The rocky intertidal is an iconic seascape of the California coast. Existing at the land-sea interface, the rocky intertidal is one of the most accessible and diverse habitats making it an extremely important resource for education, recreation, and harvest. They are particularly important to the coastal Indigenous Nations of California who have a deep cultural connection and inherent stewardship rights to their coast. Indigenous Nations have studied and observed the intertidal since time immemorial, passing on and adding to this wealth of traditional knowledge through the generations. They know the current state and the history of their specific intertidal systems better than anyone. As such, we are working in partnership with the Tolowa Dee-ni’ Nation on one of three study areas in this pilot project to combine expertise and implement a novel approach to the study of climate change impacts on the California rocky intertidal.

As a highly productive ecosystem defined by strict ecological zonation due to biological and physical tolerances, the rocky intertidal is presumed to be particularly susceptible to global environmental change, especially sea level rise (SLR). However, it has long been assumed that the biological response of intertidal organisms to climate change will occur slowly over long periods of time that more or less mirror the long term trend of SLR. This study offers preliminary evidence that this may not be the case. In this collaborative study we use large-area imaging to create 3-dimensional (3D) habitat maps and digital elevation models of the rocky intertidal at three sites: Pyramid Point State Marine Conservation Area (PPSMCA); Cabrillo National Monument (CNM); and Scripps Coastal Reserve (SCR), which bookend the southernmost and northernmost tidal regimes of the state.

The Tribal Intertidal Digital Ecological Survey (TIDES) project is a product of collaboration between Scripps Institution of Oceanography faculty and students and the Natural Resources Department of the Tolowa Dee-ni’ Nation. Over time, this partnership will build overall capacity for adaptive coastal management by combining traditional knowledge of historically observed patterns in intertidal communities with advanced imaging/mapping techniques that maximize data acquisition in the field. This project and the foundational partnership and guidance of the Tolowa Dee-ni’ Nation establishes the framework for diverse coastal communities and managers to implement high-resolution large-area imaging of rocky intertidal habitats. This collaborative approach can better inform future changes associated with SLR while creating a digital archive to address a wide range of future research questions as they arise, including areas of interest such as population dynamics of culturally important species.

Nature employs metalloproteins to mediate chemical transformations with impressive rates and selectivities. The efficiency of metalloproteins has been attributed in part to the control of the local environments surrounding their functional active metal center(s). This control is often achieved by non-covalent interactions including hydrogen bonds (H-bonds) from amino acid residues and extended H-bonding networks that include water molecules. In synthetic systems, it has been difficult to establish similar noncovalent interactions with control and predictability. In this dissertation, an approach has been used to model the active sites of metalloproteins by immobilizing metal complexes within a protein host. Using biotin-Streptavidin (Sav) technology, artificial metalloproteins (ArMs) have been designed that model several important features in both the primary and secondary coordination sphere that are seen in native metalloproteins.

Chapter 2 describes the development of FeII and FeIII artificial proteins that model key structural aspects in mononuclear Fe dioxygenases. Structural characterization showed that there was coordination from two nitrogen atom donors from the synthetic ligand and one oxygen atom donor from a nearby glutamate amino acid residue that models the 2-His-1-carboxylate facial triad found in mononuclear nonheme Fe enzymes. Additionally, the water molecules that complete the coordination sphere of the Fe center participated in H-bonding, which is also seen in native metalloproteins.

Chapter 3 discusses the efforts to bind an α-ketoglutarate analog, phenylpyruvate, and dioxygen to the FeII ArM from Chapter 2. A combination of spectroscopic and crystallographic techniques supported the docking of phenylpyruvate near the Fe active site through a pi-stacking interaction with the synthetic ligand. Further structural characterizations from multiple crystals showed that dioxygen can coordinate to the Fe center in different conformations. Mössbauer studies supported the formation of an FeIII–peroxido species within Sav.

Chapter 4 details the design of di-FeIII ArMs. An optical screen was designed to determine the proper match of synthetic ligand and Sav variant to form a di-Fe active site. The optical screen utilized endogenous phenolate coordination to produce a blue color to determine the correct match. Spectroscopic and crystallographic techniques supported phenolate coordination to the Fe center and the formation of a di-FeIII center with a µ–oxido/hydroxido bridging ligand within Sav. Additionally, studies with exogenous ligands, acetate, azide, isothiocyante, and cyanide, showed the Fe···Fe distance ranged between 3.7-4.1 Å and are comparable with native di-Fe proteins.