Living Beside the Rising Tide: Adapting to Sea Level Rise in Auckland, New Zealand

<p>The Earth's climate system is entering a period of dynamic change after millennia of relatively stable climate. Coastal communities will need to adapt to dynamically shifting coastal environments as the climate system changes and sea levels rise. This study adds to a growing literature that investigates coastal vulnerability, adaptation, and resilience to climate change. It investigates regional scale social and institutional barriers to adaptation to sea level rise; examines the exposure, sensitivity and adaptation options at two coastal settlements in the Auckland region – Mission Bay/Kohimarama and Kawakawa Bay; and it analyses coastal adaptation response options from a resilience perspective. Mission Bay/Kohimarama and Kawakawa Bay, Auckland will experience increasing coastal hazard risk as the numbers of people and property potentially affected by storm events increases as sea level rises. Findings from the present study suggest that existing settlements in the Auckland region may already be 'locked in' to a coastal adaptation approach focused on maintaining the current coastline through coastal stabilisation, an approach that will decrease community resilience and increase vulnerability in the long term, even if this is found to be a successful response in the short term. Retreat offers an alternative approach that is strongly aligned with reducing community vulnerability and increasing resilience; however, strong opposition from communities to any retreat approach is expected. Developing trusted climate science information, education around coastal hazard risk, and participatory community led decision-making are identified as central enablers for a retreat approach to be included as a viable coastal adaptation option for communities in the Auckland region.</p>

Living Beside the Rising Tide: Adapting to Sea Level Rise in Auckland, New Zealand

<p>The Earth's climate system is entering a period of dynamic change after millennia of relatively stable climate. Coastal communities will need to adapt to dynamically shifting coastal environments as the climate system changes and sea levels rise. This study adds to a growing literature that investigates coastal vulnerability, adaptation, and resilience to climate change. It investigates regional scale social and institutional barriers to adaptation to sea level rise; examines the exposure, sensitivity and adaptation options at two coastal settlements in the Auckland region – Mission Bay/Kohimarama and Kawakawa Bay; and it analyses coastal adaptation response options from a resilience perspective. Mission Bay/Kohimarama and Kawakawa Bay, Auckland will experience increasing coastal hazard risk as the numbers of people and property potentially affected by storm events increases as sea level rises. Findings from the present study suggest that existing settlements in the Auckland region may already be 'locked in' to a coastal adaptation approach focused on maintaining the current coastline through coastal stabilisation, an approach that will decrease community resilience and increase vulnerability in the long term, even if this is found to be a successful response in the short term. Retreat offers an alternative approach that is strongly aligned with reducing community vulnerability and increasing resilience; however, strong opposition from communities to any retreat approach is expected. Developing trusted climate science information, education around coastal hazard risk, and participatory community led decision-making are identified as central enablers for a retreat approach to be included as a viable coastal adaptation option for communities in the Auckland region.</p>

The Pacific Wing-Oyster, Pteria sterna, off San Diego, California

Pteria sterna is an eastern Pacific pearl oyster of commercial value from Peru to central Baja California, Mexico. The continuous presence of this species in San Diego for a decade is unique as it is approximately 600 km north of the expected range for the species. A minimum of three generations are present in Mission Bay at any point in time and the preferred substrate for attachment are gorgonian corals. The species is also found off shore in cooler water. The continued presence of this oyster raises the question as to the status of this population; is it a permanent range extension or simply a transient population and what has changed that allowed its continued presence?

The Diet of Octopus bimaculoides in Mission Bay, California (Mollusca: Cephalopoda)

A year-long survey of Octopus bimaculoides Pickford & McConnaughey (1949) dens in three different subtidal habitats was conducted in Mission Bay, California. Habitat complexity and stability were positively associated with prey species richness, species abundance, and den availability. Collectively, 38 species of bivalves and 22 species of gastropods were recorded from octopi debris fields. Two species of bivalve at each site comprised approximately 60% or greater of the bivalves in the debris fields. Bivalves species represented 85% of the take, the remainder being gastropods. With the exception of the bubble snail, most gastropods were drilled, while most bivalves were not. Crustacean remains were infrequently found in debris fields. Prey species in other phyla may have been consumed, but their remains were not found in the debris fields.

On Replicates for Comparing Species Densities in Space and Time

ABSTRACT Because benthic foraminifera exhibit spatial heterogeneity, a number of replicates or multiple biological samples are necessary to estimate population densities. In this study, we empirically examine the efficacy of taking four or fewer replicates to differentiate among mean densities in location and time using p-values as a metric for strength of evidence against the null hypothesis of no difference in taxon density. For spatial analyses, four stations along a traverse with four replicates per station were compared with ANOVA within Mission Bay, Texas, using the four most abundant taxa. The p-values for comparing mean densities among stations increased markedly for all taxa, as the number of samples per station decreased from four to two. Using a test level of 0.05, four replicates per station resulted, on average, in significant differences for three of four taxa, three replicates distinguished two of four taxa, and two replicates detected only one difference. For temporal analyses, a single station was sampled in the Indian River Lagoon, Florida, seasonally over four years. Again, p-values increased markedly as the number of samples per station decreased. Using a test level of 0.05, both four- and three-replicate groups were found to separate mean densities among the four years for three of four taxa, two replicates distinguished one taxon, and use of only one replicate could not detect any difference in mean densities among the four years. Based on these and previous field results, we recommend at least four replicates per station for environmental monitoring. However, when examining mean densities within larger ecological entities such as biofacies, just one sample at each station along a single traverse containing four stations in each bay could delineate Mission, Copano, and Mesquite bays in Texas.

Porewater Carbonate Chemistry Dynamics in a Temperate and a Subtropical Seagrass System

Seagrass systems are integral components of both local and global carbon cycles and can substantially modify seawater biogeochemistry, which has ecological ramifications. However, the influence of seagrass on porewater biogeochemistry has not been fully described, and the exact role of this marine macrophyte and associated microbial communities in the modification of porewater chemistry remains equivocal. In the present study, carbonate chemistry in the water column and porewater was investigated over diel timescales in contrasting, tidally influenced seagrass systems in Southern California and Bermuda, including vegetated (Zostera marina) and unvegetated biomes (0–16 cm) in Mission Bay, San Diego, USA and a vegetated system (Thallasia testudinium) in Mangrove Bay, Ferry Reach, Bermuda. In Mission Bay, dissolved inorganic carbon (DIC) and total alkalinity (TA) exhibited strong increasing gradients with sediment depth. Vertical porewater profiles differed between the sites, with almost twice as high concentrations of DIC and TA observed in the vegetated compared to the unvegetated sediments. In Mangrove Bay, both the range and vertical profiles of porewater carbonate parameters such as DIC and TA were much lower and, in contrast to Mission Bay where no distinct temporal signal was observed, biogeochemical parameters followed the semi-diurnal tidal signal in the water column. The observed differences between the study sites most likely reflect a differential influence of biological (biomass, detritus and infauna) and physical processes (e.g., sediment permeability, residence time and mixing) on porewater carbonate chemistry in the different settings.