Sea Technology

NOV 2018

The industry's recognized authority for design, engineering and application of equipment and services in the global ocean community

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Page 45 of 52 November 2018 | ST 45 Bacteria Levels Rise After Hurricane Flooding Hurricane Harvey brought more than 50 in. of rain and extreme flooding to the city of Houston in 2017. Floodwaters harbor bacte- ria that can cause disease. Now, researchers have surveyed the mi- crobes in Houston floodwaters. They reported their results in Envi- ronmental Science & Technology Letters. The researchers found that E. coli levels in two of Houston's major bayous were significantly elevated in the immediate aftermath of Har- vey but gradually decreased over two months after the storm to pre- storm levels. Similarly, antibiotic-re- sistance gene levels were highest three days after the storm. The highest levels of fecal bac- teria, human pathogens and anti- biotic-resistance genes occurred in homes with stagnant floodwater inside. The study indicates that residents and relief workers should exercise caution to prevent coming into con- tact with harmful microbes in the aftermath of extreme floods, espe- cially in stagnant indoor waters. Belgium Gets Systems To Assess Algae Levels The Flanders Environment Agen- cy (VMM) has taken delivery of CTG ALGAE-Wader Pro systems to assist in assessing algae levels of the water environments in Belgium. The systems supplied to VMM are configured for measurements of Chl-a, phycocyanin and phyco- erythrin and come with a handheld unit that provides graphical and dig- ital real-time data to the operator, with red, amber, green threshold- ing, and logs the data for post-mis- sion extraction. The three channels provided by the CTG TriLux fluorometer within the system will also help inform on the group type of the algae present. APT Recorders for THEMO A new Mediterranean observa- tory is using Soundnine's inductive telemetry and temperature/pressure recorders. THEMO (Texas A&M - University of Haifa Eastern Medi- terranean Observatory) comprises a shallow mooring (125 m) on the continental shelf near the edge of the Levant Basin, 25 km from Haifa, and a deep mooring (1,500 m) lo- cated 50 km from Haifa. Soundnine's Enduro APT record- ers (acceleration, pressure, tem- perature) with inductive telemetry are clamped to the jacketed wire rope mooring line at 11 depths be- tween 5 and 85 m. They communi- cate through the wire rope with a Soundnine Ulti-modem connected to the buoy controller. The two moorings have real-time RF communication with a shore station linked to the University of Haifa. AZFP to Examine Onset of Hypoxia Using Cyanobacteria Urban freshwater environments are often exposed to nutrient load- ing via groundwater movement and fertilizer runoff that can cause algal blooms and widespread fluctua- tions in oxygen levels. Through an ongoing monitoring program, Rob Bowen of Diversi- fied Scientific Solutions has been conducting surveys of dissolved oxygen, pH, oxidation-reduction potential, temperature, nitrogen and phosphorous at Swan Lake, in Victoria, BC, Canada. An ASL Environmental Sciences' acoustic zooplankton fish profiler (AZFP) was deployed late summer to collect data. Because Aphanizomenon flos- aquae are relatively large acoustic targets, it is hopeful that this new application of the AZFP will provide valuable insights into the dynamics of this freshwater system. Coastal Erosion in Arctic Intensifies Global Warming The loss of Arctic permafrost de- posits by coastal erosion could am- plify climate warming via the green- house effect. A study using sediment samples from the Sea of Okhotsk in eastern Russia revealed the loss of Arctic permafrost at the end of the last glacial period led to repeated sudden increases in atmospheric carbon dioxide concentration. Researchers from the Alfred We- gener Institute Helmholtz Centre for Polar and Marine Research (AWI) together with colleagues from Co- penhagen and Zurich have found evidence of this phenomenon for the Arctic permafrost regions show- ing that several thousand years ago large quantities of carbon dioxide were released from Arctic perma- frost due to a rapid rise of sea level. Today, the Arctic's permafrost coast is eroding severely because the region is warming rapidly. In some places, the coast is receding at a rate of 20 m per year. Coastal erosion is a key process that must be included in climate models. Climate Patterns Affect Greenland Ice Sheet Melt Scientists know that warming global climate is melting the Green- land Ice Sheet, the second largest ice sheet in the world. A new study from Woods Hole Oceanographic Institution shows the melting rate might temporarily increase or de- crease via two climate patterns: the North Atlantic Oscillation (NAO) and the Atlantic Multidecadal Os- cillation (AMO). The study found that when the NAO stays in its negative phase (meaning air pressure is high over Greenland) it can trigger extreme ice melt in Greenland during the summer season. Likewise, the AMO, which al- ters sea surface temperatures in the North Atlantic, can cause major melting events when it is in its warm phase, raising the temperature of the region as a whole. If global climate change contin- ues at its current rate, the Green- land Ice Sheet may melt entirely. Depending on how the AMO and NAO interact, excess melting could happen two decades earlier than expected or two decades later this century. This melting will affect cli- mate predictions and resource man- agement. ST environmental monitoring

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