Water Contamination Reduces the Tolerance of Coral Larvae to Thermal Stress

Coral reefs are highly susceptible to climate change, with elevated sea surface temperatures (SST) posing one of the main threats to coral survival. Successful recruitment of new colonies is important for the recovery of degraded reefs following mortality events. Coral larvae require relatively uncontaminated substratum on which to metamorphose into sessile polyps, and the increasing pollution of coastal waters therefore constitutes an additional threat to reef resilience. Here we develop and analyse a model of larval metamorphosis success for two common coral species to quantify the interactive effects of water pollution (copper contamination) and SST. We identify thresholds of temperature and pollution that prevent larval metamorphosis, and evaluate synergistic interactions between these stressors. Our analyses show that halving the concentration of Cu can protect corals from the negative effects of a 2–3°C increase in SST. These results demonstrate that effective mitigation of local impacts can reduce negative effects of global stressors

Environmental sensing and response genes in cnidaria : the chemical defensome in the sea anemone Nematostella vectensis

Author Posting. © The Author(s), 2008. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Cell Biology and Toxicology 24 (2008): 483-502, doi:10.1007/s10565-008-9107-5.The starlet sea anemone Nematostella vectensis has been recently established as a new model system for the study of the evolution of developmental processes, as cnidaria occupy a key evolutionary position at the base of the bilateria. Cnidaria play important roles in estuarine and reef communities, but are exposed to many environmental stressors. Here I describe the genetic components of a ‘chemical defensome’ in the genome of N. vectensis, and review cnidarian molecular toxicology. Gene families that defend against chemical stressors and the transcription factors that regulate these genes have been termed a ‘chemical defensome,’ and include the cytochromes P450 and other oxidases, various conjugating enyzymes, the ATP-dependent efflux transporters, oxidative detoxification proteins, as well as various transcription factors. These genes account for about 1% (266/27200) of the predicted genes in the sea anemone genome, similar to the proportion observed in tunicates and humans, but lower than that observed in sea urchins. While there are comparable numbers of stress-response genes, the stress sensor genes appear to be reduced in N. vectensis relative to many model protostomes and deuterostomes. Cnidarian toxicology is understudied, especially given the important ecological roles of many cnidarian species. New genomic resources should stimulate the study of chemical stress sensing and response mechanisms in cnidaria, and allow us to further illuminate the evolution of chemical defense gene networks.WHOI Ocean Life Institute and NIH R01-ES01591

Geographic and temporal variation in persistent pollutants in Australian humpback and snubfin dolphins

We investigated between 2014 and 2016 the concentrations of PCBs, DDTs and HCB and trace elements in blubber and skin samples of Australian humpback and snubfin dolphins collected from the Fitzroy River estuary and Port Curtis, Queensland, Australia. The concentrations of PCBs, DDTs and HCB from this study were compared with results from samples collected in 2009 and 2010 from the same areas. Our results showed that the concentrations of PCBs, DDTs and HCB have increased over time. A large proportion (~68%) of the sampled population accumulated organochlorines contaminants above thresholds over which immunosuppression and reproductive anomalies are known to occur. Results also suggest a general enrichment of some trace elements above natural levels in humpback and snubfin dolphins from the Fitzroy River estuary and Port Curtis. Extensive flooding in adjacent catchments is the most likely primary factor responsible for increased distribution and bioavailability of these contaminants into coastal waters. Land-based pollution from the adjacent catchments is an ongoing threat to coastal systems and particularly for top predators such as dolphins in the Great Barrier Reef. Climate change models predict increasing frequency and intensity of extreme rainfall events that will impact coastal Queensland and the Great Barrier Reef. Reduction of land-based persistent pollutants into coastal waters of the Great Barrier Reef will be critical for the health and survival of humpback and snubfin dolphins in this region

Fishing frequency and consumption.

<p>Frequency of the <i>Gumbaynggirr</i> communities fishing and resource consumption from Nambucca River estuary.</p><p>Fishing frequency and consumption.</p

Trace metal concentrations in tissue samples of <i>Myxus elongatus</i> (sand mullet) and <i>Saccostrea glomerata</i> (Sydney rock oyster).

<p>Mean, standard deviation (SD) and range of trace metal concentrations in tissue samples of <i>Myxus elongatus</i> (sand mullet) and <i>Saccostrea glomerata</i> (Sydney rock oyster) from the Nambucca River estuary compared with the maximum levels (MLs) and generally expected levels (GELs).</p><p>^† Guideline in inorganic arsenic</p><p>^‡ Guideline for cadmium is for molluscs but excludes oysters</p><p>Trace metal concentrations in tissue samples of <i>Myxus elongatus</i> (sand mullet) and <i>Saccostrea glomerata</i> (Sydney rock oyster).</p

Importance of the Nambucca River estuary.

<p>Evidence of the importance of the Nambucca River estuary, from narrations gathered from survey participants.</p><p>Importance of the Nambucca River estuary.</p

Absorption of metals in mulloway (Argyrosomus japonicus) after ingesting nickel-plated carbon-steel hooks

Previous research has alluded to the potential of metals being absorbed by fish after ingesting fishing hooks, which may have adverse effects on fish health and the organisms that consume them. Subsequently, this study aimed to quantify the potential of mulloway (Argyrosomus japonicus) to absorb metals during the decay of ingested nickel-plated carbon-steel hooks. Twenty-five treatment fish were allowed to ingest nickel-plated carbon-steel hooks during angling and then monitored with 25 controls (untreated fish) for up to 42 days for hook ejection and mortality. Blood, liver and muscle samples were collected from treatment, control and 14 wild-caught individuals to determine the concentrations of chromium, cobalt, copper, iron, manganese and nickel. The results showed that increased oxidation influenced hook ejection, and that hook-ingested fish had significantly elevated concentrations of nickel in their liver and blood, but not muscle. This research has shown that there is an avenue for metal absorption from ingested hooks

Aboriginal Consumption of Estuarine Food Resources and Potential Implications for Health through Trace Metal Exposure; A Study in <i>Gumbaynggirr Country</i>, Australia

<div><p>Fishing and resource use continues to be an essential aspect of life for many Aboriginal communities throughout Australia. It is important for dietary sustenance, and also retains deep social, cultural and economic significance, playing a fundamental role in maintaining group cohesion, transferring cultural knowledge and affirming Indigenous identities. We surveyed approximately 20% of the <i>Gumbaynggirr</i> Aboriginal community of Nambucca Heads, New South Wales, Australia. This paper explores <i>Gumbaynggirr Connection to Country</i> and engagement in cultural practice. It quantifies fishing efforts and consumption of seafood within the community. We found 95% of the sample group fish, with the highest rate of fishing being 2-3 times a week (27%). Furthermore, 98% of participants eat seafood weekly or more frequently, up to more than once a day (24%). Survey results revealed that <i>Myxus elongatus</i> (Sand mullet) and naturally recruited <i>Saccostrea glomerata</i> (Sydney rock oysters) continue to be important wild resources to the <i>Gumbaynggirr</i> community. Trace metals were measured in <i>M</i>. <i>elongatus</i> and <i>S</i>. <i>glomerata</i> samples collected by community participants in this study. Maximum levels prescribed in the Australia New Zealand Food Standards Code were not exceeded in the edible tissue for either species, however both species exceeded the generally expected levels for zinc and copper and <i>S</i>. <i>glomerata</i> samples exceeded the generally expected level for selenium. Furthermore the average dietary exposure to trace metals from consuming seafood was calculated for the surveyed population. Trace metal intake was then compared to the provisional tolerable weekly intake prescribed by the Joint Expert Committee on Food Additives. This process revealed that copper and selenium intake were both within the provisional tolerable weekly intake, while there is no guideline for zinc. Furthermore, participants relying heavily on wild resources from the Nambucca River estuary may exceed the provisional tolerable weekly intake for cadmium. This suggests the need for further investigation of this issue to minimize any possible health risk.</p></div