GGI Exploratory Science awards: "Marine Invertebrate Diversity in the Fort Pierce Inlet and Beyond"

Marine Invertebrate Diversity in the Fort Pierce Inlet and Beyond

INTRODUCTION

The Indian River Lagoon (IRL) is an estuary extending more than 150 miles along the Southeast Atlantic Coast of Florida. According to some sources, the IRL is considered the most biologically diverse estuarine system in North America (www.saj.usace.army; www.floridastateparks.org). A combination of salt marshes, mangrove wetlands, seagrass beds, oyster reefs and human infrastructure along the lagoon provide spawning, nursery and foraging habitats for a wide variety of marine invertebrate species (www.fws.gov/refuge/pelican_island). Both motile and sessile marine invertebrates feed on micro- and meroplankton, and in turn, are food for larger invertebrates and fishes. The larval stages of adult invertebrates provide critical dispersal stages that likely serve to connect, or disconnect, marine species between the IRL and coastal Atlantic through a series of inlets along the lagoon, including the Fort Pierce Inlet (FPI), which is the location of the Smithsonian Marine Station (SMSFP). Species within the IRL may also be connected further offshore by transport through inlets to the Florida Current of the Gulf Stream (GS) flowing northward along the eastern coastline of the U.S. However, it is not known to what extent such connections exist taxonomically, or whether the IRL or GS are sources or sinks for invertebrates along the outer coast, continental shelf and beyond. Therefore, fundamental research aimed at characterizing adult marine invertebrates within the IRL, larval invertebrates dispersing into and from the IRL, and potential offshore resources of invertebrate diversity to the IRL, should be pursued. Relatively recent efforts have begun to characterize invertebrate taxa at Smithsonian’s TMON sites within the IRL, combined with theFlorida Census of Marine Life and over a decade of sampling by the Benthic Ecology Program at the SMSFP. We propose to build upon and expand these efforts with high-resolution imaging and vouchering techniques, DNA barcoding of adult invertebrates and their understudied larvae, bait-capture of invertebrate mitochondrial genomes, collection of genome-quality DNA (gDNA) for underrepresented taxa in the Global Genome Biodiversity Network (GGBN), and transcriptome sequencing and phylogenetics of unidentified sipunculan and other larvae within the GS. 

(1) Scientific Importance

a) RESEARCH QUESTIONS

• Do the DNA barcodes of larval marine invertebrates flowing into and from the Fort Pierce Inlet match the barcodes of adult invertebrates within the inlet or at TMON sites along the IRL?
• Are there seasonal differences in the composition and diversity of larval marine invertebrate species moving through the Fort Pierce Inlet? 
• Can the mitochondrial genomes of marine invertebrates provide finer taxonomic resolution of challenging species to supplement the limitations of standard DNA barcoding protocols?
  • Do species of sipunculans and other marine invertebrates identified within the IRL, Gulf of 

Mexico and Caribbean have matching larval stages in the Gulf Stream?

b) SPECIFIC OUTCOMES

DNA barcoding of adult marine invertebrates on settlement panels in the Fort Pierce Inlet.

Collection and barcoding of diverse encrusting invertebrates and other sessile species are notably underrepresented in the GGI biorepository, and have been difficult to barcode due to co-amplification of microbes and epiphytes associated with encrusting communities (e.g. colonial tunicates, hydroids, bryozoans, sponges). Standard DNA barcoding will be supplemented with bait-capture technology for mitochondrial-encoded genes (MEG), also complementing TMON monitoring efforts in the IRL.

DNA barcoding of planktonic marine invertebrate larvae within the Fort Pierce Inlet.

Planktonic marine invertebrate larvae will be collected, imaged and barcoded for identification and matching to adult species on settlement panels, and to existing barcode records for the IRL. We will also focus on barcoding phylogenetically important taxonomic groups (e.g. spiralians, crustaceans) and the isolation of gDNA from larvae belonging to families known to be absent from GGBN and GenBank. 

Transcriptome sequencing and phylogenetics of sipunculan larvae in the Gulf Stream.

In addition to broadly screening larval and adult diversity of various invertebrate groups in the IRL, we will perform an in-depth genomic analysis of the understudied Sipuncula. We will collect, sort and barcode plankton samples from the Gulf Stream, with particular focus on sipunculan pelagosphera larvae of the open ocean. Between 12 to 20 pelagosphera morphospecies are found in the GS. None have been identified to species, and there is no published genome or gDNA available for a member of Sipuncula. We will isolate gDNA for cryopreservation, and TotalRNA for transcriptome sequencing and phylogenetic analysis of sipunculan pelagospherae and selected outgroup larvae from the GS.