CLASI: coordinating innovative observations and modeling to improve coastal environmental prediction systems

The Coastal Land-Air-Sea-Interaction (CLASI) project aims to develop new “coast-aware” atmospheric boundary and surface layer parameterizations that represent the complex land-sea transition region through innovative observational and numerical modeling studies. The CLASI field effort will involve an extensive array of more than 40 land- and ocean-based moorings and towers deployed within varying coastal domains, including sandy, rocky, urban, and mountainous shorelines. Eight Air-Sea Interaction Spar (ASIS) buoys are positioned within the coastal and nearshore zone, the largest and most concentrated deployment of this unique, established measurement platform. Additionally, an array of novel nearshore buoys, and a network of land-based surface flux towers are complimented by spatial sampling from aircraft, shore-based radars, drones and satellites. CLASI also incorporates unique electromagnetic wave (EM) propagation measurements using coherent transmitter/receiver arrays to understand evaporation duct variability in the coastal zone. The goal of CLASI is to provide a rich dataset for validation of coupled, data assimilating large eddy simulations (LES) and the Navy’s Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS®). CLASI observes four distinct coastal regimes within Monterey Bay, California (MB). By coordinating observations with COAMPS and LES simulations, the CLASI efforts will result in enhanced understanding of coastal physical processes and their representation in numerical weather prediction (NWP) models tailored to the coastal transition region. CLASI will also render a rich dataset for model evaluation and testing in support of future improvements to operational forecast models.

Phylogeography and Genetic Structure in the California Giant Salamander (Dicamptodon ensatus): Impacts of current and historic landscape features

The California Floristic Province contains numerous ecological regions and a complex geological and geographical history that make it one of the worlds biodiversity hotspots. A number of wide-ranging taxa span across these regions and show complex patterns of dispersal, vicariance and lineage diversification, making localized small ranged species with lower levels of vagility essential to understanding the overall region. Here, we investigate the biogeography and population structure of the California Giant Salamander (Dicamptodon ensatus) (Eschscholtz 1833), an endemic species localized to a narrow coastal region between two areas of biological significance in the California Floristic Province, the North Coast Divide and Monterey Bay. We sequenced one mtDNA fragment (control region) for 133 individuals and a subset of 38 individuals for the anonymous nuclear locus E16C7. We analyzed these sequences with phylogenetic, coalescent, Bayesian clustering, and population genetic approaches in order to infer population structure, phylogenetic structure, and biogeographic history. Additionally, we examined occurrence data with species distribution modeling to generate a habitat suitability map to aid our interpretation of geographic structure. Our analyses recovered 4 major mtDNA lineages, two of which are combined into 3 major lineages when nuDNA is examined. These 3 major lineages are bounded by 4 major current or past geological features; the North Coast Divide, the former Wilson Grove Embayment/current Petaluma Gap, San Francisco Bay, and Monterey Bay. Other low-vagility species linked to moist microclimates and forest habitat do share similarities with the genetic patterns of D. ensatus hinting at a larger role for the past Wilson Grove embayment and modern Petaluma Gap in California biogeography.

A novel random forest approach to revealing interactions and controls on chlorophyll concentration and bacterial communities during coastal phytoplankton blooms

Increasing occurrence of harmful algal blooms across the land–water interface poses significant risks to coastal ecosystem structure and human health. Defining significant drivers and their interactive impacts on blooms allows for more effective analysis and identification of specific conditions supporting phytoplankton growth. A novel iterative Random Forests (iRF) machine-learning model was developed and applied to two example cases along the California coast to identify key stable interactions: (1) phytoplankton abundance in response to various drivers due to coastal conditions and land-sea nutrient fluxes, (2) microbial community structure during algal blooms. In Example 1, watershed derived nutrients were identified as the least significant interacting variable associated with Monterey Bay phytoplankton abundance. In Example 2, through iRF analysis of field-based 16S OTU bacterial community and algae datasets, we independently found stable interactions of prokaryote abundance patterns associated with phytoplankton abundance that have been previously identified in laboratory-based studies. Our study represents the first iRF application to marine algal blooms that helps to identify ocean, microbial, and terrestrial conditions that are considered dominant causal factors on bloom dynamics.

Health Risks and Benefits Among Surfers After Exposure to Seawater in Monterey Bay, Santa Cruz County, California, United States

We investigated the health risks and benefits among surfers in Monterey Bay, Santa Cruz County, California, United States after seawater exposure. A total of 47 surfers enrolled and completed an online survey on the effect of the ocean environment on their well-being, physical and mental health, and provided their perspectives on ocean conservation. The majority of the surfers were white males, with a median age of 40 years, and a mean of 21 years surfing experience. Most of the participants spent over 5 h/week in the ocean. The most common health problems reported were adverse effects due to red tide exposure, surfer’s ear, back and neck problems, and allergies. A total of 41% reported upper respiratory symptoms, and 8% of the participants reported gastrointestinal symptoms. All participants reported that the ocean benefited their emotional health, and 45/47 (>96%) reported that the ocean increased their life satisfaction, happiness, and decreased their stress level. All participants reported being engaged in ocean stewardship. This study suggests surfers were significantly more likely to report upper respiratory symptoms when they had experienced adverse health effects while surfing during a “red tide” and during a bloom of the microscopic, single-celled phytoplankter, Akashiwo sanguinea.

Histologic Examination of a Sea Pig (Scotoplanes sp.) Using Bright Field Light Microscopy

Sea pigs (Scotoplanes spp.) are deep-sea dwelling sea cucumbers of the phylum Echinodermata, class Holothuroidea, and order Elasipodida. Few reports are available on the microscopic anatomy of these deep-sea animals. This study describes the histologic findings of two, wild, male and female Scotoplanes sp. collected from Monterey Bay, California. Microscopic findings were similar to other holothuroids, with a few notable exceptions. Sea pigs were bilaterally symmetrical with six pairs of greatly enlarged tube feet arising from the lateral body wall and oriented ventrally for walking. Neither a rete mirabile nor respiratory tree was identified, and the large tube feet may function in respiration. Dorsal papillae protrude from the bivium and are histologically similar to tube feet with a large, muscular water vascular canal in the center. There were 10 buccal tentacles, the epidermis of which was highly folded. Only a single gonad was present in each animal; both male and female had histologic evidence of active gametogenesis. In the male, a presumed protozoal cyst was identified in the aboral intestinal mucosa, and was histologically similar to previous reports of coccidians. This work provides control histology for future investigations of sea pigs and related animals using bright field microscopy.

A hybrid underwater robot for multidisciplinary investigation of the ocean twilight zone

Mesobot, an autonomous underwater vehicle, addresses specific unmet needs for observing and sampling a variety of phenomena in the ocean’s midwaters. The midwater hosts a vast biomass, has a role in regulating climate, and may soon be exploited commercially, yet our scientific understanding of it is incomplete. Mesobot has the ability to survey and track slow-moving animals and to correlate the animals’ movements with critical environmental measurements. Mesobot will complement existing oceanographic assets such as towed, remotely operated, and autonomous vehicles; shipboard acoustic sensors; and net tows. Its potential to perform behavioral studies unobtrusively over long periods with substantial autonomy provides a capability that is not presently available to midwater researchers. The 250-kilogram marine robot can be teleoperated through a lightweight fiber optic tether and can also operate untethered with full autonomy while minimizing environmental disturbance. We present recent results illustrating the vehicle’s ability to automatically track free-swimming hydromedusae (Solmissus sp.) and larvaceans (Bathochordaeus stygius) at depths of 200 meters in Monterey Bay, USA. In addition to these tracking missions, the vehicle can execute preprogrammed missions collecting image and sensor data while also carrying substantial auxiliary payloads such as cameras, sonars, and samplers.

Reduction of Low-Frequency Vessel Noise in Monterey Bay National Marine Sanctuary During the COVID-19 Pandemic

Low-frequency sound from large vessels is a major, global source of ocean noise that can interfere with acoustic communication for a variety of marine animals. Changes in vessel activity provide opportunities to quantify relationships between vessel traffic levels and soundscape conditions in biologically important habitats. Using continuous deep-sea (890 m) recordings acquired ∼20 km (closest point of approach) from offshore shipping lanes, we observed reduction of low-frequency noise within Monterey Bay National Marine Sanctuary (California, United States) associated with changes in vessel traffic during the onset of the COVID-19 pandemic. Acoustic modeling shows that the recording site receives low-frequency vessel noise primarily from the regional shipping lanes rather than via the Sound Fixing and Ranging (SOFAR) channel. Monthly geometric means and percentiles of spectrum levels in the one-third octave band centered at 63 Hz during 2020 were compared with those from the same months of 2018–2019. Spectrum levels were persistently and significantly lower during February through July 2020, although a partial rebound in ambient noise levels was indicated by July. Mean spectrum levels during 2020 were more than 1 dB re 1 μPa2 Hz–1 below those of a previous year during 4 months. The lowest spectrum levels, in June 2020, were as much as 1.9 (mean) and 2.4 (25% exceedance level) dB re 1 μPa2 Hz–1 below levels of previous years. Spectrum levels during 2020 were significantly correlated with large-vessel total gross tonnage derived from economic data, summed across all California ports (r = 0.81, p < 0.05; adjusted r2 = 0.58). They were more highly correlated with regional presence of large vessels, quantified from Automatic Identification System (AIS) vessel tracking data weighted according to vessel speed and modeled acoustic transmission loss (r = 0.92, p < 0.01; adjusted r2 = 0.81). Within the 3-year study period, February–June 2020 exhibited persistently quiet low-frequency noise and anomalously low statewide port activity and regional large-vessel presence. The results illustrate the ephemeral nature of noise pollution by documenting how it responds rapidly to changes in offshore large-vessel traffic, and how this anthropogenic imprint reaches habitat remote from major ports and shipping lanes.

The MBARI-WEC: a power source for ocean sensing

Interest in wave energy converters to provide autonomous power to various ocean-bound systems, such as autonomous underwater vehicles, sensor systems, and even aquaculture farms, has grown in recent years. The Monterey Bay Aquarium Research Institute has developed and deployed a small two-body point absorber wave energy device suitable to such needs. This paper provides a description of the system to support future open-source access to the device and further the general development of similar wave energy systems. Additionally, to support future control design and system modification efforts, a set of hydrodynamic models are presented and cross-compared. To test the viability of using a linear frequency-domain admittance model for controller tuning, the linear model is compared against four WEC-Sim models of increasing complexity. The linear frequency-domain model is found to be generally adequate for capturing system dynamics, as the model agreement is good and the degree of nonlinearity introduced in the WEC-Sim models is generally less than 2.5%.

Influences of Extreme Upwelling on a Coastal Retention Zone

Coastal retention zones occur in the lee of headlands and within bays of coastal upwelling environments. Because retention zones can concentrate and retain communities of coastal planktonic organisms that would otherwise be advected offshore by wind-driven transport, they are ecologically significant. While the consequences of these zones for plankton retention and recruitment have been examined, the degree to which they remain retentive under variable upwelling intensity is less well understood. This aspect of coastal plankton ecology was studied during 2012 in the retentive upwelling shadow of northern Monterey Bay, California. Environmental and biological data show that exceptionally strong upwelling can greatly diminish resident plankton populations in the upwelling shadow. Results indicate that wind-driven circulation, essential to primary productivity and the formation of retention zones, can surpass levels that allow accumulation and retention of plankton communities.