Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Related Publications
• Parameters
• Deployments
• Project Information
• Funding

Depth distribution of mussel larvae in eastern Gulf of Maine from R/V C-Hawk day cruises in the Eastern Gulf of Maine from 2012 to 2014. These data were published in Weinstock et al., 2018 (see Fig 1, 2, 3, and 5).

Related Datasets: CTD casts were conducted immediately before and after the associated larval vertical distribution sampling and on both flood and ebb tides.
* CTD data for mussel study: https://www.bco-dmo.org/dataset/783736
* CTD cast log for mussel study: https://www.bco-dmo.org/dataset/783749

Samples were collected by pumping 100L of water from specific depths and filtering the water through a 50 μm plankton net. Samples were preserved in ethanol. Bivalve veligers were sorted from other plankton and enumerated under a microscope. A random subset of approximately 33 veligers per sample were prepared for SEM and viewed. Veligers were identified to the family level based on previously published criteria for hinge tooth morphology and all veligers classified as mytillids were measured. Mytilus sp. veligers were distinguished from the much rarer Modiolus by established relationships between shell length and the number of hinge teeth. The total number of bivalve veligers was multiplied by the fraction identified as Mytilus sp. to yield the estimated number of Mytilus sp. larvae in each sample. This method did not allow us to distinguish Mytilus edulis larvae from Mytilus trossulus larvae, but the later species is rare in the bays that we sampled.

For more information see Weinstock et al. 2018.

BCO-DMO Data Manager Processing Notes:
* exported data from excel to csv file
* added a conventional header with dataset name, PI name, version date
* modified parameter names to conform with BCO-DMO naming conventions (spaces, +, and - changed to underscores). Units in parentheses removed and added to the Parameter Description metadata section.
* blank values in this dataset are displayed as "nd" for "no data." nd is the default missing data identifier in the BCO-DMO system.
* Start and end timestamp columns added (UTC) in ISO 8601 format.
* Date column converted to ISO 8601 format

Rocky intertidal habitats in the Gulf of Maine (GoM) provide a model system to examine the structure and dynamics of natural communities. Throughout the Gulf of Maine, the same species are often found in these habitats but community structure, dynamics and productivity differ markedly among 3 distinct regions (southern, central and northern GoM). Past influential work, conducted primarily in the southern and central GoM, focused on the local processes driving intertidal community structure but produced very different conceptual models of how these communities are structured. This project examines whether regional differences in rocky shore community processes are driven by differences in recruitment that are shaped by regional variation in temperature and food availability and nearshore coastal oceanography. This project will improve the understanding of how large-scale environmental forces interact with local processes to control the distribution of species and the structure and dynamics of these communities. Understanding the interaction between processes operating at different scales is fundamentally important to developing more reliable models that can be used to predict community dynamics. In addition, data resulting from this project will have important implications for regional dynamics in commercially important species and for ecosystem and fisheries management within the GoM.

The overarching hypothesis of this project is that regional differences in community-level processes are driven by very different patterns of population connectivity and recruitment in a few key species, and that these differences are ultimately caused by regional variation in temperature and food availability and mediated by physical larval transport processes. Hence, the project will test the following hypotheses with manipulative field experiments, field sampling, connectivity estimates, and integrative modeling:
1) Locally-dispersing species dominate dynamics in regions with a net export of planktonic larvae (Northern GoM), while species with planktonic larvae dominate the dynamics in regions with high settlement and extensive connectivity among populations (Southern GoM).
2) Settlement density of species with planktonic larvae increases from northern to southern regions in accord with regional variation in food availability.
3) Population connectivity varies greatly among regions, with regions differing in the degree to which they are self-seeded or serve as larval sources vs. sinks; self-seeding leads to relatively localized population dynamics in the middle portion of the GoM.
4) Patterns of population connectivity are driven by physical transport processes and can be represented by coupling basic larval behavior models with circulation models.

At 18 different sites in the GoM across ~ 600 km, surveys will evaluate variation in recruitment, food availability and secondary productivity and experiments will assess community processes in wave-exposed and sheltered habitats. We will use hydrographic, current profile, and larval vertical distribution surveys to collect data for coupled larval/circulation models. Population connectivity will be both modeled and empirically evaluated (for one species) using elemental fingerprinting. A spatially explicit metacommunity model will integrate across all project components and test the relative importance of regional and local processes in controlling community organization and dynamics.