Multiple Stressors at the Land-Sea Interface: Cyanotoxins at the Land-Sea Interface in the Southern California Bight

Abstract

Blooms of toxic cyanobacteria in freshwater ecosystems have received considerable attention in recent years, but their occurrence and potential importance at the land-sea interface has not been widely recognized. Here we present the results of a survey of discrete samples conducted in more than fifty brackish water sites along the coastline of southern California. Our objectives were to characterize cyanobacterial community composition and determine if specific groups of cyanotoxins (anatoxins, cylindrospermopsins, microcystins, nodularins, and saxitoxins) were present. We report the identification of numerous potentially harmful taxa and the co-occurrence of multiple toxins, previously undocumented, at several locations. Our findings reveal a potential health concern based on the range of organisms present and the widespread prevalence of recognized toxic compounds. Our results raise concerns for recreation, harvesting of finfish and shellfish, and wildlife and desalination operations, highlighting the need for assessments and implementation of monitoring programs. Such programs appear to be particularly necessary in regions susceptible to urban influence.

Microcystin Prevalence throughout Lentic Waterbodies in Coastal Southern California

“…The persistence of detectable microcystins across multiple years and seasons indicates a low-level, chronic presence of microcystins in these waterbodies, similar to findings in Monterey Bay watersheds [ 42 ]. Chronic exposure of microcystins can have human and wildlife health implications [ 15 , 23 , 54 , 55 , 56 , 57 , 58 , 59 ] and can be transported into riparian food webs [ 60 ] and marine shellfish [ 42 , 43 , 45 , 46 , 47 , 61 , 62 ]. The sites sampled in this study were chosen due to the designed beneficial uses that include human and wildlife exposure (such as drinking water supply, agricultural water supply and both contact and non-contact recreation) [ 63 ].…”

“…Microcystins produced in freshwater systems have been shown to cause effects far downstream of their biological origin, have been detected in downstream coastal receiving waters and near-shore marine waters and have accumulated in marine shellfish [ 42 , 43 , 45 , 46 , 47 , 61 , 62 ]. Multi-year studies of the Monterey Bay watershed have shown that downstream transport of microcystins is a persistent and prevalent issue throughout the watershed [ 42 ].…”

Physiological and Metabolic Responses of Marine Mussels Exposed to Toxic Cyanobacteria Microcystis aeruginosa and Chrysosporum ovalisporum

“…For example, high levels of MCs were found in mussels collected from San Francisco Bay, California [26]. Moreover, a monitoring study in this estuary showed that the contamination of bivalves with MCs is recurrent being detected in several years of the monitoring study [27]. Another monitoring investigation revealed a significant transfer of cyanobacteria and cyanotoxins along a freshwater-marine continuum in France.…”

“…Studies have shown that estuarine and marine bivalve species such as Mytilus galloprovincialis and Ruditapes philippinarum modulate their detoxification and oxidative-stress defense systems after exposure to MCs [23,24]. Indeed, contamination of estuarine and coastal areas derived from the flow of contaminated freshwaters from inland to the sea have been reported in different geographical regions [25][26][27], constituting a potential thread to marine ecosystems. For example, high levels of MCs were found in mussels collected from San Francisco Bay, California [26].…”

Fertilizers Effect Blue Green Algae and increasing their Toxins

“…Produced by Anabaena flosaquae, non as Di aromatic amin, highly toxic and can cause death during 15 minutes. It was distinguished at first as Anatoxin-a impact muscular nerves and cause death via paralysis of respiratory system (Tisdale, 1931), produced from three widespread types of BGA Aphanizomenon, Anabaena, Planktothrix (Tatters et al, 2017)…”