Input of plastic debris in an urban tropical river system.

Land-based sources contribute approximately 80% of anthropogenic debris in marine environments. A main pathway is believed to be rivers and storm-water systems, yet this input is rarely quantified. We aimed to quantify the abundance of land-based debris entering a river system through storm drains in an urban area of tropical Australia. To account for seasonal variability, debris was quantified pre, post and during the wet season from 2014 to 2017. Plastic items within the river were compared to those in adjacent parks to assess similarities in debris composition. A total of 27,943 items were collected (92% plastic). Debris loads in the post-wet seasons were significantly higher than the wet-season. Furthermore, variability in the portion of debris found in nearby parks compared to the river suggests that factors other than rainfall, play a role in debris abundance. These results can be used to identify targeted management strategies to reduce debris loads.

Using citizen science data to assess the difference in marine debris loads on reefs in Queensland, Australia.

The prevalence of marine debris in global oceans is negatively impacting the marine environment. In Australia, marine debris has been an increasing concern for sensitive marine environments, such as coral reefs. Citizen science can contribute data to explore patterns of subtidal marine debris loads. This study uses data from Reef Check Australia to describe patterns of debris abundance on reef tourism sites in two Queensland regions, the Great Barrier Reef (GBR) and Southeast Queensland (SEQ). Debris was categorized into three groups, fishing line, fishing net, and general rubbish. Overall, debris abundance across reefs was relatively low (average 0.5-3.3 items per survey (400 m2)), but not absent on remote reefs surveyed in the GBR region. Highest debris loads were recorded in SEQ near cities and high use areas. These results indicate the presence of marine debris on remote and urban reefs, and the applicability of using citizen science to monitor debris abundance.

Reliability and utility of citizen science reef monitoring data collected by Reef Check Australia, 2002-2015.

Reef Check Australia (RCA) has collected data on benthic composition and cover at >70 sites along >1000km of Australia's Queensland coast from 2002 to 2015. This paper quantifies the accuracy, precision and power of RCA benthic composition data, to guide its application and interpretation. A simulation study established that the inherent accuracy of the Reef Check point sampling protocol is high (<±7% error absolute), in the range of estimates of benthic cover from 1% to 50%. A field study at three reef sites indicated that, despite minor observer- and deployment-related biases, the protocol does reliably document moderate ecological changes in coral communities. The error analyses were then used to guide the interpretation of inter-annual variability and long term trends at three study sites in RCA's major 2002-2015 data series for the Queensland coast.