bacterium associated with soft coral Sinularia polydactyla collected from Bandengan water, Jepara, North Java Sea, Indonesia, was successfully screened for antibacterial activity against pathogenic bacterium Streptococcus equi subsp. zooepidemicus K6.72 isolated from infected monkey of the island of Bali and identified based on morphologic...

Laser ablation ICP/MS was used to analyze Mg, Sr and U at fine (hundreds of microns) and seasonal spatial scales in the reef coral Porites and the non-photosynthetic ``deep-sea'' corals Lophelia, Oculina, and Desmophyllum. Tropical corals display strong seasonal correlations between Mg, Sr and U, even when normal cycles are perturbed by unknown fac...

Deep-water (307 697 m) antipatharian (black coral) specimens were collected from the southeastern continental slope of the United States and the north-central Gulf of Mexico. The sclerochronology of the specimens indicates that skeletal growth takes place by formation of concentric coeval layers. We used 210Pb to estimate radial growth rate of two...

A mixed equilibrium/kinetic steady-state numerical model of coral calcification has been developed to test whether a physicochemical calcification mechanism is able to account for recent geochemical observations, in particular correlated trace-element variations presented in a companion paper [Sinclair, D.J., 2005. Correlated trace-element ‘vital e...

Primnoa resedaeformis is a deep-sea gorgonian coral with a two-part skeleton of calcite and gorgonin (a fibrillar protein), potentially containing long-term records of valuable paleo-environmental information. For various reasons, both radiocarbon and U/Th dating of these corals is problematic over the last few centuries. This paper explores aspart...

Aliwal Shoal lies south of Durban in South Africa and has been the subject of recent bathymetric, seafloor and benthic surveys. ANOVA of the biological data revealed that the biota were uniformly distributed on the reef with the exception of encrusting sponges and algae on rock. The variations in distribution of these biota were significant and, in...

The Delta14C value (reservoir age) of North Atlantic surface water is expected to vary according to the rate of North Atlantic Deep Water (NADW) formation and the air-sea exchange rate. Previous attempts to estimate the Delta14C of North Atlantic surface waters indicate potentially large changes but these prior studies involve many unsupported assu...

The deep-sea gorgonian octocoral Primnoa resedaeformis is distributed throughout the Atlantic and Pacific Oceans at depths of 65 to 3200 m. It has a 2-part skeleton of calcite and gorgonin. Towards the inside of the axial skeleton gorgonin and calcite are deposited in concentric growth rings, similar to tree rings. Colonies were collected from the...

The deep-sea gorgonian coral Primnoa spp. live in the Atlantic and Pacific Oceans at depths of 65 to 3200 m. They have an arborescent growth form with a skeletal axis composed of annual rings made from calcite and gorgonin. Lifespans may exceed several hundreds of years. It has been suggested that isotope profiles from the gorgonin fraction of the...

The gorgonians Plexaura spp. occur throughout the Florida Reef Tract, and lay down annual bands of a tough protein, gorgonin, in their skeletons. We analyzed stable isotopes of nitrogen (δ15N) and carbon (δ13C) from individual annual bands in skeletons of Plexaura homomalla and P. flexuosa from 10 locations on the Florida Reef Tract, producing a pr...

Bioerosion by Cliona delitrix and Cliona lampa was assessed at 43 sites along the Florida Reef Tract, USA, in the summer of 2001. Sponge abundances were estimated using rapid visual assessment. Tissue samples of sponges were taken for analysis of delta15N. Comparison samples were taken from Belize. Annual trends in sponge abundance were estimated f...

The longest available time series on ocean currents indicates that the southward flow of water from the Greenland Sea is weakening, and that correlative large-amplitude changes have occurred in the rate of formation of intermediate Labrador Sea water. These have been linked to changes in regional climate which, if trends continue, could within 30 y...

It has been suggested that the deep-sea gorgonian coral Primnoa resedaeformis may be an important paleoceanographic archive. Seventeen colonies collected from the upper slope of the NW Atlantic margin (229 – 447 m) were analyzed to see if skeletal Mg/Ca is related to temperature. Analyses were focused on the calcite cortex region of skeletal sectio...

Carbonate beaches are a unique example of the interaction between biological processes, creating the sediments, and physical processes, moving and often removing the sediments. On the sediment supply side, carbonate sediments are born, not made. They exist in dynamic equilibrium between production and destruction. Following the creation of carbonat...

"Poor understanding of the nutrient dynamics in the Gulf of Alaska results from insufficient uninterrupted, long-term observations" (PICES, 2004). Failing an instrumental record, oceanographers must increasingly rely on proxies. The utilization of deep-water corals as environmental recorders has only recently been recognized: they may fill in the m...

A mixed kinetic/equilibrium steady state model of trace-element co-precipitation in coral skeleton is presented, and tested against high spatial resolution observations of coral trace-element composition made previously by LA-ICP-MS. The model is implemented in PHREEQC, and simulates physicochemical precipitation from a small pocket of seawater whi...

Wunsch (2003) posed a credible challenge to the paleoclimate community by suggesting that over zealous wiggle matching of the Greenland ice core \delta 18O records to far field proxy records grossly exaggerates the geographic relevance of the Greenland¡_s millennial scale variability. Wunsch (2003) argues that regional wind fluctuations are a more...

From September to November 1997, most of Indonesia was covered by a dense blanket of haze, originating from fires on Sumatra and Borneo. Specimens of Porites lobata were collected from two locations, i.e. the Riau Archipelago, south of Singapore, where the haze was most dense, and the Karimunjawa Islands, north of Central Java, where the effects we...

Hundreds of large coral reefs up to 45 m high exist (A) on the continental shelf and (B) on morainic threshold ridges in fjords of northern, mid-, and southwest Norway. They occur in water depths between 400 and 40 m, and contain a large variety of megafauna. The most common frame-building coral is Lophelia pertusa (L.). The oldest reef found to da...

Mollusc shells of several species were deployed on racks and on the seafloor for up to two years on eutrophic and mesotrophic reefs in the Java Sea, a modern epeiric sea. Taphonomic indicators of shell preservation decreased during the study, but some ligament, periostracum, and shell color persisted throughout. Shell fragmentation was negligible e...

A subfossil fragment of the deep-sea gorgonian coral Primnoa resedaeformis was 14C AMS dated along a radial growth transect. Dates ranged from 260050 at the outside, to 292060 14C years BP near the interior, suggesting an age of –1. Based on comparisons with live-collected specimens, we estimate the entire colony may have been about 0.5–0.75 m tall...

The deep-sea gorgonian coral Primnoa resedaeformis has an arborescent skeleton composed of both calcite and a horn-like structural protein called gorgonin. We have investigated potential climate records in corals from Alaska, the eastern seaboard of Canada and the United States, and a Southern Ocean (Pacific sector) seamount. Temperatures at these...

A specimen of Desmophyllum cristagalli, an azooxanthellate (non-photosynthetic) coral was intensively and systematically sampled on all interior and exterior coeval surfaces. Even though the coral grew at an almost-constant temperature of about 2.5 °C, 18O varied by almost 3{‰} and was up to 3.25{‰} depleted with respect to aragonite–seawater oxyg...

The Java Sea, one of the few modern tropical epeiric seas, is used as an analogue to examine oceanography, stratigraphy, and reefs of Devonian strata in the Appalachian and Michigan Basins. Nearshore patch reefs and offshore “pinnacle” reefs occur in both the Java Sea and the Emsian-Eifelian Onondaga Formation in the Appalachian Basin. Nearshore pa...

There have been few seminal advances in techniques of health evaluation of coral reefs since line transects and visual fish counting were first proposed in 1972, yet the rate of resource destruction increases rapidly. Especially in Third World settings, coastal communities need access to simple techniques that have been shown to identify stress on...

The Maldives are a double chain of islands in the Indian Ocean stretching for almost 1000 km south of Sri Lanka (74,75). There are more than 1200 islands (only 202 are inhabited), grouped into 19 atolls. The word atoll itself comes from Dhivehi, a Sinhalese dialect which is the language of the Maldives, and means an administrative district (4). The...