Distribution of Gymnodinium catenatum Graham cysts and its relation to harmful algae blooms in the northern Gulf of California

Germination of cysts serves as inoculum for the proliferation of some dinoflagellates, and cyst abundance in sediments represents crucial information to understand and possibly predict Harmful Algae Blooms (HABs). Cyst distribution is related to the physical characteristics of the sediments and the hydrodynamics (circulation) of a particular region. In the northern Gulf of California (nGC) several Gymnodinium catenatum HABs have been recorded. However, the presence of resting cysts and the effect of hydrodynamics on their distribution in the nGC have not been investigated. This study evaluated cyst abundance, distribution and their relation to local circulation in surface sediments during two periods that coincided with a non-bloom year condition (July 2016) and after a major HAB registered in the nGC that occurred in January 2017. Also, a numerical ocean model was implemented to characterize the transport and relocation of cysts and sediments in the region. Gymnodinium catenatum cysts were heterogeneously distributed with some areas of high accumulation (as high as 158 cyst g−1, and 27% of total cyst registered). Cysts seemed to be transported in an eastward direction after deposition and accumulated in an extensive area that probably is the seedbed responsible for the initiation of HABs in the region. The nGC is a retention area of cysts (and sediments) that permit the formation of seedbeds that could be important for G. catenatum HAB development. Our results provide key information to understand G. catenatum ecology and specifically, to understand the geographic and temporal appearance of HABs in the nGC.

Regarding Toxin Detection Mechanisms for Harmful Algae Blooms and Current Device Apparatuses or Development

Current toxin detection mechanisms are insufficient in comparison to a software defined networking system with P2P compatibility in regards to real time detection. In regards to current mechanisms, this involves both wet chemical as well as physical devices and/or buoys. The introduction of new technologies in regards to network latency in relation to novel detection methods is what will be the cornerstone of this research. The importance of this field is to draw conclusions in regards to technological implementations in relation to detection, time, network latency and quality of the data.

Improved Cyanobacteria Removal from Harmful Algae Blooms by Two-Cycle, Low-Frequency, Low-Density, and Short-Duration Ultrasonic Radiation

Harmful algae blooms (HAB) in eutrophic lakes and rivers have become serious water quality problems that are difficult to eliminate using common methods. Previous research has demonstrated that powerful ultrasound can somewhat control cyanobacteria in HABs; however, effective and energy-efficient settings for ultrasonic parameters have not yet been rigorously determined. The results of this study showed that the effect of cyanobacteria removal was enhanced with ultrasonic frequencies, densities, and radiation durations of 20–90 kHz, 0.0005–0.1 W/mL and 0.5–10 min, respectively. Our analyses further demonstrated that the effective distance of ultrasound decreased with increasing frequency, and that damaged algae cells were able to repair themselves at low ultrasonic densities. To address the high energy consumption and small effective distance of conventional ultrasonic radiation treatments, we proposed a new cyanobacteria removal method based on two applications of low-frequency, low-density and short-duration ultrasonic radiation. We defined the energy effectiveness factors of ultrasonic radiation for algae removal as the algae removal rate divided by ultrasonic dosage. This method yielded an 87.6% cyanobacteria removal and the highest energy effectiveness factor, suggesting that two cycles of treatment provide a low-energy method for enhancing existing algae-removing technologies used in large bodies of water.