Effects of global change on algal biomineralization and benthic community interactions on California's temperate rocky reefs
Marine ecosystems are threatened by CO2-driven global change, such as ocean warming and acidification (OA). The primary objectives of this study were to: 1) assess the response of the coralline red alga, Calliarthron cheilosporioides, to global change; and 2) investigate the responses of California’s kelp forest communities to OA and sea urchin grazing. Results indicated that C. cheilosporioides growth and calcification were reduced under both increased temperatures and increased pCO2 despite increased photosynthetic rates in high pCO2 conditions. Mineralogy did not differ among treatments as a function of warming or acidification. Differences were observed in Mg incorporation into calcified walls of different cell types. Impacts of OA and sea urchin grazing on community structure differed in central and southern CA. In central CA, community structure, calcification and juvenile kelp density showed strong effects of grazing, but no effect of pCO2. Conversely, southern CA showed minor effects of grazing, but strong effects of pCO2 on community structure and calcification, with the strength of response depending on the initial assemblage. These findings suggest that some species of coralline algae may be negatively affected by increased pCO2 and temperature and that the emergent effects of ocean acidification may differ both within a reef as well as across broad spatial scales.
A simplified ATP assay for planktonic organisms with improved extraction efficiency
by Julie C. Kuo, "A thesis presented to the faculty of Moss Landing Marine Laboratories.", Thesis (M.S.) -- San Jose State University, 2015., The adenosine triphosphate (ATP) assay, a proxy of living biomass (used by oceanographers for more than 50 years), was investigated for its potential as a ballast water compliance monitoring tool. Though some ATP assays are reliable for estimating living biomass in specific microbial communities, those assays may be less than optimal for others. For this project, an ATP assay was developed to quantify ATP concentration in most (if not all) aquatic microbial communities; it was also optimized for convenient and rapid assessment of ballast water compliance for persons without a scientific background (e.g., ship engineers, mates, ballast water inspectors). The newly developed ATP assay, called “the P-BAC ATP assay,” was tested against the traditional boiling Tris ATP assay and a 2nd generation ATP assay.
From this project, I concluded that the traditional Tris ATP assay underestimated ATP concentrations by 2 to 4-fold in various natural aquatic microbial communities compared to the P-BAC ATP assay. When compared to the 2nd generation ATP kit, P-BAC extracted comparably at times and up to 3.4-fold more ATP. Furthermore, the P-BAC ATP assay was successfully executed during full-scale shipboard treatment tests at the Golden Bear Test Facility (California Maritime Academy, CSU), by measuring the change in living biomass before and after administering the ballast water treatment.
Predicting stranding patterns of live oiled seabirds, carcass deposition, and carcass retention in Monterey Bay
Beach surveys for live and dead beachcast birds are an economical and practical way of determining seabird population health. Using long-term surveys creates a baseline mortality profile by determining the areas and time of year birds are likely to strand as well as what oceanographic factors cause the deposition and retention of seabird carcasses on beaches. I hypothesized that 1) seabird initial carcass deposition in Monterey Bay would be greater in the southern part of the bay than in the northern part due to oceanographic factors, and 2) seabird carcass retention (how long carcasses stayed on the beach) would be greater in the North Bay than the South Bay due to beach profile characteristics. I utilized BeachCOMBERS beach survey data from 2005 to 2012 to determine patterns of seabird carcass deposition and retention in Monterey Bay and obtained wind speed, wind direction, wave height, tide height, and wave height + tide height (swell impact) from buoys. A backwards multiple regression on the averaged yearly deposition (birds km-1) as affected by oceanographic factors in Monterey yielded significant effects only in the year 2011, with wind speed being the main factor. A two-way ANOVA on the percent of carcasses retained from the previous month with month and zone as independent factors yielded significant effects of both, although location (zone) had a more significant effect. Variability in deposition and retention highlighted the need for continued long-term surveys to accurately determine seabird presence and mortality in Monterey Bay.
Distribution, abundance, habitat use, and respiration patterns of harbor porpoise (Phocoena phocoena) off the northern San Juan Islands, Washington
Boat and shore-based surveys were conducted from June to August 1991 and June to October 1992 to determine harbor porpoise distribution, density, abundance, and habitat use off the northern San Juan Islands, Washington. An estimated 299 harbor porpoise (1.26 harbor porpoise/km2) occurred patchily within 237 km2. Harbor porpoise occurred in water of 10.1° to 16.3°, were generally observed in expected depths>125 m and over shallow slopes (<10%), and less than expected in depths <75 m. Abundance of harbor porpoise in relation to deep waters, flood tides, and tide rips off Point Doughty, Orcas Island, may indicate the importance of these waters as foraging areas. Mean duration of dives for individuals and groups (n = 95) was 6.6 sec (SE = 0.11, n = 1,551) for dives <30 sec and 125 sec (SE = 5.32, n = 156) for dives >30 sec duration.